3-Step Guide To Filling In Small Cracks And Gaps Around Your Home's Windows

14 May 2015
 Categories: Construction & Contractors, Articles


If you have small cracks and gaps around your windows, you may start seeing an increase in your heating and cooling bill because of the air leakage. Filling in those areas could help you save up to 25% on your bill. If you would like to repair the damage yourself, use the following three-step guide for filling in the cracks and gaps using caulk and spray foam insulation.

Step 1:  Clean Out And Sand The Cracks And Gaps

The first step involves cleaning out any loose debris inside the cracks and gaps. The area also needs to be sanded. Doing this step prepares the surface for the caulk or spray foam insulation, giving either one of them a sound, clean surface to adhere to. This helps prevent the materials from cracking or coming out after they dry or set up.

For this step, you will need a utility knife, a flathead screwdriver, 800-grit sandpaper, and a soft paintbrush. This grit cleans and smooths the surface without gouging the wood or vinyl of the window frames.

Use the utility knife inside the cracks to remove any flaking paint or drywall. Run it along the entire length to ensure you find every piece. Then, use the paintbrush to brush any dust or debris that still remains.

For the small gaps, use the flathead screwdriver. If you find any large, loose pieces, use the end to pry them out. Again, use the paintbrush to clean out any loose debris.

After you have cleaned out the indentations, use the sandpaper to smooth the inside surfaces. Then, sand about an inch around the outside of the cracks and gaps. Once this is done, go on to step two.

Step 2:  Fill In Small Cracks With Caulk

In this next step, you will be filling in the small cracks with caulk. For this, you will need a tube of silicone caulk, a caulking gun, and a small putty knife.

Starting about a half inch at one end of a crack, start applying a thin strip of caulk. Use a slow, steady pace as you follow the line of the crack until you reach the other end and stop a half inch past it.

Use the putty knife to run along the caulk, applying enough pressure to press the caulk into the crack without removing it. Then, let the caulk set up for an hour.

Repeat the above for all of the cracks. Then, apply a second thin layer to add an extra protective barrier. Once all of the cracks have two layers, go on to the third step.

Step 3:  Use Spray Foam Insulation In Small Gaps

Now that you have filled in the cracks, it is time to turn your attention to the small gaps around the windows' frames. For this step, you will need a can of spray foam insulation with an applicator straw attached to help you direct the flow of the foam.

Starting at the inner edge of one of the gaps, insert the straw. Apply light pressure to the nozzle and steadily fill in the gap. As you spray the foam into the hole, it will expand to fill it up. Once you have reached the other end, let the foam set up for an hour.

Repeat the application for the rest of the gaps. Then, inspect each one to see if any holes need to be filled in with a small amount of insulation.

The above guide is only meant for filling in smaller gaps around your windows. If you have large gaps, you may want to contact a contractor from a site like http://biosenv.com/ who specializes in installing spray foam insulation. They can determine the severity of the gaps and recommend the next course of action, from filling in small areas to installing foam deeper inside your walls.