Roof Icicles Ice Dams

Heat loss from a house snow cover and outside temperatures interact to form ice dams.

Roof icicles ice dams.

But if you see icicles hanging from the edge of your roof it may be a sign of an ice dam. If the icicles hanging off your roof are an inch or longer you probably have an ice dam on your hands. That s because the same conditions that allow icicles to form snow covered roofs and freezing weather also lead to ice dams. When snow accumulates on a rooftop an unevenly heated attic can melt pockets of snow high on.

The major issue with ice dams on the roof is that they trap the melting water running down from the top of the roof and thereby cause it the melted water to rise up underneath the roofing shingles and eventually seep through the boards and walls inside our homes. 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. Small icicles along the edge of your roof. Icicles don t always mean ice dams.

Ice dams and icicles form when the snow melts runs down your roof and refreezes near the edge. It s this very melting and refreezing process that causes ice dams in the first place. Thick ridges of solid ice that build up along the eaves. This happens when warm air inside your home melts snow on the roof which then refreezes as it reaches the unheated colder eaves when temperatures drop.

Poor ventilation and temperature control in the attic can also cause ice dams. For an ice dam to form there must be snow on the roof. And only two feet of snow buildup on a roof can cause enough stress for the entire structure to collapse. One of the main safety concerns when it comes to winter weather systems is the buildup of snow and ice on roofs.

A dam will grow on the parts of the roof that are below freezing. The higher surfaces of the roof s surface must be above 32 f and lower surfaces below 32 f. This scenario is often the result of a warm attic. But they do mean snow is melting on your roof and that some of the runoff is freezing into icicles as it trickles off the edge of your roof.

The problem is these ice dams can force water up under your roof s shingles. An ice dam is a ridge of ice that forms along the edge of your roof. Nonuniform roof surface temperatures lead to ice dams.