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Abstract
The repair and maintenance costs of flat roofs are excessive, and their life expectancy is inadequate. The increasing use of insulation is accompanied by a greater incidence of problems. The conditions in cold regions amplify these experiences. Protected membrane roofs have the prerequisites for better performance, and the experience to date is encouraging. The results of measurements of the performance of three roofs built by the Corps of Engineers verify that the membrane remains at a nearly constant temperature independent of the weather and that the insulation retains its integrity despite periodic wetting. Moisture absorption is slow and appears to stabilize in time due to the self-drying nature of the roof. Heat losses are increased due to rain and should be compensated by added insulation. The resistance to fire, traffic, impact and other adverse forces is superior. So far, the initial cost of protected membrane roofs is at a premium, mainly due to the cost of concrete pavers when used instead of coarse gravel. This initial cost premium is well-justified, however, by the reduced repair and maintenance costs, as indicated to date, and the long life expectancy of the protected membrane. The high probability of superior performance and cost effectiveness is a compelling reason to incorporate protected membrane roofs increasingly in government construction.
The repair and maintenance costs of flat roofs are excessive, and their life expectancy is inadequate. The increasing use of insulation is accompanied by a greater incidence of problems. The conditions in cold regions amplify these experiences. Protected membrane roofs have the prerequisites for better performance, and the experience to date is encouraging. The results of measurements of the performance of three roofs built by the Corps of Engineers verify that the membrane remains at a nearly constant temperature independent of the weather and that the insulation retains its integrity despite periodic wetting. Moisture absorption is slow and appears to stabilize in time due to the self-drying nature of the roof. Heat losses are increased due to rain and should be compensated by added insulation. The resistance to fire, traffic, impact and other adverse forces is superior. So far, the initial cost of protected membrane roofs is at a premium, mainly due to the cost of concrete pavers when used instead of coarse gravel. This initial cost premium is well-justified, however, by the reduced repair and maintenance costs, as indicated to date, and the long life expectancy of the protected membrane. The high probability of superior performance and cost effectiveness is a compelling reason to incorporate protected membrane roofs increasingly in government construction.
Date
8/1974
8/1974
Author(s)
H W Aamot; D Schaefer
H W Aamot; D Schaefer
Page(s)
65
65
Keyword(s)
performance evaluation; protected membrane; cold regions; moisture absorption; insulation
performance evaluation; protected membrane; cold regions; moisture absorption; insulation