The primary function of a roof is to keep moisture out of the building. Period. First, a layer of close-cell polyurethane foam forms a thick, seamless barrier to prevent water penetration. Then, an elastomeric coating forms an additional shield against moisture, but more importantly offers protection from the intense ultra-violet rays of the sun. If the elastomeric coating becomes damaged, the layer of closed-cell foam will still prevent water penetration and migration. Polyurethane foam can be applied in thicknesses between one (1) inch and unlimited. Each inch of polyurethane foam provides an insulation value of approximately R-7. Because the foam can be applied at varying thicknesses, additional foam for low areas to reduce ponding water can be achieved with minimal additional labor. The protective elastomeric coatings can be reapplied indefinitely on seven to fifteen year intervals, making polyurethane foam roofing the only truly sustainable roofing system on the market. Similarly to how you apply sunscreen to your skin, in order to be effective in protecting the polyurethane foam, a fresh application of coating is recommended to extend and renew the life of a new foam roof for several decades after its initial installation. A properly installed foam roof should last the lifetime of the building...