Have you been carefully (or not so carefully) monitoring that gravity-defying overhang of migrating snow that sits atop your roof? Glistening beautifully in the sun, it has stayed up there for days; it will surely stay up a bit longer, right? Sorry, no guarantee. Avalanches are unpredictable and catastrophic events. The snow will fall wherever and whenever it wants to – on you, a loved one, your car or sidewalk.
Tags: Snow Guards, Snow stops, sliding snow, snow retention, metal roof clamps, metal roof snow stops, metal roof clips, snow rails, snow stopper, snow clips, snow fence, snow bar, exposed fastener, roof panels, rooftop avalanche, rooftop mounting, maintain warranties, maintain roof warranty, non-penetrating, clamps, installing snow guards
It is a sudden release of snow off a rooftop. Falling snow forms a temperature-sensitive bond to the surface of a metal roof. As that roof is warmed, (through sun or building heat loss), the bond with the snow is broken and a thin film of melt water lubricates the roof. This sudden release from a rooftop can dump many tons of snow below the eaves in a matter of seconds, endangering building elements, landscape, vehicles and pedestrians.
Qualifying Snow Retention Systems for Metal Roofing, from the Metal Construction Association discusses the rooftop avalanche in the following terms:
Metal roofs provide durable, long-term solutions and have been preferred by many for use in challenging northern and alpine climates where snow and its migration on and from the rooftop is a normal occurrence. Such climates can pose unique challenges for any roof. Pitched roofs of a material that has a slippery surface can pose sliding snow and ice hazards below eaves. In many instances, snow retention systems are installed on these roof types in order to reduce the risk of sudden rooftop avalanche and mitigate the hazards present in the discharge areas below the eaves.
Tags: Roof Clamps, Snow Guards, Snow stops, sliding snow, plastic snow guards, metal roofs, snow retention, S5 clamps, metal roof clamps, FAQ, Brackets, metal roof snow stops, metal roofing, metal roof clips, standing seam metal roof, snow rails, snow stopper, snow clips, snow fence, snow bar, exposed fastener, thermal movement, roof panels, rooftop avalanche
At S-5!, we don’t recommend installing adhesive-mounted snow guards on metal roofs. From both an economic and design perspective, glued on plastic snow guards typically have low holding strength and are unable to handle harsh weather-related elements. The bond weakens over time and when it fails, the guard can rip away paint and protective roof coatings, potentially leading to corrosion.
This is part one of a two-part series on qualifying snow retention systems.
There is a new (and much needed) document recently published by the Metal Construction Association (MCA): Qualifying Snow Retention Systems for Metal Roofing. This new industry consensus document is perhaps the most valuable tool in your toolbox if you are involved with any aspect of snow guards for any metal roof application.
In places where it frequently snows a lot and even in places where it doesn’t, metal is a favored material in protecting a house or other structure. On the surface, snow might appear to be rather innocuous, as it gently falls from the sky like the ending scene in the movie, White Christmas. But what the movie doesn’t show, is all through the night and much of the morning (if not longer) the light fluffy stuff piles deeper and deeper on top of the roof, incrementally increasing its own weight. Then, when the sun comes out, an avalanche of snow tumbles down onto unsuspecting persons, vehicles and landscapes below.