Wednesday, January 24th, 2018 by Ted Swanson
With the fluctuating temperature changes in the Twin Cities this January, we’ve received many calls from people seeing water dripping from their ceiling, lights, and bathroom vents. This damage is caused by frost forming in attics during cold spells. When humid air travels from the house into the attic via air leaks or “attic bypasses,” the moisture condenses and freezes on the roof decking and rafters. Once a warm day hits and temps warm up, that frost melts, unleashing water into the attic impacting insulation and damaging ceilings.
To prevent attic frost, all air leaks need to be located and sealed, which can be difficult since many leaks happen beneath attic insulation. Proper ventilation also plays a role in helping moist air escape the house through exhaust vents to the outside. In most cases, you need a professional to seal the attic leaks, and evaluate ventilation to provide solutions.
Commonly, the more humid the home, the more attic frost can occur. Homeowners can reduce attic frost formation for the interim by turning off whole-house humidifiers and running bathroom and kitchen fans for up to an hour after use.