How to Install Foam Board Insulation Siding

Hold a sheet of foam insulation board to the side of the building directly over the existing siding or sheathing. Hold the sheet to the edge of the exterior wall. Mark the location of doorways, windows or places where pipes protrude from the exterior of the building on the sheet with a pencil. Remove the sheet from the wall temporarily. Use a measuring tape to determine the location of openings that were covered completely by the sheet.

Cut through the foam sheet using a straight edge and a utility knife on your marks indicating window and door and window openings. Remove and discard the waste from the sheet.

Apply a bead of caulking around doorways and window openings just prior to the installation of the foam sheet. Raise the sheet into position. Press the edges of the sheet around any openings into the caulk.

Secure the sheet to the building with ring shank nails that have a plastic cap to prevent air intrusion around the nail hole. Use nails that are long enough to penetrate the existing siding underneath at least 1 inch. Drive the nails in with a hammer until the plastic cap makes contact with the foam sheet. Do not drive the nail in too far or the foam sheet could be compromised, causing air intrusion. Install nails every 12 inches around the perimeter of the sheet. Drive nails every 16 inches otherwise. Do not use ring shank nails around door or window openings.

Drive a roofing nail through the foam sheet every 8 inches around the circumference of window and door openings. Keep the nails 3 inches from the corners of the opening to prevent splitting the sheet.

Secure multiple sheets along the exterior wall of the building by butting the sheets together and nailing them in the same fashion. Apply a bead of caulking on all seams and places where pipes protrude through the foam sheet. Apply strips of foam insulating tape over the joints and press it down with your hand.