How to Install Tile Over a Wood Subfloor

Tile Floor.
This finished tile floor is installed over a plywood and cement backer board subfloor.

Installing tile over a wood subfloor is a lot easier today than it was when I started my remodeling career.

The old-fashioned mud method of floating a thick mortar bed in preparation for the tile has given way to using cement backer board over a plywood subfloor.

Cement board is inexpensive ($10 or less for a 1/2″ thick, 3′ x 5′ sheet), easy to install, and sufficient for most installations. Among the trade names you’ll see are Durock, made by U.S. Gypsum Corp., and PermaBase, from National Gypsum Co.

Manufacturers provide clear installation instructions with cement backer board, but there are a few other important points you need to know to guarantee a long-lasting installation.

For example, I always like to remove the old flooring material so I can check the subfloor for any water damage. Years of water seeping along the edge of a bathtub or shower can cause areas of rot that need to be repaired.

If everything is in good shape, you can then cut the cement backer board (always wear an approved respirator or mask when dry-cutting cement based products).

Next, use a notched trowel to apply thin-set adhesive to the plywood, set the backer board in it while it’s still wet, and drive corrosion-resistant screws made for countersinking into the backer board through the plywood. Do this at intervals recommended in the backer board instructions (usually every 8 inches) to ensure a firm foundation for the tile.

Use a cordless drill to screw cement backer board to a plywood subfloor.

Set the heads of all screws and any existing nails slightly beneath the wood surface, then use a lightweight gypsum leveling compound to fill and level voids or low spots. If you take this kind of care with the prep work, the finished tile won’t crack over time.

Finally, lay out the location for the tile, apply a coat of thin-set to the backer board, and lay the tile. Once the tile has set, apply grout to the joints between the tile, wiping off any excess with a damp sponge.

Setting tile on cement backer board with spacers used to align the tile.

The proper fasteners, mortar, tile adhesive and joint tape are all specified by the manufacturer, but don’t use drywall screws since they can corrode.

Another mistake I often see is grout wedged between the last row of tiles and the tub, cabinets or doorsill. Grout in these transitional areas will crack as the floor expands and contracts. These areas should get a bead of acrylic or silicone caulk instead so the joint remains flexible.

I’m often asked by homeowners if it’s possible to lay down new tile over an existing tile floor. This is not my favorite way to install tile, but it can be done, as long as the existing tile and subfloor are in good condition, and the old tile is thoroughly cleaned and scuffed up with sandpaper to allow the new mortar to grip.

The combination of newly applied mortar and tile will raise the level of the floor by at least 3/8″. Trimming the bottom of the bathroom door and building up the doorsill usually hide the fact there are two layers of tile instead of one.

Trimming the bottom of a door casing with a jamb saw so the tile will fit under it.

The subfloor under the tile should be at least 1 1/8″ thick, with a minimum of 5/8″ thick exterior grade plywood topped by 1/2″ cement backer board.

Further Information


  1. My husband and I are renovating a rental house and want to use ceramic tile in the kitchen. We were wondering what the proper technique is for installing the tile in the areas where the refridg., range, and cabinets will be installed. Should we tile the whole area or just those areas that will be exposed to the necked eye?

  2. Tiles should always be installed under the refrigerator. My opinion is that they should also be installed under the stove. However, under the cabinets is purely by choice. The only obstable is if you have a dishwasher. Installing tiles will typically cause a slight irritation if you try to remove the dishwasher after the fact, because the added height of the ceramic will snag the feet of the dishwasher. Now, if you are removing the cabinets, you may want to put in the ceramic first. This will totally eliminate any potential dishwasher problems. The other benefit is that you have fewer odd cuts to make. The drawback is that you use more materials and, if subbing it out, will pay more for installation. Again, it’s a matter of opinion. I always like to put the floor in before the cabinets in case of a future remodel.

  3. I am installing ceramic tile in my kitchen, I have installed the tile under the fridge, but when the fridge is pushed back ub place the tile cracks. What can i do?


  5. I have old pine kitchen cupboards, I have varnished them, but the tops are just too soft, and gets stained too easily. i want to tile the tops of counters. how do i go about this?

    • Adele,
      If the old cupboard tops are solid wood, seasonal movement could cause problems, so I would remove the existing tops and store them in case you ever decide to return to the wood look. After you have removed the tops, screw 3/4″ exterior plywood to the top of the cabinet (from the bottom if possible, so you can easily remove the tile tops in the future should you change your mind) and attach 1/2″ cement backer board to it with thinset mortar and screws as detailed above. The edge of the tops can be finished with either bullnose tile or a wood molding that matches the cupboards.

  6. I am removing the old particle board subfloor before installing tile. There is good plywood beneath the particle board that I am keeping. I believe the cabinets are installed on top of the subfloor. Unfortunately, at the floor level the there is about a 2 ” indentation before where the base of the cabinet meets the floor. Do you have any suggestions of how I can cut or remove the subfloor so that it is flush with the cabinet? Any recommended tools? I am not having any problems using a circular saw and a crow bar to make cuts and remove the rest of the subfloor.

  7. I have a couple of questions. First, I want to install ceramic tile in my bathrooms, currently they have the peel and stick vinyl, the subfloor is plywood, What do I need to install in order to put down ceramic tiles? I have been told two or three different things, cement backer board. a leveling compound, and I was also told I could install it directly over the plywood(which I think would be a mistake because of the properties of wood. If I use the backer board, do I need to remove the cabinets and install it under them also. and also install the tile all the way under the toilet, or just up to it? My second part of the question is I am going to install wood flooring in the kitchen(Floating) the current floor is vinyl and is in good shape with no bubbles or tears. Can I just put done the underlayment over the vinyl and then install the floor without removing all the vinyl? Also Do I need to remove the baseboards and install the wood flooring all the way to the walls(of course with the 1/4 inch gap for expansion, or can I leave the baseboard and install the wood flooring up to the baseboards and cover the edges with shoe moldings. I want to do it correctly but don’t want to go to all the trouble removing the baseboards if I don’t have to. I also am wondering this about hte bathrooms, Remove the baseboards? All the information you can give me would be greatly appreciated. I am also installing new cabinets in the kitchen and am planning on installing the wood flooring all the way under the cabinets before they are put down so I will have a level floor and won’t have any problems if I do have a problem with the dishwasher. Is this a good idea? Thanks for your help.

  8. We are putting in a tile floor in our kitchen and our current cabinets are older and cheaply made. (probobly the original ones when the house was built about 20 years ago.) Eventually I am wanting new ones, but we cannot afford them right now. How do you deal with the tile floor when putting in new cabinets? Can you pop up the tiles along the edges and then reset them after the cabinets are installed? It makes sense to me to do it that way, but I’ve always heard that you should put in new cabinets first and then tile the floor around them. What do you think? This is only the second time we’ve ever put in tile, and it was in a bathroom before. Thanks so much!

  9. PleaseI am waiting for the answer to Kenndy
    questions, because I am face with the same problems, don’t know what to do about laying tile on a subfloor or use a backerboard. Help I been dealing with this for about two years. I need some expert advice. Thanks.

  10. Hi.
    I am laying tile onto the subfloor (good condition). I am having a problem with tiles popping up. The mortar has a good set on the floor and tile but still comes loose. The mortar is almost granular.

    Is there a better (specific, please) mortar I can use?
    Also, do you think its ok that I am laying the tile directly to the subfloor (3/4 plywood)?

    thanks you

  11. Holy cow….so many questions! First of all, we’ve got a show coming up very soon on a bathroom makeover. It would be a great one to watch for some cool tips, including putting down a tile floor.

    More specifically, let me see if I can answer some concerns. First of all, tile definitely should not be put down over a wood sub-floor. However, there is a new product by Schluter called the Ditra System. It is an orange colored membrane designed as a backer for tile. It’s thin, flexible, unique in shape which is supposed to make it ideal for putting tile on wood, especially if the height is a concern. Now, understand, I have never used it, so I’m only relaying what the manufacturer claims. But, I’ve seen it at the Builder’s Show and, I have to admit, it looked pretty impressive. It is more expensive, but it could be a better alternative for some of you. Otherwise, put down a tile backer board, preferably 1/2-inch.

    Secondly, there’s really no need to remove baseboards to install tile. You can either leave a small space (no more than a 1/4 inch) between the tile and the baseboard, then grout that gap…or you can put down a shoe moulding. Personally, I don’t like shoe on tile. By the way, the same goes for that floating wood floor, Kenny. Just bring it up close to the base and let your shoe cover the gap.

    Third, tile goes under the toilet. Before you start a tile job, pull the toilet. You’ll have nothing but frustration and grief if you try to cut the tile up to the toilet.

    Mike, I think your popping tiles is directly related to the sub-floor. You need a backer. 1/2″ or try that Schluter product. You can have the best mortar in the world, but you’re getting movement and moisture coming up and it will definitely pop those tiles every time. By the way, use a mortar that is enhanced with latex. Seems to be a better bond.

    Kathryn…you shouldn’t have to pop out any tiles to remove old cabinets. Usually, they will come out without disturbing the tile if done so carefully. The trick will be finding new cabinets with the same “footprint” to replace the old ones. If you are going to get custom cabinets, that won’t even be an issue. They can match the base and toekick to fit back into place without having to do any kind of floor work.

    Wow….that’s a lot of words! Be sure to let me know about any projects you’d like to see Danny and me tackle on the show. From these comments, I think we need to test that Ditra System out. What do y’all say?

  12. Yes I think you all should come and try the Ditra system out on my basement. ( as I sit here trying to figure out what to put down instead of carpeting that won’t require the expense of a contractor) lol..

  13. I just read about another product called Blanke-UNI-Mat PRO that seems like it would be wonderful for me to try out in my bathroom, kitchen, utility room, and entryway tile installations I am about to do. I have not yet purchased it, however it is only 1/8″ thick and seems like it will be excellent to match my tile to the laminate flooring (heighth wise). Does anyone have any recommendations for transitions between tile/laminate, if any are really needed. I am considering just butting up the tile to the wood, without an expansion gap. Is this a poor idea?

  14. Justin, we had a similar transition (tile/wood) in Today’s Addition, which just aired recently. You can butt the laminate to the tile as long as they are the same height and fill any gap with a colored caulk to match the laminate. It looks really good. But, if the floor heights are different, you’ll need the transition strip. A lot of the laminate manufacturers make a strip for that purpose and it matches the flooring.

    I’ve never heard of the Blanke-UNI-Mat PRO, but I’ll sure look into it. I’d really like to see some of this stuff in a real world situation.

  15. I am installing ceramic 12 inch by 12 inch tiles in my foyer (150 sq ft). I am laying the tile on a plywood sub floor above a basement. The floors joist are 19″ on center. Should I install durock before laying the tile? I was thinking 1/4 durock and 1/4 tile which would make my floor height almost the same as my hardwoods in the other rooms. I want to ensure there is not cracking if possible. Thanks Chris

  16. Chris…definitely put down the durock. I prefer 1/2″ for tile floor, but I’ve seen 1/4″ work.

    Lee…16-inch on center is nice, but floor joists can be up to 24-inch on center depending on the material used for the sub-floor.

  17. We had a guy install ceramic tile in our kitchen and did a horrible job. He left dust all over our kitchen, family and pretty much the entire first floor our house. Then not to mention, he removed our island and put the ceramic tile under our dishwasher. Needless to say we are not happy with the work.

    But I have a few questions:

    1. I know appliances live the fridge and dishwasher should be removed but should an “island” be moved?

    2. Do you typical tile under a dishwasher or just put in a backer board? Right now, our dishwasher is not “plum with our cabinets and the feet have been removed. So it’s sitting flat on the floor.

    3. When would you use backer board thicker than 1/2 inch???

    Thanks in advance for your comments

  18. It is not necessary to remove an island. As for the dishwasher you need not put either the backer or the tile. I usually adjust the feet up all the way and insert a block of wood under neath the appliance to keep it up as far as possible until the job is done. I also make sure to run the backer board under the front feet and also the tile under the front feet going back a few inches. Most dishwashers have the adjustable feet on the front and rollers on the back. As long as you can get the front to be able to pull out of it’s opening the rest of the appliance will come out if you need to do repairs or replacement. Now, you need remove that front bottom panel and block it up and/or find some new feet at a hardware store.
    There is no need to use a backerboard thicker than 1/2″. There are ways to raise a floor lever more than 1/2″ but not necessarily with cement board.

  19. I am asking this question because I am a real novice and I am not sure that recent work I had done is right. I am having a house built and we had tile floor installed. Here is the pattern of work;
    1. Floor and framing
    2. Cabinets including refrigerator enclosure
    3. 1/2″ Fiber board and tile
    Should the fiber board have been installed prior to the cabinets? They had to remove the fiber board and tiled in order to put in the dishwasher. This just does not seem very practical, but then again I am not a contractor by trade. It would seem that the stove and refrigerator enclosures will be a half inch off now. I am not sure how to approach this and the GC keeps saying everything will look fine, but to me that does not mean it is right.

    Kind regards

  20. What a GREAT site this is!! My husband and I are getting ready to tile our entrance way, hall, bathroom, dining room, kitchen and laundry room (all connected) We were going to put hardwood floors but have decided last night to do tile. My question is: We both work full time and have three boys; can we start laying the backer board down in stages on the sections of tile that I have just pulled up and walk on it for a few weeks. Because of time, we will be doing this in sections. Will the backer board tollerate walking, possibly a food or drink spill and still do it’s job when we actually start the tiling? The floor under what i just pulled up is rough and dusty and I am afraid that my kids may get cut or splinters. (The old tile is only two years old but kept breaking and moving because the previous owner didn’t lay backer board down and went right over hardwood floor and on the other end of the room over vinyl. He wanted it to look nice for a quick sale) Second question: Can we lay and grout a section of tile like the bathroom and then next weekend do the hall and entrance way, then the following weekend do the kitchen? All the rooms connect. Thank you for what you are doing for people like us!

  21. Hey Cindy. So glad to hear you enjoy our web site! The backer board is tough stuff, so it’ll take plenty of abuse. As far as grouting in stages….shouldn’t be a problem as long as it’s not too much of a delay in between. The fact that you are planning to grout the full room, i.e. bath, hall, entry, will help. What size tile are you laying? Sounds like it’s going to make a big difference! Send us a before and after picture! I’d love to see it!

  22. Hi…I am having a ceramic floor professionally installed in our kitchen. We chose to remove the previous flooring ourselves to save money. My question: I need to remove the subflooring without removing the cabinet bases. Is there any way other than using a cut off blade in a dremel type tool to get close to the base? Thanks in advance for your time and response.

  23. Hi, I am in the process of tiling our bathroom floor and I am wondering if you can help. We have hardwood floors that have been let go for too long that they are not worth saving (it’s an 80 yrd old house). The tub toilet and cabinets sit on top of the existing hardwood floors and I am wondering if I can just install a thin subfloor over the hardwood and then tile on top of the subfloor. There is a squeak in a couple boards in the existing hardwood otherwise it is pretty solid. Could I secure the subfloor to the existing hardwood without jeopardizing the whole project? Clearance won’t be too much of an issue provided we don’t use thicker than 1/4 ” subfloor. Hopefully you can help.


  24. I have a question: I am remodeling a 1953 original bathroom in a ranch home that is built on a pier and beam foundation. The bathroom floor is constructed of the mesh, concrete mud, then tile. There is NO subfloor. The old floor is almost 1 3/4 inch thick. Should I just tile over the old floor, or remove the tiles only, or remove the entire floor, mesh, concrete and all and install plywood and hardiboard, then tile. I’d rather use the old concrete that is there because it is so sound that I think anything else will likely be more apt to crack in the future. The old tiles are a mixture of 2 inch or smaller smooth matte finish tiles with miniscule grout lines that are flush with the tile surface. Can I tile right over them especially since it is all relatively level and matte finish? Thanks Jon

  25. Hi Jon…If the old floor is in as good condition as you say, there’s really no reason why you couldn’t tile right over it. In fact, the porcelain tile we installed in a recent bathroom remodel (Show #641), was placed on the exact type of old tile bed.

  26. I am going to have tile installed in my home. I have one installor that would use backerboard and one installor that would use the mud method. Which installation method is best?

  27. This is a wonderful site. I am remodeling and would like to butt a tile floor right up next to a wood floor without a threshold covering the seam. Is there something you recommend to help? I assume there will be some separation but I would like it to be minimal.

  28. I am going to tile my kitchen that has an existing glue-down hardwood floor. I attempted to remove one small plank last night and could not believe how stubborn it was to get up. The plank seperated and left the bottom half still glued down. Some folks at a local tile warhouse siad I could screw down cement backerboard over top of the hardwood and lay the tile. Is this O.K.? If not, what is a good method of removing the hardwood without a scale saw to cut the floor into quadrants. Thanks.

  29. I am about to start a project and my question is if 1/4″ backerboard is enough ontop of an inch of ply-wood(3/4 sub plus 1/4 underlayment)? I also plan to set the the 1/4 inch backerboard in a bed of thin set as well as using screws. Thank you.

  30. I am planning to install tile in my kitchen that currently has lenoleum. I plan on removing the lenoleum and subfloor all together in preparation for the new backerboard. What is the best way to cut around the kitchen base cabinets so I can remove the existing floor up to the cabinets? Do you know of a tool that will work for this?

  31. hey Paul I just did that very thing today. I used a utility knife and repeatedly scored the lenoleum at the base of the cabinet. Also for really tough spots I used a roto-zip with a wood cutting bit.
    With what are you going to replace the sub-floor?

  32. Thanks for your reply. I plan on using 1/4″ HardieBacker as a subfloor for the tile. The floor construction uses 3/4″ plywood and I am trying to keep the height to a minimum so my transitions with adjacent flooring isn’t too abrupt.

