Can You Use Foam Board in the Attic?

If you are thinking about insulating your attic, there are several options

You can use foam board in the attic. It is an excellent installation option for the attic because it is lightweight, easy to work with, and offers high R-values. Often the R-value of fiberglass insulation is too low and requires the rafters to be retrofitted, making foam board a better choice.

What Is Rigid Foam Board

Rigid foam board, also known as foam board or insulation board, can be an excellent option for insulation. It is lightweight and easy to work with. A 4 by 8 board weighs next to nothing and can easily be cut to fit.

Typical thicknesses range from ½ inch to 2 inches, with estimated R-values of R-3 for the ½ inch to R-10 for the 2-inch board.

How Does Rigid Foam Board Work

A rigid foam board works by trapping air, making heat conduction more difficult. Heat can be transferred by three methods—radiation, convection, and conduction.

When the sun’s heat hits your roof, that heat is radiated across the roof. For that heat to make it into your attic, it must be conducted through the roofing materials.

Using rigid foam to create an air cavity makes it more difficult for the heat to conduct itself into your living space.