The science behind this inability to chemically adhere items to metal roof surfaces is simple. The subsequent ‘scar’ created by the broken bond is both unsightly and could be a potential corrosion point in the future. This can be observed after a few years on most roofs employing adhesives as the attachments (Figure 12). adhesive applied) snow guard will cause the device to fail and break loose from the roof. Ultimately, the vector force placed on a chemically adhered ( i.e. Figure 12: Adhesive attached components to modern metal roof finishes are not recommended by manufacturers due to bond failures, their short useful life, and violation of metal roof finish warranties.Ĭhemical sealants will weaken as they age because they are subjected to environmental factors such as hot and cold cycling, UV light exposure, and moisture-meaning they will not maintain a strong and measurable bond for snow guards. These chemical-based materials will not properly adhere to the metal roof surface and will damage the paint finish-subsequently invalidating the finish warranty. To maintain the metal roof manufacturers’ finish warranties, no chemical adhesive or sealant can be applied to the face of the panel. You May Also Like ‘Testing’ versus ‘listing’ To protect a metal roof so it may achieve its full useful life and maintain the manufacturer’s warranty, it is recommended to specify non-penetrating round-point fasteners in specification documents. Cup-tip fasteners are not recommended in publications by Metal Building Manufacturer’s Association’s (MBMA’s) Metal Roofing Systems Design Manual section on fasteners, and the Metal Construction Association’s (MCA’s) Metal Construction Association Technical Bulletin. This could potentially reduce the roof’s service-life. The action of digging into the metal seam by the fastener also removes the roof’s protective coatings and exposes bare metal to the corrosive elements of the weather. This intrusion into the seam of the metal roof could potentially penetrate the seam of the metal roof and void the manufacturers’ warranty. Other fasteners employ a cup-tip and are designed to ‘dig’ into the metal seam to create holding strength. The polish given to the round fastener head ensures the roof’s protective coating is intact, eliminating a place for metal corrosion to begin. The round point of the fastener is designed specifically to dimple the seam without penetrating it, and subsequently stay within the non-penetrating clause of the metal roof manufacturers’ warranty. The dimple is created by the round head of the fastener integrated with a ‘well’ in the snow guard clamp to accommodate the metal seam protrusion on the other side of the seam (Figure 11). This acts as the active holding point of the fastener. Many snow guard devices employ a mechanically attached fastener with a round, polished head that creates a ‘dimple’ in a standing seam. There is more than one fastener used with attachment devices for metal roofs and they need to be closely scrutinized to ensure they do not harm the roof and attach without voiding the metal roof manufacturers’ warranty. Such products also fall within metal roof manufacturers’ warranties. Figure 11: Some modern snow guard attachment clamps attach with round-point non-penetrating screws, which do not harm the roof.
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