Combining Exterior Rigid Foam With Fluffy Insulation
In either of these cases, you need to figure out how much rigid foam you need to stay out of trouble. To make these calculations easier, I’ve created two tables. The tables are based on the nominal value of the insulation layers, without taking into account the effects of thermal bridging Heat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel. through the studs. The tables show the minimum percentage of the total R-value of the assembly that needs to come from the rigid foam layer.