What is the difference between nominal and actual dimensions?
The nominal size is the actual size of a piece of lumber. It is also known as standard or trade sizes. The actual size is the actual width, height, and thickness of a piece of lumber. Why do I need to know which one to use when purchasing lumber? The type of lumber you purchase will depend on what you want to use it for.
What is the actual size of 2x4 lumber?
A piece of surfaced (sanded smooth) 2×4 lumber actually measures 1½ inches thick and 3½ inches wide. In rough-cut condition, a 2×4 is slightly less than 2 inches thick and approximately 4 inches wide.
What are the nominal dimensions of lumber?
The reasons why the nominal dimension of this lumber (what the lumber is called) is larger than the actual dimensions involves historical practices in the lumber industry. Originally, a 2 x 4 was cut as a rough green board that was exactly 2 x 4 inches in size, but by the time the boards were dried and planed, the boards became smaller, approaching the now-standard 2 x 4 dimensions of 1 1/2 x 3 1/2 inches in size.
What is nominal lumber measurement?
Lumber sizes are usually given in “nominal” measurements. The nominal measurements are a board’s size before it has been planed smooth (surfaced) on all 4 sides. The actual measurements are the final size. If your project calls for precise measurements, be sure to check your lumber before purchasing.
Why is there a difference between nominal and actual softwood sizes?
Softwood Lumber Sizes The first dimensions are its nominal ones, the second measurements are its actual or minimum dressed sizes. The reason for the differences is because lumber sizes are traditionally given in their nominal size. This is a well-established industry practice.
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.
Why is lumber smaller than the size it says?
Typically, that rough cut is smaller than the nominal dimensions because modern technology makes it possible to use the logs more efficiently. For example, a "2×4" board historically started out as a green, rough board actually 2 by 4 inches (51 mm × 102 mm).
Why do we use nominal size dimensions to order vs actual dimensions?
Accuracy is everything in Design & Construction. We believe in designing and specifying products and materials with their Actual sizes. Why? Because if you draw to Nominal sizes, every dimension for the set-out will be incorrect.
When did they stop using true 2x4?
Size standards, maximum moisture content, and nomenclature were agreed upon only as recently as 1964. The nominal 2x4 thus became the actual 1½ x 3½, imperceptibly, a fraction of an inch at a time. It was a 34 percent reduction in actual volume; as those in the trade would say, it's “selling air.”
Why is 2x4 not 2x4?
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.
Can you buy actual size lumber?
All of our lumber is cut to true dimensions. Meaning if you order a 2"x 4" x 10' the piece of lumber you receive will be 2 inches thick, 4 inches wide and 10 feet long.
Why is a 2x4 actually 1.5x3 5?
The 2x4 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 2x4's from a given tree if they cut them slightly smaller to begin with.
What is the actual thickness of a 1/2 inch board?
Hardwood Lumber DimensionsNOMINAL SIZEROUGH SIZEACTUAL SIZE: SURFACED 2 SIDES–1/2 inch5/16 inch (7.9 mm)–5/8 inch7/16 inch (11 mm)–3/4 inch9/16 inch (14 mm)4/4 inch1 inch13/16 inch (21 mm)5 more rows•Oct 31, 2021
How wide is a 2x10 actual?
Nominal vs. Actual Measurements of Dimension LumberNominal SizeActual Size2 x 81 1/2 x 7 1/4 inches (38 x 184 mm)2 x 101 1/2 x 9 1/4 inches (38 x 235 mm)2 x 121 1/2 x 11 1/4 inches (38 x 286 mm)4 x 43 1/2 x 3 1/2 inches (89 x 89 mm)14 more rows•Mar 27, 2020
What does a 2x12 actually measure?
Common Lumber DimensionsNominal SizeActual Size2x81-1/2" x 7-1/4"2x101-1/2" x 9-1/4"2x121-1/2" x 11-1/4"4x43-1/2" x 3-1/2"13 more rows•Jul 26, 2018
What is the difference between actual size and nominal size?
Nominal size is the size you see printed on the side of your air filter. It stems from the actual size, which is rounded up to the nearest whole inch.
Is a 4x8 sheet of plywood really 4x8?
Sheathing Plywood (Common: 3/8 in. x 4 ft. x 8 ft.; Actual: 0.344 in. x 48 in.
What is the actual thickness of a 5 4 deck board?
Thickness. The thickness is a key difference between 5/4 and 2×6 lumber as it affects the distance they can span, also referred to as the joist spacing, and how solid they feel. A 2×6 is 1-1/2” thick whereas a 5/4 is between 1” and 1-1/16” thick.
What is the actual size of a 1x8 #2 pine?
