Oddity: 2x10 dimensions and use

Happy Sunday evening to all, :smiley:

Today, I saw 2x10’s that measured 9 1/8" and less. These are used in a new apartment construction project. Worse yet, the installers used a #3 (but stamped #2,) 16’ board in a way that will eventually fail. This board, has a series of 1 1/2" to 2" knots - most than 75% protruding through the board, and on its outer edge. These knots, coupled with more knots away from the edges, have reduced the effective cross section of the 9" face to near 5". This board would not make graded if given a quality control bending stress test. If the board were rolled 180 degrees when installed these bad areas would be stressed in compression rather than tension and probably been okay. Further, several other boards were used in this same apartment with similar flaws. But wait, there’s more: the 2x4" studs measured 3 3/8" to 3" x 1 7/16 to 1 3/8". I have not seen boards cut this small.

16, three-story buildings are being built - each with 24 apartments. I was nosing around and not paid to do an inspection. Should I confront the superintendent of this project with this info or just say nothing?

(Interesting note: in the lowest floor stud walls, studs were placed on 12" centers. The upper two floors they were on 16" centers around the perimeter and 24" centers in the interior.)

Looking foreward to your comments! :slight_smile: :smiley:

I hate it when wood shrinks on site. I think they call it the “Kiln Dry” phenominom,… weird. Defective wood. Call it out.

You know, I did not consider that I may not have been Kiln Dried. None the less, the finished product should not dry to less that the requirement for the grade. Yet, it looks like “KD” lumber and I know that KD lumber will be within the norm. Since I’m poking my nose where it doesn’t belong I have to wonder if I should tell anyone, and if so, who? (but I suspect that the Developer ought to be told.) :slight_smile:

Send an anonymous letter to AHJ and let them do their job. If the board is stamped, let the installer explain to the inspector. Getting involved in something like this can only cause you grief at a later time. Nothing like being sued for slander by a shyster developer with a grudge against a trespasser.

OR find a local investigative newscaster and drop them a note. Let someone else take the heat.


Hummmm? :shock: Thanks for waking me up. I should know that this could be a very expensive endeavor for ME! Proof, once again, that two or three heads are better than one (and that tonight’s thought could be tomorrows nightmare.)

I don’t really see any problem. Framing lumber is seldom kiln-dried and always shrinks when it isn’t. 9 1/8" is on the small side but not really unusual. Dimensions vary somwhat with the mill load and always with the length of time they’ve had to air-dry.
I’ve never seen a 2x4 shrink to 3", even in the Mojave desert, but have seen trusses built of 3" material. That’s what it had been milled to.

Grading lumber is a whole different ball game and building inspectors don’t know any more about it than carpenters. I have been on sites where the framer’s super kept a couple of grading stamps, but no one ever thought anything done was dangerous. I’ve seen great-looking boards with hardly a knot stamped #3 and some awful boards stamped #2 or better. Unless one is a certified grader…

Thanks Kenton,

I have read the grading standards and actually have done QC stiffness tests on dimensional lumber so I kind of know that some of these boards would not make their stamped grade. This is normal. 5% of boards with a grade stamp are allowed not to make grade - at the speeds these boards are run through planer mills it is virtually impossible to for us humans to get every one perfectly correct. I speak to common sense - if you or I are framing a home, we will notice boards that look suspiciously limber or knotty and set them aside. When a “Craftsmen” is doing his job he more than the average do-it-yourselfer should recognize and correct flaws if at all possible.

When we HI’s inspect ‘home projects’ I would hope that when looking at rafters or trusses that we would point out sub-grade material. If we look within an attic we see hundred of boards - if one stands out by its appearance as untypical, we maybe should look for #2 or better stamp - a #3 should not be used for structural application. I see this with “low-bidder” jobs. They buy the lumber that the yard is about to take to the dump and put it in your walls, ceilings, or wherever. This stuff is just as detrimental to structures as WDO’s. Especially, when seen, it is time to look for sway, bow, etc., at a minimum.

I hope that the HI of the future will pay as much attention to lumber quality as they do to mold, moisture, wire-sizing, venting, and the like.

As far as “air dried” dimensions, I would be asking questions of the planer mill if the 17% moisture content dimension was anything less than required sizing - because architects, as we can imagine, must compute their design with standard sizing in play. That said, In the 1970’s, a 2x4 measured 1 5/8 x 3 5/8" and put in stud walls on 16" centers. In the late 1980’s I notice the dimensions were 1 1/2 x 3 1/2 - still on 16" centers. If mills keep reducing size’s won’t engineers have to change the 16" center rule?

I may not have noticed the sizing concerns except that the second and third floors were a bit “bouncy” and I wondered why.

Just my opinion - for what it’s worth. :smiley: