What Are The Actual Sizes Of Dimensional Lumber?

What are the actual sizes of dimensional lumber? Nominal vs. Actual Measurements of Dimension Lumber

Nominal Size Actual Size
2 x 2 1 1/2 x 1 1/2 inches (38 x 38 mm)
2 x 3 1 1/2 x 2 1/2 inches (38 x 64 mm)
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)

Why is dimensional 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.

What is a dimensional lumber?

Evident from its name, dimensional lumber is a form of wood which is prepared into various pre-determined sizes. Different sizes and shapes of dimensional lumber are used in various industries to make different products.

Is a 2x4 dimensional lumber?


In the past, when a timber was called a 2x4 [or "two-by-four"], it actually measured 2 inches by 4 inches. Because of this extra milling, a 2x4 no longer measures a full 2 inches by four inches. Instead, a 2x4 is really only 1 1/2" by 3 1/2".

Is plywood a dimensional lumber?

Dimensional Lumber and Modern Building

For the average do-it-yourselfer, most long, thin lumber that will be used for building is considered to be dimensional lumber. Other types of lumber, such as plywood and other sheet goods, do come in prescribed standard sizes but are not referred to as dimensional lumber.

Related faq for What Are The Actual Sizes Of Dimensional Lumber?

What is a 2x4 actual dimension?

The true measurement of a 2x4 is actually about 1.5x3. 5. When the board is first rough sawn from the log, it is a true 2x4, but the drying process and planning of the board reduce it to the finished 1.5x3. 5 size.

What are the actual dimensions of a 6x6?

Lumber Dimensions: Nominal vs. Actual

Nominal Size Actual Size
2x12 1-1/2" x 11-1/4"
4x4 3-1/2" x 3-1/2"
4x6 3-1/2" x 5-1/2"
6x6 5-1/2" x 5-1/2"

When did dimensional lumber change size?

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 is the difference between dimensional and framing lumber?

Dimensional lumber and studs are 2-inches to 4-inches thick and 2-inches to 4-inches wide. Structural joists and planks are 2-inches to 4-inches thick and 6-inches wide. Beams and stringers are at least 5-inches wide and 2-inches thick. Appearance framing lumber is 2-inches wide and 1-inch thick.

What is dimensional lumber used for?

Dimensional lumber is lumber that is cut to standardized width and depth, often specified in millimetres or inches. Carpenters extensively use dimensional lumber in framing wooden buildings.

What does 2x4x8 mean?

The 2 tells us the thickness of the board in inches, the 4 is the width of the board in inches and the 8 is the length of the board in feet.

Should I use 2x4 or 2x6 for deck?

If you use 2x4s for deck joists, it may cost more money and work in the long run. The material costs more than if you purchase 2x6s because the 2x4s can't span as far, and you must create more beams and footings for support. You also can't include guardrails and stairs with 2x4s as your support.

Can you use 1x6 for deck boards?

Never use 1x6 or 5/4x6 material in close to ground applications. Spacing between boards: You must allow space for your deck boards to expand when they take on moisture, as they will inevitably do when exposed to wet weather, rain or high humidity.

Why is lumber a half inch short?

Wood is hygroscopic, so it adjusts its internal moisture to match the external moisture of its environment. Without the rough edges, what went in as a 2-by-4 planks of rough-sawn wood is now a tongue-tripping 1.5-by-3.5, having lost approximately ¼-inch on all sides to the planer and drying processes.

Why are 2x4 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.

Why are 2x4 edges rounded?

2×4 have rounded edges as it's very beneficial to the wood itself and those working with it. They reduce the number of injuries like unwanted splinters during the handling and manufacturing process and also ensure that the lumber stays looking its best all throughout until the customer sees it.

What does 4x4 mean in measurements?

Hardwood lumber comes in thicknesses measured in quarters of an inch. 1″ lumber is called 4/4 (four quarters). 2″ lumber is called 8/4 (eight quarters). Here's how they compare.

What does it mean when someone calls you a 2x4?

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). "It hit me like a two-by-four" means that you've been hit pretty hard.

What is the actual size of a 1x10?

1x Board Sizes

lose 3/4 inch in width. That means a 1x10 is actually 3/4 inch in thickness by 9 1/4 inches.

What is SPF dimensional lumber?

Spruce-pine-fir lumber, otherwise known by the acronym SPF lumber, is primarily sourced from the provinces of BC and Alberta in Western Canada. SPF is largely used to make dimensional lumber for residential and commercial construction, in addition to engineered wood.

What is a 2x8 dimension?

A 2×8 board is 1 1/2 x 7 1/4 inches (38 x 184 mm) dimensions in actuality.

What is the strongest dimensional lumber?

Doug-Fir. Douglas-fir, popularly known as Doug-fir, is undoubtedly the best and most common structural lumber. It is most architects' and engineers' go-to lumber species and this is not just because of its remarkable dimensional stability. It is also among the strongest and most durable softwood lumbers.

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