Rigid Foam Sheathing Siding

3 benefits of rigid foam sheathing.

Rigid foam sheathing siding.

Thick narrow siding. More effective insulation with r values ranging from 3 6 to 8 0 rigid foam sheathing has much better insulation per inch than other materials i e. Use thicker siding patterns in widths of 8 203 mm or less. Moisture can get trapped between the siding and the foam leading to paint failure and causing clapboards to cup and curl.

Sheathing and penetrate framing a minimum 1 inches. Our house is 2x6 construction built in 1984 near milwaukee wi. Current pneumatic nailers have maximum fastener lengths of 3 to 3 5 which limits insulation thicknesses to 1 5 max 3 5 fastener to siding 1 embedment 3 5 0 5 1 5 1 5 max insulation therefore for insulation greater than 1 5 direct. The panels provide a continuous energy efficient surface.

The following recommendations are meant to minimize potential problems when cedar sidings are applied over rigid foam sheathing. Install rigid foam over or in place of plywood osb or other wall sheathing. Many houses built today have a double wall type of insulation with fiberglass batts fastened between the studs on the inside and rigid foam board over the wall sheathing on the outside. But if you use wood clapboard siding foam sheathing can cause trouble.

Plywood has an r value of 1 25 and fiberglass batts have an r value of 3 14. Rigid foam sheathing can cause moisture to accumulate on the back of siding and cause staining buckling and damage to finish coats. 2 in x 4 ft x 8 ft. This eliminates thermal bridging which is the energy lost through wall studs.

Insulated foam sheets are also used as an insulated sheathing underlayment for exterior siding. The cavity is stuffed with fiberglass then expanded foam sheathing followed by cedar board and batten siding.