Rigid Foam Board
Rigid foam boards come in a variety of forms ranging from Expanded Polystyrene (EPS) and Extruded Polystyrene (XPS) to Polyisocyanurate. Important differences are R-value per inch, strength, water resistance as well as porosity, coatings, and cost. All foam insulation products are derived from petroleum.
The rigid foam board with the highest R-value is polyisocyanurate, at R-7 per inch.
We use only polyiso board and are very experienced with the installation of it in an array of applications.