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Old 01-24-2010, 01:49 PM   #1
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Knots in lumber


This is a 2x10 dougfir joist I'm using on a deck. It spans 10 feet from ledger to edge of beam. Should I be concerned about the knots weakening the structure?

My contractor friend told me that I should have rejected some of the lumber. Is it common practice to send back warped and knotted lumber out of a delivered load from a local lumber yard? I remember I got lectured once by the yard person, "That's the way we get them, so you can't go picking through the stack".
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Old 01-24-2010, 05:14 PM   #2
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Ova,
Probably not going anywhere. Course, you guys get them earthquakes out there, so not sure how it would hold up to one of those. BTW, that wood looks like yellow pine to me.
Most lumberyards don't want you picking through a whole pile to find two good pieces. But if they give you a hard time about a bad piece of wood, I would find another lumberyard.
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Old 01-24-2010, 06:02 PM   #3
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that is Douglas Fir. The knots are too tight for pine, imho.
The Lumber should be stamped with a Mill number and a grading number. That looks like it would be #2 grade.
If it is graded as a #2, I would not be concerned. The knot on the bottom might be an issue in a very damp crawl space.
In my area, code allows 2 x 8 fir # 2 or better to span 10 ft on 16" centers.
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Old 01-24-2010, 09:10 PM   #4
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Thanks for the responses. This grade of doug fir is our only choice for pressure treated lumber in local yards. I might back out one or two of the bad ones and use them at other locations where less strength is required.
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Old 01-24-2010, 09:53 PM   #5
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I'd swap them out if possible, right in the middle 1/3, and within 1-1/2" of top (compression) or bottom (tension).
http://www.cciccweb.org/files/Framing.pdf

Be safe, Gary
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Old 01-24-2010, 11:18 PM   #6
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I wouldn't be terribly concerned. Lumber is graded based on placement and size of knots, and assuming it meets the span for the grade you used there's so much "over-engineering" in the span charts you don't have anything to worry about.

The yard didn't rip you off...As stated they buy it in a certain grade and those boards all fall within the grader's standardized criteria.
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Old 01-24-2010, 11:24 PM   #7
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I agree with all. I don't like the attitude of the lumberyard though. Drove forklift and delivered for one putting myself through school in the San Francisco Bay Area of all places. We never shipped anything out that was badly and obviously warped if we noticed it. Knots went with the grade purchased. Eating a piece of badly deformed was just part of the business and was reflected in the pricing.

Last edited by user1007; 01-24-2010 at 11:26 PM.
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