This specification covers the physical requirements and testing of three types of lap cement for use with asphalt roll roofing. Type I is a brushing consistency lap cement intended for use in the exposed-nailing method of roll roofing application, and contains no mineral or other stabilizers. This type is further divided into two grades, as follows: Grade 1, which is made with an air-blown asphalt; and Grade 2, which is made with a vacuum-reduced or steam-refined asphalt. Both Types II and III, on the other hand, are heavy brushing or light troweling consistency lap cement intended for use in the concealed-nailing method of roll roofing application, only that Type II cement contains a quantity of short-fibered asbestos, while Type III cement contains a quantity of mineral or other stabilizers, or both, but contains no asbestos. The lap cements shall be sampled for testing, and shall adhere to specified values of the following properties: water content; distillation (total distillate at given temperatures); softening point of residue; solubility in trichloroethylene; and strength at indicated age.
