# Ice damming and snow build up.



## Hoodoo Valley (Nov 14, 2006)

Before I explain my situation, I know we all regret Winters onset, but I really need to combat a situation right now, before the weather starts changing! I've been a builder for 35 years, and understand what causes ice damming in the first place, and how to orient roofing so that you don't get snow build up.......... Eliminate valleys, and have excellent insulation! 

So here's the issue. The original house was built by my father, and I helped him out as well as a 13 year old could help. About 14 years ago, I added on to the house, doubling the size of it after I bought it from my parents 27 years ago. I did the best I could integrating the new roof into the old roof, giving the budget, and time constraints. On the old portion, as it's a hand stacked roof with a valley that dumps on to a valley roof just below it, and having insufficient insulation, the roof ice dams severely, to the extent that left unchecked, Ice build up will approach a foot thick, and water starts running into the house, and I'll get, have gotten up to two feet of ice on the lower valley. On the front of the house it's very similar. Melting snow on the original roof causes water to run on to the new portion I built, and freezes.... up to a foot thick before I go up on the roof with a splitting maul, wrecking bar and a shovel. The original roof is 2X10s which have 10 inch insulation, and no ventilation above whatsoever. The new portion I built is trusses that I built on site, and they are outfitted with 24 inches of blown in for R 60. There is one portion of the new addition that is roofed totally separate of the old roof, and it's an 8/12 pitch. Total cold roof and zero issues apart from having up to 4 feet of snow up there and not shedding it. Other wise, not so much as an icicle on the roof eave. 

Knowing that the only real option is to build up the original roof which has been skip sheeted with 2X4s and add more insulation, or remove the old fiberglass and add closed cell....my question is this....... Is there any products available such as the heat tape that we apply to comp roofs here, or another product that can be applied to metal roofing, that would keep the ice from building up in these areas. This is a real enemy in my area. I'm fixing to fabricate some aluminum tubing that can be attached under the metal at the valleys (hidden fasteners) but lay across the metal valley's and be heated with a light bulb or some sort of minimal heating element. Anyone ever gone there before, or is there a product suited for this application? After battling this ice for 40 years literally, I'd like to see if I can make the roof a bit more user friendly!
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## Guest (Aug 20, 2018)

Here's an interesting article:
http://www.newenglandmetalroof.com/blog/how-to-prevent-ice-dams.php


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## RC Wells (Dec 26, 2008)

I am sure you have seen these type products: https://www.icedamcompany.com/ice-dam-prevention/shop/how-to-install-heat-cables/

I know they prevent ice dams in valleys and gutters, but required blind nailing the brackets and looping the heat tape in large loops to stop the ice on the ski house. If the power goes out and the stuff freezes in, the nail plates start ripping out as the ice builds up. 

I finally gave up, rebuilt the roof to a single pitch and installed standing seam metal.


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## Hoodoo Valley (Nov 14, 2006)

RC Wells said:


> I am sure you have seen these type products: https://www.icedamcompany.com/ice-dam-prevention/shop/how-to-install-heat-cables/
> 
> I know they prevent ice dams in valleys and gutters, but required blind nailing the brackets and looping the heat tape in large loops to stop the ice on the ski house. If the power goes out and the stuff freezes in, the nail plates start ripping out as the ice builds up.
> 
> I finally gave up, rebuilt the roof to a single pitch and installed standing seam metal.


I've installed a crap ton of the standing seam, including the fully floating roof systems. Expensive but top of the line.


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## Guest (Aug 21, 2018)

Were you able to open the link I sent? I'm hoping I misread or misunderstood your current situation. Did I understand that the original roof has no soffit or ridge vents and no separation between the insulation and roof sheathing? If so, that's not a good situation. The additional insulation you want could be installed on the attic flooring?


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## Hoodoo Valley (Nov 14, 2006)

Unsure how this got by me. The roof is skip sheeted with 2X4s and so there are vents up the rake at the wall line, but there are valleys, no vented ridge cap, and the felt paper has sagged in between the 2X4s over the years. I've opened the roofing up at times and there is no mold at all, but absolute signs of moisture entry in places at the wall line, but mostly from water backing up from the ice damming. Contemplating running butyl down each lap in the metal, and heat tape outside the wall line. The roof is 2X10 rafters and no attic. I was able to open the link Al, thank you!


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## Hoodoo Valley (Nov 14, 2006)

Snow isn't really the problems so much as the ice build up. When you get in excess of a foot of solid rock ice on your roof, it really wakes you up!


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## Guest (Aug 31, 2018)

For sure! Question: what is skip sheeting?


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## Hoodoo Valley (Nov 14, 2006)

Graysonr said:


> For sure! Question: what is skip sheeting?


Usually roofing is solid sheeting, be it plywood or 1X material. Up here in North Idaho (and other areas I'm sure) money is an issue, especially when I was a kid growing up. So some folks opt to space in between sort of like on a pole building with purlins. My roof, has 2X4s spaced 12 inches apart I believe? My dad bought a couple units of number 4 economy 2X4 studs from Merrit Brothers mill locally to me, at the foot of the Priest River (Merrit Brothers bridge) that crosses the Pend Orielle. The mill has changed hand so many times and is now Stimpson. Most of the lumber was better than the number 2 & better you see these days. No lie!


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## Guest (Aug 31, 2018)

Ok, I'm familiar with that method.....used normally under metal roofing..… off subject I knew a guy lived north of Vallejo CA and bought a ranch style house built in early 70's.....had a roof sheathed in tongue and groove redwood!


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## Hoodoo Valley (Nov 14, 2006)

Probably the cheapest at that time. In the 1970s cedar was cheaper than dirt and I've remodeled a few houses here that were sheeted floor, walls and roof with 1X4 solid and all triple nailed! You buy cedar now, and it's weighed out to the ounce on a triple beam!


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## tcreeley (Jan 2, 2012)

I used to get bad ice damns on my asphalt shingle roof. What I did was frame it up with 2x4s running down the rafters and then across to hold metal roofing. Air could get in at the bottom edge and vent at the top through a vent in the peak. With the flow of air I got rid of condensation and any build up of snow/ice - if it melted just ran down the metal roof. - Basically I added a 3" air gap between the old roof and the new roof - and vented it.


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## Hoodoo Valley (Nov 14, 2006)

I actually did this on one of the shed roof dormers, but the main part of the roof has more shed dormers that make doing the build up there a bit more involved. What I'd really like to do is remove the fiberglass and add closed cell foam insulation, but geeze oh that material is sure expensive!


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## Guest (Sep 3, 2018)

knowing what you have said about your plans for the future, tcreeley's air gap could work....you don't want to have to stay home just to make sure a heat tape is working. They sell foam trays that you put up between rafters to ensure the air gap stays open. You would want the air gaps even with the foam insulation. You need air flow to prevent condensation and let the surface of the roof to stay cold.


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