Commercial Standard Lumber Sizes Table Chart

Civil Engineering Design Knowledge

Commercial Lumber Sizes Chart Table

The following data is standard reference and size data for commercially available lumber within the USA. All data is in imperial units (Inches).

Mechanical Tolerance Variations of Lumber:

Per. Voluntary Product Standard PS 20-05, American Softwood Lumber Standard

Dimension lumber can be purchased as dry or green. Dry lumber that has been seasoned or dried to a moisture content 19% or less and green lumber has a moisture content of greater than 19%. Rough lumber cannot be less than than 1/8" (3.2mm) thicker or wider than the nominal finished thickness or width, except that 20% of a shipment cannot be less than 2/32" (2.4mm) thicker or wider.

Related Lumber Wood Engineering Data:

Nominal Size Actual Size  Weight / Foot **

1 X 3

.75 X 2.5 0.47
1 X 4 .75 X 3.5 0.64
1 X 6 .75 X 5.5 1.00
1 X 8 .75 X 7.25 1.32
1 X 10 .75 X 9.25 1.69
1 X 12 .75 X 11.25 2.05
2 X 3 1.5 X 2.5 0.94
2 X 4 1.5 X 3.5 1.28
2 X 6 1.5 X 5.5 2.00
2 X 8 1.5 X 7.25 2.64
 2 X 10 1.5 X 9.25 3.37
2 X 12 1.5 X 11.25  4.10
2 X 14 1.5 X 13.25 4.83
3 X 3 2.5 X 2.5 1.52
3 X 4 2.5 X 3.5 2.13
 3 X 6 2.5 X 5.5 3.34
 3 X 8 2.5 X 7.25 4.41
3 X 10 2.5 X 9.25 5.62
3 X 12 2.5 X 11.25 6.84
3 X 14 2.5 X 13.25 8.05
3 X 16 2.5 X 15.25 9.27
4 X 4 3.5 X 3.5 2.98
4 X 6 3.5 X 5.5 4.68
4 X 8 3.5 X 7.25 6.17
4 X 10 3.5 X 9.25 7.78
4 X 12 3.5 X 11.25 9.57
4 X 14 3.5 X 13.25 11.28
4 X 16 3.5 X 15.25 12.98
6 X 6 5.5 X 5.5 7.35
6 X 8 5.5 X 7.5 10.03
6 X 10 5.5 X 9.5 12.70
6 X 12 5.5 X 11.5 15.37
6 X 14 5.5 X 13.5 18.05
6 X 16 5.5 X 15.5 20.72
6 X 18 5.5 X 17.5 23.29
8 X 8 7.5 X 7.5 13.67
8 X 10 7.5 X 9.5 17.32
8 X 12 7.5 X 11.5 20.96
8 X 14 7.5 X 13.5 24.61
8 X 16 7.5 X 15.5 28.26
8 X 18 7.5 X 17.5 31.90
10 X 10 9.5 X 9.5 21.94
10 X 12 9.5 X 11.5 26.55
10 X 14 9.5 X 13.5 31.17
10 X 16 9.5 X 15.5 35.79
10 X 18 9.5 X 17.5 40.41
12 X 12 11.5 X 11.5 32.14
12 X 14 11.5 X 13.5 37.73
12 X 16 11.5 X 15.5 43.33

** BASED 0N 35LBS./CI. FT. ACTUAL VOLUME AND WEIGHT

Grades and standards for Lumber:

Individual pieces of lumber exhibit a wide range in quality and appearance with respect to knots, slope of grain, shakes and other natural characteristics. Therefore, they vary considerably in strength, utility and value.

The move to set national standards for lumber in the United States began with publication of the American Lumber Standard in 1924, which set specifications for lumber dimensions, grade, and moisture content; it also developed inspection and accreditation programs. These standards have changed over the years to meet the changing needs of manufacturers and distributors, with the goal of keeping lumber competitive with other construction products. Current standards are set by the American Lumber Standard Committee, appointed by the Secretary of Commerce.

Design values for most species and grades of visually graded structural products are determined in accordance with ASTM standards, which consider the effect of strength reducing characteristics, load duration, safety and other influencing factors. The applicable standards are based on results of tests conducted in cooperation with the USDA Forest Products Laboratory. Design Values for Wood Construction, which is a supplement to the ANSI/AF&PA National Design Specification?? for Wood Construction, provides these lumber design values, which are recognized by the model building codes. A summary of the six published design values???including bending (Fb), shear parallel to grain (Fv), compression perpendicular to grain (Fc-perp), compression parallel to grain (Fc), tension parallel to grain (Ft), and modulus of elasticity (E and Emin) can be found in Structural Properties and Performance published by WoodWorks.

Canada has grading rules that maintain a standard among mills manufacturing similar woods to assure customers of uniform quality. Grades standardize the quality of lumber at different levels and are based on moisture content, size and manufacture at the time of grading, shipping and unloading by the buyer. The National Lumber Grades Authority (NLGA) is responsible for writing, interpreting and maintaining Canadian lumber grading rules and standards. The Canadian Lumber Standards Accreditation Board (CLSAB) monitors the quality of Canada's lumber grading and identification system.

Attempts to maintain lumber quality over time have been challenged by historical changes in the timber resources of the United States???from the slow-growing virgin forests common over a century ago to the fast-growing plantations now common in today's commercial forests. Resulting declines in lumber quality have been of concern to both the lumber industry and consumers and have caused increased use of alternative construction products.

Machine stress-rated and machine-evaluated lumber is readily available for end-uses where high strength is critical, such as truss rafters, laminating stock, I-beams and web joints. Machine grading measures a characteristic such as stiffness or density that correlates with the structural properties of interest, such as bending strength. The result is a more precise understanding of the strength of each piece of lumber than is possible with visually graded lumber, which allows designers to use full-design strength and avoid overbuilding.

In Europe, strength grading of sawn softwood is done according to EN-14081-1/2/3/4 and sorted into 9 classes; In increasing strength these are: C14, C16, C18, ??22, ??24, ??27, ??30, ??35 and ??40

C14 Used for Scaffolding or Formwork
C24 General construction
C30 Prefab Roof trusses and where design requires somewhat stronger joists than C24 can offer
C40 Usually seen in Glulam

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