FOAMD4
DiversiFoam D4 Contour Drop-In Foam BackerBoard
BackerBoard is manufactured from RayLite brand polystyrene insulation. RayLite is a superior quality insulation that is extremely lightweight. It resists water absorption, will not mold, rot or decay, and will not create a second moisture barrier.
RayLite BackerBoard cuts easily with a knife or can be scored and snapped over a sharp edge.
RayLite BackerBoard's high compressive strength and R-value of 3.85 per inch at 75 degrees Fahrenheit make it an excellent siding underlayment and insulator.
Note that like many construction materials, EPS is combustible. It should not be exposed to flame or other ignition sources. Current model building code requirements should be met for adequate protection or separation from occupied areas.