300 series stainless is best for the fasteners, as it is compatible with all roof materials.” “Hardware for these systems (nuts, bolts, screws) should meet the same criteria-last as long as the roof. “Use aluminum with stainless hardware on coated steel and zinc roofing brass alloys or stainless for copper roofing anodized aluminum or stainless for stainless roofing,” adds Haddock. The compatibility between different types of metals is an important consideration when choosing a snow guard system. In its newest technical bulletin, “Qualifying Snow Retention Systems for Metal Roofing,” MCA recommends snow guard systems for metal roofs to be manufactured from non-corrosive metals. “Because metal roofs have exhibited service lives of more than 60 years in documented field studies by the Metal Construction Association (MCA), this requirement immediately rules out the use of plastics (polycarbonates) as they do not measure up to such a service life in outdoor exposure,” he adds. Snow guards are considered a life/safety product, and therefore should have the service life and durability equivalent to the roof itself, Haddock says. “The panel type and material, roof size, local snow loads and aesthetics are some other issues to consider.” Jerod Webber, sales manager, at Raytown, Mo.-based Dynamic Fastener, notes that engineering and testing is one of the main focuses when choosing a snow retention system. “Either type can work-continuous rail or discontinuous cleat-type systems-provided that either is appropriately tested, correctly installed and proven by engineered calculation to resist the in-service loads presented on a site-specific basis,” says Rob Haddock, CEO of Colorado Springs, Colo.-based S-5! Attachment Solutions. Continuous snow guards can be made up of one or multiple cross-members.Ĭhoosing the right type of snow guard is a decision largely based on aesthetic and personal preference. These have at least two components: brackets or seam clamps that are attached to the roof, and cross-members that are anchored to the brackets or clamps that restrain the sliding snow. Fastener Compatibility with Profiled Metal Roof and Wall Panelsįor more information, visit Continuous snow guards are otherwise known as rail type snow guards, snow fence, snow rail or pipe-style snow guard.Qualifying Snow Retention Systems for Metal Roofing.
Technical Resources from the Metal Construction Association:
Normally used in a redundant fashion, unitized snow guards rely on the “bridging” of a snowpack to span between adjacent devices to limit snow migration. A unitized snow guard can be a single- or multi-component and does not use continuous cross-member. There are unitized snow guards, otherwise known as discontinuous snow guards, snow cleats or pad style snow guards. Snow guards come in a variety of shapes and sizes. To restrain sliding snow, snow guards use the compressive strength and density of the snowpack immediately adjacent to the roof surface, therefore resisting the vector force of snow for a specific tributary area of the roof. Snow retention systems reduce the risk of sudden rooftop avalanches and mitigate the hazards present in the area below the eaves. The collection of snow on a roof can produce significant sliding forces, which can cause the snow to fall suddenly. The buildup of snow and ice on a pitched metal roof causes challenges in many areas around the country.
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