Nail base Insulation is a cost effective solution for one step application of EPS rigid foam insulation and OSB or plywood nailing surface saving money, time and labor for steep slope roofing or wall furring. Nail Base Insulation is manufactured from closed cell expanded polystyrene (EPS) ridged foam with Oriented Strand Board (OSB) or plywood adhered to the top surface of the EPS adding strength, durability and a nailing surface for shingles or metal roofing. Nail Base Insulation is manufactured 48” wide x 96” long, non-vented and vented square edge panels.