Spruce/Pine/Fir Common Board (Actual Dimensions: 0.70 in. x 1.45 in. x 96 in.)
What is the actual size of standard lumber?
Dimensional LumberNominal SizeActual Size2×121-1/2" × 11-1/4"4×43-1/2" × 3-1/2"4×63-1/2" × 5-1/2"6×65-1/2" × 5-1/2"13 more rows
Why are the nominal dimensions of lumber larger than the actual dimensions?
Originally, a 2×4 was cut as a rough green piece that was close to a full 2 inches thick and 4 inches wide. However, after drying and surfacing, the boards became smaller, approaching the now standard 2×4 dimensions of 1 ½ x 3 ½ inches. Green southern pine lumber shrinks in width and thickness as it dries. Surfacing removes up to an additional ¼ inch from both dimensions.
What is the difference between the first and second dimensions of lumber?
The first dimensions are its nominal ones, the second measurements are its actual or minimum dressed sizes. The reason for the differences is because lumber sizes are traditionally given in their nominal size. This is a well-established industry practice.
What is nominal size?
Nominal sizes harken back to the original rough green lumber sizes. The actual sizes are sizes after drying and surfacing the rough green lumber on all four sides. The nominal size is the standard terminology and is applicable when for buying, selling, and specifying softwood lumber.
How thick is a piece of lumber?
Technically, you can define dimension lumber as sawed softwood lumber from 2 to 5 inches (5 to 12.7 centimeters) thick and from 4 to 12 inches (10.2 to 30.5 centimeters) wide. The length of dimension lumber can range from 6 to 24 feet. The Nominal and standard sizes of lumber can be found in the Voluntary Product Standard PS 20-20 American Softwood ...
What is the width of 2x6 lumber?
The most commonly available dimension lumber sizes are 2×4 through 2×12. The 2×4’s and 2×6’s are ½” less than nominal in width and the 2×8, 2×10’s and 2×12’s are ¾ of an inch less than nominal.
How thick is a 2x4?
However, after drying and surfacing, the boards became smaller, approaching the now standard 2×4 dimensions of 1 ½ x 3 ½ inches. Green southern pine lumber shrinks in width and thickness as it dries. Surfacing removes up to an additional ¼ ...
What is Southern Pine Use Guide?
The Southern Forest Products Association (SFPA) publishes a comprehensive pamphlet, “The Southern Pine Use Guide,”. This pamphlet also lists nominal and standard sizes for all Southern Pine products. It also features the design values, span tables, and grade descriptions.
How big is 2x4 lumber?
At this point, the 2 x 4 is actually 2 inches x 4 inches, ...
How big is a 2x4 wood board?
Once the drying is complete, the boards are then planed to a standard size. Hence, what started out as a 2 x 4 now measures 1 1/2 inches x 3 1/2 inches.
How thick is a 2x6 wall?
Keep in mind that dimensional softwood lumber that is sold at your home center or hardware store is expected to be used primarily for construction projects rather than fine woodworking pieces. So, a framed wall built using 2 x 6 lumber measures 5 1/2 inches thick, but with a 1/2-inch piece of drywall attached to the wall, it then becomes a 6-inch thick wall.
How big is a 2x4 stud?
It can lead to considerable confusion if you are expecting a 2 x 4 stud to actually measure 2 inches by 4 inches, or if you expect your 1 x 6 board to actually have those measurements. What you will find is that your 2 x 4 is actually 1 1/2 inches x 3-1/2 inches and that your 1 x 6 board is actually 3/4 inch x 5 1/2 inches.
Softwood Lumber Dimensions
Softwood lumber is generally used for framing walls and floors. In the United States, softwood lumber is governed by the National Institute of Standards American Softwood Lumber Standard (PS 20).
Softwood Lumber Lengths
Softwood lumber comes in a number of standard lengths as listed in the table below.
Hardwood Lumber Dimensions
Hardwood lumber is sized based on how many sides are surfaced. Surfaced refers to a finishing process that smooths the lumber to remove all saw marks.
Glue Laminated Lumber Dimensions
The following table comes from the American Institute of Timber Construction's Standard Specification for Structural Glued Laminated Timber of Hardwood Species publication.
What is nominal dimension of wood?
The nominal dimension of a piece of wood is usually what the supplier refers to as softwood board is sold in a retail store.
What is the best characteristic of lumber?
Color is the best characteristic of lumber, and every species varies in color, a full color. If the color is even unnatural, the chances are more significant than the whole attempt to distinguish the wood is in vain.
What is dimensional wood?
