I can’t remember why it got called a 2x4 in the first place, maybe that was the rough dimension before milling, but in actuality, a 2x4 is usually about 1-9/16” x 3-1/2”. At 8” nominal and above, the actual dimension is about 3/4” less than the nominal. 1-by’s are about 3/4” thick. The stuff that’s actually 1” thick, like they make wood screen doors out of is called “four square”. It’s been this way as long as I’ve been alive and that’s quite a while.
or when dealing with finish trim, a 1” thick board is called a 5/4 (five quarter) and a 3/4” board is 4/4 (four quarter)
I was told the 2 X 4 dimension is the wet dimension. Once the wood is dried it shrinks.
Could be a load and maybe 2 X 4 was just easier to say then 1 and 3/4.
Thanks all-—I always thought a 2/4 was a 2/4.
What I don’t understand is how this decision can stand if the sizes are the same at all lumber dealers.
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I saw an explanation awhile back for why wood is not the size it is called. The measurements are the size of the wood before milling.
My folk’s house was built with actual 2x4s, probably in the late 1940s. And lathe and plaster walls.
I remember seventh grade shop class, in 1971, the teacher asked us how big a 2 by 4 was. I was the only one who knew. I said “One and five eighths by three and five eights”. I had learned that from my Dad, whose father was a carpenter, a few years before that.
In fact I have used the example of the 2 x4 more than once to point out how “trade usage” can refer to a product that is not literally what it is called, but would be understood in the trade as to what it really was, so that if someone contracted to buy 2 by 4s and you gave 1 5/8 by 3 5/8 you would have met your obligation.
I never in my life thought that a judge would actually rule this way.
Then again it’s Marin.
BTW, the two by fours in my house, built in 1910, are two inches by four inches.