Exterior Rigid Foam Insulation R Value

House wrap is a good idea even with foam on the outside of the house.

Exterior rigid foam insulation r value.

These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. 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. C or thermal conductance of these materials is the reciprocal of the r value. Polyurethane rigid foam is a.

Plywood has an r value of 1 25 and fiberglass batts have an r value of 3 14. It is available with r values ranging from r 18 to r 28 at a 3 inch thickness. R 7 5 scored squared edge rigid foam board insulation sheathing model 88wd view the owens corning exterior insulation. 3 benefits of rigid foam sheathing.

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. Closed cell foams are more dense and rigid typically about 2 lb cu. It is denser than eps and provides more r value with a rating of 5 per inch of thickness. For a 1 in thick 4 8 panel comes unfaced or with a number of different plastic facings.

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

Open cell foams are typically about 1 2 lb cubic foot. 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. This foam board insulation is available with straight or tongue and groove edges to help limit air movement. 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.