Grading lumber

[Qweaver]

I just recieved 155 treated 2x6s stamped No.1. and I'm surprised at how many of these boards have a fair amount of wane.  How can I find the specs that define a No.1 ?  While I didn't expect this lumber to be totally clear, I did not expect it to have wane that was 1/3 of the way across the thickness of the board or loose knots.  This lumber comes from a highly recommended source and I'd guess that I'm getting as good or better than from other sources.  This really convinces me that codes requiring grade stamped lumber are absolutely meaningless.  I'll make this lumber work OK by using the wood with wane in places where I can hide or cut it away.  Any info about grading is appreciated.
Quinton

[beenthere]

"Wane - 1/4 the thickness and 1/4 the width full length, or equivalent on each face, provided that wante not exceed 1/2 the thickness or 1/3 the width for up to 1/4 the length"

SPIB Wane for No.1 structural non-dense

(from SPIB grading rules)

[WDH]

Some manufacturers "push" the grade.  Well, maybe they all do .

[Dodgy Loner]

Structural lumber (like 2x6's) are graded for strength, not for appearance (well, actually they're graded for strength by appearance).   A wany edge does not reduce the strength of a board nearly as much as a large knot, which is why wany edges are acceptable in No. 1's.  Also, a loose knot is no weaker than a tight knot of the same size.  Knots are more detrimental to the strength of a board than a hole of the same size.  If you just drill, say, a 1" hole in a board, the wood on either side of it will still be running straight.  A 1" knot, however, will have wood on either side of it that "runs out", which significantly weakens the board.  The size of a knot and how close it is to other knots are the primary concerns in grading lumber, not whether the knot is loose or not.  (I promise knot to say not again... )

That being said, I have ordered #2 2x10's and received everything from selects to #3's, so unless you are familiar with the SPIB grading standards, you may not be able to tell the difference.

[Don P]

The Nat'l Grade Rule for dimensional lumber reads the same as Beenthere's SPIB quote.

"Prime" is the stamp that defines low wane.
This isn't really a grade but the big box stores noticed that the first thing DIY'ers rejected from their lumber piles was wane. This didn't have anything to do with strength of the grade or suitability for use. However to help with sales and customer relations they came up with "prime" #1 and #2 that has tighter wane restrictions than straight grade. It is prettier lumber although still has the same strength properties... ie the defect isn't wane, so its likely limited by knot size. A waney edge limited board can be otherwise clear. Often I'll find a large door header in a waney piece, the grader had to knock down a select to a #2 for wane. So in that case I get a select structural board for #2 money.

The code requirements are not meaningless, they assign strength values to lumber based on the amount of good wood remaining. Straight #2 is not pretty, it has strength values that reflect the uglies.  Knowing how much strength is required and what species and grades will satisfy that need is the key.

Another example, "Stud" grade is a #3 strengthwise with #1 wane restrictions. They knew the stud would be vertical use as a column so didn't need a whole lot of strength but it did need good edges for the drywall and sheathing to nail to. People tend to forget but studs are better than they used to be. Course, a weekend warrior buys studs and nails them up for porch ceiling joists  .

[Don P]

Sitting on the porch admiring some fine lawn rangering and sipping on a cold beverage and I looked at the railing. Here's a #2 Prime stamp. Timber Products audited the graders at mill #283, they kiln dry to below 19%/heat treat to above 150*.

[inspectorwoody]

Some manufacturers "push" the grade.  Well, maybe they all do .

We....push grade.....no....never! 



 

[ARKANSAWYER]

  Also they are allowed by grade rules to have 5% of lumber below grade and still stamped.  So you take a large mill that produces 150,000 bdft per 8 hour shift that means that 7,500 bdft is below grade.  You just got a chunck of that 5%.


  The best grade lumber is done by this company



 

[WDH]

Arky,

Your avatar says that you are sawing blind, but must not be grading blind .

Inspectorwoody,

You are our role model .

[Qweaver]

The code requirements are not meaningless, they assign strength values to lumber based on the amount of good wood remaining. Straight #2 is not pretty, it has strength values that reflect the uglies.  Knowing how much strength is required and what species and grades will satisfy that need is the key.

Another example, "Stud" grade is a #3 strengthwise with #1 wane restrictions. They knew the stud would be vertical use as a column so didn't need a whole lot of strength but it did need good edges for the drywall and sheathing to nail to. People tend to forget but studs are better than they used to be. Course, a weekend warrior buys studs and nails them up for porch ceiling joists 

Don, my point is that I am using my own, and to my eyes, much better lumber to build my cabin than the SPIB No. 1 that I just bought from a large supplier AND much of this grade stamped lumber does not grade out as number 1 when I apply the SPIB rules.  So in essence the code is actually allowing me to build with below grade lumber.  It is great that we have a system in place to assess and set the strength values for lumber...not so great that it is, apparently, routinely ignored by the graders...and yet many/most? codes require graded lumber to be used.
Quinton

[beenthere]

Quinton
I would be willing to guess that your No. 1 by the SPIB rules meets the No. 1 grade.
But what are you finding that doesn't meet the grade?  Wane? knot size? grain angle?
Contacting SPIB with some good examples of any errors in grading, if found, is what I'd do. They don't condone below grade lumber, I'm certain of that.

And I don't doubt your own lumber exceeds the lumber as found in a suppliers yard.