Frost On Roof

An ice dam is a hump of ice that forms at the edge of a roof under certain wintertime conditions.

Frost on roof.

2 the car roof cools radiatively. Now comes the ice or snow torrent and you are under insulated. Ice and water protectors sometimes called ice and snow shields in cold climates are made with polymer modified bitumen. The overhang porch and garage keep ice on them longer.

In other words the sequence might be as follows. Ice and water protector sometimes also referred to as ice and water shield is a waterproof roof underlayment membrane developed to protect vulnerable areas on a roof from ice and water damage. However if nothing is different about your home compared to your neighbors you may have a problem. If the morning sun directly hits your home and not your neighbors lack of frost may just be attributed to the sun s heat.

This leaves a border of frost on the outside edges of the living area. When warm air from inside the house escapes traveling up through the bypasses the moisture condenses on the roof boards and rafters where the frost can form. Warm shingles don t allow frost to form as readily as cold shingles. During winter conditions attic frost is a problem associated with attic bypasses.

It will put gutters and downspouts at risk too. Is the absence of frost an indication of heat loss thru the roof via poor insulation. A lack of frost can indicate that heat is leaking out through your attic space onto the roof and melting the frost. On my roof some areas will have frost and others not.

These dams can tear apart your home so limit them by keeping your roof clear of snow. When the outside temperature rises again the frost thaws water collects and can leak into your house. And here s the clincher. Something i implied above but didn t say explicitly is that when frost forms on the roof the roof is below freezing.

Ice dams happen when ice melts trickles down the roof then freezes again. 1 initially the air and the car are at temperature 37 f and the dew point is 35. Once in the attic it warms the air over the living space. Homes that let heat escape more rapidly than others will keep ice on the overhangs but not over the living area.

That warm air makes contact with the roof deck and warms it up. Weeee we now have leaks inside the warm wall the ice builds up on the overhang but melts over the heated areas and you have a back up of water that goes under the shingles. If you see icicles hanging from your roof you most likely have an ice dam. Ice dams are a common sight in northern new england winters and home partners has dealt with quite a few.

That heat then conducts up all the way to the shingles.