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Lumber Grading

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Bill,

Grading rules for lumber are very complex and detailed to go into on the 
list.  I would suggest going to a library or a lumber company and asking to 
look at their copies of the WWPA or WCLIB grading rules.

The chamfered edges would by limited as "Wane."

The knot location and size would be limited by "Knots" in the grading rule 
for the grade, and also at the rear of the grading rules for location of the 
knots.

I would also look carefully at the grade stamp.  If the grade stamp is not 
from WWPA or WCLIB, I would check to see if the grading agency was approved 
to grade the species.

And finally, grading rules permit 5 percent (one piece of every 20) of any 
visually graded shipment from the mill to be below the marked grade!  If your 
visual inspection shows that the lumber is below grade, the contractor would 
probably replace it without complaining to the supplier.

Hope this helps.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Bill Allen wrote:

>>During a structural observation, I noticed a couple of headers that looked
pretty bad. On some areas, the corners are chamferred, there is some
blackened or distressed areas and knots on the tension face near midspan.
The design documents specified DF #1. There is a grading mark on the
headers. On one, there is a "DF 1" and, believe it or not, on the other
there is a mark that reads "SEL STR".

Can I reject these pieces of lumber even though they are marked to meeting
specifications?<<

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