Caulk Cracking Around Window Trim – How To Fix

A few years back, I got new windows and while overall they have been pretty good, I noticed the caulking trim around the outside and corners would start to crack during the winter when it would get cold. These cracks were unsightly and allowed cold air to seep in.

The first solution I tried was a squeeze tube of caulk from the local hardware store. I just got one that was cheap for about $1 - $2. One thing to note is that is was an acrylic caulk which I found out later was not the best option. While this was ok for a short term solution, I found that before long, even as soon as a few weeks later, it would start cracking again.

I would try to add more caulk to seal up the new cracks and even tried painting over the caulk to give it an extra seal. Again it would be ok for a while but then as the temperature got cold, it would start to crack again. This was pretty annoying especially since the caulks said they had a multi-year guarantee.

So I did a little research and found it was recommended to use 100% silicone caulk. I looked at the ones I had been using and both were acrylic. One had a silicone blend but it was still acrylic. So I decided to look for the 100% silicone style.

At the hardware store, I found it and it was more expensive than the acrylic caulk, which is probably why I did not try it in the first place. I picked up a small squeeze tube of the 100% silicone caulk which was about $4.

At home, I started to scrape away the old caulk off the window trim. I used a few different tools such as different size flat head screwdrivers, small knife, and small scissors. They are probably not the most efficient tools for the job, but I did not want to buy a specialized tool just for this project.

After removing the old caulk and cleaning it up, I applied the 100% silicone sealant. I was surprised at how the texture was a lot more soft and fluid-like compared to the acrylic caulk which is more thick and has more of a chalky texture. The 100% silicone also seems to take longer to dry which can be helpful in case you make a mistake since it can be easily cleaned up.

So far it seems to be holding up well against the cold weather. I will plan to update this article with a long term review to see how well the 100% silicone holds up over time.

Update 1-25-19:
It has been a year and the weather has gotten cold once again. The silicone caulk held up better than the acrylic but it is starting to crack again because of the cold weather. I was able to apply some more to seal up the new cracks. I still had about half of the tube left but the plastic part around the nozzle broke in 2 places so now I can't really seal it closed properly. I managed to tape it closed so hopefully I can get at least one more use out of it. Overall it seems there is no good long term solution to prevent these cracks when it gets cold.