Exterior Rigid Foam Insulation R Value

Rigid foam insulation one option is to use polyurethane rigid foam insulation.

Exterior rigid foam insulation r value.

For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. Polyurethane rigid foam is a. House wrap is a good idea even with foam on the outside of the house. This foam board insulation is the rigid pink or blue panels that can be found at home centers in many different thicknesses.

Owens corning foamular 150 1 1 2 in. Foam insulation densities vary among closed cell vs open cell forms. For a 1 in thick 4 8 panel comes unfaced or with a number of different plastic facings. Closed cell foams are more dense and rigid typically about 2 lb cu.

This foam board insulation is available with straight or tongue and groove edges to help limit air movement. C or thermal conductance of these materials is the reciprocal of the r value. Open cell foams are typically about 1 2 lb cubic foot. It is available with r values ranging from r 18 to r 28 at a 3 inch thickness.

These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. For example a house with 2 6 walls in climate zone 6 would need rigid foam with a minimum r value of r 11 25. 3 benefits of rigid foam sheathing. The article explains that the r value of the rigid foam layer needs to be high enough to keep the osb or plywood sheathing above the dew point during the winter.

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. The 1 inch foam on the outside of the 2 8 is ok but you ll need more r value planning on more insulation in the wall cavity. Also included is the hugely helpful insulation zip code calculator that spells out the suggested amount of r value necessary for the different portions of a structure like foundation interior and exterior walls attic and more. R 7 5 scored squared edge rigid foam board insulation sheathing model 88wd view the owens corning exterior insulation.