  33. I had a contractor replace the 12×12 cermic tile in my kitchen and he used an acrylic mastic instead of backerboard and thinset. he said the mastic would be sufficient and that I did not really need the backerboard. Now i have a few tiles that are loose and the grout lines are cracking. My contractor guaranteed the floor for a year and he will come back but I am concerned that he will never fix the problem. What can i recommend he do to these loose tiles so that they do not become loose again? Thanks

  34. I am preparing to tile a kitchen floor. The subfloor is 1/2 inch particle board on top of 3/4 inch plywood. I plan to install 1/4″ hardyboard as a backing for the tile. Do I need to remove the particle board and bond the hardyboard directly to the plywood or can I bond the hardyboard to the particle board? What type of mortor will work on the particle board if any? Thanks.

  35. I have some questions regarding waterproofing before installing tile in a kitchen. Is it necessary/recommended? I have seen two types: One called RedGuard from Custom Building Products (avail. at Home Depot) is a roll on/trowel on product. The second I saw in a DOI book is a thin film/membrane that is laid over an adhesive. Which is recommended? Also, My subfloor is OSB with Exposure 1 rating. Can I use either on my subfloor? What about the 1/8″ expansion joints in the floor – should I avoid filling them with the membrane (RedGuard) or is that not an issue. Thanks for whatever input you can offer.

  36. Hi I have a question about porcelan tile installation? My floor is 1×12 boards laid diagonal to the floor joists, which are on 16 in centers.I was hoping to use half inch cement backer board and thinset to lay the tile. I know this is done with osb wood flooring, which comes in 4×8 sheets. A contractor stated I would need to lay osb on top of the 1×12 or remove the 1×12 and lay osb.He said it would be due to the 1×12 wood drawing moisture and flexing during season changes. Installing osb on top of the 1×12 could possibly create heighth problems with the dishwasher,outside door, and transition with the carpet. thanks

  37. I may be in trouble…….

    I was looking for some advise on Grouting and have read about applying tile.

    Here’s the issue, I put Ceramic Tile and Thinset directly to 3/4″ OSB on 12″ engineered trusses 16 on center WITHOUT A CEMENT BACKER BOARD…… I am not going to rip it all up to start over now.

    My question:
    What should I expect and how long before I endup replace or….. will it most likely be OK?

  38. We have 1/2″ plywood subfloor in our kitchen. Tiler is planning on installing 1/2″ Durock over this and laying 13″x13″ porcelain tile. Will this subfloor be strong enough?
    Thank you for your help

  39. hi i’m trying to install porcelain tiles in two bathrooms( upstairs). the bathrooms have vynil flooring now.
    my first question is : can i just install backerboard over the vynil and then the tiles? and if it’s the case do i need 1/4″ of 1/2″ backerboard for the application?

    second question: if i decide to remove the vynil( if it’s the best option), do i have to remove only the sheet of vynil or is there something else that i have to remove or install before installing the backerboard( the house was built in 2004 so the subfloors are still in good shapes)


  40. Hi i have a question i was wondering if you can help! I recently layed ceramic tile under my wood stove in my family room. They have cracked and broke all over… I was then told that i needed to have a sub floor… What do i do? Would 3/8 in plywood work? I’m so confused… Please give me your advice

  41. I’m replacing my tile in the foyer/entryway of my home. My husband pulled up all the old marble, and we are replacing it with ceramic tile. I have a contractor who told me that he plans on laying concrete first instead of Durock; have you ever heard of that?
    Durock was used in both of my bathrooms.

  42. I am interested in putting ceramic tile in our laundry room where we now have linoleum. Because it will be difficult to remove the washer/dryer and extra fridge, is it possible to move the appliances out from the wall and tile there, then wait until the tile is dry then move them back over the new tile and do the rest of the floor?

  43. Hi I am tiling the floor in my bathroom, should I remove the toilet and tile underneath or should I tile aound the toilet.

  44. I am turning a 3×5 wash closet into a 7×10 bathroom. I have everything framed out and the plumber is coming in to rough in everything. My question is the flooring. I exposed the subfloor and and is 2×5 wood planks. What should i do if i am to put tile down? should i rip out the subfloor and put in 3/4 plywood, then use durok, or a self leveling compound? or do i put self leveling compound ontop of the existing subfloor? do i put plywood on top of the sub floor and then durlok or self leveling? Does the bathroom floor have to be level with the floor in the hallway ( it is about 3/4 higher right now) whould should i do?

  45. Reading all the questions & answers is a great lesson in what to do & what not to do concerning tiling. I feel like I’ve learned alot in the time it took to read through.

  46. Jackie, Sorry I shd have been more specific. See middle of October 18th ‘Allen’ posting above for toilet/tile answer.

  47. Hi,
    Do I leave a space around the island in the kitchen when putting down ceramic tile as I will wround the walls and use trim or should I just put the tile flush with the island?


  48. We are building a raised hearth for under a wood burning stove. The hearth is BCI’s topped with 3/4″ OBS subfloor. The next layer is 1/2″ Hardibacker. The final surface is ceramic tile.
    Is motar needed between the OSB and Hardibacker? If yes, what is recommended for under a woodburning stove. Can we use the same motar or thinset for the tile as well? Or do you recommend a different approach?

  49. Hello,

    I think I really messed up my tile project. I recently removed lenolium from my bathroom floor there was still a lot of backing from the lenolium left on the floor that I didn’t remove. On top of that I put the tile on the original wood floor. There is an area in the bathroom that creaks. I used the morter that I was told to use, but now I am really afraid that after my hard work and sweat, my floor is going to crack. What are the chances of that happening and how can I prevent it or fix it? I plan on doing a little more homework for the next project I take on…

  50. Hi,

    I’ve read through all the comments and I see that others have had the same issue I’m having, but I still don’t fully understand how the solution. I’ve got 1/2 inch hard wood flooring in my kitchen and I’m replacing it with tile. The flooring was laid first and the cabinets on top. What tool do I use to cut around the base of the cabinets? I have a roto zip saw, but did not see an attachment that would work. Thanks for your help in advance!

  51. I am installing ceramic tile in my kitchen, dining room and laundry room which are all seperated by standard door ways. My stepdad came to town and began laying the tile in the dining room. He did not have time to lay it in the kitchen and laundry room. We installed backer board, thin set and then tile. When we got to the kichen door the backer board and subfloor ware perfectly even and it would allow us to continue without using a transition strip. A neighbor suggested that we just put mastic over the subfloorand tile…not using the backer board. Is this possible? If so what is the difference between mastic and thin set??
    Thanks for your help, I am clueless!

  52. We are right smack in the middle of tiling our shower-tub.We were told by an employee at a home depot in the tile department that we should tile the walls over OSB and not the drywall. The employee stated that the drywall would absorb the moisture of the adhesive, and that the OSB would not. Soooooo.. we install OSB on the walls of the shower-tub, over drywall. So, here I am reading these forums…and now we are out of finances to re-do or install any other kind of walls. We are out of finances because the township made a mistake on our building permit on another home we had spent 4 years building, and had to sell it as a ‘camp’. Thats another very painfull story at a loss of about $80,000…so now we are starting over, just one mile up the road. We are remodeling and guttig walls..etc, but now we are on a very very very tight budget. So, I need encouragement that we can do this tile on OSB and is there any kind of paint or sealer that I need to paint over the OSB to help protect it before I put the tile up. We are also ‘busting up’ the tile pieces. We want a mosaic look, no straight lines to have to deal with..we’ve dealt with enough, we don’t need to have to deal with straight lines too. 🙂 … and if you’re wondering, we did not sue the township, small town, turns out it was a family member that made this shocking mistake, and would have lost his job, and he has 2 babies at we opt to sell the home as a ‘camp’ and move on. So back to encourageing us. Since we did go on the advice of the home depot employee, is there anything we need to do to the OSB ‘before’ we install our ‘busted up’ pieces of tile?

  53. Hey Liz….A lot of people tend to interchange the words “mastic” and “thinset” with the mentality that they are the same thing. And, sure enough, both are good adhesives. Mastic is usually used in dry locations and CAN be used to set floor tiles. However, thinset is what I recommend for tile flooring, especially the modified version that has a latex additive. It will do a superior job and is easier to work with. Of course, this is all just my humble personal opinion..:-)

  54. We paid professional to lay 12×12 tile in mudroom,kitchen and foyer last summer. Floor is 3/4″ T&G ply, 2×10 joists 16″ OC. Put 1/4″ hardibacker on ply, screwed in app. every 8″, no thinset under it. I have loose tiles in foyer (not enough thinset around edges), but what concerns me more is the “crunching” sound in the kitchen high-traffic area, where no grout is cracking (yet). I can pull up loose tiles around edges of foyer and reset/replace them, but what do I do about the areas that are just noisy, look sound? Should we put in more (1″ or shorter) screws from underneath (basement)?

  55. My home is on a concrete slab. If I am going to replace all kitchen cabinets and tile the floor, optimality, should I tile the whole floor then place the new cabinets on the new tile?

  56. A friend told me that I should use a layer of thinset between my backer board and subfloor to create a solid surface that will prevent tiles from loosening or cracking. Another friend said that if I do that I would have to rip out the subfloor if I remodeled in the future. What is your suggestion?

  57. Hi good insites thank you, do you have a phone number for ditra systems for tile over wood and what about lows in sub floor.

  58. I am preparing to lay VIFAH Diagonal Deck Tiles
    over a recently rebuilt wood subfloor of a small (4’x10′) bathroom. These indoor / outdoor
    eucalyptus wood tiles seem perfect for this project, but I have two concerns:
    The tiles are raised off the floor by plastic
    interlocking grids under the wood slats (12″x12″) which snap together and require no glue, nails, etc.; nor grout between them.
    What should I use over the subfloor to allow
    water and moisture to wick between slats and not cause rot and mold?
    Also, have you tried this product, and do you have any other product options for a wood deck type flooring in the bathroom?

  59. My wife and I are looking to finish off a small outside courtyard and were considering tile vs pavers vs concrete.

    Can we build a subfloor for the courtyard, and tile over it, or are we doomed to failure and replacement with pavers or concrete?

  60. My kitchen has hardwood floors on top of 2x4s (wide side down)on top of a concrete slab. I’m wondering if all I have to do is put down backer board to be able to have a tile floor. My bathroom already has tile, but I would like to take up the tile and put down new tile so that the floor will be the same height as the hallway. How would tile have been laid in a 1955 ranch? If a mud job was implemented how hard will it be to take the tile up?

  61. I was told by a sales rep for porcelain tile. He told me that I should space the hardy board and thin set in between them, and thin set underneath them to reduce vibration cracks. Is this necessary? What are some other ways to help if I already placed the hardy board?

  62. To follow Mr. Perez, is it necessary to leave expansion spaces between the hardy board or at the edges meeting the wall?

  63. This is a great site! I am a disabled housewife and my husband works odd hours and all the time. I am determined to give our kitchen and adjoining dining area a face lift. I have started the removing years of stain, varnish and paint that was on the cabinets when we moved in and also took a peak under the cracking ceramic tile flooring. I found that there was no type of moister barrier between the sub floor which looks like plywood and the ceramic tile itself. I am hoping to get some suggestions on how to handle this. I want to make sure that when I do rip up the flooring that I make sure that what ever type of flooring I replace it with will have a good sound sub floor under it so it will last this time. So I guess I have many questions the first being: After I rip up tile, what can I lay over the sub floor to make sure that it will be sound and water resistant without having to put a new sub floor in. (the sub floor should be still in good condition)?
    If I choose to install a floating floor all the way through from dining area to kitchen, what steps should I take to make sure that it is done correctly? (the dining room already has a wood flooring on it however it appears to be laminate and needs to be replaced because of water damage in front of back door area? Please help with advice and maybe good inexpensive materials to use. Thank you so much


  64. I installed my down stairs tile on concrete and it turned out great but now i have moved upstairs and people are talking about water damage from the thinset which is where i learned about back boarding then something came to mind, the walls are always bowed and thier is a space between the boarding and the wall, what do i use to seal these areas, and should i put plastic under the backboarding to decrease the risk of water damage.
    P.S. i live in vegas

  65. When my house was built, the builder encompassed my jetted tub with 3-4 inch square tile. He only left a wooden access door for servicing the motor. Now I see that this was not such a great idea, since, I now need to conduct some maintenance on the push button on/off switch, which by the way has no access and can not be reached from the motor access door. When I removed one of the tile I noticed that there’s wood in which the tile is attached. Also, the tile is just hanging on the wood without any backer board, is this normal? Once I decide to remove enough tile and cut a hole in the wood to access the switch, how will I replace the removed tile with some type of wooden access door. Is the process of attaching tile to a verticle base the same as attaching tile to a wooden floor (horizontal base)?

  66. I am getting ready to lay ceramic tile in my kitchen, hallway, and both bathrooms. I have pulled up the sticky back linoleum. I have 3/4″ plywood floors. I have been told that I can use Ultraflex2 mortar without using the cement board. Is this okay?

  67. This is in response to Mr Danny Lipford’s statement regarding the installation of ceramic tile, porcelain or natural stone over a wood subfloor. Please read carefully.

    If someone tells you that a tile installation is only as good as its foundation and its preparation, you better believe it. In the case of tile floors the structure must be a suitable one. Not all structures are suitable for a tile installation. Floor deflection is one of the major causes of a floor tile installation failure.

    The maximum allowable deflection for any ceramic tile floor is what is known as: L/360.

    Some of the more common and readily available hard-surface tile underlayments are called “cement board” or “Cementuous Backer Units” or in the trades “CBU’s”. CBU’s come in several forms and generally two nominal thickness sizes 1/4 and 1/2 inch.

    Half-inch CBU’s are always used over wall studs; shower walls, tub surrounds, steam rooms, etc, never use the quarter-inch version on walls or ceilings. Quarter-inch and/or half-inch CBU’s however can be used on floors. You should know that CBU’s offer ABSOLUTELY NO STRUCTURAL BENEFIT and they are simply a proper “tooth” for the tile-setting materials to bond with. CBU’s are not in any way detrimentally affected by moisture or water submersion. Any structural improvements required to meet minimums should be completed before the CBU’s go into place.

    A traditional CBU is basically a sheet of cement and aggregate between two layers of fiber-mesh. There are other variations that have the same attributes and there are versions that have a waterproof covering on one surface. All CBU’s used on the floor are required to be installed in a full bed of thinset. The thinset is used not to bond the CBU to the substrate but instead to insure there are no voids anywhere under the CBU. In addition fasteners are used to install the CBU products. Follow the printed manufacturer’s instructions available with all CBU products.

    In addition to the CBU style underlayments there are also a variety of plastic underlayments that serve a slightly different purpose. These plastic underlayments are not necessarily interchangeable with the above CBU’s and usually have a specific purpose.

    Here are a few (underlayment related) things you wouldn’t want to do when installing your new tile.
    • Tiling directly to plywood isn’t recommended.
    • Tiling directly to vinyl flooring also is not recommended under most circumstances.
    • Tiling directly to particleboard or luan plywood is FORBIDDEN, it just doesn’t work. In fact, here’s what the industry has to say on that subject:

    AN-2.4.3 CAUTION: Wood-based panels such as particle board, composite panels (veneer faces bonded to reconstituted wood cores), luan plywood and soft wood plywood all expand and contract with changes in moisture content and are not recommended as backing materials for ceramic tile…

    In english. DO NOT USE CEMENT BOARD of any kind. A mud sub floor over wire mesh and felt is the only way to ensure a proper foundation. In addition to the structural properties of a mud sub floor it also takes out any imperfections in the existing floor. Cement board follows the flow of the existing floor and so will the tile.

    It is advice like this and installers who practice these methods that give this trade and industry a bad reputation.

  68. we have an old house that currently has carpeting in the kitchen that absolutely needs to be replaced. When we pulled up a section we saw that there was a vinyl tile beneath the carpet (which has a lot of glue on it from the carpet installation) and beneath that is the original hardwood floor. Our first preference was to keep the hardwood floor, but given all the glue and vinyl tile it may not be possible. Is there some type of coating of layer that can be put on top of the vinyl (glue surface) so a new hardwood or laminate wood can fairly easily be installed? Thank you!

  69. I am going from a bathtub to a ceramic tile shower (hopefully). My concern is, my house is on piers and I’m scared if I put in a tile shower my house will settle and the tile will crack or slide. Is there a way I can install tile safely and not have this happen?

  70. Your question is a good one. I have done several custom tile & stone installations for customers who reside on waterfront property and whose homes are on piers. The installation process is the same for your particular home as one that has been constructed on a concrete slab or foundation. However, before any installation is started you need to take into consideration what kind of settlement issues have occurred previously if any, and the cause for them. If your home is structurally sound and has had no prior cause for concern you should be fine. I have seen settlement cracks occur in home’s built on top of concrete slabs, foundations, and piers. If the ground is going to shift or move the force is so great that there is nothing you can do about it, but this should not deter you from wanting to accomplish this project. The most important thing to remember is to contract someone who is licensed, insured, and who uses quality materials for the installation of your project.



  71. I am considering tiling my kitchen, laundry, and powder room. Our existing floor is vinyl/inlaid. Subfloor is 5/8″ OSB glued to 2″x10″ Fir joist, 16 o.c. with 5/8″ plywood underlayment screwed to joists. The maximum span is 13′ and the estimated L value is 458 or maximum deflection of 0.341″.

    I am considering using Ditra after applying screws every 6″ o.c and using an embossing leveler. Will an expert in the industry care to comment on this potential floor system? Does anyone have any feedback on the Ditra?


  72. I want to replace the tile under my wood stove in my family room. Is there any special type of tile I need to use that will be sturdy enough to support the wood stove as well as heat resistant? Is ceramic ok? 1/4 inch thick enough? Do I need a layer of some material before the tiles?

    The wood stove isn’t a very big one, it stands about 4 inches off the ground on 4 legs. Currently there is just a layer of tiles on top a sheet of plywood on a built up platform. Any help in this matter will be appreciated. Thanks!

  73. Thanks NC Tile & Stone for the CBU information. That helps.
    I’m considering laying wood floors and ceramic tiles through out my first floor…where there is vinyl and carpet now. Do I lay the wood floor first or the tile to achieve that even transition between materials without using transition strips?
    First Major DIY project…and am a little intimidated. Thanks for the advice.

