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RE: Wood Difference[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: <seaint(--nospam--at)seaint.org>
- Subject: RE: Wood Difference
- From: "Scott Maxwell" <smaxwell(--nospam--at)umich.edu>
- Date: Thu, 26 Jun 2008 23:31:05 -0400
The one thing that I would modify is that not all timber sizes are always specified in nominal dimensions. Some are specified in net dimensions (aka "real" dimensions). You can see this often in the timber framing industry. Of course, those dimensions might be when they are green timbers, so the real dimensions for in use after the timbers have reached an equilibrium moisture content in use will typically be smaller due to shrinkage.
And while I am no grading expert (I know enough to be dangerous), you are correct in that timbers technically must be re-graded if their length is modified. This is due to the grading being a function of the number of knots within particular section of length...if the overall length of that member changes, then that reference length can change as well. I don't believe that is true of lumber material (i.e. 2xs) if I recall correctly.
As to "naming", technically in the NDS, typical stick framing is "dimesion lumber", which is lumber that is 2" to 4" thick (nominal) and 2" (nominal) or more in width. Then, there is "beams and stringer" lumber and "posts and timber" lumber...both of which are commonly referred to as "timbers"...both of which are 5" in each dimension or greater, but with "beams and stringers" being at least 2" wider than they are thick and "posts and timbers" being less than 2" wider than thick (i.e. "beams & stringers" are more rectangular" while "posts and timbers" are more square). But, officially, the NDS refers to it all as lumber. But, the common terminology is lumber for the "stick" stuff and timber for the "beefy" stuff.
- Re: Wood Difference
- From: Jordan Truesdell, PE
- Re: Wood Difference
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