Ice Damming On Metal Roofs

This rise in temperature melts the underside of the layer of snow on top.

Ice damming on metal roofs.

When warm indoor air escapes through a rooftop it warms the roof sheathing. Metal roofs ward off ice dams pretty well to begin with but a steeply pitched metal roof is kryptonite to an ice dam. This only occurs when part of your roof warms to above 32 degrees f warm enough to melt the snow while the roof edge remains below freezing. It s possible the ice can get a grip on the raised metal screws commonly used to attach the metal sheets to the roof deck.

The melted snow then moves down the slope of the roof toward the eaves where it freezes into ice. Even on a metal roof keeping valleys eaves and gutters clear can only be achieved by keeping the refreeze from occurring by keeping the melt liquefied and allowing it to get off the roof and then too the ground. 2 the metal roof allows for unrestrained cascading of snow and ice onto the surface below. There are products out on the market that can prevent ice dams and keep them from forming.

As the water tries to flow down the overhang which is slightly colder it will refreeze and as it builds up will hang over the eave. In colder climates ice damming can also potentially be a problem. This event happens when it is cold outside and snow melts in spots on the roof where it is warmer. This is fine when it is the backyard.

Metal roofing can be just as susceptible to this as. Ice damming on the metal roof. Most ice dams are a result of building air barrier flaws. Ice dams on roofs form when accumulated snow forms an insulating layer under cold conditions that would cause the freezing point to be within the snow layer if it were not subject to melting.

This scenario is often the result of a warm attic. Ice dams and icicles form when the snow melts runs down your roof and refreezes near the edge. On a metal roof there s almost nothing for an ice dam to adhere to. Ice dams occur on heated buildings with sloping roofs in cold climates with deep snow accumulation.