Houses with full home humidity systems are at risk for attic frost if the home s level of humidity is excessive.
Frost in the attic information.
While bypasses are certainly the most common cause of frost there are other ways it can happen and these are much more.
This post is largely a re blog of my last post on attic frost but that was from 2013 and it s time for a reminder about all of this.
Check out my post on moldy attics for some.
Bypasses are what allow moisture in the attic to begin with and this is what needs repair.
The fix for frost in the attic is sealing attic bypasses these are passageways from the conditioned household space to the 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.
That s about it pretty simple.
When moisture gets into the attic it condenses on the roof sheathing in the form of frost.
Frost gets into the attic from air leaks or attic bypasses.
Inadequate attic air sealing.
The frost itself doesn t do.
Full home humidity systems.
Frost shows up in the attic when moisture laden air from the house gets into the attic.
I have a 1000sqft attic floor area with two 301 maximum static roof vents.
To start frost accumulates when moisture laden air from the house gets into the attic.
When the moisture gets into the attic it condenses on the roof sheathing in the form of frost.
During winter conditions attic frost is a problem associated with attic bypasses.
I noticed that i have frost in my attic in the winter and that one of my 2 roof vents is forming condensation which is dripping onto the insulation.
Lack of attic air sealing also allows frost to form as warm air penetrating into the attic causes moisture to condense on chilly surfaces.
That s about it pretty simple.