  74. l was thinking of putting tile on the second floor. Can l do this? Is the floor strong enough? Our house is 8 yrs old. The joist are 16 inches on center, and we have a plywood sub floor.


    l just lifted the carpet off the floor up there, my kids have spilt drinks etc and l’m not sure if the floor is ok or patches need replacing. How can l tell whats good and whats not good enough to keep.



  75. We were painting the wall behind our refrigerator/pantry cabinets and accidentally broke a tile and cracked another. The tiles broke way too easily so I was suspicious and when removing the pieces of tile I found wood rot which caused a hollow effect under these tiles (tile over wood subfloor). The house is 25 years old and this is the original tile. This floor in question is the second story of a two-story home. Is there any easy way to fix this? Who should check it out and how can it be repaired with minimal damage to first story ceiling?

  76. I am seeing in the distance the Home stretch on my basement re-do. Two current Dilemmas.

    First one: I am installing a plywood subloor on 1 3/4″ joists on concrete. I had planned to use 1 inch plywood for a really firm subfloor amenable to any eventual floor covering, but I see 3/4″ subfloors bandied about everywhere. Is 1 inch overkill? There is a moderate possibility an upright piano might make its way down there eventually. (I am putting things together so that if I ever (Heaven forbid!) need to repair/reinforce/inspect I can remove sections of either wall or floor without unduly disturbing surrounding sections.)

    Second dilemma: Do I install the drywall right to the concrete floor and then install the subfloor, or keep the bottom edge of the drywall at or slightly above the subfloor level? I have explored and searched and have not had much luck from online publications I can find about this.

    With great thanks,


  77. Love this thread- it’s a big help. DIY’ing my master bath, to include re-tiling the floor. In tearing up old tile, discovered that it was installed old-fashioned way- lots of mortar right on top of wood subfloor. Tiles are coming up easily, but mortar is not. Any hints to make this demo (removing old mortar) easier? Or do i just use a self leveling compound across the floor before installing backer board (rather not as this will make things too high.)

    • To Chris B:
      The thick layer of mortar mix served the same purpose as today’s cement backerboard, so you should be able smooth it out and apply new tiles on top of it without using cement backerboard.

  78. I am currently in the planning stages of a pretty major kitchen re-do. The floor is currently parkey and I am planning on removing it and installing tile. As I am going to be replacing the cabinets & appliances, I was going to start by removing everything in the room and tiling the whole floor. I am planning on having an island in the middle of the kitchen with bar seating. Is these feasible to have an island over tile flooring? If so, what would be the best way to keep it from moving? Thanks.

    • To Liz B.
      You can either put the island in place and tile around it (in which case the tile will hold it), or tile first. Islands can be pretty heavy, so you might not need to attach it to the floor at all unless your building codes call for it. If you do attach it to the floor, attach blocks of wood to the floor inside the island with concrete anchors, then set the island over it.

  79. First I have an older home with 3/4 subfloor with tung and grove. I bought 1/4inch cement board. I want to tile with 1/2 travertine tiles. Should I use a vapor barrier between the sub and cement? Also would you please explain why you should never use deck screw to attach the two floors? Also the room is a little office space 6’x8′.
    Thank you

  80. I removed an engineered wood floor that was glued down to tile. The tile came with it.. It is in an entry way and I was going to install tile there anyhow. There is a 2-3″ cement/mortar bed the tile was on that is still in tact. There is the remanats of the thinset on top. Can I just knock down the thinset high spots and apply a new layer of thinset to secure the new tiles or is there somthing I should do to prepare the mortar bed? Thanks, John

  81. We are going to tile our entry way, and had to rip up some old linoleium, that was on top of linoleium 🙂 Under that is a soft wood subfloor, and I was wondering if we need to install anything else on top of the subfloor or can we just tile over the softwood?

  82. We are trying to tile our outside bar, but haven’t been able to figure out what to use for a base layer. The bar is currently made out of pressure treated plywood on the sides and we want to tile over that. I know we need some kind of waterproof barrier to protect the wood from warping. Suggestions we’ve gotten include Tyvek, and an ice guard product typically used on roofs. What are your thoughts?

  83. We are tiling our adjoining kitchen and living room with 12×12 porcelain tiles. House is older and floors are very strong and don’t flex. We are going to use 1/2 inch cement backerboard. Only problem is floor is painted. Can we use a type of thinset that will adhere to these floors if we rough up the surface….We really don’t want to put down plywood over the floors as that will raise the floors over and inch higher than floors in adjoining rooms. I checked with tile store and they said we could mix raw thinset with a latex material that would make it adhere well, but I just wanted to get your opinion too. Thanks in advance for your reply…

  84. we live in Kenya East Africa and operate a small guesthouse for a mission hospital. we have a second floor that is all wood and the showers are leaking and nasty. we want to replace the tile with new 13 x 13 tile. can we do this and what needs to be done?

  85. I need some advise with our bathroom. We live in an unstairs condo with a gybcrete sub-floor poured throughout the place for sound proofing. We tiled the bathroom floor over the gybcrete almost two years ago. The grout started cracking 9 months later. We tried replacing 8 tiles and sealing the gybcrete under those nine tiles a year later. 9 months later we were getting more cracking grout. We went to pull the tile yesterday were we had sealed the gybcrete and ended up pulling the tile along with the 3/4 inch of gybcrete. We then proceeded to pull the entire gybrete sub-floor out of the bathroom area. What would you suggest to replace the gybcrete and how would you make sure the replaced materical connects with the hallway and laundry room? The floor joist are 24″ apart and I have screwed down the plywood that was under the gybcrete. I’m just a bit skeptical on what I need to do now to proceed. Thanks for your help!

  86. I am looking to put slate down in my entry way of my house. there was carpet there. I have it down to the subfloor. Should I use a tile backer board for the slate?

  87. hi… I am planning an interior art project… a wall mural. I wish to install a mix of glass & ceramic mosaic tiles (3/8″ to 1″) onto a series of 3′ x 3′ x 1/2″ exterior grade plywood panels that will be bolted onto a sheetrocked wall. I plan to use a latex-modified thinset & grout. I am getting mixed opinions regarding how to prep & seal the plywood… whether to use a wood sealer, urethane or some type of primer… to keep the moisture from the thinset absorbing into the plywood & still allow for good adhesion to the thinset. Your help is appreciated.

  88. Help!! Want to tile my kitchen. It’s 10′ by 19′. Home was built 6 yrs ago. Subfloor is 3/4 inch osb over 24 inch centers. I want to add 1/4 inch or 1/2 inch HardiBoard, then lay ceramic tile. Can I do it? Will the floor be rigid enough? I don’t feel any “bounce at all”. Is my project doomed?

  89. We are tiling a bathtub/ shower combo that has a window recessed over the tub. Because of the window’s design, my contractor lined the window sill / jamb with pine as opposed to cement board (he had to plane the wood to the right depth). Since we can’t use cement board / hardi, is there any way to waterproof the wood sufficiently to avoid problems down the road. Is it sufficient to just prime the wood?

  90. We need to replace a toilet and want to tile the bathroom too (we have carpet now and want to get rid of it)…….my question is do we replace the toilet first or tile the bathroom first.


  91. Wow what a very informative site!! Thank you for having it!
    I have begun to remodel my bathroom. I would like to make a fully ceramic tiled shower. The sub floor threw me for a loop though. It appears to be 2×6’s laid diagonally with a small space between them. I’m thinking that I may need to replace the subfloor with a solid plywood before I can build the shower, would that be correct? Also, someone has mentioned to me that I need to “Hot Mop” the area. I didn’t understand exactly what he meant…any suggestions?

  92. I am in agreement with most of you that this is one of the most impressive sites I have come across. Any comments would be appreciated concerning my kitchen floor install. Due to a settling foundation in a very old home (which has been subseqeuntly reinforced), the 3/4 inch hardwood floorboards in the kitchen and dining room are uneven. The previous owner put vinyl over the hardwoods. Therefore, I put down 1/4 inch particle board, applied a layer of self-leveling cement, and plan to put down 1/4 inch backer board. First of all, the self-leveling cement is cracking. Is it OK to lay the backerboard over the cement? Secondly, is 1/4 inch backerboard enough? I would like to keep the height consistent with new carpet that was installed. Thanks for your suggestions.

  93. I’am installing a new floor in the master bath.the owner before has carpet there now,when I removed the carpet and pad I found just chip board.I want to install a pell and stick tilles,DO I need to put down a luon sub-floor first,for smoothness. And is the anything else I should put down before applying the pell and stick tile?

  94. I am remodeling my kitchen. I have 3/4″ particle board over 1/2″ plywood sub floor. The kitchen floor meets with hardwood floors at hallway and livingroom. All are level now but I want to put tile in my kitchen without having a big transition. What do I do? There is a basement under the kitchen (floor joists are 2×10 16″ on center) and have a solid 30 year old home.

  95. I am having a new home built. The tile installer is suggesting to tile directly over the 3/4 osb board using a modified thin set. Should a cement board not be used?
    If not cement board, what system is best?

    • Hi Jason,
      I would put either cement backer board or one of the thin underlayment membranes like Schluter-Ditra on top of the OSB before tiling to be sure the tile doesn’t separate from the subfloor or crack.

  96. i want to install a ceramic tile floor in my apartment which is above my garage. i dont want to add alot of weight but i want a nice job done. what can you recomend. its a wood floor right now i just recently pulled up the old tile which was just stick ons.i would really appreciate your advice.

  97. Our floor seems to be 1x5s laid diagonally we want to lay 40x40cm ceramic tiles in our kitchen and dining room what is the best way to do this? Can we lay plywood sheets straight onto this and then start tiling? I think I need step by step help. Waiting to get advice from any one Thanks

  98. What is the best mortar to use when tiling directly over tile? The floor is in very good shape…I just don’t like the tile and want something nicer. Also, any other advice you can share regarding tiling over tile would be appreciated.

  99. I have engineered wood flooring in my entry way that glued down to the slab/foundation . I want to install 1/2″ thick stone tiles on the top of the engineered wood surface. Can it be done? what is the recommendation for installation in this instance.

  100. We are remodeling our living room and would like to put wood floor however, our subfloor is not leveled. How would we go about this? How do we fix a floor that is not leveled?

  101. I would like to install my tile in my condo, but in order to do this I will need completely install the tile in one half of the condo, and then move everything to that side and then complete the other half. Is this okay to do? or will it cause problems in the future?

  102. i have installed an 18 by 18 ceramic for a store in my home town. they have got me to tile overtop of a one side good fir plywood. now the job is failing is there anything i can do to the wood to make my tiles last longer?

  103. My kitchen floor is 3/4″ plywood over the joists, covered in 1/4″ luaun, with vinyl linoleum on top. Should I remove BOTH the vinyl and the 1/4″ underlayment before placing the cement backer board? If so, can I just cut the underlayment where it goes under the cabinets (which I am not going to tile underneath)? Thanks for your help!

  104. I am installing ceramic tile in a kitchen that was built in 1900. The wood floor boards are somewhat warped and not in the best of shape. I have removed several layers of luaun, tar paper and linoleum. I am left with many nails protruding through the 3″ floor boards. Rather than attempting to remove all of the nails and straighten out the floor boards, I am wondering if it is feasible for me to remove the floor boards and just place the cement boards directly over the subfloor. I am concerned that there may be too much flex in the subfloor between the joists.

    • Michael,
      Removing the wood flooring and adding a layer of cement backer board on top of the subfloor for tiling is certainly a possibility, but you are right to be concerned about flexing, as cement board adds little in the way of strength to the floor. It would depend on what center the joists are on, the thickness and material used for the subfloor, and the condition it is in. If you can deflect it by walking on it between the joists, you probably should add an additional layer of 1/2″ to 5/8″ plywood on top of the existing subfloor, before applying the cement board.

  105. I am installing an electric heated floor on top of a concrete pad in a basement which ceramic tiles will then be placed overtop. I have been told that I should insulate the heating floor system from the concrete pad to prevent heat loss down into the pad and encourage it to move up into the tiles. A couple options considered are:

    1. Install 1/4 inch cork by thin-setting it to the concrete pad, then installing the heating system by fastening it to the concrete pad (through the cork), followed by applying a self-leveling mortar over the cork and heating system and finally tiling over top that.

    2. Lay down a vapour barrier overtop the concrete pad, then fasten 3/4 inch plywood using a Ramset to the concrete pad (through the vapor barrier), then install the heating system to the plywood, followed by applying the self-leveling mortar over top the heating system and plywood and finally installing the tiles over top that.

    Does one system sound better then the other? Any suggestions?



    • Hi Mark,
      For the under floor radiant heating system in our project house, we used treated plywood nailed to the slab, but that was more to have a way to attach the Uponor Quik Trak system than for insulation purposes. I would think the manufacturer of your system would be able to supply you with installation guidelines for it. For more info on the under floor heating system we used, check out our video on Installing Radiant Floor Heating and article Today’s Addition Nearing Completion.

  106. I’m installing ceramic tile on my bathroom floor. It’s currently covered with peel in stick vinyl squares and the floor underneath is old hardwood. I do not know exactly what condition the wood is in. I plan on pulling all the vinyl out, screwing down cement backerboard right on top of the hardwood, thinset mortar, and tile. Would you recommend anything else???

    • Adam,
      Sounds good to me. If the vinyl square are stuck down good, you could save yourself some trouble and leave them in place and screw the backer board down on top of them.

  107. We’re preparing to install tile in our kitchen and bathrooms. The kitchen is 20×22, and we’re going with 16×16 tiles. We intended on laying 1/2″ cement board over the subfloor prior to installing all of the tile, but were told by the main tile guy for the builder of our home that we don’t need to install the cement board in the kitchen. Apparently, our builder installs 1/2″ plywood over the subfloor in all rooms except in the baths and says it does just as good a job of holding up as cement board. I already ordered the cement board and am inclined to stick with it. Advice?

    • Hi Susan,
      I’m with you, I’d stick with cement backer board since the adhesion between it and the tile should be much better than with plywood.

  108. We are planning to tile our kitchen this weekend. We have it all ready with concrete board. My question is how soon after you tile and grout can you move your stove and fridge back into the kitchen.

  109. Question: I pulled up the tiles in my hallway and scraped off ALL the thinset. Now, the floor is 1/2 inch plyowwd over 3/4 inch subfloor. The floor is solid and the plywood really held the tiles on strong. It took me and my wife many hours to get them up and scrape the floor. I really don’t want to pull up the 1/2 inch plywood since it is SO solid. Can I install new tiles over this pre-existing plywood? I know backerboard is better these days, but didn’t they used to use plywood back in the day? I have read numerous websites on installing tile and about 1/2 say don’t use plywood and 1/2 say it is ok.
    Advice please. Thanks.


  110. Oh. one more thing, The tiles were down for seven years and we NEVER had a problem with then. I am just chaning them because we are installing ones with different color. We are remodeling. Thanks

  111. Changed my mind. I am gonna rip up the old plywood and put down backerboard. People keep telling me to use liquid nails instead of thinset for below the backerboard. Will this work?


  112. i wanted to share that i used the schluter ditra membrane that was discussed in some of these posts. it was my first tile job, and i cannot say more good things about it. it is very easy to cut (with scissors), and as soon as you lay it, you can lay tile over it. I installed it over my OSB subfloor in a bathroom. It was easy to work with, as the cellular membrane is flexible. i specified it for an architectural project (a college dormitory renovation to an old building), and it seems to be holding up very well. i am definately going to use it for my next bathroom!
    it is easy to find at most home improvement stores…but it is a bit pricey

  113. I’m so glad to hear that, Ingrid! As it happens, I’ll be installing a tile floor tomorrow for a segment in our show and I’ll be using the Ditra. Here’s a quick tip for anyone thinking about using it…If you’re using a latex-fortified adhesive, only use it between the membrane and plywood, but not between the membrane and tile. The latex doesn’t like to stick to the membrane material.

  114. I am in the process of installing tiles in my kitchen floor. I leveled the subfloor with quick level thinset the best I could. Now after having installed the 1/4 inch backerboard i have realized the floor still has a few valleys and hills, is there a way to fix this? I am placing 18×18 tiles. Thank you

  115. I’m installing a ceramic floor in my kitchen. There was a ceramic floor there before that’s been pulled up, no backer board, just a wood subfloor, is there any need to and/or anything available to seal the wood, without putting down backer? How did people lay ceramic flooring over wood subfloors BEFORE all this backer board stuff was invented?

    • Hi Bryan,
      Before backer board was used, the common method of laying a tile floor was to pour several inches of mortar on top of the subfloor. Once it had hardened, the tile was laid using thin-set on top of it.

  116. I have 5/8 inch solid subfloor over 16×16 joists OC. The floor is solid with absolutely no flexibility. It’s very stiff and sturdy. Everything I read pretty much says you need 1.125 inches of plywood for travertine. The contractor I had over today does loads and loads of jobs and he recommended a minimum 3/4 inch. I just don’t see the difference between my 5/8 and his recommended 3/4 being worth the extra cost and effort. Please tell me if a 5/8 subfloor CAN actually work with a 1/4 inch of hardibacker installed on top for a travertine install…

  117. I want to install tile outdoors over a plywood deck. The plywood has a thick membrane type paint/coating on it. How should I proceed?

  118. Thanks for the very informative site. I want to install 1″x1″ mosaic tile on a 4″ high backsplash behind my sink. The sink is on an island and the backsplash is the backside of a breakfast bar. The backsplash is made of 3/4″ maple and is finished with a varnish. From what I’ve been reading, it sounds like I shouldn’t apply the thinset directly to the wood. Is there an alternative to using a backerboard? The wood is only 3/4″ so there is not much depth to screw the backerboard to. Can I apply some waterproof primer to the wood and then apply the thinset to it? Thanks in advanced for any info.

    • Hi KC,
      I wouldn’t apply your tile to a solid wood backsplash since wood shrinks and expands as humidity and temperature levels change which would tend to pop the tile loose over time. If the wood backsplash is firmly attached, 3/4″ is plenty thick to screw backerboard into, or you could remove the existing backsplash and screw the backer through the drywall and into the studs.
      Good luck with your project.

