Civil Engineering Reference
In-Depth Information
15
Roofing Materials
1.0
INTRODUCTION
The use of polymers as a roofing material is continuously increas-
ing. The function of a roof is to protect the building from environmental
factors such as light, wind, rain, snow loads, temperature changes, hail, and
storms. Therefore, the material used on a roof must withstand those factors
for many years.
The performance of a material or system depends on the environ-
ment and the degrading effects to which it is exposed. Until the early 1990s,
methods of measuring the properties and predicting the durability of
products were not well known, hence, much of the knowledge about
building materials was based on experience from long-time use.
An estimate of 90% of all flat roofs in Canada used in industrial,
commercial, and public buildings are protected by bituminous roofing, and
essentially all sloping residential roofs are covered with shingles having a
bituminous-felt base. In recent years, changes in building practices have
produced roofs of unusual design for which these materials were not
suitable. This led to the development of new rubber and plastic roofing
material, which, in turn, led to the development of rubber- and plastic-
modified bitumen and bitumen-modified rubbers and plastics.
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