Ice/Frost in Attic

[ThePenIsMightier]

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I've never ventured into my attic because I'm grossed out by spiders/bugs etc. But seeing this thread, I'm gonna take a peek. Also try to pinpoint how to fix my bathroom vent, you can hear it flapping when its windy out.

I don't think you can fix that flap. A spring that would hold it down would be too tight to let it open when you turn the fan on. All of mine flap in the wind. It's annoying but I think there's nothing you can do

[redblack]

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Ya my hatch is already insulated, just not well sealed i think.

All of my frost is gone too. I replaced the seal around the hatch and spray foamed around my bathroom vent as well. I’ll probly check it again at the next cold snap.

[CokerRat]

I dealt with this problem last winter, when we had the ~2 week cold snap in early February followed by a chinook. It resulted in hearing drip-drip-drip in my interior walls and some water coming through the ceiling over the course of four or five days. For context, this is a 2007 2-storey construction.

I talked to three contractors. Predictably, maybe, the blown-in-cellular insulation contractor said it was underinsulated and to add 6 inches. The foam-insulation contractor said it was poorly sealed, but that replacing all our cellular foam insulation with spray foam would fix it --for about $12K! And the ventilation contractors said it lacked proper airflow.

Here's what I believe. Air egress from the living space into the attic is totally normal and largely unavoidable and, when it does, it will always freeze on the underside of the roof. In warmer weather, that frost melts and if you have adequate natural air flow, then that water will leave as humid air and only a small amount will dribble down the roof/walls as liquid... probably gets caught by the insulation etc and the homeowner is none the wiser.

Ventilation is normally accomplished by soffits (ie. the perforated panels under the eaves along the "long" sides of the house) and then vents in the roof. Turtle-style vents, the common low-profile things you see sticking off most roofs, can get easily blocked by snow and ice -- potential problems. In my case, it turns out my house has no soffits!! Just an artifact of an unusual roof design where there are no "long sides to the house" and therefore no soffits, ergo inadequate ventilation. So I had a contractor put in some high-volume "stack" vents which can move more air and won't be blocked by snow. Unfortunately... I heard drip-drip-drip earlier this week in our chinook, but it was only one day and so I am maybe surmising that more of the water was carried away by the airflow -- definitely better than last year but not totally solved.

I am planning just live with the situation, monitoring. If I get another stint of several days of dripping or water coming through the ceiling again, I'll probably go the (expensive) spray foam insulation route to reduce moisture getting into the attic.

Hope this helps.

[suntan]

So you still have no soffits?

[gyromonkey]

Due to Fire code, lots of houses have no soffit and or solid soffit. It is very common practice to see a lower set of roof vents 4' up from the eve's along with with a set along the upper ridge. This allows the roof to act in the same manor of as it would with vented soffit. most zero lot line and multifamily homes are done this way.

[88CRX]

Like Coker decided, adding more vents is the proper solution. And making sure your access hatch is as air tight as possible.