How To Caulk Effectively
Interior, Painting & Finishing, Repairs and Installation by Danny Lipford

Life seemed much simpler when the hardware store carried only three 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 and seam 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 in. or more, or where the caulk must join dissimilar materials, use urethane caulk because it’s more elastic. For joints more than 3/8 in. wide, pack the crack with foam backer rod before applying caulk so the seam won’t crack later. And bridge gaps up to 1 in. with a combination of backer rod and urethane caulk, but don’t try to caulk anything wider than that.
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 3×3-ft. space, which would be just like leaving a window open all the time.
7 Comments on “How To Caulk Effectively”
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June 21st, 2007 at 18:22
[...] Fill the grooves with caulk [...]
June 21st, 2007 at 18:51
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
December 21st, 2008 at 11:27
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
February 10th, 2009 at 14:24
I am planning on repainting my house this spring or summer. There are several places that I know need caulking. Would it be best to do that now, or wait until right before I paint?

Ben Erickson Says:February 11th, 2009 at 08:37
You could go ahead and caulk now. Don’t wait too long before painting, however, as the caulk could begin to degrade or mildew.
November 29th, 2009 at 14:53
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.

Ben Erickson Says:November 30th, 2009 at 10:55
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.