How to Attach Extruded EPS Sheeting to Interior Basement Walls

Walk to one corner of the basement and measure the height of the wall, using a tape measure and, if needed, a stepladder.

Measure the height of one of the XEPS foam boards to determine if you will need to cut it to size. If the panel it too high, mark a cut line across the board, using a pencil. Cut along the pencil line with a utility knife.

Place the extruded expanded polystyrene foam board up to one wall of the basement and slide it into the corner as far as possible. Place a carpenter's level vertically on the side of the panel to make sure that it is level. If it is not level, insert wooden shims under the bottom edge of the foam board until the air bubble in the level is centered.

Measure and cut a second board. Place it against the wall next to the first panel. Ensure that it is level just as you did with the first foam board.

Place a wooden furring strip vertically in the channel created between the two panels. Secure the wooden strip every 12 inches, using masonry screws and a power drill.

Attach additional XEPS foam panels and wooden strips until all the walls in the basement are covered.

Apply strips of fiberglass tape over all of the joints between the wooden strips and the foam board to prevent air from seeping between the tiny cracks.