  119. Same question as Hans Boerner asked on May 24th about laying external tile over a wooden deck, possibly using Ditra as a waterproofing underlayment over exterior plywood.

    Any advice would be appreciated. Most tile installers tell me to forget it. But I have to believe the technology we have available now should solve the problems.

    We live in Raleigh, NC, so the winters are relatively mild, although I can’t count out freezing rain and a fluke ice storm or snow.



  120. Hey Larry…

    Actually, we just did that on a project out on the Fowl River in south Alabama. We used the 1/2-inch backer board instead of the Ditra. I can’t tell you why, but I just think the backer board would be better in an exterior situation. I’m probably being totally paranoid. I’ve used the Ditra in interior situations and absolutely love it. If you do opt for the Ditra, make sure it’s the thicker one. They came out with a new size this past year, I want to say they call it Ditra Ultra, but you want the original…just plain Ditra. Also, when you purchase the tile, make sure it’s porcelain tile, not ceramic.

  121. What’s the difference between using wire-mesh with thinset versus Ditra? (I will be putting it over wood subfloor) Also, do you have to apply a thin layer of thinset underneath the Ditra before laying it? Thanks for the advice.

    • Hi Dean,
      Ditra is specifically made for floor tile applications. You do lay Ditra in a layer of thin-set fortified with latex, then apply another layer of thin-set (without latex additive) on top of it to lay the tile. You can watch it being done, and read more about it in our episode on Flooring Solutions for Your Home.

  122. I purchased a 58 year old house and had to have the kitchen gutted and the joists and subfloor replaced. There currently are hills and valleys in the subfloor. It does not move when you walk on it, but isn’t level. I want to tile the floor but am concerned about trying to level it all before starting with the tile and backerboard. I have thought about a leveling compound but not am sure since the 3/4″ OSB floor meets up with the old 1x10s laid on 45s leaves holes all around the edges that the compound would pour out of. What would be your suggestion on moving forward with this kitchen renovation? What should I apply first, leveling compound or backerboard/ditra?

  123. We are getting ready to install ceramic tile where we previously had linoleum. When we removed the linoleum, we found that there is wood subfloor under the majority of the floor that is in really good condition. However, at the edge of the kitchen, where it meets our breakfast room, there is a concrete step that is level with the existing wood subfloor (The breakfast room was an addition, so the step used to be the step to enter the house. With the linoleum, they had an extra threshhold where the concrete meets the wood. Will we have to keep that with the tile, or can we just continue the tile pattern there? I am worried that the wood will expand and contract at a different rate than the concrete.

  124. Our bathroom had vinal flooring. After removing the flooring and 1/2 inch plywood,there was 1/6 inch diag. sheeting. Can I just use 1/2 inch backer board on top of the 1/6 and lay my floor tile on top of that. Thanks in advance.

  125. I want to install porcelain tile in Kitchen, hall and bath.
    I’ve taken the floor down to the plank subfloor. ( t&G 2×6 )

    Can I just lay 1/2 hardibacker over that or is neccessary to also install plywood befor the backer board??

    • Hi Richard,
      Since a solid wood subfloor can cup and move with changes in humidity, it’s best to screw the boards down well, then screw 1/2″ plywood (exterior glue) down, followed by a layer of cement backer board.

  126. It should be noted that it is okay to use a Gypsum board for flooring or counter tops only and NEVER for a shower or areas that tend to get wet frequently. Most tile product companies do not warranty a installation on gypsum board in a shower or water areas– even if waterproofed properly. Think of what happens to cardboard when you get it wet.

  127. Dan,

    I am replacing a glass enclosed corner shower with a low threshold type shower that uses a weighted curtain versus a glass enclosure. I am concerned about water escaping the shower and would like to install a tile floor. Currently the floor is constructed two layers of 1/2″ OSB with glued vinyl floor covering. If I remove one layer of OSB and put down 1/4″ hardibacker along with a waterproof membrane and then install the tile my floor level will be the close to where it started but will one layer of OSB be sufficiently rigid?

    • Mark,
      Exterior grade plywood is the preferred subfloor under tile rather than OSB, since it deflects less and is more resistant to water and moisture. A plywood subfloor should be a minimum of 5/8″ thick (depending on joist spacing) topped by 1/2″ cement backer board.

  128. We had a tile floor put in our kitchen and both bathrooms and hate it. We want it removed so we can put vinyl or hardwood back down. We must do it ourselves in order to afford it. It was over a wood subfloor so cement backer board was put down under it then it was attached using grout. My husband & I are neither physically able to do it but must so what is the easiest way to do it? What equipment would help? We are not at all experienced so any advice would be appreciated! Thanks!

  129. First, thank you so much for your web site. It is a wonderful resource for those of us who prefer to do our own work. I have learned a lot and I am so glad I found you before going forward. My house is 46 years old and on a concrete slab foundation. The garage portion (next to the kitchen) is 4 ¼ inches lower than the rest. We have tiled the kitchen with ceramic tile and now wish to continue the tile into what was the garage but will now be the laundry room. So after reading your message board I tried to come up with a plan for the sub-floor. How does this sound?
    1. Build a structure of 2X3’s with 8 inches of space between the boards. The 2×3’s would be standing up on their side so that the height is actually 2 ½ inches.
    2. Lay down ¾ inch exterior plywood and screw into the 2×3’s every 8 inches.
    3. Lay down ½ inch exterior plywood (the opposite direction) and screw to the ¾ inch plywood but not the 2×3’s.
    4. Apply un-modified thin set on top of the plywood.
    5. Lay down ½ inch Hardy Backer Board leaving 1/8 inch gaps between and ¼ inch around the outside edges. Screw it down with those big backer board screws and apply the mesh tape & thin set to the gaps.
    That all adds up to 4 ¼ inches which will give me the proper height. Originally I was going to use 2X4’s for the bottom structure which would have been 3 ½ inches high, ½ inch plywood, and ¼ inch backer board, for a total of 4 ¼ inches. But, after reading your message board I realized that I would not have 1 1/8 inch minimum under the tile. With the scenario above I will have
    1 ¾ inches under the tile. Is that too much? Also, if you have a better suggestion please let me know. I eagerly await your response.

    • Hi Robin,
      While your plan sounds fine, I would use pressure treated wood for the 2x3s in case there is a moisture problem with the garage floor. As far as the thickness of the subfloor goes, the 1 1/8″ minimum thickness includes the 1/2″ cement backer board, so you could get by with one thick layer of plywood (5/8″ or 3/4″ thick) topped by cement backer board with wider joists under it to make up the difference. Using two layers of plywood as you mentioned is fine, but it would add more to the cost. See my Sept. 17, 2009 post above for more info on subfloor thickness including a link to a good article on the subject.
      Good luck with your project!

  130. I am a “handywoman” and plan to install a bathroom in my basement, doing as much of the construction as I am capable of doing. I want to put in a tile floor and it will be installed over the poured concrete basement slab. I will remove the existing toilet before tiling and will also have the lavatory/vanity installed after the floor is tiled.

    I have 2 questions.

    First… When the original concrete floor was poured, the temp. dropped below freezing that night so parts of the top surface spalled and crumbled. The builder came back and put a layer of Armstrong brand S-172 Floor Patch and Skim Coat over the basement floor, but several areas now sound “hollow” when you walk on them, including areas where the new bathroom will be. I don’t feel comfortable installing tile over the hollow-sounding skim coat surface. Should I try to break up and remove the skim coat in those areas and use proper installation techniques for tile over concrete slab or can I trust the skim coat layer? I watched them apply the skim coat and they did not use any type of concrete-to-concrete bonding solution of any type (of course, I don’t know if that was necessary or not) and it happened too long ago to ask them to fix it now.

    Second.. I will be having a new tub/shower unit installed. Should I install new tile under the area where the new tub unit will sit or should I install the tub/shower, then tile up to it and put some type of base trim at the tub/floor edge?

    Thanks for any information you can give me.

    • Hi Mitzi,
      Regarding your first question, if the existing skimmed over concrete appears to be solid and in good condition, I would tile over it. However, it sounds like from you description it may not be adhering well, in which case you may be able to hit it with a sledge hammer (not too hard) and break it up while leaving the bottom layer of concrete in place.
      On the second question, while it doesn’t hurt to tile the floor under the tub/shower unit, it’s a waste of time and money, so I would install the tub, then tile up to it and caulk where they meet with silicone caulking. Installing a molding where they meet would just be an invitation to water from the tub/shower getting behind it and rotting the molding over time.
      Good luck with your project!

  131. Laying travertine over resilient flooring – I did a ton of research on this and as well as on deflection and FINALLY decided to go ahead and lay right on top of my resilient flooring. Of course first I installed the HardiBacker board. With the use of the mortar and all the nails required to install the HardiBacker board that resilient flooring isn’t moving ANYWHERE. My floor came out beautifully and I used the 18″ X 18″ travertine tiles. It was my first home project ever…and I nailed it!! Time will tell on how it wears, but I really feel that it is there for good and there will not be any problems down the road. It was a fairly large job too 315 square feet…Whatever you do don’t skimp on the mortar, that larger tile needs a big thick mortar base.

    • Way to go, Mark!
      Sounds like you got it right the first time. It’s important to use cement backer board to ensure a good bond between the tile and subfloor. Thanks for the feedback.

  132. I am currently working on putting tile in our bathroom and need to take up the particle board that has linoleum on it to be replaced with cement backer board. The problem is that the particle board runs under the vanity. How do you suggest I cut the particle board so that it is flush with the bottom of the vanity?

  133. Not an official answer, but I know that stuff is usually fairly thin (at least it was under the vinyl at my house). You might be able to deeply score it with a box cutter and pry it up with a screwdriver or similar tool.

  134. I work in a snowboard shop and we are working on a special project. We are going to cut up old snowboards and tile them in our entry way (about 8’x8′). However, due to door clearance issues, there is not enough room for a backer board. Since this isn’t actually tile, would we be ok to attach directly to the sub-floor and what would you recommend for the best bond? Also, do you think grout would still be appropriate between ’tiles’? Any other tips with this unique project?

  135. I am installing porcelain tile in my kitchen. My existing flooring is 3/4″ Advantech subfloor with a 1/4″ layer of luan that is glued solid and stapled every 1-2 inches to it. (1) Can I screw the HardiBacker board over the luan and subfloor? (2) Do I have to apply a layer of thinset on top of the luan before laying the HardiBacker, or can I just screw the HardiBacker down? Any advice would be GREATLY appreciated! Thanks in advance.

    • Hi Darren,
      While it’s a good idea to adhere the backer board to the subfloor with thin-set as well as screwing it down, it’s usually not required as long as the 6″-8″ screwing pattern is followed. Check your local building codes to be sure.

  136. Ben,
    Thanks for the reply. I am following the screwing pattern that is designated on the Hardiebacker Board with 1.25″ screws (which is the total thickness of the subfloor, luan, and HardieBacker. Wish me luck.

  137. I agree this is a really great site. I am a big DIYer and haave recently remodeled my master bathroom and half bath. The stairs leading from my lower level in my condo I want to replace with ceramic tile and it has a plywood subfloor. I wanted to know if there is anything special to doing tile on stairs versus on a regular flat floor. The tile store I went to showed me a metal trim I need to use versus the bullnose since this should not be stepped on. I was looking for a step by step on installing tile on plywood stairs. Any help would be greatly appreciated.


  138. Ben,
    Drive longer screws through the backerboard into the joists, or put longer screws through the subfloor into the joinst BEFORE laying the backerboard?

    • Hi Darren,
      Actually I was thinking of driving them through the backer board into the joists, but either approach would work.

  139. I am installing ceramic tile in a 10 x 10 kitchen with diagonal plank sub floor and tongue & groove hardwood floor. Floor joists are on 16″ centers. Can I thinset and screw the 1/4″ backer board to hardwood floor? I was told this was not a good idea. It seems to me that the more the structure under the tile the better. Am I wrong? The floor seems solid and I plan on installing many screws into the underlying joists

  140. Wow! I am so happy to have found this site It ‘s proven to be a valuable resource and I am grateful for any info. Anyhoo, I gutted my bathroom down to the studs and I’m moving right along with the remodeling. I have 1/2″ plywood over 16″ O.C. floor joists. I’d like to put 1/2″ Hardibacker board before tiling but every thing I’ve read seems to indicate I need to put down more plywood. Is that so? If I put more down, what would I need: 1/2″? 3/4″? Could I avoid doing so altogether by simply using Shuler Ditra? Thanks in advance for any info.

    • Hi Dennis,
      Glad to hear that our site has been a help. Most building codes call for a 11/8″ thick subfloor including the backer board. That means a minimum of 5/8″ plywood topped by 1/2″ backer board. Since backer board adds little in the way of strength to the floor, having thick enough plywood is important. If it doesn’t cause your floor to get too high, I would add a second layer of 1/2″ plywood, topped by either backer board or a membrane like Ditra. Or you could tear out the existing subfloor and put down one layer of 5/8″ plywood (topped by backer or membrane) instead. If you look back at my Sept. 17, 2009, reply, you’ll find a link to a website that has more detailed info on subfoor thickness. Good luck with your project!

  141. I’ve read many of the questions but can’t find one that exactly addresses my situation. I want to put 18 X 18 X 7/16 Travertine in one of our bathrooms. I ripped up the vinyl to find 1/2 inch plywood over 3/4 inch plywood subfloor. Even if I remove the 1/2 inch plywood the new surface will be between 1/4 and 1/2 inch above the adjacent floor(1/4 inch backer, 2 layers of thinset, 7/16 inch Travertine). That’s unacceptable, besides my wife would kill me! Any suggestions???

  142. Hi Ben, and thanks for the prompt and concise response. It’s greatly appreciated! BTW, based on what you said, I may simply swap out the 1/2″ backer board for 1/4″ stuff due to potential floor height issues. Thanks again!

  143. Ben,
    So right now the Kitchen floor has thin vinyl tile squares. Not sure what is underneath. I am going to remove the tiles before installing ceramic tiles. If I put that backer board down first and then the ceramic tile, won’t that raise the floor up too much in comparison to the wood floors in the dining room and hall?

  144. dear,Danny
    im looking to install porclen tile in my parents home the house is about 40+ years old my dad lacks the exsperence in this area i know alil the flood in not all that cracked up to be well its not all great at all like i said its a old house i guess my question would be can we ues 1/4 backer board and what could i fill the holes in the floors to make it even to lay the backerboard down
    thanks rusty

  145. I am redoing my upstairs bathroom and want to put in ceramic tile. The previous owner had 5/8 subfloor that had an 1/8 inch spacing between the sheets of plywood. The shower leaked and rotted the floor a little, so I replaced the subfloor with a 5/8 inch osb subfloor. I went to a tile store and the guy said they recomend to put another 5/8 inch plywood down for support of the subfloor. I guess I am confused, what type of subfloor and how thick should I use for ceramic tile? Thanks Joe

    • Hi Joe,
      Check out my comment above posted on September 17, 2009, to find the answer to your questions.
      Good luck with your project!

  146. Ben,
    My tile is finished!! Thanks for your advice and counsel. I put down pre-sealed porcelain tile and did not seal it prior to grouting. About 10% of the tiles still have a visual haze when the light hits them just right. What can I do? I have tried a haze remover from a hardware store, but no luck. The porcelain tiles have a dull finish, if that is something you need to know. Please help, these hazed tiles are driving me crazy!!

    • Hi Darren,
      Try a 50/50 solution of white vinegar (which is a mild acid) and water with a scrub brush or plastic abrasive pad. If that doesn’t work you could try phosphoric acid or muriatic acid, diluted to the recommended strength. Be sure you have plenty of ventilation, wear protective clothing, gloves, and goggles, and experiment first to be sure they don’t soften the grout or damage the tile.

  147. I am going to tile over an existing tile floor as shown on your bathroom makeover. I have been told to acid etch the tile first to help the thinset adhere to the old tile. Do you recommend this ? or should I just clean the old tile floor and apply thinset, then the tile? Thanks for any advice you can give.

  148. Jerry, as long as the tile floor is clean, you don’t really have to acid etch it. I realize some folks may want to argue that point until they’re blue in the face, but it just isn’t necessary. I’ve done similar jobs in the past 25 years and not once has there been an issue with tiles popping loose. I did use a de-greaser on that bathroom makeover episode, but that’s it. I also like to use the fortified thinset. It costs a little more, but I’m more comfortable with it.

  149. Hi Ben,

    So in attempting to install ceramic tile, the demo of the old floor which is self sticking vinyl squares atop linoleum. The problem is that the backing of the linoleum will not come up by scraping. Any good solutions to removing that backing?

    Thanks for any help you can offer.

  150. We have 30-year old house with 2×6 T&G subfloor on 4′ OC joists and am installing 12×12 porcelain tile over backer board in kitchen, dining room, hall & baths (continuous run of tile). The kitchen has height limitation for diswasher & fridge, hence the backboard onto subfloor; otherwise would install ext. plywood between subfloor & backerboard. Is that joist span too wide for tile?

  151. I have just finished ceramic tiling my 3 bathrooms. The tile were laid over 5/8 T&G on 2 X 10 on 16″ centers. The tile walked on the most are coming loose. How can I re-install them so they will not come loose?
    I was think about removing them all and adding a layer of 3/8 plywood on top of the the 5/8 TG. Would this help?

  152. Question, I need to replace the sub-flooring in BOTH bathrooms of my double wide manufactured home due to water damage, (Mostly around the toilets and in front of the shower) it’s currently 31/32″ particle board and I can’t seem to find that size in a plywood product locally.

    Could I:

    Use 19/32″ – 23/32″ with 1/4″ cbu and tile over that?
    (I’ve always heard that putting a tile floor in a manufactured / mobile home was a no-no.)
    Do I have to remove the tubs / shower and cabinets along with the toilets?

    Any flooring recommendations besides tile? I hate the thought of putting carpeting back down, that’s just nasty!

    • Hi Johnny,
      You should use exterior grade plywood rather than particle board for a bathroom subfloor, since water can cause it to disintegrate. If you plan to use 1/4″ cement board on top, you need at least 3/4″ plywood for the subfloor. Another common bathroom option beside tile that would resist water damage much better than carpet is sheet vinyl.

