Roof Icicles Ice Dams

A dam will grow on the parts of the roof that are below freezing.

Roof icicles ice dams.

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. When snow accumulates on a rooftop an unevenly heated attic can melt pockets of snow high on. When icicles grow large and have a long way to fall they can cause serious injury and even death. Ice dams and icicles form when the snow melts runs down your roof and refreezes near the edge.

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

Small icicles along the edge of your roof. An ice dam is a ridge of ice that forms along the edge of your roof. It s this very melting and refreezing process that causes ice dams in the first place. And only two feet of snow buildup on a roof can cause enough stress for the entire structure to collapse.

The problem is these ice dams can force water up under your roof s shingles. If the icicles hanging off your roof are an inch or longer you probably have an ice dam on your hands. 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. Icicles hanging along the eaves of your house may look beautiful but they spell trouble.

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. That s because the same conditions that allow icicles to form snow covered roofs and freezing weather also lead to ice dams. Nonuniform roof surface temperatures lead to ice dams. But if you see icicles hanging from the edge of your roof it may be a sign of an ice dam.

For an ice dam to form there must be snow on the roof. Icicles don t always mean ice dams. Thick ridges of solid ice that build up along the eaves.