Moisture in my attic

Frost in your attic?

Attic frost/Ceiling Dripping Call: 701-223-9249

What causes it?

Excessive moisture from inside the house condenses against the uninsulated outside building material and creates a layer of frost. Traces of frost are normal in the cold northern states, but a coating like you see in this picture is a sign of a more severe issue. It's typically a venting issue, either warm moist air from the home is being incorrectly vented into the attic - usually from a bathroom or dryer vent - or the roof vents are not functioning adequately to allow the moisture to escape.

Is it a problem?

As the roof is warmed by the sun, the frost will melt and evaporate. Since cold air cannot carry as much moisture, excessive frost stays liquid and begins to drip into the insulation, and in some cases through to the sheetrock ceilings below, causing water staining and in extreme cases drywall tape lines will come loose, paint will bubble and water may even run out of light fixtures and other openings.

How do I deal with it?

In the case of this extreme photo, the bathroom vent was not correctly attached to the vent tube that leads outside the house. After removing the wet insulation, the venting issue was fixed and high-volume fans were temporarily placed in the attic to create moving air to help suspend the evaporating moisture until it could be carried out through the existing roof vents. The insulation was then replaced and ceiling damage repaired. In some cases, adding a power vent will allow moist air to be removed before it becomes frost.