We use a 2 lb. closed cell polyurethane foam which contains zero ozone depleting blowing agents, catalysts, polyols or fire retarding materials. The closed cell nature of this product is ideal to use in situations where there is a concern for condensation since it acts as a waterproof and vapor proof barrier. This product has an R-value of 6.9 per inch. This insulation also adds structural rigidity to metal panels on the building.