[Strawbale] Dual-slope roof (was Re: Planning a home of BigBales 2011 in Estonia)

[RT]

On Tue, 01 Mar 2011 05:38:00 -0500, Nikolay Marinov <nikvesmar at gmail...>  
wrote:

> If you make the roof more steep in the central part, and leave the slope  
> like this at the
> end, it will reduce the hevy snow loads. The snow from the steeper part  
> will push the snow from the lower roof, and
> in snowy days it will be self-regulating.


I would not recommend such a roof design in snow country.

Experience here in Canada has shown that it is a recipe for ice damming  
and subsequent water damage to the materials in the roof assembly, ceiling  
materials and living space below.

What happens is that snow tends to collect in the "valley" at the junction  
of the two roof slopes and then freeze/thaw cycles results in snow melt  
backing up and defeating the flashing.

Generally speaking, a 7/12 slope (30 degrees) is close to the ideal slope.

It is steep enough to shed snow efficiently in winter but not so steep as  
to make wind a major concern WRT to live loading.

-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada
< A r c h i L o g i c  at  Y a h o o  dot  c a >
manually winnow the chaff from my edress if you hit "reply"
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