Modiflex MP-180-FS-Base Fully Adhered Base Sheet is constructed of a tough non-woven reinforced polyester mat strengthened with select glass fiber strands. Coated top and bottom with select SBS polymers and premium quality asphalt, the product’s top surface is covered with a thin micro-perforated film which disappears upon heat welding, while the underside is sanded to allow installation via mopping asphalt or an IKO-approved cold process adhesive. Modiflex MP-180-FS-Base is an excellent choice as the “lay flat” base sheet in a layered membrane construction system.