  153. I purchased a house and hated the sheet vinyl in the bathroom, not to mention 6 layers of wallpaper! I ripped out two layers of sheet vinyl, a thin sheet of wood, and am now taking out the particle board. Underneath all of this is the original oak hardwoods – it was originally part of a room that was converted into a bathroom. At the hardwood level the bathroom is level with the hallway. I plan to put down ceramic tile. What would I need to put on top of the hardwoods before tiling? Or should I rip the hardwood flooring out too and then put cementboard down? I have time and energy, I just need to know the best route to take.

    • Hi Rebecca,
      Since hardwood flooring can cup and warp, I would either take it out and put down plywood followed by cement backer board, or screw make sure the hardwood is well attached and cover it with a layer of plywood followed by cement backer board.

  154. I am wanting to install ceramic tile flooring in my upstairs bathroom in an old house. It currently has linoleum in there. I am wanting to install 3/4 inch backer board directly over the linoleum, and then the tile on top of that. The floor is in good shape, but I don’t know what type of subfloor is under the linoleum. The bathroom floor is elevated up about 4 inches higher than the bedroom, like they made a platform in the bathroom for some reason. I am worried about cracking of the tile from the bathroom being on the 2nd story and from the floor being on this platform. What is your opinion on this???

  155. We are about to start tiling in our kitchen and have a huge argument brewing! We have fortified powdered thinset (with the powdered latex). My mother insists that it would be better flexibility etc. to mix it with the 5 year old liquid latex she has left over from an old tiling job. I say it’s already fortified and good ol fresh water would be best. Can you “over-fortify” this stuff, i.e., use too much latex? Is 5 year old left over latex okay to use? Thanks much and there’s money riding on this, not to mention a very nice kitchen floor!

  156. My husband and I are remodeling a kitchen. We have taken old flooring out down to subfloor, installed OSB and have durock to lay. Question: is it necessary to use thinset between OSB and durock or can you screw straight down without thinset? We plan to install 12″ tile over durock.

  157. Okay so I’ve done quite a bit of tile for a DIYer and I’m stumped. I want to put down a thermal break under a remodel bathroom floor. The original floor was concrete over bridged joists in this case all the bridging and sister joists were 3/4″ . The concrete was 1 1/2″ thick w/ tile. So here is my q? I want to drop 1″ high density foam down right on top of the joists and bridging from the shower all the way to the other end of the bathroom. Then drop my 3/4″ 7 ply subfloor, then 1/2″ cement board, then tile. My issue is I’m going to be at almost 3″ thick floor after I do all that. I can raise my shower/toilet flanges (have the tear them out anyway) but I was worried about having a 1 1/2″ “step” going into the bathroom. The idea of the termal break is the same with a basement. Seperate the existing air temp with the tile so the room is warmer and the tile isn’t 30 degrees in the winter!
    Plan B was to install a resistance mat heated floor, but I didn’t think I could put that in a shower.
    thanks guys!

  158. My husband and I are remodeling a kitchen and want to lay ceramic tile down, we have a island in the middle and are wondering if we need to pull up the island or just tile around it.

  159. Hi
    I am tiling a small (9’x6′) utility room. If the first course starts at the door opening (to ensure a perfect match relative to the entry), I will tile myself into a dead end. Can I kneel on the just-laid title to final courses in the dead end? If not, can you share the secret?

  160. Lucy – Unless you’re also pulling up all the perimeter cabinets, I would tile around it. Otherwise, it will be taller than the other cabinets.

    Ron – You CAN do that, although it’s a bit of a hassle and I don’t really recommend it because you’ll cause the tiles that you’ve just put down to shift. Even if you are extremely careful, you’ll probably have to do a little adjusting of the affected tiles as you back out of the utility room. A different approach which I have done is you can lay the first course at the door, then just go all the way down one side with one row until you get to the end, then work backwards so that you end at the doorway.

  161. I am about to tile a bathroom with ceramic tiles. I have removed all existing flooring and installed a new 3/4″ plywood after coating it with water sealant.

    Do I put a tinset on the plywood before installing my backer board?


  162. I am having my kitchen redone. This is the first time in my life I am not doing the work myself. My wife wont let me. Seems I take too long. The People who are installing my kitchen are telling me that they will not use hardy backer. They have informed me that is the incorrect way to do it. This is only for walls. Are they looking for the easy way out or is that true. They said they will install another layer of wood using liquid nails and screws. Just want to make sure it is done correctly. I have always used 1/2 backer board when installing tile on floors.

  163. I have see on remodle shows the use of what looks like a dimple role or sheet instead of the concret board. They lay down thinset then then roll out the dimple board then thinset again. After that they lay down the tile, have you ever seen that done?

  164. I have installed porcelain tile throughout my kitchen & dining room combo, with your expert advice. In doing so, I used an undercut saw to allow the tiles to fit nicely under the door casing. However, I cut a little too much off of them, leaving a 1/8″ gap, and I do not like it. How can I fill in this gap and match the profile of the trim casing at the same time?

  165. I’m remodeling my kitchen. The floor needs to be replaced with tile. My subfloor is made of 1 x 8 planks with approxiamately 1/2″ to 1″ of gap between each plank. I need to build up the floor to meet the height of the 3/4″ hardwood floor in the dining room. Would applying 1/4″ cement board with 1/4″ tile, along with 1/8″ thinset under the cement board and 1/8″ thinset under the tile, do the trick? Should I rely on thinset when determining the height of the floor? Can I even spread thinset on the 1 x 8 planks with the 1″ gaps present to apply the cement board to or would this cause a void under the cement board? Replacing the 1 x 8 plank subfloor would be a challenge. Please advise.

  166. I would like to put ceramic tile in my mud/laundry room but it has an access hole approx. 2’x4′ in size how would i go about this, the hole is directly in front of the dryer on the fllor and all i can figure is using linoleum on the whole floor like the previous owner has done. i need to still get under the floor to the crawl space due to a well pump under the floor.

  167. Hi!

    I’m planning on tiling a small domestic bathroom in the next couple of weeks and was hoping for some definitive advice, as I’m getting conflicting opinions from all angles!

    The floors are finished in inch thick OSB, on joists placed 8 inches apart throughout. I plan to lay tiles on a sealed layer of Ditra, which I think should solve moisture and structure issues?

    My main problem is the wooden stud wall, which is now well finished with 1/2 inch OSB. Do I…

    1 – Treat the OSB and tile directly to it? (the recommendation of my heating engineer/plumber)
    2 – Apply a 1/2 inch cement backerboard (Knauf Aquapanel as I’m in Europe) and tile to this?
    3 – Screw in a layer of green plasterboard, which is the recommendation of a ‘professional tiler?’

    I’m confused, and I want to get this right! Help please!


  168. Hi,
    My husband and I are planning to re-tile our kitchen floor. The problem is that the existing tile in completely under our cabinets and all appliances. How do we remove the tile just up to the cabinets without removing the cabinets or the tile that is under them?

  169. i have done a bath floor with porcelain tile over backer board. now i need to replace the baseboard with a border tile. my question is: the border tile sits on top of the floor tile. i will leave a space, the same as between the floor tile. should i caulk(off white) this or apply grout(grey) as i did the floor?

  170. Let me see if I can tackle a couple of these questions…

    I personally like Option #2, however, since this is wall tile as opposed to floor, I think you’d be fine with just 1/4″ backerboard. The green board will work, but I prefer backerboard.

    You should have a piece of 3/4″ round moulding at the base of those cabinets. If you remove it, you can use a cold chisel to score the line directly in front of the cabinets and snap off the tile. Once the new tile is in place, you replace the 3/4″ round and hide all the evidence! You can also rent an angle-style grinder with a small-diameter masonry cutter on it. It’s quicker, but kicks up a lot of dust.

    Definitely go with grout. It’ll look a lot better.

  171. We would like to tile our master bathroom but if we place backerboard and then the tile on top of that it will be much higher than the carpeted bedroom floor. We have found a product called SnapStone Floating Porcelain Tile System which can be installed over existing floor. It is actually thick porcelain tile permanently attached to a tough plastic. This would solve the problem of matching to the bedroom floor. Have you ever heard of this product or used it?

  172. Danny, Could you answer John’s question from the 29th. I have the same issue in a bathroom that I am remodeling.

    Thanks very much!


    • John and Ray,
      Due to problems with seasonal wood movement and cupping, putting 1/4″ cement backer board directly on top of a solid wood subfloor is not recommended. A better option, if you can’t take the wood up, is to put a layer of plywood on top of the wood flooring, followed by cement backer board and tile.

  173. Hi… My kitchen floor consists of a 1/2″ plywood sub floor, then another 5/8″ ‘sub floor’, then linoleum, then 1/4″ plywood, then some more linoleum, then vinyl square tiles. I want to remove all except the 1/2″ sub floor then go over that with the backer board, then the ceramic tile? I don’t see a need for the second 5/8” sub floor, do you? I think with the backer board, then the tile, it should just about match the height of my ¾” hardwood. What do you think?
    Thanks for any advice.

    • Hi Barry,
      The general recommendation is that the total thickness of the subfloor under tile be a minimum of 1 1/8″ thick. So while 5/8″ plywood topped with 1/2″ cement backer board would be okay, 1/2″ plywood would be a bit on the thin side which might cause problems with deflection. Also, keep in mind that backer board doesn’t provide much actual support as far as deflection is concerned.

  174. we are taking out an old linoleum floor in a bathroom, and going to replace it with tile. There is a small section of plywood on the floor near where the fiberglass tub was..(we took it out) The plywood is a bit rotted out, and has mold, too. Do we tile over it? replace it? or what is this concrete layment i am hearing about? backer board? does that go on the floor OVER the plywood?
    I am concerned about the mold… and the rotted plywood.

    • Hi Donna,
      You should remove and replace any rotten wood before tiling. Make sure you have a good solid plywood subfloor, then screw down a layer of 1/2″ cement backer board on top of it to serve as a base for the tile.

  175. Hi we are getting ready to install a new tile floor in our kitchen, we are doing a complete remodel the sub floor is concrete and I have just one question how long does the tile need to sit before I can put my fridge and stove back in as well as have a functional kitchen as we have three children and were hoping for just a few hours of down time but if I am reading right we will have a full day 24hrs worth of down time.

  176. Hi,

    Is a 1/2″ subfloor followed by 1/2″ underlayment (plywood) followed by 1/4″ durock sufficient stability for ceramic tile?


    • Barry,
      A total of 1″ of subfloor topped with backer board should be fine. The general recommendation is a total subfloor thickness (including backer board) of 1 1/8″ or more.
      Good luck with your project!

  177. Ben,

    One last question please. The backer board instructions state to, along with screwing down the board, to ‘bond’ the board to the subfloor but associates at my home store state that most ‘contractors’ only screw it down. Is screwing it down sufficient?


    • Barry,
      The most secure approach is to apply thin-set to the plywood subfloor with a notched trowel, lay the cement backer board on the still wet adhesive so it adheres to the subfloor, then screw the backer board down to the subfloor while the thin-set is still wet. That being said, I’ve seen flooring contractors who just screw it down as well. Alos, you can use either 1/4″ or 1/2″ cement backer board under a tile floor.

  178. I am installing ceramic tile on my interior stairs. To take care of the bullnose, I am using a 5 1/2″ stained hardwood stairnose installed upside down with the 1/4″ notch facing upwards, with 3/4″ plywood to complete each step. Can I apply my mortar directly to this or do I need to use a backer board?

  179. Wow! I’m been bombarded with useful information scrolling from the top. But what led me here is this:

    I have enclosed a space by which we now want make it a bathroom. It is built with 2″x3″ wood frame. We used GI flat sheet for the outer wall and 1/4″ plywood on the inner wall. As we now want to convert it to a bathroom, we want to put tiles with it. The floor is concrete so we don’t have much problem with it. The problem is the wall. How shall we go about it? Is there a way to put ceramic tiles without removing the plywood? I have read from the link about some ideas but I am not sure how to proceed. Please advice. thanks in advance.

  180. I’m installing a raised hearth for our gas fireplace. Currently, I have framed out the hearth with 2×4’s and attached it to the floor. It is about 3ft deep and 5.5ft wide. Do I need to put a subfloor under the 1/2″ cement board before installing my 13″x13″ tile? If so, what thickess of subfloor do I need?

    • Hi Jackie,
      Cement backer board does not provide much in the way of support, its main function is to provide a stable surface that adheres will to tile. So the answer is yes, you would need to install a plywood subfloor under the cement backer board before applying the tile. The thickness of the subfloor (including the cement backer board) should be a minimum of 1 1/8″ thick, so if you use 1/2″ backer board, you would need at least 5/8″ plywood. Good luck with your project!

  181. I want to add a screened in porch to my house I would like to know if I can use a plywood sub floor then cement backer then tile the porch? I don’t want to go with the normal decking because i don’t want ants or bugs coming through the decking cracks.

  182. Am fully remodeling my old pier and beam Houston house. A subcontractor wants to concrete each corner of the each room under the wood piers to prevent future movement. Then I have a choice to tile all the floors or use only tile in the wet areas and perhaps laminate in dry areas. I hear stories of tiles that move or pop up as settling occurs after a subcontractor goes out of business. What flooring would you use and why? Should all the sound old oak floors be removed first?

  183. Hi, I am remodelling an old bathroom, with the end product on teh floor being 18×18″ travertine tiles. It is an old house (1930’s) and the original tile was set on a bed of 1.5 inches of concrete on top of T&G fir planks, whihc themselves rest on 16″ o.c. joists. Once I ripped up the cement, I noticed the fir planks had some cupping to them. Can I just screw 5/8″ plywood to the planks and then add the backboard and tile, or do I have to remove the planks? I’m worried the cupping with transmit through the plywood.

  184. We are installing 12″ x 12″ porceline tile over our 1/2 inch plywood subfloor. One person told us to use 1/2″ backerboard. Another person told us to build up our floor first by placing down 5/8″ tounge and groove plywood ontop of the current plywood and then use the 1/4″ backerboard. What do you recommend?
    Also, our current floor is not level and varies 1/4″ in a wave pattern. Will the new plywood fix this problem or is there another step we need to take. Thank you.

    • Hi Michelle,
      Either 1/4″ or 1/2″ cement backer board will work as long as the subfloor under it is firm and flat. You should definitely make the current floor as level as possible before applying another layer of plywood on top. This can be accomplished by using a floor sander on any high spots then filling in the low spots with a self-leveling floor compound (make sure there aren’t any cracks or gaps for the compound to leak out). You can find out more by watching our video on How to Level a Subfloor.

  185. We have Quarry tile throughout our kitchen, dining room, and foyer. The tile is embedded in 1 1/2 inches of concrete/mortar over hardwood floors. How do you go about removing the tile in dining room and foyer and then building the floor back up for hardwood flooring to transition into kitchen. Or is it easier to just take up all tile and start fresh?

  186. Do I need to do anything different to lay tongue and groove wood flooring over concrete board (previously had tile floors)

  187. Hi to all!
    I am thinking about laying tile on my deck. the deck is about more than 10 years and made by treated wood. It is still in good shape, however, my little girl want to run bare foot on them and she got alot of splinters on her feet. that is how i want to lay tile on them.
    My concern is I need the tile whichi is very light on weight to put on them. the one can survive in the severe winter (last winter, the deck always had around 2foots of ice on them) and the temperature last 2 years in the winter down to -11F.
    because I concern about the light tile, I dont want to make the big bed for tile, my question is any glue, adhensive work well for wood surface and tile? or any light bed could apply for my case?
    thanks your all your contribution

  188. we want to make a continuos run with the kitchen and dinning room flooring. The kitchen floor that mets the dinning room floor is 1/2″ higher. What do I have to put on the dinning room floor to meet the kitchen floor.

    • Hi Bob,
      I’d put 1/2″ plywood down to level the two floors before installing tile. If the existing subfloor is a slab, you would need to attach the plywood down with mastic, then shoot fasteners into the slab to hold the sheets in place.

  189. I have a question about ceramic tile installation? My subfloor is 1×12 boards laid diagonal to the floor joists, which are on 16 in centers.I might add this is over a basement.I want to do the entry way to the Kitchen and kitchen floor. The kitchen has linoleum. I was going to take up the kitchen floor and put down new subfloor on top of the 1 x 12’s.I also want the ceramic to meet the wood flooring in the living room if possible. I have 3/4″ to work with. The tile is 3/8’s thick. What do you suggest?


  190. Has anyone used the new Snapstone Floating Porcelain Tile System? It does not require cement backer board to be installed.

  191. I have plywood subflooring in my 55 year old brick home. The contractor accidently cut my copper pipes in an upstairs bathroom. He replaced them with PVC pipes wich I didn’t want now he and wants to replace my perfectly good plywood subfloor with concrete board. Is concrete board used in place of plywood sub flooring and will it support the weight of the toliet and vanity on the upper level of the house? Thanks

    • Hi Shami,
      Cement backer board is not designed for structural support to carry the weight of the floor on floor joists, but to provide a stable surface for the tile to bond. In addition, you need a plywood subfloor (5/8″ thick or thicker) under the cement backer board to provide a firm foundation and support the load on the floor.

  192. Hi there my husband and I are remodeling one bathroom and we are putting down heated floor. He had an electrician come in and put down the heat coils. Tonight when he was putting down the self leveling floor, he put it down to thick and it did not level out. If he chips up the concrete it is going to ruin the heat coils but if he tries to level the unlevel floor it is going to make it incredibly thick. What can we do?

  193. Hi,

    I’m going to use 1/4″ durock over 1″ of subfloor. The subfloor is high in a couple spots. Can the floor be somewhat leveled the way it is sometimes done for Hardwood floors? Can you put asphault shingles in the low spots, then the durock?


  194. Shawn…wow, tough call there. To me, it’s weighing the cost difference of the repair method. How much were the coils? How thick is too thick? See if the coil manufacturer can verify if they will be affective or not with the thickness you have. Otherwise, there is another option. You can rent a concrete grinder, much like a floor polisher, to grind away the excessive floor leveling compound. I haven’t priced them, but it’s worth looking into. Also, ask if they have the dustless capabilities.

