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The prevalence of splitting in built-up roofing during recent years has prompted special studies to be undertaken by the Division of Building Research to determine the causes for these serious failures. The determination of certain engineering properties of the components used in built-up roofing and the complete membrane have received special attention. To determine these properties, a roller-coating technique was developed to prepare membranes and a special grip arrangement was constructed for the tensile studies. These studies were made at 75 F and at -20 F, using two rates of straining. The results emphasize the secondary role of the bitumen in the strength of the membrane. At both temperatures the felts contribute 80 to 90 per cent of the strength of the membrane, although the actual strengths increased by 70 to 250 per cent as the temperature changed from 75 F to -20 F. The small amount of creep and of notch sensitivity also serve to confirm the secondary role of the bitumen., Recent Research on Bituminous Materials

Le présent Digest traite des propriétés, des avantages et des inconvénients de nouveaux matériaux de couverture synthétiques, y compris les membranes préfabriquées appliquées en feuilles et les membranes appliquées sous forme liquide.

Concern has been expressed that increasing the amount of insulation to improve the thermal resistance of conventional roofing systems might adversely affect the performance of the membrane. Lower membrane temperatures caused by increased thermal resistance could induce higher stresses in the membrane, thus increasing the incidence of splitting failures. It is also feared that additional insulation could result in larger stresses in roofing membranes partially covered with snow. This Note evaluates the possible effects of increasing the amount of insulation on roofs.

Quality control of roofing and waterproofing membranes occurs at four distinct stages: 1) characterization of raw materials with respect to degree of purity required for an established formulation prior to production; 2) control of processing and manufacturing variables during production to permit necessary corrections before defective materials are produced; 3) testing and evaluation of finished products for conformity with the established standards or as agreed upon by the supplier and purchaser; where the latter is a large company or a government agency, compliance with a specification is usually required; 4) control and inspection of workmanship quality on the job site during the application in accordance with the architect's, engineer's or project manager's detailed job specification. Stage 3 has already been discussed in the author's previous publications. This paper highlights some of the quality control aspects and methods that could be implemented in stages 1, 2, and 4., 5th International Congress on Roofing and Waterproofing: 01 June 1983, Strasbourg, France

This paper introduces built-up-roofing, single-ply and liquid elastomeric membranes and polyurethane foam roofs. It discusses the factors concerning the performance of membranes, and how they are related to standards., Building Science Insight 1989: Roofs that Work: 1989, Canada

One of the most important decisions regarding building construction is the type of roofing system to be installed. This includes the type of deck, vapour barrier, insulation, membrane and roof finish. This paper discusses the factors to be considered in making this decision. These are: code requirements. -- design considerations. -- construction considerations. -- maintenance considerations. -- cost considerations. -- other considerations., Building Science Insight 1989: Roofs that Work: 1989-10, Canada

In the last 20 years several new types of roofing material have been introduced to the construction industry, including various inorganic and organic materials and their combination, generally prefabricated. This paper deals only with single-ply membranes made from such materials as flexible polyvinyl chloride (PVC), elastomers, that is polyisobutylene (PIB), ethylene propylene diene monomer ( EPDM), hypalon (CSPE), and other rubber and rubber-like materials and reinforced modified bitumens. As there is need for criteria to facilitate appropriate selection and for specifications to ensure proper application, several test methods have been evaluated that assess physical, mechanical, and weathering properties of single-ply membranes. Some have been incorporated in the Standards of the Canadian General Standards Board (CGSB). Some of the more important tests include those for lap-joint performance, dimensional stability, water absorption, stress- strain properties, low-temperature flexibility, static and dynamic puncturing, load-twist, and the so called wheelbarrow test., Symposium on Single-Ply Roofing Technology: 24 June 1981, Detroit, MI, USA

This paper discusses the design of correct roof details, strategies a designer can pursue to improve the potential for proper roof construction and a general approach to an integrated roof management program., Aussi disponible en francais: Conception, exécution et entretien, Building Science Insight 1989: Roofs that Work: 1989-10, Canada

New synthetic roofing materials, including prefabricated sheet-applied membranes and liquid-applied membranes, are described. Their properties, advantages and disadvantages are discussed.

This paper focusses on the nature and performance of roof systems, assemblies and components. It deals with the factors that fall within the responsibility of the designer., Aussi disponible en francais: Performance des composants et systèmes, Building Science Insight 1989: Roofs that Work: 1989-10, Canada

Several hundred new roofing materials have become available in the past two decades. This paper describes the materials under three main generic classes: synthetic thermoplastics, thermosetting vulcanized elastomers, and polymer modified bitumens. Comparisons are made with conventional roofing materials and techniques, and some considerations necessary for selecting an appropriate roofing system are discussed.

Worldwide, there are more than 40 tests to assess the properties of nearly 400 conventional and new roofing products that exhibit wide ranges in a given property. New roofing materials can be divided into six distinctly different groups: 1. Hot applied rubberized asphalts; 2. Cold applied liquid membranes; 3. Prefabricated elastomeric sheeting; 4. Flexible polyvinyl chloride (PVC) membranes; 5. Prefabricated, reinforced, modified bituminous membranes; 6. Sprayed polyurethane with weather-resistant top coats. Each of these groups has its own specific characteristic properties that must be taken into consideration at the design stage. Test procedures were selected or, where necessary, developed to quantify properties before and after subjecting the materials to accelerated exposure conditions. This paper highlights the state of evaluating new roofing materials and describes test methods for this task. The concept and rationale of selecting tests for the different types of membranes and the tentative limits for various properties are discussed., Proceedings of Second International Symposium on Roofs and Roofing: 1981

A development study of test methods and criteria for evaluating new roofing materials is described: prefabricated polymeric and elastomeric sheets, prefabricated modified bituminous membranes, and liquid applied membranes. Results are summarized for a number of materials selected as typical of the three groups in order to illustrate the problems and the limitations associated with the different tests., Proceedings of the 1st International Conference on Durability of Building Materials and Components: 21 August 1978, Ottawa, Ont. Canada