Exterior Rigid Foam Insulation R Value

Open cell foams are typically about 1 2 lb cubic foot.

Exterior rigid foam insulation r value.

Polyurethane rigid foam is a. Falls in the middle of the three types of rigid foam insulation in both cost and r value used most in walls or below grade applications recyclable and at about r 5 per inch costs around 42 per sq. 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. House wrap is a good idea even with foam on the outside of the house.

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. 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. 3 benefits of rigid foam sheathing. Foam insulation densities vary among closed cell vs open cell forms.

This foam board insulation is the rigid pink or blue panels that can be found at home centers in many different thicknesses. 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. Rigid foam insulation one option is to use polyurethane rigid foam insulation. Owens corning foamular 150 1 1 2 in.

It is available with r values ranging from r 18 to r 28 at a 3 inch thickness. 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. C or thermal conductance of these materials is the reciprocal of the r value. 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.

These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. Closed cell foams are more dense and rigid typically about 2 lb cu. Plywood has an r value of 1 25 and fiberglass batts have an r value of 3 14. R 7 5 scored squared edge rigid foam board insulation sheathing model 88wd view the owens corning exterior insulation.