[Cob] Slightly OT: Info on reduced snow load on roofs?

[Amanda Peck]

Where did I read recently that the problem with using site harvested round 
poles was grading?  That the problem is not roundness but whether or not 
somebody has looked at the cut and peeled wood officially to make sure that 
there are no bad spots in each log.  Whoever it was got a professional 
grader from one part of the country to tell a local guy what to look for, 
and for not too much money, the problem was solved.  You might find out if 
that's the problem--if so, it sounds rather as though there might be local 
experts, since they've written a book.  You might need a certified lumber 
grader more than an engineer.

You could use lighter timbers in your rafters if you put them closer 
together.  Whether or not that would reduce your overall dependence on 
store-bought (grade-marked) wood I don't know.  But it might be worth 
thinking about.   Also remember that rafters get shorter, although maybe not 
by enough to significantly affect your cost because that would cause other 
changes in your design, if you lower the angle of the roof.  But 12--or even 
more--in 12 rise does look nice.

But that stuff will be calculated with some if not all of the architectural 
drawing plans--I think even the very inexpensive 3D Home Architect version 3 
does that.  It's widely considered--on another list--as having one of the 
shortest learning curves--but it's not instant!  Version 3, no longer either 
supported by the manufacturer or compatible with the current product of the 
name, is the one to get--on the internet, likely to be under 10 bucks 
including shipping, especially if you buy another title to lower the 
shipping costs per title.  Sometimes available on the bargain shelves of the 
local computer or software store.

I can imagine, it's the kind of thing more apt to happen in the South, a 
horrid situation where, due to a confluence of freezing rain, ice storm, and 
freeze and thaw cycles, ice dams, all the precipitation would stay on even a 
very steep and slick metal roof.  Don't know if it's ever happened, though, 
or if in Anna's area she should plan for it.


...............................
Anna wrote (snipped):
We are putting our plans in to our local building inspector with the change 
he suggested from round horizontal poles to dimensional lumber to avoid 
having an engineer involved. He has been extremely helpful in our building 
process so far, but says there is no recognition in the municipal building 
codes for a reduction in snow load with an increase in roof slope, and as a 
result is asking that we beef up our roof beams to giant 5-ply 2x12 
monsters, as the snow load here is now up to 52psf after a blizzard a few 
years ago. Most of our roof is on a 45' slope and metal so any snow will not 
be there for long!