Question on soffit venting-long, sorry!!!

Old 01-09-09, 10:16 AM
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Question Question on soffit venting-long, sorry!!!

Last summer we put a sizable addition on our house. We used Corbond insulation, doubled proper vents (approx. 10 feet on each side), then poly under the trusses (It's a low angle roof with no access to attic) that they blew 18 inches + of fiberglass into. We used metal roofing, with a roof vent and soffits that are vented.

2 weeks or so before Christmas we had high winds and snow, around 40-60 mph gusts and sustained winds of around 20 mph. Not a ton of snow, but it blew around pretty well. Then the temps dropped and we had 10-12 days of temperatures that the highs were below or at 0 degrees F and the lows ranged down into the -25 area.

Christmas day we started seeing leaks at the area where the ceiling and wall meet. They've stopped leaking, even with more snow/rain.

The roof is about 6 months old. THe contractor came out to look and says the roof looks good, but that there are two possible problems or a combo of the 2.

We could have had snow get into the roof and/or soffit vents, and we could have condensation from the living space, since the ceiling is not fully finished yet.

My brother runs the section of the place that did the insulation and he says that in 17 years, they've never seen this problem until this year...that he has pictures of snow drifts in attics on the proper vents. He believes that negative pressure with the wind caused the soffit vents to suck snow up into the proper vents, then it froze solid and didn't start to melt until Christmas day. He is recommending to their customers (of which we are one) to replace half or all of their vented soffits with unvented soffits.

Any opinions or comments? I know this is long, but we're just mystified.
Old 01-12-09, 01:09 AM
Join Date: Jan 2008
Location: rockland county,new york
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I doubt it`s the soffit vents,You are getting an ice/water backup,the escaping home heat is melting the bottom of the snow,melting it,and it runs down to the overhang area,where it freezes there ,and in the gutters--this same frozen water in the gutters will melt on the warm side(house side)and cause this melting water to go over the back of your gutters,over the top of your fascia board ,and into the soffit where it runs to the house,and typically down the bearing walls,and/or onto ceilings/wall of living area----you need to have an eave flashing installed behind the gutter,and onto the roof(closes gap between fascia,and roof sheathing),usually a custom bent 3"x3" works well--then install ice and water shield,so it goes minimally 2 ft. past the interior bearing wall---with the metal roof in place,you may have an issue where the metal roof meets the gutter/lack of flashing,or wrong flashing-usually a drip edge is used to hem the roof panels bottom 1" to-the bottom of this drip edge sits above the gutter,and water can push under it-a custom eave flashing should be used instead--pictures help,as well as location ,in figuring out problems

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