What Makes Foam Board a Good Insulator?

Moisture Resistant

• Foam board is an especially attractive option for unvented roofs and low basement walls where moisture can flow through. The insulation warms the wall surface where it is installed, which prevents condensation. Lack of moisture from condensation minimizes rot and mildew growth in walls. Installing a vapor barrier on the warm side of the wall will provide additional protection against moisture.

Pest Resistant

• Insect pests can eat and burrow into soft fiberglass or blown-in insulation, leaving holes which allow drafts to flow through. Insects will never eat foam board, and the rigid material is more difficult to burrow into. For added protection against insect pests, purchase foam board treated with a borate-based insecticide.

No Small Particles

• Loose-fill and fiberglass insulation contains small particles that irritate lungs and trigger allergies when released into the environment. In addition to being unhealthy, these particles make a substantial mess during the initial insulation process and any subsequent remodeling. Foam board retains its rigid shape and doesn’t release airborne particles.

High R-Value

• Foam sheets have a high R-value (5.8 to 8), which means minimal thermal leak between the inside and outside of the house. Foam sheets provide twice or three times the protection as the same volume of traditional insulating materials. Higher protection in a smaller package makes foam sheets ideal for shallow walls and other small spaces.