DIY Network

How to Seal Gaps in a Home

Learn how to create a natural barrier against penetrating winds by sealing three common air gaps around the home with these easy step-by-step instructions.

More in Remodeling

  • Time

    Several Weekends

  • Price Range

    $100 - $250

  • Difficulty



Step 1: Fix the Air Leaks

At the fire box, determine the source of the air leaks. Use expanding foam and seal off all of these openings.

Note: Make sure to fill the voids to seal the leaks.
To fix the air leaks around the switches and outlets, use a screwdriver and remove the cover plate.

Install foam sealing gaskets that have been cut to size. If the gap is large enough, add some caulk to further seal the leak. Then simply replace the cover plate and screw down.

Step 2: Seal the Siding Gaps

Remove the siding in the problem area. Install a solid sheet of aluminum above the vented soffits. Nail the sheet in place.

To reinforce the wind barrier, add a second layer of tar paper (Image 1). Staple the sheet in place.

With the double barrier secured, replace the siding. Nail the siding down leaving about a 1/16" to allow the siding to expand and contract (Image 2).

Place a nail every 16" or so to firmly secure the siding in place. Place the next piece of siding and lock into place. Nail down and repeat.

As an added wind barrier, place a bead of caulk at any gaps between the brick and the siding of the house. Use expanding foam to seal off the open ends of corner moldings.

Step 3: Install Window Flashing

Remove the window trim to expose the leak underneath. Use a flathead screwdriver or similar tool to help pry the board off. Measure and cut the piece of metal flashing to size using tin snips.

Lay a bead of silicone (Image 1) along the edges of the exposed trim beneath the window and put the flashing in place.

Add an additional amount of sealant on top of the piece of flashing (Image 2) to allow the trim to adhere. Once the trim is back in place, seal the edges with another bead of silicone.