    Barry…Yes, I’ve seen some contractors use shingles to level the surface. I’ve never followed up to see if it held up over the years, but I’ve never heard any complaints up to now. I would caution you, though, to make sure you use a good floor adhesive to glue down both the shingles AND the durock, in addition to screwing it to the subfloor. You don’t want any kind of spongy areas that will eventually cause cracked tiled and grout.

  195. I would like to know what (if anything) *has* to be installed between the wooden sub-floor and the tile on an outside second stroy balcony. Is cement backer board enough? There isn’t living space under the balcony. Thanks!

    • Hi Leslie,
      Yes, you should always install cement backer board on top of a plywood subfloor before tiling to allow the tile to adhere properly. Attach the backer board using corrosion resistant screws, and put mesh tape over the seams. Good luck with your project!

  196. Hi,

    I really need some advice. I have gutted my kitchen entire kitchen down to the concrete slab. I am having new cabinets installed and also laminate flooring. The problem im having is that the kitchen installers are telling me to install the laminate flooring first and then the cabinets on top, so i can remove the dishwasher in the future. The flooring people are telling me to install the cabinets first in case i need to change the flooring for whatever reason. I have read online that some people place plywood on the concrete slab under the cabinets in order to raise the cabinets by 1/2″. Is this a good idea? If so, is there a certain type of plywood that should be used? Does the plywood need to be secured to the floor with thinset or something? The kitchen installer wants to come in tomorrow morning… id really appreciate any help!!!


    • Hi Reza,
      My preference would be to put plywood under the cabinets that’s the same thickness as the laminate, install the cabinets, then floor up to it. That way the dishwasher will slide in and out, the cabinets will be the right height, and you can easily replace the flooring without having to cut it. You could glue the plywood down using construction adhesive, then screw or nail it; or just screw or nail it. Personally, I wouldn’t worry with the adhesive.
      Good luck with your project!

  197. Hi Ben,

    Thanks so much for the info… youre a life saver! Before i run out to home depot… is there a specific type of plywood that i need to get? I went to look last night and i was lost amongst all the different types

    Thanks again!!!

    • Reza,
      I would use a rough exterior grade of pine or fir plywood (the glue is more water resistant in case you have a leak, and exterior glue has lower VOCs) the same thickness as your flooring.

  198. Ben,
    Thanks for a great site!
    Installing a new kitchen floor. The old vinyl and 1/4 masonite has been removed. Old tiles (circa 1970) remain, but can be removed. Below is either 1/2 or 5/8 sheathing with joists 12″oc. On top of this is 3/4 t&g plywood flooring.
    An area of the “new” remodeled kitchen used to be the dining room and I’ve removed the t&g oak flooring and replaced with the 3/4 plywood flooring. The floor is now level and seems sturdy. It also is now the current height of the oak flooring in the living room and the hallway that adjoin the kitchen/foyer that I’m tiling.

    Will use 16×16 porcelain tiles.

    Have looked at your links and answers all the way back and have these questions based on what I read:
    1. I can tile directly over this floor because it is more than 1 1/8″ thick without adding backerboard (would have to remove all plywood to do this) – correct?
    2. Have contemplating using 1/4 backerboard, but this, with the tile and the 2 beds of thinset would create a 1/2 to 5/8″ height descrepancy at the oak flooring in living and hallway. Should I still consider the 1/4″ backerboard on the floor? And if so, what kind of transition threshold would be used?
    3. I’ve read at multiplaces in your responses and other places about using something other than thinset – or thinset with latex , or EGP type portland cement or epoxy. Given the base (plywood) can I just use the standard thinset, or this thinset with an additive or a totally different thinset?

    Thanks in advance for your assisstance!

    • Hi Barry,
      The purpose of cement backer board is to provide a stable surface for the tile that doesn’t expand and contract, and to provide good adhesion between the tile and thin-set. If the floor is rigid, thick enough (7/8″ or more), and flat, 1/4″ cement backer board should be fine. I would not try tiling directly on a plywood subfloor. Another option that is a bit thinner than cement backer board is a waterproof underlayment membrane (1/8″ thick).

  199. Thanks Ben,
    With the 1/8″ or 1/4″ and tile, I will be about 3/8″ to 1/2″ above the hardwood at the transitions to other rooms.
    What do you recommend for transitioning so that people don’t trip.

    Is 1/2″ typical?

    Thanks in advance!

    • Barry,
      I would use an oak strip finished to match your floors with a rabbet cut in the bottom to match the transition between the rooms. Be sure to round or chamfer the edges for a smooth transition.

  200. We are about to tile our bathroom. We have the subfloor leveled & are about to put down the durarock & I was wondering…do we need to put the durarock under the tub? or put the tub in 1st & then put the durarock up to that…I wasn’t doesn’t seem right…like it will be to high up above the tub once you have the 3/4″ durarock & then the tiles on top of that…PLEASE HELP! 🙂

    • Hi Jennifer,
      You don’t need to put cement backer board under the tub, but you can if you want to make the tub higher.
      Good luck with your project!

  201. My wife and I just moved into a rental home a couple months ago and it’s floors are part original hardwood floor (really needs some TLC) and part tile.. The tile range from 12″ to 18″ and since we moved in we noticed the grout coming out and the tiles shifting and worst of all cracking. It’s mostly the smaller tiles that have a grout lines, because the bathroom has no grout line and seems to be holding firm, but that could be because it’s a small area and doesn’t flex like the rest of the floor as you walk. And the large tiles are also degrading and moving but not to the degree as the small ones. I did notice under one of the bathroom cabinets a cloth mesh so i guess that’s the problem , they didn’t not back it properly, use the right materials , and didn’t seal the grout… I’m looking for your expert opinion so I can go back to the owners and let them know about this, so they don’t just blame us.. HELP…

  202. We plan to tile our kitchen, living room and dining room which all flow together in a larger rectangle with the fireplace being in the center. There are no doors separating any of the entrances. Where do we begin to lay the tile so that the rooms flow into each other? The center of each room? Center of one room?

    • Hi Penny,
      I would center the tile on the main room, then tile off it using full tiles in the doorways and on into the other rooms.

  203. We have tiled a considerable amount of floor using Ulay 3/8 inch underlayment over 3/4 inch plywood subfloor. It’s supposed to be an excellent underlayment for tile. I used thinset with polymer additives. Do you know anything about ulay underlayment? it’s a plywood product. We hated using concrete backerboard because it needs to be installed with thinset under it or it could crack. So, to every take it up would be a nightmare.

  204. I removed all fixtures in my bathroom and have replaced subfloor with glued and screwed 3/4″ exterior plywood. I plan to install 1/4″ thick ceramic floor tile and want the new tile height to match hardwood floor height(3/4″) at entrance. I will use backerboard or membrane under tile depending on best matching height. 1. What tile system over subfloor would be best for matching hardwood floor height? 2. Is there any advantage or disadvantage to installing backerboard or membrane under new cast iron bathtub?

    • Hi Duane,
      Cement backer board will make the floor thicker than if you used an underlayment membrane. Either 1/4″ or 1/2″ cement backer board, or 1/8″ underlayment membrane will work under the tile, so it really depends on how thick you want the floor to be. The disadvantage of installing cement backer board under a tub is the time and materials it would take to do it. There’s no real advantage to putting cement backer board under a tub, other than to make the tub a bit higher. Good luck with your project!


    • Hi James,
      If the old subfloor is in good shape, you don’t need to replace it. If the subfloor is plywood, install a layer of cement backer board on top before tiling. If the old subfloor is covered with a thick bed of mortar that’s in good condition, you can tile over it. If the mortar bed is uneven or cracked, apply a leveling or patching compound as needed first. Watch this video on How to Level a Subfloor to find out more.

  206. Hi. I want to replace the carpeting in my 84 sf 2nd floor bathroom in a 12 year old townhome. How do I know if the subfloor is sturdy enough to support porcelain? Also, the laundry area is close the the bathroom on the 2nd floor and I am wondering if the washing machine vibration will affect the tile. Thank you!

  207. Hi,

    Can you please tell me if you apply thin set mortar to both the durock and the ceramic tile or just the durock. My cermaic tile is 5/16″ thick.


    • Hi Barry,
      You apply thin-set to the surface you plan to tile using a notched trowel, then lay the tile in the bed of adhesive. It’s not necessary or desirable to apply thin-set to the back of the tile. Good luck with your project!

  208. Hello,

    We are intalling ceramic tile inour kitchen over durock. We’re half done now and have now seen a good sized chip on one of the tiles. The thinset is hardened now for four days. If you can please tell me what is the best method used in removing the damamged tile?


  209. one day i saw my friend laying durarock cement board over a wood sub floor and he would lay morter down under each piece of cement board and then use roofing nails to secure the cement board downt to the wood sub floor, I was concerened about the fact he was using roofing nails ive been in the bussiness for 30 years and never heard anyone using roofing nails to secure the cement board to the wood floor and he tells me that you(Danny) knows what you are talking about,Ithink you do! could you help me please

    • Hi Gilbert,
      When securing cement backer board to a plywood subfloor before tiling, screws provide better holding power and have less chance of working their way out than roofing nails.

  210. My old damaged subfloor is being ripped out. I was surprised it was only 1/8″ thick. That’s the problem. I’m worried that your minimum specs 5/8 + 1/2 would put my new kitchen floor too high from the surrounding hardwood floors. The same 1/8″ sub flooring is installed throughout the house.
    What’s your take on this? Thanks in advance.

    • Hi Ed,
      There’s no way an 1/8″ subfloor over wood joists could support a tile floor. Even if you had hardwood on top of it before, I’m surprised it’s that thin. I’d stick with a minimum of 5/8″ plywood topped with cement board then tile, or 3/4″ plywood topped with a flexible membrane then tile.

  211. Thanks for the reply, Ben.
    1/8? , it confused me too! It’s a old house built in the 60s. After taking out the old flooring on closer inspection I see that the flooring is supported by 5.5″ wide, 3/4″ thick solid wood planks nailed diagonally on top of the joists. There is a 3/16″ or so gap between each plank. My guess is this is the real subfloor. On top of these planks are stapled sheets of 4×4 ,1/8 thick plywood. This wood is being replaced. My question is since the planks are load bearing can I use a thin ¼” plywood sheets with ½” cement board on top?

    • Ed,
      That makes much more sense. Yes, the 1/4″ plywood topped with 1/2″ backer board should work just fine. Before putting the plywood down, I’d give the wood subfloor a once over to make sure it’s attached to the joists securely (screws would work best) and use a hand plane or belt sander to knock off any high spots on the board if some have cupped or warped. Then attach the plywood and backer board (again, screws are best), putting the fasteners into the joists, and you should be good to go. Before tiling, cover the seams in the backer board with mesh tape and thinset. Good luck with your project!

  212. Being a professional carpenter I more than understand the importance of level, plumb and square. Unfortunately I was unable to have enough time to jack up the center red iron I-beam under the floor to aide in the leveling process for tile before the Granite Counter tops were installed. So not to compromise the granite seams and counter top level I am using Self Leveling Concrete. Here in lays my problem. Website after website says do not attach backer board to self leveling concrete. Obviously, I would look past this if it was only an 1/8″ – 1/4″ of S.L.C. But I have more than a few places where it is 5/8″ – 3/4″ thick. It’s about 325 sq. ft. kitchen with about 75 sq. ft. with the S.L.C. Would a hammer drill and tapcons be feasible in this application? Thank you for any reply.

    F.Y.I. : From what I’ve read on the Schluter Ditra System. It is a tried method from thousands of years of laying tile from Europeans. Must be good as most all homes in Europe are tiled. But, I think many professionals here in the U.S. have been using the same concept by mortaring the backer board before fastening. It essentially makes the floor one solid structure rather than a joist by joist structure, thus if the floor gives it gives over a wider span rather than between joists. Less chance for tile damage. I like to mortar and tape backer board joints as I install them so not to create a dry joint between mortar bed and seams.
    Thanks again for any info, and I hope I helped with any questions about the Schluter Ditra System.

  213. Re: Old kitchen with several sub-floors, nails, etc. We have been very successful in cutting through and removing layers, but now have come to a layer that is even with the kitchen cabinets (on one side of the kitchen).

    How do we remove this sub-layer that extends underneath these cabinets without removing the cabinets?

    Ultimate goal is to get to the sub-floor that allows us to put porcelain tile so that it fits nicely underneath the molding without using a jamb saw.

  214. Maybe in your neck of the woods they have done away with floated floors for tile work, but any job site I have been on if you try to use backer board they would kick you off the job site.
    I don’t under stand why tile setters have gotten lazy and started to use this product? I have been setting tile for 20 years now and we mud set every thing, Then again we are not a jack of all trades we only do tile work.

    You should never set tile on wood, sheet rock, green board. The use of backer board and wonder board started when every one and there mother thought they were tile setters. One look at there jobs and you will see pinched corners on walls, hook on floors waiting to trip you up, wavy walls and floors.

    If you ever set tile to any of the above, you will be replacing it about every 5 to 10 years and if it is in a bathroom or kitchen were there is lots of water it will be sooner than that, most of the time just out side the contractors warranty.

    The only way to do the job right is to vapor tight the areas and float it out for a true install that will live longer than most people will own the house.

  215. I have a few questions, is it better to lay tile before meeting up with a wood floor or vise versa. I have to lay down a floating wood floor and also a tile floor that will meet up in two area. Also I have a concern on how to lay tile at a doorway that leads in the basement. The stairs are carpeted but not sure how you butt that up to make it safe for people going downstairs. Thanks

  216. Its a 1950’s home where the 9’ x 14’ kitchen and 12’ x 13’ dining room currently has 3/32 vinyl tiles on 9/32 Masonite (3/8” total), on 3/8 plywood which is over tar paper on a 7/8 tongue and groove plank subfloor perpendicular to 2 x 10 on 16” OC joists. It is level and no squeaks. The vinyl and Masonite, as least, will be removed and tile laid. The question is whether to remove the plywood and replace it with backer board? Or just add some screws and tile over the plywood? The current height, where the vinyl floor meets the oak floor at doorway, matches perfectly. So, if I can just tile over the plywood, it would be the correct height and the 1¼ subfloor (7/8 + 3/8) would have sufficient thickness. Is moisture enough of a concern, since it is a kitchen, to replace the plywood with backer?

    • Hi Mark,
      Leave the diagonal board and 3/8″ plywood in place, and screw down cement backer board on top of it. Good luck with your project!

  217. Thanks Ben, but by adding 1/4 backer on top of the plywood, the tile would then be 1/4 higher than the mating harwood floor. So is it worth removing the plywood and relplacing it with backer? Or is there a clean way of transitioning the hardwood to tile height difference?

    Thanks again,

  218. I am laying tile in a 16′ x 27′ room. I am struggling with a height problem. I have 3/4″ of height to the sliding door threshold. The subfloor is 3/4 OSB. The floor joists supporting the subfloor are 2 x 12’s at 16″ O.C. I have thoroughly inspected the subfloor and have added 2×4’s between the floor joists (glued and screwed) underneath all the OSB tongue and groove joints (along the 8′ sides)for added rigidity. The floor feels very solid at this point. I am considering 2 options and would like your recommendations.I initially planned to use Ditra. My only concern with this approach is that I do not want to apply mortar directly to the subfloor as it would make any future changes by me or a future owner very difficult due to the fact that the subfloor which is glued down would probably have to be replaced at that point. I could use luan below the Ditra but schluter does not recommend that. They indicate only plywood or OSB are acceptable underneath their product. The only other option I can come up with is to use 1/4″ Durock, screwed down, instead of the Ditra. If the floor is solid, will the Durock act as a separating membrane similar to the Ditra? FYI – The floor previously had 3/16″ Luan, stapled down, with 8″x8″x1/2″ ceramic on top of it. That floor was in place for 20 years with no evidence of cracking. I am planning on laying a 16″x16″x3/8″ porcelain. Thanks in advance for your recommendation.

  219. I recently removed an old tile floor in my kitchen and dining areas which I had previously installed 15 years ago. Underneath the tile floor was a new subfloor 1/2″ plywood stock which was installed properly and very secure. During the process of removing the old tiles, some of the old mortar stuck to the wood floor. I used an electric demo hammer to remove the tiles and it did a nice job but there are some very minor peaks and valleys in the floor. Would it make sense to cover the wood sub-floor with 1/4″ backer board before I install the new porcelin tile or should I just go directly over the existing subfloor? Note: the leftover old mortar on the subfloor would be very difficult to remove at this point. My other thought was to remove the subfloor entirely and start fresh with a new backer board. I’m just not sure of the best route to take at this point. Thanks in advance for your help!

  220. Hey,
    We’ve got a roughly 2×10′ area in the kitchen down to the old wood floor in one spot, subfloor in another, and the bare joists at the last. Prior owners tiled the floor, except for this area (under cabinets) and we want to finish the tiling before putting new cabinets down.

    Issue is – they leveled things over the old wood with concrete, and the bare joist to under the tile is roughly 3″ of height difference. Our plan was to use 3/4″ plywood->SLC->1/2″ concrete tile backerboard then tile, but we still have a large height difference to account for.

    So, use more plywood to keep raising things up, or go ahead and use concrete/SLC on top of what we’d planned to make up the difference, since it’s already there in the rest of the room anyhow?


  221. I have an older home built during the early 60s. The bathroom floor tile needs to be replaced, unfortunately the builders used wall tile on the floor. Floor tile is generally cheaper and more durable than wall tile and ideally I would like to use floor tile to tile the floor. My only concern about using floor tile for the floor is the hardwood floor in the hallway will not be level with the floor tile if I use floor tile instead of wall tile. What would you recommend I do? Should I use a threshold? Should I just use wall tile on the floor? How thin can the cement board safely be (so as not to easily fracture)? Thank you.

