Temperature induced stresses on modified bituminous low-slope roofing systems

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Conference13th Canadian Conference on Building Science and Technology: 09 May 2011, Winnipeg, Manitoba
Subjectmodified bituminous roofing, temperature, shrinkage, insulation, displacement, cover board, low slope; Roofs
AbstractIn Canada, where the design temperatures are above freezing, the SBS modified bitumen roofing membrane are the most commonly used and are in practice since 1950?s. The modified bituminous roof membrane system is a two-ply system comprising of a base sheet and a cap sheet. Existing literatures on the thermal stresses induced in the modified bitumen systems indicate that these systems have a history of problems such as blistering, rupturing, splitting and slippage, however, with the improvement in the manufacturing process and better system designs, these issues subsided with time. In the recent past, the issue of membrane ridging on low sloped modified bitumen systems was brought to the attention of National Research Council of Canada. Membrane ridging sometimes referred to wrinkling was a common failure mode observed on BUR systems over the past decade, however this seems to be emerging on the two-ply mod-bit systems. However, the question is whether the ridging is the effect of any material or whole system performance. The present paper presents two case studies showing the membrane ridging on two roofs and also discusses a small scale experimental study that was conducted at the National research Council of Canada to understand the thermal induced stresses in modified bituminous roofing systems.
Publication date
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedYes
NRC number54459
NPARC number20374458
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Record identifier28f596a9-fddd-475a-9d8a-8ceddadc1a43
Record created2012-07-23
Record modified2016-05-09
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