GlasBase™ Plus is an SBS rubber modified, asphaltic base sheet that incorporates the features of a strong fiber glass mat with a coating of blended synthetic rubber and a high quality asphalt. This coating is designed to help the sheet lay flat in built-up and modified bitumen roofing specifications that require the use of mechanical fasteners on nailable decks. The modified asphalt blend lends elasticity and flexibility to the product. GlasBase Plus employs a unique fiber glass mat to aid in the reduction of wrinkling that can occur in nailed specifications.