Snow covered roof equals warmer house?

This is exactly what is going on. I love knowing snow is coming because of this.

Johnny_Fiv3 said:

This is exactly what is going on. I love knowing snow is coming because of this.

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I certainly hope so. In Palermo you need all the reasons you can get to love knowing that snow is coming!

ewdudley said:

I certainly hope so. In Palermo you need all the reasons you can get to love knowing that snow is coming!

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ROFL, no kidding. It does hold the heat in nice when you get a foot up there. It's when you get 3-4 feet up there that it sucks since now you have to clear it off.

From a search:
Ten inches of fresh snow with a density of 0.07 inches, seven percent water, is
approximately equal to a six-inch-layer of fiberglass insulation with an
insulation R-value of R-18.

DougA said:

From a search:
Ten inches of fresh snow with a density of 0.07 inches, seven percent water, is
approximately equal to a six-inch-layer of fiberglass insulation with an
insulation R-value of R-18.

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So I should be sad when it starts to roll and tumble off the roof?

Actually, I notice a difference when the snow gets deep enough to cover most of the foundation of my house. Hadn't thought about the roof, but I do have pretty good attic insulation anyway.

More snow on the roof is always better - until the roof caves in.

Wet snow is awful insulation.

Good insulation but also starts the ice damming.

DougA said:

More snow on the roof is always better - until the roof caves in.

Wet snow is awful insulation.

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That's why up in Vermont, we have always had steeply pitched roofs and as slick a roofing material as possible. Once upon a time, that was slate shingles. Now it's metal. Roofs just a bit further south, for reasons that totally escape me, are much less pitched and usually covered with rough asphalt shingles, and appear to be deliberately designed to hold onto snow until it melts and runs off into the gutters. We have the occasional roof collapse on a badly made modern barn here or there, but I've honestly never heard of one on a house.

There's no excuse at all for flat roofs anywhere north of the Mason-Dixon line.

I actually shoveled some against the foundation this past weekend to help make an air barrier. It keeps the wind from sucking the heat away as quickly.

My A-frame roof holds up some snow for a little while, but the majority of it slides off. What stays will quickly form into ice from the escaping heat and then it ROARS down the roof in a landslide. Scares the heck out of ya sometimes. I also get great icicles hanging off the sides.

Holzstapel said:

My A-frame roof holds up some snow for a little while, but the majority of it slides off. What stays will quickly form into ice from the escaping heat and then it ROARS down the roof in a landslide. Scares the heck out of ya sometimes. I also get great icicles hanging off the sides.

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I've got good attic insulation, so no big ice problems on most of the house (except for an uninsulated south-facing enclosed porch add-on to the house whose fairly short metal roof isn't very steep). But that rumble-rumble-CRASH-thump! goes on periodically most of the winter and catches me unawares pretty frequently. The cats think the world is coming to an end and run for their lives. But it sure is nice never to have to worry about ice dams, just not to get too close to the roof edges when I'm messing around with firewood or shoveling or whatever outside...

gyrfalcon said:

....Actually, I notice a difference when the snow gets deep enough to cover most of the foundation of my house.

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You can have that "difference" all the time by insulating the foundation walls. Doing it on the outside means some excavation, plus covering the foam with something to protect it against UV and other physical damage. Doing it on the inside means access to the wall surface (of course), plus covering it with something to provide thermal and ignition protection, per code. Here is a good place to start reading, found by searching on "insulate basement wall" over on greenbuildingadvisor.com: http://www.greenbuildingadvisor.com/blogs/dept/musings/how-insulate-basement-wall

DickRussell said:

You can have that "difference" all the time by insulating the foundation walls. Doing it on the outside means some excavation, plus covering the foam with something to protect it against UV and other physical damage. Doing it on the inside means access to the wall surface (of course), plus covering it with something to provide thermal and ignition protection, per code. Here is a good place to start reading, found by searching on "insulate basement wall" over on greenbuildingadvisor.com: http://www.greenbuildingadvisor.com/blogs/dept/musings/how-insulate-basement-wall

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Thanks for the link. I'm actually saving my pennies to do something like this, but in the meantime...

gyrfalcon said:

There's no excuse at all for flat roofs anywhere north of the Mason-Dixon line.