  222. I am about to tackle a Small bathroom renovation project for a friend whom is daring enough to let me experiment on his home. The TILE question, he wants to remove the tub and do a complete stand up tiled in shower area, can this be done using the cement board various sealants and caulking alone or does there need to be some kind of underlayments or special/custom fitted matting membrane or all of the above and what other advice could you provide me, other than leave it to the experts “LOL” Thanks so much!
    Dwayne NJ

  223. Hello,
    I am installing ceramic tile in my kitchen and my installer told me that the sub-floor is weak and inspite of putting a cement backer board over the wood sub-floor before tie tile is laid, I would also need to brace the joists as they are 24″ on center and not 16″. The installer is charging me an additional $500 to brace the joists for a 100 SF area. Can anyone please tell me if this is absolutely necessary and if so, do I need to do it before the tile is laid down or can I do it later.

    Please advice.

  224. Hello,

    I have an entry way in need of both a new front door and new tile. We have an old entry door that leaks like a sieve and parquet wood tiles, in terrible shape, on top of a plywood sub-floor. There has been some water damage to the parquet tiles and I suspect this extends to the plywood sub-floor. It all needs to be replaced, and my main question is what is the proper order to replace all these items? Is it remove the entry door, replace the plywood sub-floor, install new door, install cement backer sub-floor, install new tile?


  225. I am redoing my kitchen. It is completely gutted to the studs. The sub floor is cement but retains a lot of moisture. I read you can buy a liquid waterproof membrane. I was wondering if I should waterproof then put thinset and attach cement board with the thinset and or nails that go through cement, then the tile. I’m concerned that the moisture from the cement will create mold (my. Baby has asthma). Also I’m tiling over the bathroom tub all the way to ceiling. Should I nail exterior plywood over the studs then put up Cement board? What about putting cement board in the kitchen versus the mold resistant drywall (I intend on tiling the back splash and wall behind the stove).
    Thanks in advance!

  226. I’m laying 3/4″ hardwood in my vanity/closet area. It is on the second floor of a central California home. I stapled 1/4″ luan just to smooth over the already level wood subfloor. My question is do I need to put down the “vapor barrier”?
    I wouldn’t think there would be a problem as there is no “dirt” underneath the floor?
    James Boulton
    Hayward Ca 94542

  227. Hi, My husband and I live in a house that my Dad and I built ourselves three years ago. We hadn’t quite finished the house (trim work, kitchen counter tops, etc. still to do) when we moved in and for the last three years our bathroom floor has just been the plywood subfloor. We are getting ready to put down tile and a under floor heating system. I’ve been trying to decide whether to use Hardibacker or cement board over the plywood. Does one work better than the other? Is there any benefit or extra prep needed when using these products with the radiant floor warming mats? Also, is there something extra I’m supposed to do to waterproof this stuff? I keep seeing that mentioned in forums and I’m not really sure how that applies.

  228. Hi,
    I plan to tile my kitchen with ceramic tiles. The kitchen currently has vinyl flooring on top of hardwood flooring on top of of wood sub-flooring. I have read that cement backboard is the way to go when laying tiles, but I’m worried that it will add far too much height to the kitchen floor compared to the floors of adjacent rooms.

    So should I rip out the vinyl and hardwood flooring first then put the backerboard on top of the subfloor, or just put the backerboard on top of the current vinyl floor, or do I even need backerboard at all in this situation?? Thanks.

  229. Hi everyone,
    I have just had installed porcelian tile over hardibacker, over wood floor as a hearth area for my freestanding Pedestal Vestal wood stove. The tile man says the tile should be enough insulation for the floor, but since we used a metal undermat for years (before we had the tile)because the area around was carpet, now I am wondering if we should get another metal mat to put over the tile before resetting the stove. Trouble is I cant seem to find one. Maybe I dont know the correct term for the metal mat? It certainly looks better without one, but I dont want to chance a fire after all these years accident free.

  230. I want to replace the wood floor in my kitchen, but was told it would be a lot of work to pull up the old floor, which was laid on top of concrete. Would it be possible to install a travertine floor directly on top of my old wood floor instead of removing it?

    • Hi Greg,
      You shouldn’t tile directly over a wood floor, and while the best approach would be to take up the wood floor and tile directly on the concrete slab, if the wood floor is in good condition, you may be able to attach cement backer board on top of the wood flooring then tile over that. You can find out more in our article How to Tile Over Hardwood Flooring. Good luck with your project!

  231. We just began a very large tiling project and are now facing some large issues with uneven wood sub flooring. In some areas the level is off by a 1/2 inch in a 4 foot area. If we use leveling compound, can the hardibacker be placed on top of it? Will the screws needed to keep the hardibacker in place go through the leveling compound? How do we make a visually unlevel floor level? We are using 18″ ceramic tiles set on a diagonal. Thank you!

  232. My wife insists I get more opinions. We have a 30 yr old house we bought last year and are re-modeling. The 1st floor, over a basement, is mostly ceramic tile over sheet vinyl(!) over Potlatch Stur-I-Floor, over 3/4″ ply on 12″ stringers, 16″ OC. We are replacing the tile/vinyl with porcelain tile. Question is, should we remove the Strud-I-Floor, an OSB even though it looks like particle board, and cover the entire area with Hardibacker, install the Hardibacker directly over the Sturd-I-Floor, or install the tile directly over the Sturd-I-Floor. My big concern is a quality job that will last a long time and not give me cracks in the tile.

  233. Hello,

    I’m laying down new ‘mosaic’ tile on the bath floor. I’ve got 1″ plywood subfloor and will put down 1/4″ durock. Is some sort of a waterproof membrane needed or advisable on top or below the durock?


    • Hi Barry,
      You don’t need a waterproofing membrane under a bathroom or kitchen tile floor. You would need one, however, when tiling the floor of a shower stall. Good luck with your project!

  234. Hi Barry. Great info here, thanks!
    In prep for tile work in my small 4×5 bathroom, I recently put down backer board over a new layer of plywood subfloor. I put adhesive mortar cement under the cement backer board then screwed the board down. The next day I got a crunchy sound when walking on parts of the backer board. I believe I didn’t mix in enough water in the adhesive cement mix. I was aiming for a “peanut butter” consistency, but by the time I got it on the floor it was likely too dry. When I troweled it accross the wood it would at times not even stick, but just glide over without “damping” the board. Now that I’ve walked on the “crunchy” spots quite a bit, they have diminished considerably. I imagine the dried compound has broken into smaller granules and settled, therefore causing less of the crunch I got upon first walking on it.

    My question is, should I unscrew the cement board, scrape off the improperly mixed/too dry cement and redo? It is still an option at this point.

    Or am I being paranoid about minor sounds that seem to be diminished now, and will probably be further sealed in, when the tile and grout and base trim acoustically “seal in” the floor.



  235. I took out our vinyl kitchen floor,to replace it with cermaic tile. Under the vinyl flooring is 3/4in plywood that is in good shape.but thay used tar paper on top of the plywood,for the old vinyl flooring.This tar paper is impossable to get up. Can i cermaic tile over the tar papered plywood?

    • Hi Joe,
      Your best bet is to put down a layer of cement backerboard on top of the plywood subfloor and felt paper then tile over it. Good luck with your project!

  236. Hello,
    I am in need of help.. My husband and I hired a contractor to come in a redo our bathroom, kitchen, and dinning room with ceramic tile. It hasn’t been 6 months and 90% of the tiles are loose, the grout is chipping out of the cracks, the tiles are breaking, and when walking on the floor you can hear the floor pop, and makes a cracking sound, and when getting in and out of the bath tube you can hear a cracking noise. We had a wood subfloor and the contractor laid 1/4 cement board on the floor. What do I need to do to fix this problem? Thank you

  237. We are doing a total remodle on our kitchen and we are laying title with the 1/4 inch cement backer board my question is: do we need to lay the backer board on the entire floor or can we leave the title and backer board out from under the new cabinets?

  238. Hi,
    I am going to tile our kitchen & bathroom. We have floor joists 16″ OC, with 3/4″ pine boards run at a 45 degree angle as the subfloor.

    Can I simply apply a 1/2″ hardibacker directly to this? If so, do I need to apply mortar? The problem is that the mortar would leak between the pineboards into the basement 🙁

    It’s more work, but I could always put down a 3/8″ plywood followed by a 1/4″ backer board of some type.

    • Hi Pat,
      I don’t recommend putting cement backerboard directly over a solid wood subfloor. Your best bet would be to take the subfloor up, then put plywood down topped by cement backerboard. If that’s too much trouble, or your subfloor runs under the walls, you could put a layer of plywood followed by cement backerboard over it, if the solid wood subfloor is flat and stable without any cupping or warping. Good luck with your project!

  239. I had great results redoing my interior, second floor laundry room wooden floor 14’x10′

    This is what I did:
    Removed old plywood
    Installed new 2″x6″, 16″ to the center using metal hanging brackets
    Installed new 3/4″ plywood, glued and screwed to the floor joist with exterior grade screws
    Installed 1/2″ cement board, [opposite running direction to plywood] glued and screwed with exterior grade screws
    Taped the board joints with fiber glass tape
    Sanded and smoothed out joints [not too fuzzy]
    Applied cement based glue
    Installed tiles
    Applied grout
    Sealed grout with silicone

    Absolutly wonderful, best thing I’ve ever done!!!…and I’m not a pro!!!, just a homeowner, but I read every piece of information on the subject prior to starting.

    Things to check:
    Load bearing for the floor, both dynamic and static load…you don’t want the structure to collapse under the weight

    Deflection [movement will cause the tiles to pop loose] this is a critical component, the subfloor cannot move!!, use plenty of screw, nail and glue, screw, nail and glue, screw, screw, nail and glue.

    Good luck

  240. Thank you for the responses! I’m going to screw down 1/2″ plywood over the top of my 3/4″ pine boards.

    I’ll then put a layer of mortar down followed by 1/4″ cement board or hardi-backer (screwed of course)

    Thanks again!!!

  241. I am installing 18×18 granite tiles on a 15×15 foot area. My subfloor is 5/8 particle plywood with 1/4 underlayment over that. I have resecured the 2×10-16oc joists with 2×10 in between each joist. These are in lines 4 foot apart. If I put 1/2 concrete backerboard on top of subfloor, would this be sufficient and firm enough given the reinforcement mentioned?

  242. I am istalling 18×18 granite tiles on a 15×15 ft area. The floor joist are 2×10-16oc. I have resecured the floor from underneath by cutting 2×10’s and placing them inbetween each joist in rows 4ft apart. The subfloor is 5/8 particle ply with 1/4 on top of that. My question is if I put 1/2 concrete backerboard on top,will this be secure enough for the granite? I have about 1-3/8in to spare for the front doors to open now without the 1/2 granite and 1/2 backerboard. Thank You- Mike I

  243. I looked over this thread and couldn’t find this question but sorry if I am repeating. I am putting tile in a bathroom with a plywood sub floors. I am putting 1/2″ hardieback backer board down, and I was curious how tight around the toilet flange I should be with the backer board. I am figuring I should leave some room around where the bolts slide into the flange if I ever need to replace them. But should I try to get the backer board as sung around the flange as possible, and then leave a little room with the tile? When’s it’s all said and done with the tile thin set and backer board I will be about 1/2″ to 3/4″ above the flange. Thanks!!

  244. Hi,i am planning to tile my bathroom in uk,the floor is made of osb i think,old victorian style,i heard from a friend to use something like a net on top of them then apply a small layer off cemet,but i was thinking to screw some thin boards of plywood ! what do you think is the best way to do it ? ! thanks and keep up the good work 🙂

  245. We are installing tile in our kitchen and getting ready to lay durarock. It seems to be warped slightly when laying against the floor. It is still okay to use?


  246. My house is off the ground, the contractor that installed my ceramic tile but the hardy back cement board down first, my tile are cracking in a line all the way across my kitchen, any suggestions as to why and how to fix it? is it a foundation problem?

  247. We have gutted our kitchen. I was told to tile the whole floor before putting in the new cabinets. Is it true that I need to put the ceramic tiles under the cabinets? Thank you in advance.

  248. This is a great site! I have had many questions answered just reading the comments; however, I can’t find a solution to this problem: My house was built in 1915 in southeast Texas (hot and humid) and the floors on both floors are old long leaf pine(tongue and groove flooring– very hard). They are nailed to floor joists and that is it! There is no other subflooring over that. The upstairs bathroom floor squeaked in lots of places and we screwed the boards to the joists and got most of the squeaks out. Now we are going to put down a mosaic porcelain tile, 12″x12″ with the mesh backing and a 3″x6″ border around the room. In order to make a more stable floor, the plan is to screw down 3/4″ plywood on top of the long leaf pine and 1/4″ hardibacker on top of that. The porcelain tile will add another 1/4″. Now the problem has to do with the two doorways, one that goes out into a central hall upstairs and the other which goes into a bedroom. There will be a 1-1/4″ height difference between the bathroom floor and the wood floors. I know there has to be some kind of a transition threshold but I haven’t been able to find anything that makes that big a transition. Any advice you can give me would be great! Thanks,Jan

  249. I had about 600 square ft of tile installed at the end of March in my home. The subfloor was wood so they layed cement backer board down. I am having problems with my grout cracking all over and I also have a cracked tile. They put the backer board down with nails not screws. Also, didn’t use any mortor to put down the backer board and didn’t put anything on the seams of the backer board. I have been told by several other tile layers that this is my problem. Do you have any thought on this? Thank you!

    • Hi Sandra,
      When attaching cement backer board to a subfloor, screws hold much better than nails (though both are acceptable). Also, it’s a good idea to use thin-set to glue the cement backer board to the subfloor and to tape the joints in it before applying the tile, so all of those steps would have made for a more secure tiling job. In your case, however, it sounds like the problem might be in the grout that was used and how it was applied. In any event, you need to contact the company that did the work and have them fix it. Good luck with your project!

  250. I have an existing concrete floor with vinyl tiles glued to the concrete. I have removed the vinyl tiles but the glue remains, do I need to remove the glue as well prior to using thinset and ceramic tiles?

  251. Hi there. I was wondering if you could help me tile my patio table. It’s a wrought iron table (just the base)..I took of the ruined top and heard I use concrete backer board. I can’t seem to find any info. as to how to do this part of it. I can’t wait to tile! Thank you!!

  252. Hello, I recently laid tile in three rooms. My floor was 3/4″ plywood which I screwed down, pulled any loose nails and put a sub floor of 5/8″ tounge and groove which I screwed and glued and crossed the old floors joints. Its been 6 months now and I’ve had 5 tiles crack 4 in the bathroom 3 of which are the first row as you enter the bathroon and one adjacent to the tub and corner stud. They cracked at different times and they are single hairline cracks in each. My house is 26yrs old and I used the proper materials. Is it just too thin of a layer of thinset or could it be possible house shifting?
    Any help is appreciated

    • Hi Trevor,
      You didn’t mention whether you installed a layer of 1/2″ cement backer borad on top of your plywood subfloor. If not, you should have, since it gives the tile a stable surface and allows the thin-set adhesive to bond well. It’s also possible that the floor joists in the house are not big enough or close enough together to allow for a firm floor.

  253. Hello,
    I am just starting a tiling project in our master bath. We are in the process of removing the old tile right now. The tile was cracked in multiple places and the grout was coming up too. As we started removing the tile, it was as we expected, applied directly to the plywood subfloor. My question is, as we remove the tile, a bit of glue etc is stuck to the slubfloors that we will not be able to remove. Will we need to replace the subfloors before we layer the hardiboard? We are planning on adding mortor between the floor and the backer board, so will that even everything out?
    Thank you for your help!

  254. I am installing tile in my kitchen. The subfloor is only 1/2″ plywood. It was covered by 3/4″ particle board which I removed. My first question is, can I add another 1/2″ plywood over the lower subfloor and will those two layers of 1/2″ plywood be sufficient strength? The joists are 16″ on center. Or would it be better to rip out all of the subfloor and replace it with 3/4 inch plywood? (In other words is one layer of 3/4″ plywood better than two layers of 1/2″ plywood?) My next question is, can I then tile directly onto the plywood using a latex reinforced thin set? I do not want to add a backer board if I can avoid it because I want the top of the tile to be flush with the dining room oak floor at the kitchen entry. I could use a backer board if I went with just a 3/4″ subfloor. Problem is I do not want to rip all that out. It is obviously easier to just cover the 1/2″ with another 1/2″ layer. Thanks!

    • Hi John,
      The subfloor over tile should be at least 1 1/8″ thick. You can use 1/2″ plywood over 1/2″ plywood for the subfloor (I would stagger the joints and glue the two layers together with construction adhesive), but you still need a layer of either cement backer board or underlayment membrane under it so the tile will adhere properly. Underlayment membrane is only 1/8″ thick, so using it would make your floor lower than backer board. Good luck with your project!

  255. Thought I’d comment on my bathroom floor since we got it done. I mentioned in another post that my subfloor was 3/4″ longleaf pine from the early 1900s nailed to 1×6 floor joists 24″ OC. The tile guys used thin set mortar to glue down 3/4″ plywood over the subfloor and they screwed the plywood to the subfloor every 3″ in all directions. 1/4″ cement board was than glued and screwed over the plywood. Then a 12″ x 12″ mosaic tile on a mesh backing was the tile we used. Talk about stable! The floor looks great and there have been no problems at all. The only problem we had was there was a 1-1/4″ difference in the floor height of the bathroom and my hallway which has the same old long-leaf pine tongue and groove flooring. We needed a threshold that would account for the floor height differences but there was nothing on the market that you could just buy. That problem was solved by using the nicest-looking, straightest framing 2×4 I could find. My handyman took the door molding off, cut the 2×4 and molding to fit the opening and then created a lip to fit over the tile. We then beveled the top edges–one bevel on the bathroom side and one bevel on the hallway side. He used 3″ screws to screw the transition threshold to the wood floor underneath and also used a countersink drill bit so the screws wouldn’t show. I filled the holes with wood filler, stained and varnished the threshold and it looks beautiful. He created this threshold using only a circular saw. I was very impressed.

