Tag Archives: lumber defects

Hart and Home Youtube Episode III

Hart and Home YouTube – Episode III

If you missed our previous episodes, please go to bottom of this article, on left, and click on arrow twice to go to Hart and Home YouTube – Episode I. Moving forward:

For those following along at home:

Lumber OffloadingSome discussion will be made here about “allowable defects” in lumber. Our main struggle with lumber quality is clients having unrealistic expectations. Lumber is chosen for strength characteristics, rather than due to “pretty looks”.  If an expectation lumber will be clear, vertical grain, knot and wane-free, a severe disappointment will occur. Wood is an organic material. While produced in a “factory” environment (a sawmill), lumber is subjected to naturally occurring defects accounted for in grading rules. These characteristics are taken into account in strength values for allowable design. Minor dimensional differences in individual boards are a function of shrinkage due to moisture content, wood species and even individual tree characteristics. Shrinkage is more prominent across grain – hence variations in the board’s wide face are more pronounced. Ultimately these small dimensional differences do not affect the finished building.

All structural dimensional framing lumber used in Hansen Buildings will be at least graded as #2 (or “standard”) or better.  For discussion’s sake, we will limit scope to this grade. Four inch and smaller (e.g. 4×6 and any two inch – 2×4 through 2×12, 4×4 and 4×6), are all graded under “joists and planks” rules. Characteristics listed below are unintended to be all-inclusive, but merely to be a frequently seen item overview.

In any given lumber “production run” typically 5% is allowed to be outside grading rules (to have more defects than expressly allowed) and still have a sum total declared as “on grade”. 

Checks – seasoning checks are unlimited. Through checks at ends are limited as splits. Splits can be equal to 1-1/2 times board face width (e.g. 8-1/4” on a 2×6, 16-7/8” on a 2×12). Keep in mind, many times these boards will be trimmed off, especially when used as girts, purlins or rafters.  A split portion may thus be removed when trimmed to be put into service.

Knots – on a 2×6, up to 1-7/8” at wide face edge, 2-7/8” at wide face centerline; on a 2×12 up to 3-3/4” at wide face edge, 4-3/4” at wide face centerline.

Holes – (from any cause) on a 2×6 1-1/2”; on a 2×12, 3”.

Wane – up to 2/3 thickness and 1/2 width for 1/4 length.   An example would be on a 12’ long 2×6, wane could be 2-3/4” on wide face, 1” in depth across 1-1/2” face and 3’ in length.

Bow (or Crook) – a board size and length function. As an example: for a 2x6x12’ – 5/8” would be acceptable, with greater amounts allowable with longer lengths.

Twist – for a 4x6x16’ would be allowable up to 1-1/2” and still be within grade.

Timbers

5” x 5” and larger are graded as “Posts and Timbers” and have their own characteristics. Again, addressing #2 grade, they include:

End splits – up to twice post face are permitted: (Ex: 12” on a 6” face.)

Wane – 1/3 of face.

Bow, crook and twist are NOT limiting factors under grading rules for posts and timbers.

It is essential any suspected shortage or damage be reported immediately. Vendors become highly suspicious of possible jobsite damage, as it increases with time. An example of this is when (after several months on a jobsite) a client asked for replacement of some damaged steel – his provided photographs actually showed tire marks where it had been run over!

Construction Manual – we do frequent updates and additions to it, often several times annually. Since Kevin and Whitney’s investment, more and more of our clients have gone to wet-set brackets, rather than embedded columns. Hence, we have added several pages of wet-set bracket specific details and instructions to Chapter 5, Setting Columns.

Solid sawn vs. glulam columns. We agree totally with Kevin’s analysis, glulams are a superior product and I would highly recommend them to any client (for extended reading, please see https://hansenpolebuildings.com/2014/10/glulam-4/). One downside is distribution, as they are manufactured in limited and highly scattered locations, costs of shipping and time delays can become issues.

