{"id":15443,"date":"2012-11-01T09:39:45","date_gmt":"2012-11-01T13:39:45","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=15443"},"modified":"2016-04-15T15:19:24","modified_gmt":"2016-04-15T19:19:24","slug":"establishing-critical-barriers-with-insulated-metal-panels","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/establishing-critical-barriers-with-insulated-metal-panels\/","title":{"rendered":"Establishing critical barriers with insulated metal panels"},"content":{"rendered":"
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All images courtesy Centria<\/figcaption><\/figure>\n

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Providing adequate rainwater management and control for air, vapor, and heat flow through the building enclosure is critical to long-term performance and durability. In contemporary wall assemblies with layered materials, the complexity of coordinating these various demands can be overwhelming.<\/p>\n

Historical developments of building enclosure design and construction evolved through the centuries from monolithic, load-bearing mass walls through transitional masonry to today\u2019s modern building enclosure systems. Thanks to technological advances over the last several decades, emerging construction materials, methods, and techniques have led to thinner, lighter, and more complex exterior walls consisting of multiple material layers.<\/p>\n

Contemporary building enclosures perform a multi-faceted role in managing what is typically referred to as \u2018environmental loads.\u2019 In addition to transferring dead and live loads, the enclosure must manage moisture in both liquid and vapor states\u2014transported through air leakage and diffusion\u2014as well as the flow of thermal energy. In design practice, these elements are controlled by using water, air, vapor, and thermal barriers.<\/p>\n

Each barrier function may be achieved with a dedicated material, but one can serve more than a single prescribed function. In one example, fiberglass-batt insulation functions as a thermal barrier in resisting the transfer of thermal energy across the wall assembly\u2014thus providing the thermal barrier. Above-grade waterproofing membrane, on the other hand, often serves multiple functions and can be used as drainage plane or vapor barrier and can comprise an integral part of the air barrier system (provided certain physical properties are met).<\/p>\n

Selecting the appropriate materials and their arrangement within the wall assembly may not always be a straightforward process. Nevertheless, it is essential in preventing moisture-related performance problems. A case in point being the use of low-permeable interior wall finishes in hotels in southern climates during the 1990s, which led to widespread moisture-related problems in exterior walls.<\/p>\n

\"A<\/a>
A proprietary insulated metal panel (IMP) assembly, paired with a metal-framed backup wall. IMP walls combine metal skins with foam insulation for optimal thermal, air, moisture, and vapor barriers in a single panelized component, providing quick and easy installation for all climates.<\/span><\/figcaption><\/figure>\n

Another example during the 1990s was the use of substandard exterior sheathing materials and improper detailing and installation of the waterproofing layer. This led to moisture-related failures in exterior insulation and finish systems (EIFS) in coastal regions of Canada and warm coastal climates in the United States. Such failures brought about extreme hardship to the owners, insurance companies, and financial institutions involved.<\/p>\n

Avoiding failures<\/b>
\nThe examples of past failures emphasize two critical aspects in ensuring properly functioning building enclosures:<\/p>\n