#Actual dimensions of a 2x4 full#

So now in most places, you should see both the nominal size and the actual dimensions on the label, or other sign, at the point of sales.ĭimension lumber is lumber cut and finished S4S, (surfaced four sides) and is available in standardized sizes. According to the American Wood Council, the National Institute of Standards and Technology permits stores to label lumber with nominal dimensions if the label or other sign clearly states that the size given is a nominal size and states “the actual or minimum measurements.” The size labels now have a new requirement. However, there was one change mandated by the courts.

The lawsuits were settled, and it was found that the use of nominal sizes to describe lumber sizes was a long-standing and accepted standard industry practice. Builders, design engineers, architects, lumber buyers, and sellers of lumber are all familiar with the differences between the nominal and actual sizes of lumber. The courts eventually found that lumber sizes are appropriately described in nomina l inches in the US, or in millimeters in other countries. Modern sawing, drying, and planing technologies are much more precise, and the boards can be cut a little smaller than 2×4 inches and still leave the board large enough to dress after drying at 1 ½ inches thick and 3 ½ inches wide.Ī few years ago consumer groups brought several lawsuits against some of the big box stores and a few hardware and building supply chains for false advertising by selling lumber that they maintained, was undersized.

#Actual dimensions of a 2x4 full#

Today the boards are no longer cut green to a full 2×4 inches. Green southern pine lumber shrinks in width and thickness as it dries, and surfacing removes up to an additional ¼ inch from both dimensions. Originally, (almost 100 years ago), a 2×4 was cut as a rough green piece that was close to a full 2 inches thick and 4 inches wide, but by the time the boards were dried and planed the boards became smaller, approaching the now standard 2×4 dimensions of 1 ½ x 3 ½ inches in size. The actual measurements are the final dried and surfaced size. The simple answer is the nominal measurements were derived from a board’s size before it has been dried and planed smooth (surfaced) on all 4 sides. Why are the nominal dimensions of lumber larger than the actual dimensions? This is a well-established industry practice. The reason for the differences is because lumber sizes are traditionally given in their nominal size. The first dimensions are its nominal ones, the second measurements are its actual or minimum dressed sizes. Why isn’t the 2×4 at the lumber yard 2 inches thick and 4 inches wide? The 4×4’s are 3 ½ x 3 ½ and the 1×6’s are ¾ of an inch thick and 5 ½ wide.

To the novice do it yourselfer softwood lumber sizes can be hard to understand. Author The SPIB Team Softwood Lumber Sizes