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View Full Version : New Lower Span for Pine Ceiling Floor Rafters etc.



Wayne Carlisle
10-14-2011, 11:18 AM
It was recently determined that the modulas elasticity for pine has been over rated. The new tests conducted show that the span will be reduced by as much as 30%.

I don't know how this is going to affect you guys but I wanted to make you aware of the new ruling coming up.

http://www.sbcindustry.com/docs/2011_10_12_Developments_regarding_Design_Values.pd f

Southern Pine Potential Design Value Reductions - Impact on Light Frame Construction Market | SBC Magazine (http://sbcmag.info/news/2011/oct/southern-pine-potential-design-value-reductions-impact-light-frame-construction-market)

Wayne Carlisle
10-18-2011, 06:28 AM
No comments? I'm surprised!

Do you guys think this will affect your inspections in any way?

Bruce King
10-18-2011, 09:26 AM
This will likely just result in better grading of lumber since anywhere from 20 percent to 50 percent gets a higher grade than it deserves. I writeup bad lumber all the time during predrywall inspections and any important piece that has a major weak area from large knots gets written up no matter what the age of the home is. I find failed floor joists at times that failed only because the lumber was not really the grade it was supposed to be.
I wish I would have kept a really bad 2x4 that came in a bundle when I built my house. It was so bad the guy complained when I sent it back. I guess he thought I found it somewhere and just wanted credit. I think they call it "high speed grading". This may all be a way to raise prices on sawn lumber since lots of engineered lumber is being used these days.

Ken Bates
10-19-2011, 08:32 PM
I never studied dendrology so my opinions may be flawed or have no basis in fact.

Having read some of Eric Sloan’s books on Americana (e.g. “A reverence for wood”), I know there are many facts about wood that are not considered or understood even by those who should know them.

I read about an occurrence that may be true that relates to the owner of a toothpick factory who got a wooden bridge in New York for practically nothing but could not cut the wood into toothpicks because it had strengthened with time. E.g. Concrete continues to strengthen beyond the 28 day cure time.

Beyond counting knots, etc, I think age is the most critical factor. Old growth wood is found in old houses and there are a lot in my area. New construction utilizes a lot of tree farm wood. ( My blood boils when I see ads by mining companies that rape forests and brag about replanting -- ten year old lumber is junk!! ) So, revising modulus elasticity results on Yellow Pine for example, should take into consideration the age of the wood.

We could have good wood for new construction if our politicians had not been bought by lobbyists bribing them for tariffs on old growth Canadian lumber.

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Rolland Pruner
10-21-2011, 07:16 PM
Pine and redwood are never good for strutural members, Most of the time fir or hemfir is used in new home construction (or metal).

Pine is great for interior trim work! Red wood good for decks!

Billy Stephens
10-21-2011, 07:34 PM
Pine and redwood are never good for strutural members, Most of the time fir or hemfir is used in new home construction (or metal).
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What? :confused:
Applications: Structural Components :: Southern Pine (http://www.southernpine.com/applications_structural-components.asp)
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