How long is a true 2x4 classified as 8 ft.?

Question

I know that 2x4 is a misnomer and its really 1.5x3.5, so when the piece of lumber says its 8 ft., does that really mean its 95.5 inches, truly 96 inches, or some random number below 96 inches?

Answer 1

It should be within 1/16" of eight feet.

The allowance fro shrinkage in the  '2 x 4' dim.s

does not apply to length.

Answer 2

Kiln dried lumber is exactly 8 feet (96").  Pressure treated lumber is usally 1/2" longer than the dimension because it will shrink as it dries.

The misnomer you refer too is actually a result of planing and sanding in the processing of wood into lumber. The sawmill (rough cut lumber) is actually cut very close to the 2x4 dimension before being shipped to processing and drying.

Answer 3

I just bought some 10' pressure treated 2x4s at Home Depot this weekend, and they were 10' 1". PT really tends to warp, so if you really need 8', you might consider getting 10 footers so you have a little extra to take the best 8' from.

Answer 4

There are studs-92-1/4" and there are 8'X 2X4"s- they should be universally 96" long or better, anything less and you are being short changed, anything more and you should be told that they are random length.

Answer 5

lumber lengths come out as follow's

2x4 = 1 1/2 x 3 1/2

2x6 = 1 1/2 x 5 1/2

2x8 = 1 1/2 x 7 1/4

2x10 = 1 1/2 x 9 1/4

2x12 = 1 1/2 x 11 1/4 to 11 1/2 (depending on the species, pine is usually 11 1/4, while most fir 2x12's are bigger nearing 11 3/8"

1x = 3/4"

5/4 = 1 1/16"

LVL's or microlams are 1 3/4"

plywood is usually a 16th smaller than what is described

3/4" cdx is about 23/32

board lengths are

8' precuts = 92 5/8

9' precuts = 104 5/8

10' precuts = 116 5/8

8' = 96"

10' = 120" to 120 1/2"

12' = 144 1/2" to 144 3/4"

14' = 168 1/2" to 168 3/4"

16' = 192 1/2" tp 192 3/4'

any board over 20' usually get and inch added on.

i have owned a rough carpentry company for 15 years and these lengths are always the same.  only in the 10's have i seen them cut exactly to 120".

doesnt matter if its treated or not.  one of the few things in have noticed in treated lumber is that most of the time they are closer to 1 5/8" thick and the 2x10's and 2x12's are slightly larger.  problem with treated material is that within 6 months or so it will dryout, leaving the boards either cupped, lengths shorter than you inititaly cut them and your miters will shrink at the short point.  i dont not suggest using any treated for finishes, only framing members.