Unintended Consequences of an Efficient Attic
Shortly after buying a couple 1960’s ranch houses as rental properties about 6 or 7 years ago, I air sealed the ceilings, installed custom-fit vent channels and eave blockers, then blew in a foot or more of cellulose or fiberglass over the existing batt insulation.
It was evident over the next few years that the effort paid off. While neighbors and some of my yet-to-be upgraded houses experienced ice dams most winters, the two ranches were ice-dam free.
This winter has been unusual in coastal Southern New England. Weekly snow storms for the past 6 weeks have covered us with about 6 ft. to 8 ft. of snow (now settled down to about 3 ft. around me) and temps haven’t broke freezing for most of that time. It’s the prefect conditions for ice dams and you can see them on nearly every house. But the two ranches are ice dam free (for the most part).
The problem now is the snow piling up on the ranch roofs. So much snow is piling up that weight may become an issue – especially if it rains. Though the other neighborhood homes have ice dams, they have very little snow on the roofs. And of everyone I know in the area, only one home has experienced a roof leak due to the ice dams; and it was a small leak.
So I spent 11 hours shoveling 2+ ft. of snow off the two ranch roofs and just 3 hours breaking up ice dams on three other houses to reduce the chance of water leaks.
Lying in bed aching after shoveling, the thought ran through my mind – was it worth doing all the air sealing and adding extra insulation and roof vents if the result is having to shovel off these two roofs?
Or would I have been better off just leaving them as they were and dealing with the ice dams?
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This 1961 ranch had a insulation upgrade 7 years ago. Now it doesn't get ice dams - but the snow piles up and up with each successive storm.
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Shoveling 2-1/2 ft. of snow off a 1500 sf roof takes 4 to 5 hours without a break (unless you count the back).
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The ridge vent is covered by 2 ft. of snow. A small hollow in the snow developed where a small amount of warm air escaped through the vent slot.
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Neighbor's house with heavy ice dam in the process of being removed.
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Gee- a sudden flurry of articles / blogs / questions about winter storms.
MAYBE ... here is the makings for a special FHB issue, to be on the stands in September - while there is still time to prepare for winter?
Imagine .... an issue dedicated to improving EXISTING homes, from crawl space to rooftop. Articles on venting, heat trace, thawing / fixing pipes, inspecting before and during storms.
Mike,
Do any of your properties have a standing seam roof? Do you see this happening with SS? I'm guessing the roof in the photo is 5/12 - 7/12 (hard to tell), do you think a steeper pitch would make a difference, or just make it harder to shovel?
Here you go, Renosteinke. These cover a lot of what you are looking for, but you can use the search bar at the top of the page to find much more on these and other subject. Members can access 35 years of FHB. -Brian
https://www.finehomebuilding.com/how-to/articles/sealing-damp-crawlspaces.aspx
https://www.finehomebuilding.com/how-to/articles/attic-insulation-upgrade.aspx
https://www.finehomebuilding.com/how-to/articles/a-crash-course-in-roof-venting.aspx
https://www.finehomebuilding.com/how-to/articles/low-risk-reroof.aspx
https://www.finehomebuilding.com/how-to/articles/10-roof-goofs-how-to-fix-them.aspx
https://www.finehomebuilding.com/tool-guide/articles/surviving-the-storm.aspx
https://www.finehomebuilding.com/how-to/articles/fixing-leaky-copper.aspx
Airithol - Metal roofs tend to shed snow and ice more readily than asphalt shingle so in some high snow areas roofers will install metal on the bottom 4 ft. of the roof and then asphalt above that.
Slope doesn't seem to have an impact on ice dam formation. I've removed ice dams on 4 pitch roofs and 12 pitch roofs. The only advantage of a steeper slope is the puddle behind the ice dam doesn't tend to extend up the roof as far as one on a low slope roof. That's just a function of geometry.
Here is a link to something new - at least "new to me"...
http://avalanche-snow.ca
I have seen a couple videos on tools similar to this - call it a "snow-slide" or ??? - but it enables you to slide snow off the roof from the ground - no more fear of stepping off the edge... -
Not sure where these are being sold in the USA - and there are other products "just like it" coming out - so competition may being the price down -
GH
Gord,
Thanks for the tip on the Avalanche Snow Removal system. It looks pretty slick in the videos.
I dug a little deeper and located the manufacturer's website. They have a 'Dealer' search box where you can plug in your Zip and see who sells the tool nearby. I found a few retailers within 20 miles of my house.
Here's the link:
http://avalanche-snow.com/dealers/
I have a ranch home as well in western CT that I air sealed and blew about 8-10 inches of cellulose in the attic (and would like to double that) I barely have an icicle on my roof edge but have had the same problem with snow build up. I've probably had at least 3' near the ridge at one point. I finally decided to go shovel some off. Not because I was worried about leaks but of a roof collapse if the weather were to warm up or if we ended up with rain. It was a long painful time shoveling from the ridge down and finishing from the ground with a roof rake but I'm glad I did it and glad I spent the time air sealing the attic. It has saved me money in the long run and I'll be much more diligent in clearing snow before I end up with 3 feet of the heavy stuff. I guess we each need to decide what's best but if I were building a new home I'd be sure to make the roof strong and air seal and insulate as I have now. The only reason I shoveled is because these 50's and 60's ranch homes were built with only 2x8's and maybe less but I love seeing the snow up there and no ice.
Here is another interesting snow removal system.
MinnSNOWta Roof Razor®
I can't use it as I have a raised rancher but it looks very useful.