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TOPIC: Ice Buildup

metal solve ice dam problem?

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I have a low sloped roof with open ceilings inside. The ceiling is cedar follwed by shingles, no insulation. The heat going through the roof is causing ice dams followed by a leaking roof. Being a log home, I would prefer to keep the cedar 1x6 planked ceilings and try to fix the problem from outside. Would a standing seam metal roof eliminate my water problem? If I go metal, can I add ridgid insulation over the ashphalt shingles and then apply the metal roof? I am having a hard time seeing how metal is applied over the ridgid. There must have to be some type of strapping applied?
Guest User

1/25/2005
You need ventilation, insulation, interior air barrier and an exterior air barrier. The best way way to fix this properly is to remove from the top down, reframe as required and insulate with sprayed in place, then istall a moisture barrier underlayment and your roof covering leaving a min 1" vented air space.
Allan Reid
Dura-Loc Roofing Systems, Inc.

1/26/2005
hello, I have a 1950 sq ft roof with a 60' slope. Currently shingled with 2 dormers on the cold side and a porch on the warm side. The 2nd floor (1 1/2 storey house) was insullated and vapour barriered but not sealed with tape (barrier plastic had about 1 foot of overlap but not taped). The house was heated intermittently throughout the winter and suffered serious ice damming. In the spring the roof leaked where there was ice damming. I have been told that sealing the vapour barrier would solve the issue next season. I have also been told that I may need to put a metal roof on the house. I would entertain the thought of reroofing with metal but the shingles appear to be in good condition. My questions are: What % of my ice damming issues are related to the 2nd floor vapour barrier not being sealed with tape? If the roof appears to be in good condition but leaks where there is serious ice damming, is re-roofing the next step? What is advisable, re-sheet, seal and re-shingle, OR metal roof over everything? My air flow in the attic seems fine but I was told to buy a better roof vent and when it is installed to close up any other venting I may have. I have at least 4 vents in the attic right now (according to the ventilation code requirements). Do I have to seal them up? thanks,
Guest User

4/11/2006
Unfortunately you have not provided complete enough information to best answer the question. If you insulated the space in the roof rafters, then you have stopped the air flow. The building code requires vented air space between the insulation and the roof covering and the insulation would block the air flow. Second then is the heat loss that goes through the joints taking moist air that condenses and freezes, third is the warm air that gets through, melts the snow and ice on the roof in sections causing ice dams and water leakage and fourth is that you may have not used enough insulation. Start over and correct the problems. Make sure you allow for proper air flow from the soffit to the ridge. Calculate it as it should be balanced. Add the proper amount of insulation, which in ceilings is an R40. You will probably have to frame out to receive this. Then install the air barrier sealing all penetrations and laps.
Allan Reid
Dura-Loc Roofing Systems, Inc.

4/12/2006
as soon as fellow engineers and AIA's start considering eves as part of their design job description then maybe I will not spend two or three months each Spring repairing expensive damage. I now offer AIA's solutions for this problem that existed as long as I have been alive when(six decades)[email protected]
Guest User

4/19/2010