Insulate Between the Interior Window Trim and Wall

Step 1: Remove Trim

One of the best ways to seal drafty windows is to insulate around them. Remove interior trim around the window so you can access the space between the frame and the wall. First, cut through any dried paint along the edge of the trim with a utility knife. Then slide a flexible 3-inch putty knife behind the trim by a nail and pry out slightly. With the knife in place, wedge in a pry bar and pry the trim out an inch. If it seems as if the trim is about to crack, insert a second putty knife between the pry bar and the trim. Move to the next nail and repeat. Continue prying out the trim a little at a time down its length. Then go back to the beginning and pull the trim off.

BONUS TIP: You’ll need to use new nails when you reinstall the trim. To remove the old nails, don’t pull them back through the front of the trim. They might splinter the wood. Instead, pull them through the back using pliers. Use just enough pressure to pull the nails to avoid cutting them off. If one breaks off, use nippers to cut it as close as possible to the wood and leave it. That nub will just bury itself in the drywall when you reinstall the baseboard.

Step 2: Remove Insulation

Pull out any loose insulation in the gap between the wall and the frame.

Step 3: Add New Insulation

Apply DAP No-Warp Foam in the gap. First, make sure the surface is clean of debris. Then shake the can, hold it upside down and slowly pull the trigger to release the foam. Fill no more than 1/3 full; the foam will expand to fill the gap for an insulating seal. Because it exerts very little pressure as it cures, it won’t bow or warp the window frame.

Step 4: Remove Excess Insulation

After the foam has dried, use a utility knife to cut away any excess. Then reattach the trim.

Step 5: Seal Gaps

Clean out any debris in the gaps between the trim and the wall. Use DAP® ALEX FLEX® Premium Molding & Trim Sealant to fill any gaps or cracks. It’s easy to apply and smooth, is low in odor, cleans up with water and is paintable in just 30 minutes. Cut the cartridge nozzle at a 45-degree angle to the desired bead size. Insert the cartridge into a caulk gun. Slowly squeeze the trigger of the caulk gun to apply the sealant to the gap or crack, and tool or smooth immediately, if needed, with a finishing tool. Wait 30 minutes to paint.

Seal Gaps Around Exterior Windows

Step 1: Remove Old Sealant

Remove old sealants between the window trim and siding with a putty knife. Clean out any debris from the areas to be sealed so the sealant will adhere properly.

Step 2: Apply New Sealant

Fill gaps or cracks with DAP DYNAFLEX 230 Premium Indoor/Outdoor Sealant. It’s silicone tough, 100% waterproof and weatherpoof and ready for paint in two hours. Cut the nozzle of the cartridge at a 45-degree angle at the desired bead size. Load the cartridge into a caulk gun and squeeze the trigger, using steady pressure as you move along.

Temporarily Seal Drafty Windows and Doors to

Improve Comfort and Energy Efficiency

Step 1: Use Temporary, Removable Sealant

Use DAP DRAFT ATTACK Original Removable Weatherstripping Sealant. It applies easily like a caulk to provide a clear, temporary, waterproof and weatherproof seal. Cut the nozzle at a 45-degree angle to the desired bead size, puncture the inner foil seal and insert into a caulk gun. Be sure you don’t seal fire exits.

Step 2: Apply Sealant

Wipe away any debris from the surface where you want to seal—for example, where the window meets the sill. Fill the gap but don’t tool it. Make sure you provide adequate ventilation when applying the sealant.

Step 3: Remove Sealant

When you’re ready, you can easily remove the sealant up to one year after it has been applied. Just pull up one end and easily peel it away from the surface. Then wipe the area clean of any residue with mineral spirits or rubbing alcohol.