Ice Dams and Snow loads

My wifes sister just sent us some pictures from Nova Scotia CANADA, they lost one of their second floor ceilings due to ice dams and having no insulation in their attic.

Today I installed 96 l/f of heat tape for a customer who had a frozen pipe last week.

I shoveled off 4 ft of snow drifts from my flat roof this week. We are also dealing with some ice dams too but nothing like some of the folks who have major heat loss from their eaves. Some homes have water seeping behind their sidewall and leaking out during the day when its warm out.

This is absolutely not a typical winter in my part of the country this winter.

Who else has some of this stuff to share?? Roof collapses? water damage due to icing?
unpassable roadways that used to be 2 lanes etc etc??

 

I mentined it in the various storm threads... Major ice damming here, mostly on the addition. The house has been insulated but there is not enough venting into the attic space over the addition so we get ice buildup. Water is coming into the attic.

Ive been raking it for a week but have to do a major cleanup before this next one, will try to get some photos.


Interestingly the C.1700s part of the roof does not ice up nearly as bad.

 

Only experience with ice dams was last winter.

I got some calcium chloride tablets (think hockey puck size) and placed them on the uphill side of the dam. Worked liked a charm.
in case you are wondering, that's the best ice melt $ can buy. Works down to negative 25 degrees.

 

NH canopy collapsed yesterday. This... before the next snow load coming this weekend. You guys who've put the time and sweat into getting snow off your roofs have to feel perty good about it...

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Couple weeks ago had an ice dam right above the mud room door. Water ran down a rafter right over the crack between the door and jam. Filled the crack all the way to the floor and froze. Couldn't get out the door. WTF
We had 35-40 temps last Sat/Sun so I shoveled the eves/ice off Saturday and Sunday it was loose enough that a 3lb hammer busted it up and off. Sunday night we got an ice storm and everything is coated now. Already tired of walking around like a cat on wet glass chitting needles.

 

The latest warning release from the NWS is warning people to remove snow from roofs. I have a lot of work to do today.

* IMPACTS...PERIODS OF HEAVY SNOW WILL MAKE TRAVEL CONDITIONS
SLIPPERY AND LEAD TO LOW VISIBILITIES. GUSTY WINDS AND BLOWING
SNOW COULD LEAD TO ROOF COLLAPSES ON AREA ROOFS NOT CLEARED
FROM PREVIOUS SNOWS.

 

Don't forget the home's venting. Dig way away from them. One to two feet of snow anticipated this weekend in blizzard conditions.

 

This is my neighbor's newly built garage, it shows some water and ice damage on the exterior wall from ice damming on the roof. People often claim ice damming is caused by heat getting through the attic, but this garage was not heated and there was still significant ice damming.
It's interesting to note that this is a band new building with everything built to code, including the roofing. There was even a waterproof membrane put down that covered the entire roof,,, before the shingles were put down.

and the other side of the building.

 

I would consider metal roofing for that

 

Where's the heat coming from? The sun? I'd be rip chit if that was my newly built garage.

 

That's why I have metal on my roof. In fact the neighbor re-roofed the house you see in the background just last year and did it with metal this time.

The only heat could be from the sun warming the roof and then re-freezing when it got cold again. I saw them roof this place, everything was done according to code, in fact the inside is also built according to code (insulation, vapor barrier, etc..), but since the place was never heated it should not have come into play.
After seeing this with my own eyes I can only come to the conclusion that ice damming problems like that can be caused by weather related conditions alone, and shingle type roofs with low pitch are particularly susceptible to ice damming leaks. (this is a 4/12 pitch roof, so the pitch is code as well) It's also worth noting that I heard of many other people having similar problems on their houses that year where they never had problems before, which also points to the weather related freeze thaw cycles that year being the cause.

 

Lumber-Jack that roof looks pretty good for around here! I think you are right, even built to code and well insulated we can not control mother nature. Hopefully the ice & water shield prevent real damage.

 

I didn't look at the pics very close Lumber-Jack . The first pic didn't have a downspout from a gutter and I thought the second pic was the same side. Duh. Now I don't think anything, as far as what's on the roof itself, is their problem. Now that I see there are gutters on both sides, that's where the entire problem is. Sun is always gonna melt snow at the very edge of the roof, even if it's a little below freezing (that's when it's the problem). Soon as that water hits the gutter, it's frozen solid. Capillary action is running the water back under the eaves and down the wall. That's why the water shield under the shingles couldn't help. Look and you'll see there's no ice on the roof, only from the gutter up to the roof. My SIL & daughter's place has that exact problem all along their house. It was solved by heat cord that runs along the bottom of the gutter and down the drain pipe. When he remembers to hit the switch before ice starts building, they're all set, when he forgets, it does exactly what your neighbor's garage does. If they install that heat cord in their gutters and down the drainpipes, they should be good. My 2 cents.

What a mess in the meantime.

 

A valley on a metal roof is very vulnerable to ice dams. My BILs leaked like crazy last winter. He has R 60 in his attic too...overkill for around here.

 

I believe you are correct about the ice dam building up because of the gutters, however it still proves my original point that it has nothing to do with heat loss through the attic. And just to clarify one thing you said, the ice dam did back up onto the roof as well.
It's crazy that the only solution might be to install heat tape in the gutters. I mean the vast majority of houses don't have heat tape in their gutters and never have a problem.

Again a case of ice damming likely not at all related to heat escaping through the attic.
I'm glad my metal roof doesn't have any valleys in it. Although it does have one area where it transitions from a high pitch roof down to a low pitch roof with a overlap seam and possible leak area. I try to clear the snow off the low pitch part of the roof as much as possible.
I also installed my gutters low enough that the snow slides right over top them, but allows the rain water to run into them.

 

"still proves my original point that it has nothing to do with heat loss through the attic." ... I assume you mean this guy's garage? The vast majority of ice dam problems in Maine are pretty obviously from heat loss up thru the roofs as many don't have gutters and the ice goes up the shingles 3-4 rows sometimes. And, the older houses are in really bad shape. For sure, heat is heat, no matter how it gets to these damm roofs and man can it do a number on em when the snow melts and re-freezes. When I was a kid, I remember it "raining" in the kitchen from a 6" thick dam running the length of the roof. My father and I out there, in the rain, slamming 2 hatchets at it... taking half of the shingles off with every other swing. Lots o fun.

 

I have a basic 1 story Ranch style house built over a crawl space. It has a 4-12 pitch roof with about a 2.5ft. overhang (eave and soffit) on the East and West faces of my roof. This is the West side of my roof.



This ^^^^ picture was taken the day after the blizzard we had here on Feb. 1 and before I "raked" my roof. I don't have an "after" picture of my raked roof; but I only rake the lower 2-3 feet on each face of my roof..................or the part of the roof the projects out from the house proper. That's enough for the sun to warm the shingles and clear the lower portion of the roof and the gutters. I've been here 12+ years and have never had an ice damm. This ^^^^ picture also shows almost 2 feet of snow on this face of my roof.