Do you use the nominal or actual size to order a board from the lumberyard?
Do you use the nominal or actual size to order a board from the lumberyard?
At the lumberyard, board sizes are typically given in “nominal” dimensions, but those aren’t the true sizes. Which means, for example, three 2×4 boards laid side by side will not measure a foot across. Because a nominal 2×4 board is really 1-1/2 inches by 3-1/2 inches.
Why are wood sizes not the actual size?
Maybe you’ve noticed that lumber sizes are often misleading. 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).
What is the nominal size of a 2×10 board?
Nominal vs. Actual Measurements of Dimension Lumber
| Nominal Size | Actual Size |
|---|---|
| 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) |
| 2 x 12 | 1 1/2 x 11 1/4 inches (38 x 286 mm) |
| 4 x 4 | 3 1/2 x 3 1/2 inches (89 x 89 mm) |
Is a 2×8 actually 8 inches wide?
The larger 2x boards (2×8, 2×10, etc.) lose 3/4 inch in width. That means a 2×10 is actually 1 1/2 inch in thickness by 9 1/4 inches.
Is a 2×6 really 2×6?
2x Board Sizes 2×4 and 2×6 boards lose 1/2 inch in thickness and 1/2 inch in width before leaving the mill. That means a 2 x 4 board is actually 1-1/2 inches by 3-1/2 inches. The larger 2x boards (2×8, 2×10, etc.) lose 3/4 inch in width.
Why have 2×4 gotten smaller?
The simple reason why 2×4 is not 2 inches by 4 inches is that lumber mills trim off rough or warped surfaces of a 2×4 to give it a more polished and finished look. By planning the lumber on all four sides, the original 2×4 is now reduced to 1 ½ inches by 3 1/2 inches.
How do you convert nominal size to actual size?
If the nominal size is larger than 2” and smaller than 8” then the actual size is 1/2” smaller than the nominal size. If the nominal size is 8” or larger, then the actual size of the board will be 3/4” smaller.
Why do they call deck boards 5 4?
There are several differences between these two wooden boards, however, the main difference is that they are different sizes. While they are both 5.5 inches wide, a 5/4 board is 1 inch thick, whereas a 2×6 board is 1.5 inches thick.
Why is a 2×4 only 1.5×3 5?
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.
