The length of life of prepared roll roofings is a prime consideration in their selection. The durability of the various brands of roofing on the market varies widely. The useful life of a roof made of roll roofing is influenced by the degree of exposure to the weathering agencies, the condition of the sheathing and the inherent qualities of the roofing material itself. This bulletin is a summary of the results of an investigation, conducted cooperatively by the Agricultural and Engineering Experiment Stations, to determine the quality factors of three-ply prepared roll roofings as they were sold on the market at the beginning of the project in 1913.

One roll or square of each of 35 brands of prepared roll roofing which were made by 19 manufacturers was purchased on the open market and included in the experiment. This provided sufficient material for one strip to be placed on the shed for weathering tests and enough additional for laboratory tests. Table I presents some general information and data of the physical qualities of the roofing sample.

A review of literature on the subject reveals little work directly comparable with that given here other than the development of testing methods and specifications for prepared roll roofings.