Frost And Ice In Attic

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.

Frost and ice in attic.

Depending on the temperature and the insolation ie. If this cycle repeats over several days the freezing snowmelt builds up and forms a dam of ice behind which water pools up into large puddles or ponds. Frost in your attic space is a sign that warm humid air is somehow getting into your attic space. When the snowmelt runs down the roof and hits the colder eaves it refreezes.

In order to eliminate frost build up in the attic space we have to understand what causes it in the first place. During winter conditions attic frost is a problem associated with attic bypasses. When you see water and ice on the nails the actual temperature of the nails is at or below the dew point of the air in the attic that is saturated with water vapor. Water vapor is migrating upward and eventually filtering into the attic.

When the temperature in your attic is above freezing snow on the roof will likely melt. Ice damming usually occurs with a significant depth of snow on the roof. The frost itself doesn t do any damage but once it melts things get wet which is when the damage. Frost itself doesn t do any damage but once it melts things get wet and then damage occurs.

As more melting snow or rain runs down the roof it meets this mass of ice and backs up sometimes under the shingles and into the attic or the house. When the outside temperature rises again the frost thaws water collects and can leak into your house. In the parlance of building scientists these cold wooden house parts make up a condensing surface much like a cold glass of ice tea beads with water on a hot summer day. Can sun get to the roof you will have either frost or water collecting.

Since our minnesota winters are usually dry the only other source of humid air is your living space. Frost and ice forms in attics when warm humid air accumulates and condenses on the underside of your roof sheathing. Ice dams are the large mass of ice that collects on the lower edge of the roof or in the gutters. When it reaches the cold surface of the roof sheathing and framing it turns to frost.