Henry 180SS Modifiedplus NP180s/s Base Sheet 2.2mm is designed for use as a base sheet in a variety of Elasto-Seal 790-11, Green Roofing, Modifiedplus modified bitumen systems and other waterproofing and roofing systems. NP180s/s Base Sheet is designed for use as a base sheet in variety of Elasto-Seal 790-11, Green Roofing, Modifiedplus modified bitumen systems or other waterproofing and roofing systems.