Dimensional wood is wood that is cut to regular pre-defined sizes. Dimensional wood sizes apply not to length but depth and width. The dimensional wood is sawn, designed, and often thinned to be ready for many applications immediately.
What is the most common type of wood used for construction?
Size wood is the most common type of wood used for construction, as its uniform size enables building manufacturers to use it interchangeably in exclusive use.
What woods have pore structure?
There are different types of wood species, and their lumber bye product differs, such as oak or mahogany, with a pore structure. To achieve this, check the lumber texture.
What is nominal size?
The nominal size corresponds to the board’s original condition before secondary processing.
How much shrinkage does greenwood have?
The measurements and sizes decrease as the wood dries, whether through artificial or natural methods. Shrinkage can vary from 2 to 15 percent, depending on the wood species, especially the wood grain direction. Which may help lead to a reduction in actual size.
How much does a 2x4 board lose?
2x4 and 2x6 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 (2x8, 2x10, etc.) lose 3/4 inch in width. That means a 2x10 is actually 1 1/2 inch in thickness by 9 1/4 inches.
How thick is a 2x10?
That means a 2x10 is actually 1 1/2 inch in thickness by 9 1/4 inches. See for Yourself. On your next trip to Home Depot or Lowes, take along a tape measure and head over to the dimensional lumber aisles.
Is oak a hardwood or softwood?
For starters, you'll need to know that softwood (like pine, spruce, and fir) is measured and sold one way, and hardwood (like oak, maple, and cherry) is measured and sold in a totally different way. Don't get the two mixed up or you'll really be confused.
When was the first national size standard for lumber?
This nominal labeling has been used for many years and is the common practice within the lumber industry. 1924 was the first year that the national government imposed a national size standard on lumber. Until this time, each state had it own standards and lumber sizes would vary from state to state.
What is a 1x6 lumber?
So, what started out as a 2×4 ends up being 1 ½ inches thick x 3 ½ inches wide, and a 1×6 is actually ¾ inches thick x 5 ½ inches wide.
Why is kiln drying wood so slow?
The process of air drying the wood was slow and not overly effective since wood is hygroscopic, meaning that the wood absorbs the moisture from the air around it. This led to kiln drying the lumber in order to speed up the drying time.
How to calculate board feet?
A board foot is 144 cubic inches. A board that is 1 inch thick and 12 inches wide equals 1 board foot. To figure a board foot use the following formula: 1 Length x width x depth = cubic inches 2 Divide that answer by 144 in 3 3 The answer will be the board foot of your piece of wood.
What is a cant in wood?
Originally, when trees were cut for lumber, they were cut into cants, A cant is the largest possible chunk you can cut out of a tree. The cants were then cut into straight planks that measured 2”x4”, or 1”x4”, or whatever size was needed. These planks were rough-sawn, left in their natural state after being cut into lumber, and set out to air dry. Wood that is air dried can still contain up to 20% of its moisture which makes it retain its original, or very close to its original 2×4 inch size, therefore referring to the lumber by its size was easy, direct and for the most part accurate… and a 2×4 was pretty much a 2×4.
How much moisture does air dried wood retain?
Wood that is air dried can still contain up to 20% of its moisture which makes it retain its original, or very close to its original 2×4 inch size, therefore referring to the lumber by its size was easy, direct and for the most part accurate… and a 2×4 was pretty much a 2×4.
How is hardwood measured?
Hardwood is measured in two ways; in a unit of volume know as the board foot or in a unit of measure referred to as quarters. The actual size of hardwood varies also, depending on how many sides the board has been surfaced. This will be denoted as S1S, surfaced on one side, or S2S, surfaced on two sides.
Softwood Lumber Sizes
Why Are The Nominal Dimensions of Lumber Larger Than The Actual Dimensions?
- The derivation of nominal measurements was from a board’s size before its drying and surfacing on all 4 sides. The actual measurements are the final sizes after drying and surfacing. Originally, a 2×4 was cut as a rough green piece that was close to a full 2 inches thick and 4 inches wide. However, after drying and surfacing, the boards became smal...
Softwood Dimension Lumber Sizes
- Dimension lumber is lumber cut and finished S4S, (surfaced four sides) and is available in standardized sizes. Framing of buildings commonly uses the construction lumber and that is where the name framing or Dimensional lumber comes from. Technically, you can define dimension lumber as sawed softwood lumber from 2 to 5 inches (5 to 12.7 centimeters) thick an…
in Conclusion
- Now you understand why the nominal size is different from the actual size. Nominal sizes harken back to the original rough green lumber sizes. The actual sizes are sizes after drying and surfacing the rough green lumber on all four sides. The nominal size is the standard terminology and is applicable when for buying, selling, and specifying softwood lumber.