when/why did north american 2x4 framing lumber become standardised at 1-1/2 x 3x1/2 ?

[Tom Bainbridge]

on the forum and on a this is carpentry ive occasionally seen wording that hints that north american lumber wasnt always 1/2 inch smaller than stated/nominal

cost is obvious, the reason why and when it changed is not obvious to me

[Happy Home]

http://www.fpl.fs.fed.us/documnts/misc/miscpub_6409.pdf

[Tom Bainbridge]

happy, very long document. so i "scanned" it

my conclusion. is that there was a need to standardise, and it went to the TOP, "Hoover" i believe was a president

when presidents get involved, descisons get made

is this close enough ?

[Happy Home]

It is a long document without a table of contents. Its also unique to N. America so wouldn't blame if you just took a scan as I would a comparable UK doc.

Prior to posting I thought from my initial const training it had something to do with the aggregation of US Industrial Standards / Classifications (from1900) by the gov't just after WW II and the need for uniform standards, modularization adopted for war production and the boom that followed. I wasn't fully correct but my assumption that the influence of WW I and II upon the industry was.

I got from the document the technologies and logistics developed during the conflicts resulted in less regional commerce (different size 2 x 4's in different areas) and more national commerce thus the gov't got involved in setting standards.

In the opening summary what got my attention was the marketplace preference for price above quality and how a smaller 2 x 4 can result in more units being shipped from the mill thus a greater profit per unit. Aside from the US Justice Dept getting involved I believe that's the reason why a 2 x 4 is what it is today.

[Dick Seibert]

From my experience lumber is milled rough at 2x4 (or 2x12) and was sent from the mills that way, sometime in the early 30s S2S lumber was milled at the mills, giving us full 2" widths but smooth consistent widths of 3-5/8" that dried down to 3-1/2". after WWII the mills started milling all four sides for S4S lumber giving us 1-5/8" by 3-5/8", when asked I was told that builders were willing to pay more for S4S and it made it lighter for shipping. As late as the 50s I could, and did, order rough (2x4), S2S (2"x3-5/8"), or S4S (1-5/8"x3-5/8").

[Slaughter Construction Co]

I didn't read the document and I wasn't around when Hoover was president.

When I got involved in the construction industry in 1956 a 2 x 4 was 1-5/8 x 3-5/8".

I was going to college in the AM and working for a prefab company in the PM. When I left that company to go out on my own in 1967 a 2 x 4 was 1-1/2 x 3-1/2
.
That is as close as I can get. I don't know what all of the reasons for the change, but it certainly made all math calculations much simpler. They didn't have calculators in those days that would add, subtract, multiply and divide fractions.

[Lavrans]

There was a nice period in the 20s/30s where the studs were at 1-3/4" x 3-1/2". I run into them mostly in the nicer quality homes built around that time. I notice the lower cost homes had more rough lumber- generally it was still around 3-1/2", but the width could be anywhere from 1-1/2" to 1-7/8" in the same home.

[dave_k]

I don't know the answer for sure but I would be willing to bet there are 2 reasons.

1. Standardized machining, if all the 4 sided planers are using the same tooling it's cheaper so the standard is set at 1-1/2" x 3-1/2" etc.

and most importantly 2. Standardized lift sizes for shipping. Ad an eight in both directions and suddenly you're shipping few units/load. Lifts may have to be under a certain height / width to fit into ship holds or on trains.

[Tom Bainbridge]

i love the answers you blokes are giving me

evolution not revolution is sounding like the answer

[JoshAndrews]

I'm curious how dimensions pan out in Europe...

Can you go to the store and buy an 8 footer or a 16 footer?

Do you have 92 5/8" or 104 5/8" studs to make an 8 or 9 ft. ceiling that accommodates 4' or 52" drywall without a rip cut at the bottom?

I'm sure the dimensions are close, but what about the thickness of a board comparable to a "2x4"?

[Sweep8]

In 1961, at a meeting in Scottsdale, Arizona, the Committee on Grade Simplification and Standardization agreed to what is now the current U.S. standard: in part, the dressed size of a 1 inch (nominal) board was fixed at 3⁄4 inch; while the dressed size of 2 inch (nominal) lumber was reduced from 1 5⁄8 inch to the now standard 1 1⁄2 inch.

from "History of Yard Lumber Size Standards", Sept 1964 by Forest Products Laboratory,
Forest Service, U. S. Department of Agriculture

[Tom Bainbridge]

josh, the quick answers to your questions are..............

timber (lumber) is avaliable in 300mm increments (rather than 305mm..... 1 foot increments)

so 8 and 16 feet lengths are avaliable, but they are clearly slightly shorter

a british 4x2 (read 2x4) finishes at 45x95 mm (1-3/4 x 3-3/4)

i could give a more complicated, more reasoned answer, but it involves british building regs (codes)

and rather more complicated.............. american / canadian 2x4 is avaliable here that meets our building regs

dont get me into differences between "metric" gyproc and "imperial" sheathing/ply

lets just say.......... economics defines the framing centres

[JoshAndrews]

thanks Limey, that's cool

[hambone]

It's not always just 1/2" under nominal size either. At least around here, anyway. Once you go up to x8 the dimensions are 3/4" under nominal, so a 2x8 or 1x8 is 7-1/4" and x10 is 9-1/4" etc...

[Slaughter Construction Co]

Tom, Every time is see your question I want to ask this question, so I'm going to ask it.

When and why did you Brits go to the metric system. :>)