Page 74 - 365411 Findley 92pp A4 PBound.pdf

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Flat roofing
Flat roofing was first introduced around the 1960s.
The original flat roofing method was using tongue and groove boards with green mineral Bitumen felt.
Following many studies on flat roofing, it has been proven that the average UK flat roof expands and contracts 1-9 feet over the course of a year. With this in mind, that is the reason why green mineral Bitumen felt has a shorter life expectancy compared to other materials.
Over the years, many different materials have been tested for flat roofing. To date, the most durable of materials has been EPDM rubber. The oldest flat roof in the world is on Chicago O’Hare Airport and was originally fitted in the mid-1960s; over this lifespan, the roof has been tested for degradation on the material and wear. After the test results, it has been shown that the material has improved because of the weather conditions as opposed to degrading.
Other materials for flat roofing that have not stood the test of time are:
Green mineral Bitumen felt
GRP (glass reinforced plastic or fiberglass)
Tar and gravel
Modified Bitumen felt
Asphalt