This is the first time I have seen this happen in my 6+ years of owning my home. It is an older home (45+ years), but has gable vents on both ends (facing east and west). It has always vented well in winter as I've never had too much issues with ice dams.
Last year I re-roofed and also put on soffet/fascia. Since it vented well enough, we did not put a ridge vent on.
My bathroom fan vents up through the attic, but comes out through the wall a little ways underneath the west gable vent.
Recently (the last week and half) we had single digit and even below zero weather. The bathroom fan vent seems to work fine with no issue, but with the cold weather (plus some blowing snow a couple times the last few nights) I now have both gable vents clogged up.
What gives? My immediate question is to find out how in the world do I clean these out? Second, how do I prevent this from happening another time around?
Best Answer
I have to wonder if the bathroom vent is really "fine" or if it's failed in some manner so that it vents out of the bathroom, into the attic (rather than out of the bathroom, through the attic and out of the wall) - that would certainly add a lot of water vapor to the attic...which would be one way to clog up the vents.