Figure 7-8. - Repair of minor splits using stitch bolts.

Built-Up Roofing

Built-up roofing is exactly what the name implies—a membrane built up on the job from alternate layers of bituminous-saturated felt and bitumen. The bitumen used to saturate the felt and used as a plying cement and coating for the saturated felts may be asphalt or coal-tar pitch. These can usually be distinguished by their odors. Asphalt has a distinctly oily odor and coal-tar pitch a somewhat pungent odor. These odors can be detected best with freshly broken specimens or from fumes of specimens that have been ignited and freshly extinguished. It is important that you determine the type of the existing bituminous material before making or recommending