Tiling Over a Tile Floor: What You Should Know

You can lay new tile directly over an old tile floor, but only if the existing surface is flat, secure, and free from major cracks or movement. This approach can save you time and demo costs, but it comes with some trade-offs — especially when it comes to floor height and prep work.

Expect to spend between $9 and $20 per square foot, including materials and labor. For a standard 100-square-foot bathroom, that’s about $900 to $2,000 total. And it’ll cost more if your layout is complicated or you need significant floor leveling.

The biggest challenge isn’t the tiling itself — it’s making sure the original tile is stable and properly prepped. You’ll need to rough up the surface, apply a bonding agent, and fill old grout lines with a leveling compound to create a smooth, flat surface for the new tile. And yes, you’ll probably have to trim doors and pull the toilet if you’re working in a bathroom.

Done right, tiling over tile is a durable, cost-effective update. But if you skip steps or rush prep work, you risk cracked tiles and wasted money down the road. In this guide, we’ll show you exactly how to do it the right way — and when you should call in a pro.

Before You Lay Tile Over Tile: Key Considerations

Installing tile over an existing tile floor is a real time-saver — no demolition, no hauling away debris. But it only works if the original tile is in solid shape. That means no major cracks, no loose tiles, and no signs of shifting or water damage.

Before you dive in, here are the key things to check:

• Surface condition: The existing tile must be firmly attached and level. Any loose tiles should be removed and re-secured with thinset. Fill missing tiles with leveling compound so the entire floor is flat and smooth.
• Height issues: Adding a second layer of tile will raise the floor, usually by 1/2 inch or more. That can affect baseboards, transitions to other rooms, and whether doors still swing freely. You may need to trim door bottoms or adjust thresholds.
• Plumbing fixtures: In bathrooms, remove the toilet before tiling. You’ll likely need longer closet bolts for the toilet flange to match the new floor height.
• Subfloor strength: Make sure your subfloor can support the added weight — especially in older homes or upstairs bathrooms. Cement board underlayment isn’t needed here, but if there’s noticeable flex in the floor, this may not be a good candidate for tile-over-tile.

How to Install Tile Over Tile Floors

Here’s the right way to do it — shortcuts will only lead to cracked tiles and wasted money.

1. Clean thoroughly: Start by degreasing and scrubbing the old tile. Any dirt or residue can prevent good adhesion.
2. Cut door jambs: Use a jamb saw or handsaw with a spacer block to trim the bottoms of door casings so the new tile slides under cleanly.
3. Rough up the surface: Sand the old tile with 100-grit sandpaper to create a better grip for bonding primer and thinset.
4. Apply a bonding primer: This helps the new thinset stick to the old glazed surface.
5. Level the surface: Mix and pour a floor-leveling compound to fill in old grout lines and smooth out any low spots. Let it dry completely.
6. Plan your layout: Use chalk lines to mark straight layout lines along the longest wall or key reference points in the room.
7. Set the tile: Apply thinset with a notched trowel and press new tiles firmly into place. Use spacers to keep your lines consistent.
8. Grout and finish: Once the tiles are dry (usually 24 hours), remove spacers and grout the joints. Use a rubber float to work grout into the lines and a damp sponge to clean the excess.

Final Thoughts

Tiling over tile can be a smart, efficient upgrade — but only if the existing floor is solid and the prep work is done right. Skipping steps or ignoring height and leveling issues will lead to costly problems down the line.

If your current tile is stable and your layout allows for the added height, this project can save you both time and money. But when in doubt, bring in a pro to assess the floor — it’s better to get it right the first time than to redo the job later.

Further Information

• How to Lay a Tile Floor (article)
• How to Tile over Hardwood Flooring (article)
• How to Tile Over Vinyl Flooring (article)
• Installing Tile Over a Wood Subfloor (article)