How to Affix Foam Board Insulation to Wood

Use a tape measure to determine the length and width of the wall you’re covering with foam panels. Use the panel’s dimensions to plot out on a piece of paper the most efficient coverage of the wall using the fewest panels. You can place foam panels both vertically and horizontally, so find the placement orientation that’s best for your wall size. Add 10 percent to the total number of wall panels you’ve determined you'll need to allow for any mistakes in placement.

Cover the wood with a polyethylene vapor barrier to prevent the movement of water vapor through the wall and into the structure’s interior. Staple the barrier to the wall with a stapler every 12 inches. Wrap the barrier around the edges of windows and doors before stapling it in place to avoid any leaving any gaps around the openings.

Set the boards against the surface of the wall using the predetermined orientation so that it lies flush. Nail the board into place using cap nails placed every 12 inches on center. Be careful not to indent or otherwise damage the board during installation.

Butt the next board against the first and nail it in place as well. Continue to nail the boards to the wood sheathing, cutting the rigid foam board where needed to fit a partial space, or around an opening in the wall, with a utility knife.

Tape over all of the joints between the boards with insulating tape to prevent heat escape from the gaps.