Lumber Facts for Kids

Mountain ash logs at a sawmill in Australia

Lumber (or timber) is wood that has been cut for use in building.

Dimensional lumber
Related pages
Images for kids
See also

Dimensional lumber

Dimensional lumber is a term used in North America for lumber that is finished/planed and cut to standardized width and depth specified in inches.

Softwoods

Softwood Dimensional Lumber Sizes
Nominal	Actual	Nominal	Actual
1 × 2	¾″ × 1½″ (19×38 mm)	2 × 2	1½″ × 1½″ (38×38 mm)
1 × 3	¾″ × 2½″ (19×64 mm)	2 × 3	1½″ × 2½″ (38×64 mm)
1 × 4	¾″ × 3½″ (19×89 mm)	2 × 4	1½″ × 3½″ (38×89 mm)
1 × 6	¾″ × 5½″ (19×140 mm)	2 × 6	1½″ × 5½″ (38×140 mm)
1 × 8	¾″ × 7¼″ (19×184 mm)	2 × 8	1½″ × 7¼″ (38×184 mm)
1 × 10	¾″ × 9¼″ (19×235 Mm)	2 × 10	1½″ × 9¼″ (38×235 mm)
1 × 12	¾″ × 11¼″ (19×286 mm)	2 × 12	1½″ × 11¼″ (38×286 mm)
3 × 4	2½″ × 3½″ (64×89 mm)	2 × 14	1½″ × 13¼″ (38×337 mm)
4 × 4	3½″ × 3½″ (89×89 mm)	6 × 6	5½″ × 5½″ (140×140 mm)
4 × 6	3½″ × 5½″ (89×140 mm)	8 × 8	7¼″ × 7¼″ (184×184 mm)

Examples of common sizes are 2×4 (also two-by-four and other variants), 2×6, and 4×4. The length of a board is usually specified separately from the width and depth. It is thus possible to find 2×4s that are four, eight, or twelve feet in length. In the United States the standard lengths of lumber are 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 feet.

Non-North American sizes

Examples of Dimensional Lumber Sizes (Softwood and Hardwood)
Inch name	Sawed	Swedish	Australian
2 × 4	50 x 100 mm	45 × 95 mm	45 x 90 mm
1 × 3	25 × 75 mm	22 × 70 mm	19 x 70 mm
3 × 3	75 × 75 mm	70 × 70 mm	70 x 70 mm
2 × 7	50 × 175 mm	45 × 170 mm	Not used
2 × 3	50 × 75 mm	45 × 70 mm	45 x 70 mm
1 × 4	25 × 100 mm	22 × 95 mm	19 x 90 mm
1 × 5	25 × 125 mm	22 × 120 mm	19 x 120 mm
2 × 5	50 × 125 mm	45 × 120 mm	45 x 120 mm

Outside North America sizes of timber vary slightly. Sizes are, in some cases, based on the imperial measurement and referred to as such; in other cases the sizes are too far removed from the imperial size to be referred to by imperial measurement. Lengths can be sold at every 300 mm (a metric approximation of 1'). Common sizes are similar to the North American equivalent; 2.4, 2.7, 3.0, 3.6, 4.2, 4.8, 5.4, 6.0. But also in running lengths, where each plank in a given packet is different, from 2500mm to 5500mm, though shorter and longer may be present.

Hardwoods

Hardwood Dimensional Lumber Sizes
Nominal	Surfaced 1 Side (S1S)	Surfaced 2 sides (S2S)
⅜″	¼″	3/16″
½″	⅜″	5/16″
⅝″	½″	7/16″
¾″	⅝″	9/16″
1″ or 4/4	⅞″	13/16″
1¼″ or 5/4	1⅛″	1-1/16″
1½″ or 6/4	1⅜″	1-5/16″
2″ or 8/4	1-13/16″	1¾″
3″ or 12/4	2-13/16″	2¾″
4″ or 16/4	3-13/16″	3¾″

In North America sizes for dimensional lumber made from hardwoods varies from the sizes for softwoods. Boards are usually supplied in random widths and lengths of a specified thickness, and sold by the board-foot (144 cubic inches).

Engineered Lumber

Engineered lumber is lumber created by a manufacturer and designed for a certain structural purpose.

Images for kids

Wood cut from Victorian Eucalyptus regnans
The harbor of Bellingham, Washington, filled with logs, 1972
A sawmill with the floating logs in Kotka, Finland
A common 50 by 100 mm (2 by 4 in) board
The longest plank in the world (2002) is in Poland and measures 36.83 metres (about 120 ft 10 in) long.
Special fasteners are used with treated lumber because of the corrosive chemicals used in its preservation process.

Lumber facts for kids

Contents