Architectural specifications define the end product and the performance objectives in order to provide a basis for the selection of materials. There are correlations between the changes in the chemical, physical and mechanical properties of the materials and the environments to which they are exposed. The results from laboratory testing 2 and on-site observations assist in the development of material standards and performance criteria. In establishing these criteria many tests have been developed to obtain qualitative and quantitative results for the assessment of the effects of stresses that are encountered during manufacture, application and the service life of roofing membranes. Some tests are designed to measure strength, elongation and flexibility, others measure resistance to puncturing, tearing, surface erosion and water vapor transmission.
Special tests determine the effect of unusual in-service environments.
Such tests, aimed at ensuring the satisfactory performance of materials and achieving intended service life, form part of the standard requirements. Although several European standards dealing with many new roofing and waterproofing materials exist, they are not directly applicable in Canada because of different weather conditions. A number of material and application standards for synthetic roofing and waterproofing materials have been published in Canada and others are in preparation. Information about current standards can be obtained from the Canadian General Standards Board, Supply and Services Canada, Ottawa, Ontario, K1A 1G6. Concluding remarks Synthetic roofing membranes have desirable properties but there are some limitations.