For the last few years, the media has highlighted roofing failures caused by wind. Although these problems sensationalize the effects of global warming, they are not new and have occurred since buildings were first constructed. The major contributing factor to many of these failures is the roof or perimeter flashing was not properly designed to meet the project requirements––such as location and occupancy type. Depending on its direction, wind acts on the building in different ways. As it collides with the structure, it travels up and over, increasing in speed––similar to the effects of an airfoil on a wing.
In both Canada and the United States, there is increasing awareness of the building envelope’s role in conserving energy. New energy codes and standards include prescriptive requirements for continuous insulation to minimize heat loss associated with thermal bridging.
The 2010 editions of the National Model Construction Codes—the National Building Code of Canada (NBC), the National Fire Code of Canada (NFC), and the National Plumbing Code of Canada (NPC)—were released last November. Published by the National Research Council Institute for Research in Construction (NRC-IRC), the new codes contain about 800 technical changes.
Annex D of Canadian Standards Association (CSA) A23.3-04, Design of Concrete Structures, introduces a new and comprehensive limit states design (LSD) procedure for determining factored tension and shear resistance of both cast-in-place (CIP) anchors and pre-qualified post-installed mechanical anchors installed in cracked and uncracked concrete.