Lumber is supplied either rough or finished. Besides pulpwood, rough lumber is the raw material for furniture-making and other items requiring additional cutting and shaping. It is available in many species, usually hardwoods. Finished lumber is supplied in standard sizes, mostly for the construction industry, primarily softwood from coniferous species including pine, fir and spruce (collectively known as Spruce-pine-fir), cedar, hemlock, but also some hardwood, for high-grade flooring.

Terminology

In the United Kingdom and Australia, "timber" is a term also used for sawn wood products (that is, boards), whereas generally in the United States and Canada, the product of timber cut into boards is referred to as lumber. In the United States and Canada sawn wood products of five inches (127 mm) (nominal size) diameter or greater are sometimes called "timbers".

Dimensional lumber

Example of 2×4. Dimensional lumber is a term used for lumber that is finished/planed and cut to standardized width and depth specified in inches. Examples of common sizes are 2×4 (pictured, also two-by-four and other variants, such as four-by-two in the UK, Australia, New Zealand), 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.

Note: Treated 8x8 SYP pilings are actually 8" x 8"

Solid dimensional lumber typically is only available up to lengths of 24 ft, yet since builders have a need for lengths beyond that for roof construction (rafters), builders use "finger-jointed" lumber that can be up to 36 ft long in 2×6 size (see Engineered Lumber below). Finger-jointed lumber is also widely used for smaller lengths like studs, the vertical members of a framed wall. Pre-cut studs save a framer a lot of time as they are pre-cut by the manufacturer to be used in 8 ft, 9 ft & 10 ft ceiling applications, which means they have removed a few inches of the piece to allow for the sill plate and the double top plate with no additional sizing necessary by the framer.

In the Americas, two-bys (2×4s, 2×6s, 2×8s, 2×10s, and 2×12s), along with the 4×4, are common lumber sizes used in modern construction. They are the basic building block for such common structures as balloon-frame or platform-frame housing. Dimensional lumber made from softwood is typically used for construction, while hardwood boards are more commonly used for making cabinets or furniture.