Depends what you are optimizing for -- roof collapse in a high snow load local or the level of efficiency for thermal properties. You can drive for high efficiency of your thermal properties but when your roof collapses those efficiencies are meaningless.

Home design is a game of engineering tradeoffs with the occasional new technology to improve things or lower costs.

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UltraSane 4 hours ago | parent [-]

An A-frame is a overkill solution to snow load when you can just make a shallower roof stronger.

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dathinab 2 hours ago | parent | next [-]

only to a limit

enough snow, especially if compacted, especially if it involves melting + refreezing cycles turning part of it too ice and even robust concrete building can have some surprising issues

but it's true that for what most places in the world need a slightly tilted and structural stable roof is good enough, if you know how to clean it if things to south

	▲	UltraSane 20 minutes ago \| parent [-]
		If you get that much snow you should build heating into the roof to melt the snow just enough to slide off

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pastage 4 hours ago | parent | prev | next [-]

Tradition says that this is not true but honestly I have no real experience except I have done the calculation for our roof. According to our local building standards at 60⁰ you basically have zero snow load, I am not sure what angle a shallow angle roof is but 30⁰ is max load. 6kN/m² is a lot of extra strength.

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cheeseface 3 hours ago | parent | next [-]

In Finland, where you can easily get 30cm or more snow, all roofs are required to stand 100-300kg/m2 by law and most roofs are less than 30 degrees (e.g. 1:2 ratio).

A-frame or even 45degree angle roofs are very rare.

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jaggederest an hour ago | parent [-]

30cm is just kinda cute. Try 600cm - you'll find a lot of A-frames up the mountain, where they routinely get >700cm of snow each year and generally no thaw until spring. Alaska, similarly, but there you'll find more domes and steep-roofed chalets, since it gets proper cold (-40) and insulation uber alles is the rule.

The other benefit of an A-frame is that the snow drifts deeply enough that winter-only cabins don't need as much insulation, because there's a 4m drift on all sides except the front.

Those kinds of places are also where you find "doors to nowhere" on the 2nd floor, because that's the winter access. One door at ground level for summer, one door ~1.5-2m up for winter.

I love visiting, but I'll never live there!

	▲	jimnotgym 9 minutes ago \| parent [-]
		I read this as in Finland you can get 30cm snow in a day. And the second person is comparing that to 600cm in a year. Am I right?

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UltraSane 3 hours ago | parent | prev [-]

The only limit to how strong you can make a roof is really money. If you space joists or trusses half as far apart you will about double the max snow load.

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xnx an hour ago | parent | prev [-]

Why not "just" make a weaker roof steeper?