Frost And Ice In Attic

When the temperature in your attic is above freezing snow on the roof will likely melt.

Frost and ice in attic. When it reaches the cold surface of the roof sheathing and framing it turns to frost. In order to eliminate frost build up in the attic space we have to understand what causes it in the first place. The frost itself doesn t do any damage but once it melts things get wet which is when the damage. The water develops on the roofing nails first because they readily conduct cold.

Since our minnesota winters are usually dry the only other source of humid air is your living space. When moisture gets into the attic it condenses on the roof sheathing in the form of frost. Depending on the temperature and the insolation ie. 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.

Can sun get to the roof you will have either frost or water collecting. During winter conditions attic frost is a problem associated with attic bypasses. When the outside temperature rises again the frost thaws water collects and can leak into your house. 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.

Ice dams are the large mass of ice that collects on the lower edge of the roof or in the gutters. Water vapor is migrating upward and eventually filtering into the attic. Ice damming usually occurs with a significant depth of snow on the roof. 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.

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. 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 and ice forms in attics when warm humid air accumulates and condenses on the underside of your roof sheathing. Frost in your attic space is a sign that warm humid air is somehow getting into your attic space.