Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). Lumber has many uses beyond home building. Lumber is sometimes referred to as timber in England, Australia, and New Zealand, while in most parts of the world (including the United States and Canada) the term timber refers specifically to unprocessed wood fiber, such as cut logs or standing trees that have yet to be cut.
Lumber may be supplied either rough-sawn, or surfaced on one or more of its faces. Rough lumber is the raw material for furniture-making, and manufacture of other items requiring cutting and shaping. It is available in many species, including hardwoods and softwoods, such as white pine and red pine, because of their low cost.
Finished lumber is supplied in standard sizes, mostly for the construction industry – primarily softwood, from coniferous species, including pine, fir and spruce (collectively spruce-pine-fir), cedar, and hemlock, but also some hardwood, for high-grade flooring. It is more commonly made from softwood than hardwoods, and 80% of lumber comes from softwood.
Terminology
In the United States and Canada, milled boards are called lumber, while timber describes standing or felled trees.
In contrast, in Britain, and some other Commonwealth nations and Ireland, the term timber is used in both senses. (In the UK, the word lumber is rarely used in relation to wood and has several other meanings.)
Re-manufactured lumber
Re-manufactured lumber is the result of secondary or tertiary processing of previously milled lumber. Specifically, it refers to lumber cut for industrial or wood-packaging use. Lumber is cut by ripsaw or resaw to create dimensions that are not usually processed by a primary sawmill.
Re-sawing is the splitting of hardwood or softwood lumber into two or more thinner pieces of full-length boards. For example, splitting a 2×4 () into two 1×4s () of the same length is considered re-sawing.
Plastic lumber
Structural lumber may also be produced from recycled plastic and new plastic stock. Its introduction has been strongly opposed by the forestry industry. Blending fiberglass in plastic lumber enhances its strength, durability, and fire resistance. Plastic fiberglass structural lumber can have a "class 1 flame spread rating of 25 or less, when tested in accordance with ASTM standard E 84," which means it burns more slowly than almost all treated wood lumber.
History
The basic understanding of lumber, or "sawn planks", came about in North America in the seventeenth century. Lumber is the most common and widely used method of sawing logs. Plain sawn lumber is produced by making the first cut on a tangent to the circumference of the log. Each additional cut is then made parallel to the one before. This method produces the widest possible boards with the least amount of log waste.
Lumber manufacturing globally is determined by the preferred style of building; areas with a "wood building culture" (homes were built from wood rather than other materials like brick) are the countries with significant sawmilling industries. Historical wood-frame home building regions are: Europe, North America, Japan. Different areas of the world are recognized as significant timber suppliers; however, these areas (Indonesia, Sarawak, New Guinea, etc.) are exporters of raw logs and do not have a significant domestic lumber producing industry.
The largest lumber manufacturing regions in the world are: China (18%); United States (17%); Canada (10%); Russia (9%); Germany (5%); Sweden (4%).
In early periods of society, to make wood for building, the trunks of trees were split with wedges into as many and as thin pieces as possible. If it was necessary to have them still thinner, they were hewn, by some sharp instrument, on both sides, to the proper size. This simple but wasteful manner of making boards is still continued in some places.
Otherwise, logs were sawn using a two-person whipsaw, or pit-saw, using saddleblocks to hold the log, and a pit for the pitman who worked below.
In 1420 the island of Madeira an archipelago comprising four islands off the northwest coast of Africa and an autonomous region of Portugal was discovered. King Henry VI sent settlers to Madeira and ordered sawmills to be erected for the purpose of cutting the various species of excellent timber with which the island abounded. About 1427, the first sawmill in Germany was built.
