Ice Damming On Metal Roofs

In colder climates ice damming can also potentially be a problem.

Ice damming on metal roofs.

When warm indoor air escapes through a rooftop it warms the roof sheathing. 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. Metal roofs ward off ice dams pretty well to begin with but a steeply pitched metal roof is kryptonite to an ice dam. On a metal roof there s almost nothing for an ice dam to adhere to.

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. There are products out on the market that can prevent ice dams and keep them from forming. This event happens when it is cold outside and snow melts in spots on the roof where it is warmer. Ice damming on the metal roof.

1 the metal roof has allowed the snow to slide into the valley where it compacts and forms an ice dam that results in leaking into the home and icicle formation. This rise in temperature melts the underside of the layer of snow on top. 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.

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. Most ice dams are a result of building air barrier flaws. Ice dams and icicles form when the snow melts runs down your roof and refreezes near the edge.

By installing a metal roof that has a special coating designed to shed snow and ice causing it to fall off the roof before it has a chance to form into an ice dam you can completely eliminate ice dam formations on your roof in the first place. The melted snow then moves down the slope of the roof toward the eaves where it freezes into ice. This scenario is often the result of a warm attic. This is fine when it is the backyard.