  256. Hi,

    Just gutted bathroom and took two closets out to make 50’s bathroom more of a normal size. Now 8×7, has tongue and groove subfloor, cut out old rotted area, replaced with 3/4 in plywood. sistered joists. Plumber says put down another 1/2in plywood, then backerboard then tile. Dont want to raise floor that much compared to hallway. wondered if backerboard is OK to put over original subfloor? Thanks,
    great site. Mark

  257. I suggest Schluter Ditra. I’ve used it now for several installs and it beats all other backer material. Well worth the price when you consider the time and back breaking work of using hardie backer or cement board. Don’t believe I’ll ever use those again. PS. make sure to follow the instructions explicitly. Fortified thinset to adhere the schluter to the floor and un-fortified to set the tile to the schluter. watch the video on schluters website.

  258. I’m trying to lay 24×24 tile upstairs on wood floor with 1/2 “backer board.the tile company says it is to heavy.wants to sell me 18× this correct?
    thanks Billy

  259. I want to rip up the tile in my master bathroom. We bought the house a couple years ago so the previous owner had the house built and he used OSB board for the subfloor then mortered and screwed down another layer of OSB and tiled on top. I know I can remove the tile but since this is in a bathroom I also want to remove that top layer of OSB. I am looking for a good, efficient way to get that top layer of OSB off so I can use a cement board then tile. What is the best way to remove this layer of OSB without destroying the subfloor?

  260. I’m planning to tile my foyer. The subfloor is 19/32″ exterior grade board and I plan to put down 5/16″ plywood on top of it and then use ditra (1/8″) on top of all this. Tiles are 13″x13″ and are 5/16″ thick. I am trying to bring this tile floor level with hardwood on stairs (3/4″).
    My question is should I account for the thinset used under tiles (on top of ditra) or not? If yes, how much? Is 5/16″ plywood enough?

  261. I just had an addition put on the back of my house. the contractor wants me to turn the heat on 24hrs before they come lay porcelin tile. Is this really necessary? i live in Richmond,Va and the current outside temperature is 62-80 degrees.

  262. I am planning to tile my kitchen. I have to bring it level to hardwood floor in other rooms. Joists are 16″ O.C.. The subfloor is 19/32″ exterior grade board and I plan to install heated wire mesh (1/8″) on it and then put 3/16″ modified mortar. Lay ditra on top and then install 13″x13″ tiles, that are 5/16″ thick. My question is, would this be strong enough to hold tiles? Thanks!

  263. I live in South Louisiana and having moisture problems. do you recommend ceremic tile on a house on blocks? any tips? Is the cement board a moisture barrior?

  264. It has been a year and 5 months since I ripped out my kitchen and I have yet to find the right man for the job. The contractor I am working with now laid cement board right over the floor joists. He put a lot of screws in the joists before he put the cement board down and used a thin set to glue it down solid. I asked him if plywood should be laid first and he said that is it strong and fine without it. I am greatly concerned because it is a high traffic area and the man from the tile store said you want at least 1 1/4 when the floor is all said and done including tile. I am greatly concerned about this matter and need the right answers. Funding is getting low and I don’t want the tile to move or crack in time after spending all that money. Is this not the right way? Can it be done this way? The floor is already down this way minus the tile. I would greatly appreciate any advise.

  265. You have 2 questions. #1 Hardwood = when installing flooring you always need to consider the stability of the “structure” that will be under the tile. ie. is the hardwood 3/4 solid and on top of a plywood sub-floor? Is the hardwood flooring securely attached to the sub-floor or does it “squeek” when you walk on it ? When installing tile to any type of wood substrate it requires a “backer” material. There are 3 types, cement backer, hardi backer, and the “schluter” system. While schluter is more expensive, it is thinner and uncouples the tile from the hardwood which will dramatically reduce the possibility of cracked grout joints. #2, when you say “laminate”, I’m making the assumption you have a “floating” floor system in which you should NEVER tile over.

  266. I have two layers of plywood under the current vinyl flooring. Would it be advisable to remove one of the plywood and install the cement floor before setting the tiles? One contractor is recommending that we tile right on top of the vinyl floor which I am not too keen on doing.

  267. I currently have a tile floor in kitchen, with a large center island where the sink and dishwasher are. I am planning a floating bamboo floor on top of the tile. I asked about the option of removing the tile to install the floor and was told that the island would need to be moved to remove the tile under it (I don’t even know if there is tile under the island). Can’t I just have the floor installed up to the island? I really do not want to have the island moved as it is too large and has a quartz counter (very heavy). Thank you in advance.

  268. I want to tile my front entryway (a space thats about 4’x4′). I have put down a sufficient thickness of plywood, but there is some variation to the grade. I was thinking of pouring a thin layer of self leveling cement, and putting the backer board on top of this. Doe’s anyone see any problems with this?

  269. I am having new tile put in the entryway into my home. The tore out the old tile today and there is a ton of old mortar. They claim it is okay to put new mortar over it and put the new tile down…I am not comfortable with this, what is your suggestion? It is not concrete underneath, I am assuming it is plywood underneath old mortar.

  270. I’m putting down a porcelain tile floor 12″ x12″ tiles on concrete plus a heating coil this room is at grade it has solid cement 30 years old and is 300 square feet frost is in my area the room is inclosed with sliding patio doors. My question is that I made a mistake I think. I put Delta MS for foundation walls not the floor Delta product and then I put 5/8 tongue and groove particle board on top of the concrete and fastened it down with tap con screws this was to simulate the DriCore panels because I didn’t want to loose my heat through the concrete and then I wanted to tile on top of the particle board the problem is that the adhesive I was told will not stick to the particle board what should I do rip it up or put backer board on top it seems pretty solid as the MS is on the concrete please advise I would greatly appreciate an answer ASAP thanks again Don

  271. We have a heartbreaking situation in a new home. We have concrete pavers installed over about 1600 sq. feet of our main floor area. We’ve been living here for just a few weeks, and already our tile floor grout is cracking and chipping away. We can feel the floor give in some spots. After researching many a site including this one, we have concluded that the subfloor is the problem – our contractor used 3/4″ OSB or particle board of some kind. My husband questioned him about this at the time and was told that it was just as strong as plywood. On top of this, the tiler simply used a cement board. Of course, we now know that the subfloor just isn’t solid enough – and that is allowing movement. What we are wondering is if there is anyway that we can strengthen/support it from below? We have not yet finished our basement, and so there is access from below. Our pavers are installed under every appliance, cabinet, piece of molding – and even the kitchen island which is topped by a 5×8 (heavy) sheet of quartz counter top – it would be a nightmare to try to take everything out and pull up the pavers in order to start again.

  272. Dear sure or madam, My name is Sophal and I’m planing to install a tile name Premium Porcelain 18×18 on my kichen and family room floor. My question is, after I remove the 1/2 inch particle boards can I just replace with the 1/2 backer board on top of 2×6 wood surface floor then install the tile? or I have to put the flywood before I put backer board? Please help??

    Thank you very much for your time and help in advance.

  273. 1. what are the steps for preparing a wooden floor for a ceramic floor?

    2. will vinyl or plastic be needed under the hardi-board?

  274. HELP!!! We are wanting to put in 20″ poreclain tiles on our complete upstairs (4 bedrooms & 2 bathrooms) & on our stairs but we were told it is dangerous because of the weight, ceiling cracking, movement/shifting…even with backerboard. The stairs could also be too slippery. We were advised to use wood instead & tile only in the bathrooms. The problem with wood is all the scratching, cleaning & upkeep.
    We REALLY need some expert advise!!!

  275. you don’t mention that the manufacturer’s recommendations for installing durok are (1) not to screw into the joists, use (2)appropriate fasteners and to use thinset between plywood and backer.

    • Hi Fred,
      I read the installation instructions for both Durock and Hardi backer board, and couldn’t find anything about not screwing it into joists, though since you’re supposed to attach it every 8″ a lot of the screws or nails would by necessity not be in joists anyway. Good point about applying thin-set to the subfloor and adhering the cement backer board to it. We’ve recommended that in other posts on our site but not this one, so I added it to the article.
      Thanks for the feedback!

  276. In a rent house with varnished hardwood floors where dogs were kept need refinishing. Almost all paint worn off. How can I refinish short of resanding?

  277. I would like to put slate in an upstairs bathroom. We currently have Real 2×12″ floor joists (not 2×2″ with OSB centers) and 3/4″ plywood sub floor. when we tiled our kitchen we added an extra 3/4″ plywood sub floor and fastened it ever 4″. My question is when installing slate, will we need to add the extra subfloor? Being a rock substance slate shouldn’t crack… should it?

  278. Hi,
    The tiles have been placed on my kitchen floor already, and a membrane which was installed underneath due to the tiles are 30 cm x 60 cm to prevent cracking. As the tiles were layed there is a beam, not noticed, and is making 4 tiles in the kitchen uneven and a teeter totter effect is happening, what can be done to? can more pre mixed thin set mortar be used underneath? Also the tilers used the mortar as grout and did not clean the tiles? how can I clean that…. and thirdly can I add grout to the mortar (the grout is uneven)? thank you in advance.

  279. Why do I need to use thinset between the subflooring and backerboard? My house is only 12 years old and the subfloor is good. I have just screwed the backerboard to the subfloor before with no problems.

    • Hi Ken,
      While many tilers simply screw or nail the cement backer board down to the subfloor, it will provide a more solid surface if thin-set adhesive is used to adhere the backer board to the plywood subfloor.

  280. I am DIY’ing my condo kitchen (15 yrs old, steel and masonry high density building).

    The kitchen floor was originally a vinyl tile directly adhered to concrete. The previous owner installed hardwood flooring on 1/2″ plywood base throughout the condo except in the kitchen. In the kitchen they adhered a 3/8″ engineered floor directly to the vinyl that mimics the hardwood and abutted to the toekicks. The result was a 1 and 3/8″ drop into the kitchen with no visual indication that this was a different floor.

    I would like to lay porcelain tile in the kitchen. My question is would a 3/4″ plywood subfloor, adhered and mechanically fastened to the engineered floor, be an adequate base? Will I also require a moisture barrier or concrete board for the tile bed? Accounting for the tile I have reduced my drop into the room to 1/4″.

    Should I be applying a 1/4″ mortar based (poured or board) sub to this mix? Or, given a compatible thinset, could I proceed with laying tile on my existing subfloor?

  281. We have radiant heat in our slab and are planning to lay porcelain tile over it. We need to have as little interference with the heat conduction as possible, and we are concerned that settling and cracks over the years have made the floor uneven. Two competing interests. How do you recommend we prepare the floor for the tile given those two things. I know this thread was started a long time ago. I appreciate your patience with me. I really need your input. No one I have talked to truly has experience with old-fashioned radiant heat in a cement slab. Thanks!

  282. I am planning to put tiles as flooring covering for an exterior wood balcony. It is a wood balcony of a 2 story house with walkout. There are wood beams supporting my balcony and I am afraid if not too heavy to put tiles on existing plywood exterior balcony. Do I have other better options or do I risk anything using tiles? The balcony is covered with the top level ceiling but open in laterals outdoor. Do you advice me to put tiles on existing plywood with cement/mortar or there are better options? Another balcony I have now has some stained duradeck vinyl…

  283. Help Please,
    I made a mistake of putting vinyl floor on top of wood floors and years later durock and ceramic tile attached to durock. Now, I want to restore my old oak wood floor. How can Ido it? Will it possible? Please advise.
    Thanks Much!!!

  284. I was needing some help. I was wanting to lay tile in my kitchen, but was needing to know if my subfloor could support it and the added weight. What are the minimum flooring measurements for the plywood and joists that are recommended?

  285. I would like to know if I place 1/2 ” plywood and then 1/4″ backer board or wonder board down on top of the existing 3/4″ particle board the builder used on the floors. Will this be strong for my 18″ x 18″x 1/2″ thick travertine tile I want to use. I will be putting down a skim coat under the backer board on top of the plywood and screwed down also before I lay the tile.

  286. I have an old style “mud” floor in my 2nd floor bathroom which is failing and needs to be demo’ed and replaced. From the scarce info I can find on this old technique of creating a floor, it was created by laying slats (akin to Lathe and Plaster for walls)and then covering it over with construction felt ( I think that’s what it’s called) and mesh then “pouring” the floor. Is there a material that would work better today than the slats, say 3/4 ply, under the construction felt, to make this process just a little less complicated? No work has begun because of lack of definitive information.

  287. We are converting a garage to a room in a vacation home. The contractor is leveling the existing concrete garage floor with wood. We intend to lay tile for the final flooring. Can that tile be successfully applied on top of the plywood subfloor or what do you suggest? One flooring contractor said the floor should be leveled with poured concrete or the tile and grout will crack due to expansion and contraction since we do not heat the space year round.

  288. We would like to install tile on the second floor and also the stairs; however, we removed the carpet and as most homes in California the sub floor is the wood and we are concern that it may be too noisy. Do you know if it gets really loud as to when people walks and/or talks? The tile person said it would but not much? Also, it seems that carpet is more appealing to most people when it comes to second floor (bedrooms and stairs), but since this is a rental property it is rather costly to continue replacing the carpet and the tile it is way more durable, suggestions?

  289. Have 8 x10 back hall with laundry area. Had to remove old ceramic tile due to washing machine leak. After removing tile, it was put over sub floor. Have only half inch of space for door to open. What can I put in that is good, durable, etc. in the area? Want it to look good.

  290. I am going to lay ceramic tile in the “dog room”, can I lay this directly on the plywood sub-floor? I live in such a remote area and have no pick up to get the concrete backer. Any advice would be appreciated!

  291. our house is two story, upper level is around 80m2(861 sq.foot) is it safe to change the carpet into porcelain from a weight point of view as adding load to the carrying wood. i.e. would it be structurally fit to add this weight.
    baring in mind box of porcelain says net weight 33kg(72 pound) for 1.75m2(18.8 sq.foot) i.e 3.83 pound/sq.foot which is adding around 3300 pound to second level.

  292. I just put an addition on my house now I’m going to finish my ensuite bathroom my question is do I put hardieboard over the entire sub floor or just where I’m going to tile the floor or do I put in under the shower and tub.thx

  293. Please could you advise me on laying tiles over tiles over a sub ground floor the tiles that are already down are travatine and some are cracked and not compleatly level in some areas thanks

  294. After many years we are going to rip up our carpet upstairs. When I started to remove a small area I noticed a subfloor of approximately 1/2 inch. On the edge by the stairs I can see part of the original flooring. Wood with a darker brown stain and poly. Why would someone cover this up? What would be the chance that, that floor went through out our upstairs? Should I try and pull some up or just lay the new floor on this subfloor?

  295. We are installing large porcelain tile (16″) in our bedroom. Subflooring is plywood. My husband has gone under the house and determined that our joist spans are HUGE! Not the standard 16″. More like 24 to 30 something which causes the floor to bow wen we walk on it. Should we stabilize between the joists before laying/installing the cement backing and doing the tile work? Our concern is getting it all laid down, installed and then having the tiles/mortar crack when we walk across the floor or put our furniture in the room.

  296. I would like to just install 3/4 inch plywood over the existing mobile home particle board floor, my concern is what about supporting the plywood at the wall

  297. Please could you advise me about laying tiles over tiles on a sub floor? Sub floor is floorboards half inch ply on top.
    thank you

  298. First, I love your show! This site (and the computer) is new to me, I’m not sure where to ask my question but I’d like to ask how to paint over paneling. Is there any way to do this that the paint will stick? I don’t know how paneling is attached to the wall, how to get it off OR what might be behind it – I believe the room the paneling is in used to be an ‘outside room’, perhaps brick on one side and I don’t know what on the other 3 sides. Thank You!

  299. Hello, I have just removed the tile from my sub floor, areas of the mortar sub floor crumbled as the tile came up and were stuck to the tile which left the area of sub floor in poor shape around the shower, can i replace this section of sub floor and leave the rest that is in good shape, or do i need to replace the whole thing? It also appears that there is a small amount of water damage and soft floor boards exposed underneath at the entrance of the shower. what is my next step?

  300. Hello Party people!

    Ok,so i recently removed 5 (yes 5) layers of vinyl flooring from my kitchen in preparation to lay down tile. after removing the base boards i noticed a small gap around the perimeter of the kitchen. Would it be ok for me to lay down hardi board and slide it under the wall a bit and then tile up to 1/4 inch around the perimeter or is hardi under the wall an no no. There is enough space for the hardi to slide in easily.

  301. Hi. We’re completely renovating the kitchen in our 1938 house. Everything (cabinet, appliances) have been removed. Kitchen was last remodeled about 30 years ago with ceramic tiles over plywood. We’ve removed the tiles and plywood, and are down to 3 1/2 wide southern yellow pine tongue & groove planks (i think 1/2 thick). Those planks are installed over diagonal wooden planks installed the joists. We also removed all of the paper from an old vinyl floor that was adhered to the pine boards.

    We had considered refinishing the pine floor, but it’s beyond repair, so we’re going to re-tile.

    So here’s my question: can we install the tile directly on the pine floor, or do i need to first lay backer board? The floor seems very sturdy and secure, so i’m not sure why they laid plywood under the tiles previously. It may just have been to cover the vinyl paper. Thanks.

  302. I have wooden subfloor under my shower. Do I follow the same procedures as the video above for a shower or do I need to put some other type of waterproofing on the floor?

  303. i removed my hardwood floors throughout the house because of a flood. i also removed the subfloor all paper and glue’ my . i am not putting the hardwood back, so i need to know what is the best method to build the floors up to lay tile or laminate. the foundation is concrete

  304. I had the sliding door removed between the living room and lanai along with the metal runner it ran on. Now I have a gap where the runner was with Berber carpeting on either side. A couple of handymen I’ve hired had ideas on what to put in the gap and it’s been a disaster. I just recently moved to Florida from the west coast and am on a low, set income. I can’t afford to keep paying people to fix the problem, that don’t have a clue what they’re doing. I thought you might be able to tell me what would be the best idea, so I can get it done properly once and for all. Thank you in advance for any advice you can offer!

    P.S. The length is a 11 10″, and width about 5″.


    • Dear Judy, we would love to give you some advice on this. But we would need more information.

      If there’s any way you could snap a photo of the area it would help us greatly in providing a good answer.



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