This specification covers unreinforced vulcanized rubber sheets made from ethylene propylene diene terpolymer (EPDM) or butyl (IIR), intended for use in preventing water under hydrostatic pressure from entering a structure. The tests and property limits used to characterize these sheets are specific for each classification and are minimum values to make the product fit for its intended purpose. Types used to identify the principal polymer component of the sheet include: type I - ethylene propylene diene terpolymer, and type II - butyl. The sheet shall be formulated from the appropriate polymers and other compounding ingredients. The thickness, tensile strength, elongation, tensile set, tear resistance, brittleness temperature, and linear dimensional change shall be tested to meet the requirements prescribed. The water absorption, factory seam strength, water vapour permeance, hardness durometer, resistance to soil burial, resistance to heat aging, and resistance to puncture shall be tested to meet the requirements prescribed.