My Attic Has Frost

Many people s first instinct when they notice frost in the attic is to add insulation.

My attic has frost.

See the picture above. It can lead to mold wet insulation and find a way back into the home resulting in water stains on the ceiling. The exhaust from the rooms below gets released into the open air in the attic if not sealed properly causing lots of moisture in the air. A bathroom vent has been left to pump warm air into the attic.

When the moisture gets into the attic it condenses on the roof. Insulation is irrelevant when your attic bypasses are left open for warm air to pour into the attic. Since our minnesota winters are usually dry the only other source of humid air is your living space. That is not a solution.

To start frost shows up in the attic when moisture laden air from the house gets into the attic. Left unchecked moisture in the attic can lead to serious mold and decay expensive to repair and potentially unhealthy for anyone in the house. 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. Therefore my suggestion is that if one finds frost in the attic one first has to identify which of the three causes is contributing to the problem.

If it s due to air infiltration from the living space then air sealing should be the first thing you do not the last. What ends up as frost in the attic starts as water somewhere else in the house. During winter conditions attic frost is a problem associated with attic bypasses. Frost in your attic space is a sign that warm humid air is somehow getting into your attic space.

That s about it pretty simple.