How To Caulk Effectively

How To Caulk Effectively

Life seemed much simpler when the hardware store carried only a couple of kinds of caulk. Now, home centers dedicate an entire aisle to caulk. As a result, confusion reigns when it’s time to do a very simple job, but caulking doesn’t need to be complicated.

Other than specialized caulk for specific tasks, like patching gutters, I’ve found that a high-quality siliconized acrylic-latex caulk is an excellent choice for almost all interior and exterior uses. That’s what my crews use most of the time.

I know people who have paid $5 to $6 per tube for 100 percent silicone caulk and filled every crevice with it they could find. It was only at the end of the job that they discovered that paint won’t stick to silicone caulk.

They were left with a job that could have looked much better. On the other hand, acrylic latex caulk can be painted, cleans up with water, and is almost half the price of 100 percent silicone.

But there are a few exceptions to that rule. You should use silicone tub-and-tile caulk in the bathroom because it resists mildew and doesn’t shrink. For gaps of 1/4″ or more, or where the caulk must join dissimilar materials, use urethane caulk because it’s more elastic.

For joints more than 3/8″ wide, pack the crack with foam backer rod before applying caulk so the seam won’t crack later. You can bridge gaps up to 1″ wide with a combination of backer rod and urethane caulk, but don’t try to caulk anything wider than that.

Caulking siding joints.
When applying caulk, more is not always better. If you apply too much caulk to a joint and then smooth it out with a finger, the caulk tends to spread onto adjoining surfaces. This is just plain unattractive. And outdoors, this thin layer of caulk will weather differently than the rest of the seam.

Getting an even bead of caulk is easier with a high-quality caulk gun, so skip the 99-cent special. Just remember to cut off the plastic tip at a 45-degree angle, which will help you apply the caulk evenly.

Another tip: Take advantage of the many colors that caulk now comes in. They help paint cover much better than regular old white.

Besides caulking around tubs and sinks (where you are protecting against water damage), don’t forget to seal around window and doors, and any crack that leads to the outside. I tell people that if they were to add up all the cracks and holes in a typical 20-year-old house, it would amount to a 3’x 3′ space, which would be just like leaving a window open all the time.

Previous articleHome Problems and Solutions
Next articleHome Automation
Backed by his 40-year remodeling career, Danny served as the home improvement expert for CBS’s The Early Show and The Weather Channel for more than a decade. His extensive hands-on experience and understanding of the industry make him the go-to source for all things having to do with the home – from advice on simple repairs, to complete remodels, to helping homeowners prepare their homes for extreme weather and seasons.


  1. This is an excellent article. “If you can’t fix it, caulk it.” I aways say. An average carpenter comes out looking like a champ if he has the ability to caulk well, especially when remodeling older homes. Finding square, level and plumb is sometimes challenging and caulking helps projects to be more forgiving. One tip on how to save a bundle on caulking is to go to the big box stores and buy it in case lots. You still get the high quality products but often pay much less than the 5 or 6 bucks that it costs to buy one tube at a time. One trick I use for extra smooth beads is to use a wet finger to smooth the surface. A wet finger collects very little caulk while a dry rag seems to pick up way too much. I knew an old time master painter that used a wet paint brush to really smooth caulk beads nicely. In my experience, the best technique is to take your time and not overdo the size of the bead. You know you got it right when you are not taking off much caulk when smoothing with a wet finger. Too much caulk will definitely result in caulk squeezing past your finger and leaving wasteful, unsightly and messy ridges. If you have a cheap caulk gun, take it in your hand and throw it as far as you can. The caulk that you save with a quality tool will more than pay for the small investment. The aggravation factor will be much smaller as well. Don’t forget the clean rags, both wet and dry. Happy caulking.
    Ty the Handyman

  2. Yea, I am a single mother of five and I had to do some repairs myself after the Ike storm. I really like using my wet finger rather than a cloth. First you can see what you are doing, then your clean up is alot easier. PLEASE GET A GOOD GUN!!!!!!!! or STOP

    • You could go ahead and caulk now. Don’t wait too long before painting, however, as the caulk could begin to degrade or mildew.

  3. we have an older house covered with cedar board – we find the house very cold on windy days and believe that this is due to bad caulking on the outside. What is the best time of the year to caulk? and also is it better to have a professional company do this. we will are also planning to re-stain the cedar this coming summer Thank you for your reply.

    • Hi Joan,
      As long as the outside temperature is within the range recommended on the caulking, you can caulk any time of year, though it will set up faster in warm weather.

  4. Hi,

    I am in the middle of re-caulking my bathtub, and after I removed the old caulk, I found really huge gaps between the tile (tumbled stone) and the tub…also there was some wetness behind the old caulk and some mold.

    I have no idea where the wetness is coming from (I live in a coop apartment building), but I’m wondering if it’s because of the gaps (?) or a bad grout job (?). I can’t afford to redo the walls and the tile, and I need to shower, so can I just let it dry it overnight (with a fan) and re-caulk tomorrow?

    And if that is ok, how do I deal with the huge gaps? All the videos I see online are fixing what they call huge gaps, but seem like 1/4″ or less…my gap is more like an inch… 🙁

    Thanks for any help you can offer!

  5. I had a windowsill that was badly cracked and somewhat soft from weathering. I first sanded the sill and applied wood hardener (Minwax), then primed, then tried to fill the cracks with caulk but ended up (because of so many cracks and the uneven surface) both filling the cracks and actually coating the sill with the caulk (latex sealant). Is it a problem that the sill is actually coated with caulk? I tried to make it look as smooth as possible and sure looks better than the uneven and cracked sill.

  6. Hardware stores these days have so many different options of caulk. It’s just so hard to choose. While one might also applaud all the other options, while it’s a good thing, having so many options can also be troublesome. Choose wisely!


Please enter your comment!
Please enter your name here