Getting ice dams after polyurethane insulation, is it normal?
Mike
7 years ago
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7 years agoRelated Discussions
How to insulate a conditioned attic after framer mistake
Comments (44)It's helpful to know the code requirements and unfortunate that the builder was not familiar with them and did not follow the contract documents. Your builder and architect should have already presented you with all of the possible alternatives. One alternative should be to remove the non-complying work and building the roof as required by law and the contract. Section 9.19. Roof Spaces 9.19.1. Venting 9.19.1.1. Required Venting (1) Except where it can be shown to be unnecessary, where insulation is installed between a ceiling and the underside of the roof sheathing, a space shall be provided between the insulation and the sheathing, and vents shall be installed to permit the movement of air from the space to the exterior. 9.19.1.2. Vent Requirements (1) Except as provided in Sentence (2), the unobstructed vent area shall be not less than 1/300 of the insulated ceiling area. (2) Where the roof slope is less than 1 in 6 or in roofs that are constructed with roof joists, the unobstructed vent area shall be not less than 1/150 of the insulated ceiling area. (3) Required vents are permitted to be roof type, eave type, gable-end type or any combination of them, and shall be distributed, (a) uniformly on opposite sides of the building, (b) with not less than 25% of the required openings located at the top of the space, and (c) with not less than 25% of the required openings located at the bottom of the space. (4) Except where each roof joist space referred to in Sentence (2) is separately vented, roof joist spaces shall be interconnected by installing purlins not less than 38 mm by 38 mm on the top of the roof joists. (5) Vents shall comply with CAN3-A93-M, âÂÂNatural Airflow Ventilators for BuildingsâÂÂ. 9.19.1.3. Clearances (1) Except as provided in Sentence (2), where venting is provided to a roof joist space, not less than 63 mm of space shall be provided between the top of the insulation and the underside of the roof sheathing. (2) Where venting is provided at the junction of sloped roofs and exterior walls and where preformed baffles are used to contain the insulation, the baffles shall, (a) provide an unobstructed air space between the insulation and the underside of the roof sheathing, that is, (i) not less than 25 mm in dimension, and (ii) of sufficient cross area to meet the attic or roof space venting requirements of Article 9.19.1.2., and (b) extend vertically not less than 50 mm above the top of the insulation. (3) Ceiling insulation shall be installed in a manner that will not restrict a free flow of air through roof vents or through any portion of the attic or roof space. 9.19.1.4. Mansard or Gambrel Roof (1) The lower portion of a mansard or gambrel style roof need not be ventilated. (2) The upper portion of roofs described in Sentence (1) shall be ventilated in conformance with the requirements in Articles 9.19.1.1. to 9.19.1.3....See Moreice dam problem
Comments (5)We had ice dams this winter, too, and we have 6' of membrane under our shingles! We think the water was going between the gutter & facia board, then running into the window & leaking. It all melted in 1 day so we dind't have to do anything other than DH getting on the ladder & pounding the ice with a hammer, but I did read online that you can fill pantyhose with calcium chloride and lay them on top of the ice in the gutters, and it will melt the ice. If it happens again we will do that. We have a Cape Cod style house and they are bad for ice dams. Could it be the style of your house? Do a google search on "ice dam removal" and you'll find a ton of ways to remove - but a lot of the cites mention the panty hose & calcium chloride so it must work....See MoreFixing ice dam/fascia problem with...a silicone bead?
Comments (12)Ya, that why I said "much" of the problem. I've always increased the size and slope of my eavestroughs to facilitate the ability of that near frozen water to get gone as well. Aggressive slope cures lots and you can trim it or paint it to minimize the street look. We have a few homes in Calgary and it can Chinook on you, be well above freezing and then drop, leading to immense ice issues if you don't get out in front of them. Between air sealing, insulation and good drip edges along with attention to the troughs and downspouts (don't make freezing water travel too far before you divert it down) we have substantially minimized our issues. And Brick is right, each home is a bit different, each geographical location is a bit different and here in Canada we don't have stuff like air handlers, hot water tanks or aircon in our attics, so you have to watch for those variables as well....See MoreMayday: Ice Dam!!!!
Comments (11)I just made a long post to answer someone else's question about ice dams over on the Old House Forum. I'll attach a link. But your situation sounds slightly different. For first aid, I would take advantage of the slight moderation of temps and get up there and get the ice and slush knocked out of the gutters, ASAP. Start at the down spout point and clean up along the line to get past the point of blockage. A hair dryer can help, particularly if you have aluminum gutters. It won't do much to solidly frozen run, but to hasten the removal of slush it works OK. A flat panel paint burner can help, too, but takes some experience to avoid damaging the surrounding surfaces. With both these please use a GFI outlet to plug them in since you'll be awash in water and using an appliance at the same time. I would never allow anyone to use a torch to do this, though. Too dangerous. After the gutters are clear, and until you can make any necessary changes to insulation, slope of gutter, flashing, roofing or underlayment, etc., you will just have to rake the roof after every snowfall. It's not that hard to do. I always used to let my DH do it, but last year he was laid up so I found it could be done pretty easily. I was doing it on my second story this afternoon. The good thing is that ice dams seem to be an artifact of of early, unusually cold and snowy winters. Later on in the season the sun is higher and it's less of a problem. HTH, Molly Here is a link that might be useful: Ice dam question on Old House forum...See MoreMike
7 years agolast modified: 7 years agoVith
7 years agolast modified: 7 years agoMike
7 years agoUser
7 years ago
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