[Strawbale] plwood vs. osb for arch gussets

[Chris Green]

Rob Tom wrote:
> Since you've sawn them yourself, it's reasonably safe to assume that the  
> 2x10s weren't graded and there's nothing wrong with that *iff*  (ie the  
> mathspeak "if and only if" )
> you are well-versed in lumber-grading procedure and can adequately assess  
> the quality of each piece using the same standards that a real lumber  
> grader would use.
>   
It is my understanding that any lumber used in load-bearing construction 
in Canada has to be inspected and grade-stamped. ( I read that in 
Harrowsmith magazine... ) The majority of the grade stamps have to be 
visible on studs, sills, headers, and what-not when the inspector comes 
around, but not on the shorter pieces like drywall blocking and such.

This might not apply to "agricultural buildings", though....

You can saw and plane your own lumber, but it can be quite difficult to 
track down a free-lance lumber grader who will bring along grade stamps 
and go through your piles. You might be able to contact someone through 
the following National Lumber Grades Authority link: I notice there are 
at least two grading authorities which operate in Alberta, the Alberta 
Forest Products Association, and Macdonald Inspection Service.
http://www.nlga.org/app//dynarea/view_article/2.html

Macdonalds link:
http://www.gradestamp.com/

I used to grade lumber under a conditional lumber grading permit from 
the ILMA, many years ago, and my average accuracy rate was around 98% ( 
rather high, even compared to veteran graders of my day, who only have 
to be above 90%. ). The condition on my permit was that I was supposed 
to take the classes and get my ticket. However, every time I started the 
classes, I got laid off from whichever mill I worked at.

Trusses:
The minimum thickness of ply for plywood gussets is 3/4", by the way, 
with gussets placed on both sides of the  #2 or better SPF 2x X member, 
and nailed through from both sides with spiral or 'concrete' nails just 
long enough to poke through the other side. Or about 3" long.
Canada Plans Service is a government agency which supplies brochures 
about various farm related things, including how to build roof trusses 
for farm buildings. Download their pdf. about DIY roof trusses here: 
click on Roof Trusses.
http://www.cps.gov.on.ca/english/be9000/index.html

You'll want both plans M-9100, and 9101: 9100 supersedes the older plan 
9101, but 9101 shows assembling the trusses ( with 1/2" ply, since 
changed to 3/4" ply), and has some other important advice.

Would I use beaver barf-- I mean, OSB-- for gussets? Not if I can avoid it.

Cheers,

Chris Green.








Cheers,

Chris Green.