Foam board insulation is easy to use and a great DIY way to add some insulation. It comes in standard-size 4×8 sheets and smaller sizes, in thicknesses from 1/4-in. to two inches. Some types of ...

All of these are referred to as foam board insulation. They’re typically installed against a wall surface and have a wide range of r-values from 3 to 8 per inch. Structural Insulation Panels.