[MustardTiger]

>This isn't about building codes. It's about stickers and permits

That is the building code. It is all about stickers and stamps. Why is a tree that grew on my land that I cut myself not acceptable? It has nothing to do with the wood obviously, it has to do with creating make work jobs for bureaucrats to "inspect" and stamp lumber.

[employee8000]

Trees are not covered under building codes. They are covered under city ordinances. And I cut down 3 trees on my property because I wasn't going to spend $150 per tree so that city hall could get themselves a nice Christmas bonus for doing nothing except filling out paperwork.

[MustardTiger]

Acceptable as a source of lumber to build a house. You know, like the article we're discussing?

[DannyBee]

actually. Depending on a lot of circumstances, it may not actually be acceptable :) That is why these grading standards exist in the first place.

They were done due to failures, not because government was bored.

[MustardTiger]

No, they were done because of lobbying from the lumber industry. If you have any evidence that stamped lumber is superior in any way I would love to see it. Because if you've ever built a house, you'd know you have to throw away about 10% of stamped lumber because it is trash.

[DannyBee]

"No, they were done because of lobbying from the lumber industry. "

This is simply false. Seriously. I'd love to see where this history came from? Do you have any real source, or is this typical "lobbyists did it" bluster.

Here is the history of stamping in the US: There were failures and complaints in ~1920's from mills/etc starting to sell substandard lumber due to the depression. Code enforcers wanted a sane way to ensure the houses being built weren't being built with substandard lumber. Folks asked Dept of Commerce to come up with voluntary standards for grading and inspection. NIST (well, what is now NIST) created a set of simple voluntary grading standards. They've revised it a few times.

Literally the only thing the grading agencies do is grade. They don't actually care about the end result. They don't make more or less money one way or the other.

The grading standards are also pretty simple. It's not like it's rocket science.

Note that most mills stamp their own lumber. You just have to have someone trained to do it. In wisconsin, for example, it takes 1 day to be certified.

One of the 7 grading agencies randomly inspect, and if they find enough errors, they'll hold you up.

As for the amount of waste, most waste i've seen is from 1. later-bent studs due to wood movement. This is not structurally unsound (just nobody feels like re-straightening them), so the stamp still is doing it's job of saying it's sound. 2. damage during transit.

Your other question was "evidence stamped lumber is superior in any way".

okay. that's easy. Two grading methods include machine stress rating and non-destructive evaluation. See http://www.southernpine.com/grade-methods/ for example.

I will strongly assert that lumber machine tested and evaluated for actual strength and stamped as such is superior to random lumber that is untested and unknown.

Visually graded lumber is usually graded based on things like knot size and slope of grain, both of which have a significant structural effect on lumber (structural strength decreases as grain deviation increases).

Assuming grading is being done properly (and again, there's a lot of checks going on), yes, the lumber is structurally better.

But maybe you don't believe the physics, and think that things like slope of grain don't impact the structural properties? If so, i guess i can't solve that problem for you. It's pretty well studied:

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/390291... has a bibliography

Also note the table showing that wood with significant slope of grain will support half or less of what wood without significant slope of grain would.

See also http://www.conradfp.com/pdf/ch4-Mechanical-Properties-of-Woo... and "Failure Analysis of Wood and Wood-Based Products" https://www.accessengineeringlibrary.com/browse/failure-anal...