DIMENSIONAL LUMBER: In the past, when a timber was called a 2×4 [or “two-by-four”], it actually measured 2 inches by 4 inches. Now, most timber is milled and planed to give it a little more of a finished look, and a little more of a consistent size and profile.
The 2×4 refers to the rough-cut green wood: it shrinks during drying, then the dried wood is planed smooth, so the finished lumber is supposed to end up at 1.5″x3. 5″. While it doesn’t really shrink that much, the mills get more usable finished 2×4’s from a given tree if they cut them slightly smaller to begin with.
Beside this, Why is lumber not the actual size?
The “nominal” cross-section dimensions of a piece of lumber, such as 2 X 4 or 1 X 6, are always somewhat larger than the actual, or dressed, dimensions. The reason is that dressed lumber has been surfaced or planed smooth on four sides (called S4S). The nominal measurement is made before the lumber is surfaced.
Likewise, When did lumber dimensions change from actual to nominal?
Early concepts called for rough lumber to be of full nominal size, often in the dry condition. After World War I, the increasing demand for construction lumber led to the first national size standard in 1924. This was revised in 1926, 1928, 1939, and 1953, while still another revision is proposed for adoption in 1964.
Also, Why are 2×4 half an inch shorter?
Now, most timber is milled and planed to give it a little more of a finished look, and a little more of a consistent size and profile. Because of this extra milling, a 2×4 no longer measures a full 2 inches by four inches. Instead, a 2×4 is really only 1 1/2″ by 3 1/2″. The same is true of pine.
Why is lumber not true to size?
The “nominal” cross-section dimensions of a piece of lumber, such as 2 X 4 or 1 X 6, are always somewhat larger than the actual, or dressed, dimensions. The reason is that dressed lumber has been surfaced or planed smooth on four sides (called S4S). The nominal measurement is made before the lumber is surfaced.
17 Related Question Answers Found
Why is lumber a half inch short?
Back in the olden days of cutting trees into framing lumber, a 2×4 did actually measure more or less two inches by four inches. … High production builders demanded smooth surfaced lumber to work with, rather than the rough sawn lumber primitive mills had been cranking out.
Why are 2×4 not actually 2×4?
Now, most timber is milled and planed to give it a little more of a finished look, and a little more of a consistent size and profile. Because of this extra milling, a 2×4 no longer measures a full 2 inches by four inches. Instead, a 2×4 is really only 1 1/2″ by 3 1/2″.
What does a 2 by 4 mean?
A two by four is a common format for a piece of wood: A length of sawn wood of cross section 2 inches by 4 inches, most often employed as structural framing lumber (dimension or dimensional lumber). … So it means a piece of wood with sides of two inches and four inches.
Why is wood half an inch shorter?
The 2×4 refers to the rough-cut green wood: it shrinks during drying, then the dried wood is planed smooth, so the finished lumber is supposed to end up at 1.5″x3. 5″. While it doesn’t really shrink that much, the mills get more usable finished 2×4’s from a given tree if they cut them slightly smaller to begin with.
Why does lumber have nominal dimensions?
The “nominal” cross-section dimensions of a piece of lumber, such as 2 X 4 or 1 X 6, are always somewhat larger than the actual, or dressed, dimensions. The reason is that dressed lumber has been surfaced or planed smooth on four sides (called S4S). The nominal measurement is made before the lumber is surfaced.
When did a 2×4 get smaller?
This pressured further compromise because thinner 2x4s were a way to compete in price with wood alternatives. Size standards, maximum moisture content, and nomenclature were agreed upon only as recently as 1964. The nominal 2×4 thus became the actual 1½ x 3½, imperceptibly, a fraction of an inch at a time.
What is the actual size of a 2 by 4?
Because of this extra milling, a 2×4 no longer measures a full 2 inches by four inches. Instead, a 2×4 is really only 1 1/2″ by 3 1/2″. The same is true of pine. A 1×6, for example, actually measures 3/4″ x 5 1/2″.
What year did lumber sizes change?
Early concepts called for rough lumber to be of full nominal size, often in the dry condition. After World War I, the increasing demand for construction lumber led to the first national size standard in 1924. This was revised in 1926, 1928, 1939, and 1953, while still another revision is proposed for adoption in 1964.
What does a 2 by 4 actually measure?
Nominal Size Actual Size
———— ———————————-
2 x 4 1 1/2 x 3 1/2 inches (38 x 89 mm)
2 x 6 1 1/2 x 5 1/2 inches (38 x 140 mm)
2 x 8 1 1/2 x 7 1/4 inches (38 x 184 mm)
2 x 10 1 1/2 x 9 1/4 inches (38 x 235 mm)
Why is a 2×4 not 2 inches by 4 inches?
Now, most timber is milled and planed to give it a little more of a finished look, and a little more of a consistent size and profile. Because of this extra milling, a 2×4 no longer measures a full 2 inches by four inches. Instead, a 2×4 is really only 1 1/2″ by 3 1/2″. The same is true of pine.
Why is dimensional lumber smaller?
Historically, the nominal dimensions were the size of the green (not dried), rough (unfinished) boards that eventually became smaller finished lumber through drying and planing (to smooth the wood). … After drying and planing, it would be smaller by a nonstandard amount.
Why is lumber not actual size?
The “nominal” cross-section dimensions of a piece of lumber, such as 2 X 4 or 1 X 6, are always somewhat larger than the actual, or dressed, dimensions. The reason is that dressed lumber has been surfaced or planed smooth on four sides (called S4S). The nominal measurement is made before the lumber is surfaced.
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