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A lady once broke up with me because we were driving by a Frank Loyd Wright house and I just could not keep my big mouth shut. That guy designed nice-looking houses, but with flat roofs and no gutters, he had some nerve building them in the Midwest. Every FLW home I have visited is always trying to raise another $1 - $3 million to last another 25 years because the foundation rotted, the roof supports are sagging, and there is water damage on the north-facing wall. God help you if you suggest they spend $2,000 on gutters this time when they drop $1 million for a new 20 year roof. It's like I insulted Led Zeppelin or something....

So I said "FLW was a clown", and that was it. How was I to know her whole family were fans of FLW? I was at the University of Chicago last month and talked to the guy in charge of building maintenance about their FLW building on campus. He rolled his eyes. High maintenance.

End of rant.

That is why Eskimos you igloos to stay warm. Put a stove in one and you will get wet.

Just make sure that snow isn't followed by rain because you made exceed the snow load capabilities of the roof. Roofs are designed to handle ~35 pounds/sq-ft. So some is good, but not an excessive amount.

My house was made by one of FLW's top apprentices, and i am just now learning that while beautiful, the roof design is POOR. I moved in in june so this is our first winter here. Have to do some serious thinking this year on how to improve the situation.

TheRambler said:

My house was made by one of FLW's top apprentices, and i am just now learning that while beautiful, the roof design is POOR. I moved in in june so this is our first winter here. Have to do some serious thinking this year on how to improve the situation.

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A good commercial roofer can put on a layer of foam, tapered to whatever sides you want water to run off, then cover with TPO. There will be little change in appearance.

DougA said:

From a search:
Ten inches of fresh snow with a density of 0.07 inches, seven percent water, is
approximately equal to a six-inch-layer of fiberglass insulation with an
insulation R-value of R-18.

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I would have never thought that snow could be such an insulator but it does make sens.

TheRambler said:

My house was made by one of FLW's top apprentices, and i am just now learning that while beautiful, the roof design is POOR. I moved in in june so this is our first winter here. Have to do some serious thinking this year on how to improve the situation.

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This may help you calculate your snow load

https://courses.cit.cornell.edu/arch264/calculators/example2.3/index.html

TheRambler: I always had good discussions with the curators and managers of FLW homes. As long as you refer to FLW as "The Master", they can offer suggestions on improving the drainage. I learned that many FLW homes have done these non-visual "improvements", unbeknownst to the ignorant heathen who pay $20 a visit.

Stunningly beautiful homes....just needs a few improvements. Anyway, call up some of these houses or visit one, and you will get plans, advice, and suggestions for your home. Just don't say that you want to "improve on the design"....unless you are packing heat.

Snow is an excellent insulator. Why do you think all those farmers in Florida spray water all over their orange tree fruit if there will be more than 24 hours of temps in the teens? Because ice stays at 32 degrees and insulates what is inside- keeping it from getting colder. Gardeners use foam cones to cover plants, and like it when snow covers those cones, because it won't get much below 32 degrees.

My house is easily 4-5 degrees warmer with 6 inches of snow on the roof.

Especially when loose, show contains a lot of air which will act as an insulator; actually not quite unlike fiberglass batts. However, when snow on the roof is able to insulate the house then the attic insulation is not enough. The attic should be unconditioned space meaning close to outside conditions. Thus, a snow layer on the roof should not make any noticeable difference.

Grisu said:

Especially when loose, show contains a lot of air which will act as an insulator; actually not quite unlike fiberglass batts. However, when snow on the roof is able to insulate the house then the attic insulation is not enough. The attic should be unconditioned space meaning close to outside conditions. Thus, a snow layer on the roof should not make any noticeable difference.

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Party pooper.