Window Seal Repair: How to Reseal Windows

Lead Image for Window Seal Repair: How to Reseal Windows
  • 1-4 hours
  • Beginner
  • 10-25
What You'll Need
Caulking Gun
Putty Knife

Heating your home for the winter costs a lot of money and that's why window seal repair is so important. Windows will always let a certain amount of heat escape because of gaps around the frames. That's a source of both wasted heat and money. You will need to learn how to re-seal windows to make them much more efficient. This will be even more important if you are repairing older style houses which often have much less efficient windows.

There are a number of different tools that you will require to seal windows however the project itself is actually pretty easy. With the right tools and materials, this project should only take you a couple of hours at most.


First, you will need to inspect the area around your windows and doors to make sure that they are free of gaps. Also, spend the time to check that the window frames themselves are in good repair. The newer your home is, the less likely they are to leak. Even new homes can suffer from leaky windows, however, which can affect their energy efficiency. Take a close look at where the frames of your windows and doors meet the siding on your house, if there are any open gaps then these will be something you need to look at.

Preparing the Gaps

The gaps will need to be prepared so that you are able to work on them. If there is any loose or cracked caulking then this will need to be picked out using a putty knife or other knife. Now cut the end off the caulking nozzle using a pair of scissors and put it into the caulking gun.

Filling the Gap

If you are working with large gaps, then you might first need to fill these with foam filler before starting to use any caulking. The caulking can then be used to fill the surface of the gap. Try to apply a smooth even bead of caulking so that it is as neat as possible. Remember to do it all around the window and not only in the locations that you can see. You should also caulk under the window sill to prevent air from escaping.


Now you can smooth out the caulking using a putty knife. This is done so that the caulking properly fills the entire gap. Pressing the caulking down in this way will also ensure that the caulking looks tidy.

Use a damp cloth to smooth down the caulking but be careful to make sure that you don't wipe away the caulking out of the gap. You could also dampen the tip of your finger and use this to smooth out the caulking.


If you chose paintable caulking then you will be able to paint the caulking as long as you wait for it to dry completely first.