How to Seal a Basement Egress Window

  • 2-4 hours
  • Beginner
  • 25-50
What You'll Need
Putty Knife
Urethane foam
Soapy water

If your home came with a ready-made basement egress window, then you may be considering sealing this up, in order to prevent draughts, and to ensure that intruders cannot gain access to your home through this route. Your basement egress window is more susceptible to cold, allowing draughts, moisture and frost to get in through small cracks in the frame of the window.

In addition, the cement caulking can deteriorate, or even be penetrated by insects. In order to reduce these incidents, you can seal the basement window, and prevent cold from invading the basement. With some basic home improvement skills, and by following some simple guidelines, you can get this project done quickly and easily.

Step 1 - Clean the Windows

Before you start to seal the windows, they will need to be totally clean. This is to ensure that dirt and debris doesn't become trapped under the caulking or foam, as it can erode over time, and leave gaps where cold can penetrate. Firstly, remove any hanging materials such as curtains from the inside of the windows. Then, using soapy water, wash around the glass, and clean the wooden frame at the same time. Make sure that you thoroughly wash both sides of the windows, and then leave to dry.

Step 2 - Remove Old Caulk

Before the windows have dried properly, you should begin chipping away at the old caulking, You may want to wear safety gloves while you are using the putty knife to hack the caulk off, as the knife will probably slip a few times, and skinned knuckles can really hurt. Brush down the window with some soapy water and a damp cloth, removing any traces of the caulk.

Step 3 - Examine the Frame

With the caulk removed, go around the edge of the window, and look for any large chips, cracks or holes in the fabric of the window. If you see any, then you should try and fill this out using some expanding, or urethane, foam. When the foam has settled on the desired point, leave it to dry before you carry on with the next steps.

Step 4 - Add More Caulk

Once the old caulk is gone, and the window frame is completely dry, you can add a new layer of caulk to the edge of the window frame. Spread it over thickly with your putty knife, ensuring that it covers all of the nooks and crannies where air might be able to get into the house. Begin at the top and work your way slowly to the bottom, trying to caulk as much as possible in one go. You may prefer to use a caulking gun, which can be used to apply a constant stream of caulk.

Step 5 - Finishing

Once the caulking has been added all the way around, leave it to dry for quarter of an hour, and then check to ensure that there are no gaps in the line of caulk. Once you have mended any holes, you can re-install your curtains on the inside of the windows.