Watch for our final episode of this series – coming soon!

Not Burger King Crowns

My readers will recognize my 19-year-old son Brent’s name from recent articles on the construction of a pole building storage building here in Browns Valley.

After two weeks of working together, I have learned something important (yes, 56 year old Dads can learn new things).

Growing up, my brother Mark and I worked for Dad and our Uncles. Other cousins were also participants – my Uncle Lyle’s son Kim; Uncle Gil’s son Scott and Uncle Dave’s son Randy. It wasn’t until now the real feelings of bonding between father and son were recognized by me in us being able to build and create together. As a teenager, I didn’t have the ability to appreciate what this meant to my father. My Uncle Gil is the last surviving member of his generation whom I worked for (and with) – so I hope to be able to pass along some appreciation to him.

Back on track – Day Numero Uno on the job for Brent involved putting roof purlins into place. I’d previously cut them all to length and had put an upward pointing arrow on each one, to indicate which side of the board was to be placed up.

Several years ago I had written an article on crowns in lumber: https://www.hansenpolebuildings.com/blog/2011/08/lumber-defects-crowns-arent-just-for-royalty/

CrownGuessing my son had not read the particular article, I set about explaining crowns to my son. Brent’s prior experience with crowns was most likely going to Burger King®. Back in the day The Burger King™ was maybe not such a frightening character to youngsters, and the paper Burger King crowns seemed to miraculously grow upon the head of any youngster whose parents drug them in the door.

We sighted down a few pieces of lumber together, and Brent quickly caught the gist of what to be looking at.

Before the building began, I had predicted to one of my co-workers at least one of the purlins would be placed with the arrow pointed down instead of up.

Good thing I am not a betting man…..I haven’t found one yet. Brent was a quick learn!

LVL: I Woodn’t Use It

I Woodn’t Use It (pun intended)

For those of you who are unfamiliar with LVLs (Laminated Veneer Lumber) here is a good primer:

https://www.hansenpolebuildings.com/blog/2013/01/lvl/

For the thousands of my regular daily readers, you know Justine well – she is the one who makes sure all of the good stuff arrives at client’s jobsites when they are supposed to, and in the condition intended.

Black LVLJust the other day she forwards me a photo of what appears to be an LVL which spent too much time on the beach with me in Ecuador. In lumber terms, “It is sunburned”. As Justine asked me, “Black Lumber”?

I was able to find (courtesy of https://www.internationalbeams.com) the correct storage procedures for LVLs:

  • LVL should be protected from the weather and stored lying flat.
  • Product must not be stored in contact with the ground.
  • Store LVL in wrapped bundles, provide air circulation and support
    bundles with 2×4 stickers.
  • On the job site, protect from the weather both before and after
    installation. LVL is intended for use in covered, dry conditions only.
  • Do not install wet or visually damaged product.

I will admit it was really difficult to find “expert” opinions on whether to use this LVL or not.  Is it still structurally sound?  So I thought I would share a few “less than expert” opinions I found on various message boards on the ‘net:

“I would pay close attention to the layers to make sure they are still holding tight. LVL beams are GLUED together, if enough moisture gets in there the glue could start peeling apart making the beam considerably weaker. I wouldn’t take my chances unless I knew it never got wet.”

 

I would have to see it, but if there is no rot or mold growing on the beam, I would still use them. Few months outside just seasons the wood.”

 And my favorite (this is pretty scientific, so hold on):

“If the LVL got wet enough to swell up and then they dried out and show any sign of delamination, they lose a lot of strength. I tested this, they break much easier. If they just weathered, they should be ok. If you have a new piece of LVL, Cut a test piece, drive a car or tractor over it to see what it takes to break it. Do the same test with a weathered piece.”

My advice to Justine was, “I would ask the supplier to either replace it, or to provide a letter from the company which manufactured it, to confirm it is adequate to be used structurally.”

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