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Lumber, also known as timber, is
wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. ...

wood
that has been processed into beams and planks, a stage in the process of
wood production Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
. Lumber is mainly used for structural purposes but has many other uses as well. Lumber may be supplied either rough-
sawn
sawn
, or surfaced on one or more of its faces. Besides
pulpwood Pulpwood is timber Lumber, also known as timber, is wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk ...
, ''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
hardwood is a popular hardwood Hardwood is wood Wood is a porous and fibrous structural tissue found in the Plant stem, stems and roots of trees and other woody plants. It is an organic materiala natural composite material, composite of cellulos ...

hardwood
s and
softwood Scots Pine, a typical and well-known softwood Softwood is wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or t ...
s, such as
white pine ''Pinus A pine is any conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...
and
red pine ''Pinus resinosa'', known as red pine or Norway pine, is a pine native to North America. It occurs from Newfoundland (island), Newfoundland west to Manitoba, and south to Pennsylvania, with several smaller, disjunct populations occurring in the A ...

red pine
, because of their low cost. ''Finished lumber'' is supplied in standard sizes, mostly for the construction industry – primarily
softwood Scots Pine, a typical and well-known softwood Softwood is wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or t ...
, from
conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ex ...
ous species, including
pine A pine is any conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The divi ...

pine
,
fir Firs (''Abies'') are a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology Biology is the natural science that studies life and living organisms, including ...

fir
and
spruce A spruce is a tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including ...

spruce
(collectively
spruce-pine-fir Spruce-pine-fir (SPF) is a classification of lumber Lumber, also known as timber, is a type of wood that has been processed into Beam (structure), beams and plank (wood), planks, a stage in the process of wood production. Lumber is mainly use ...
), cedar, and
hemlock Hemlock may refer to: Plants *Several poisonous plants in the family Apiaceae **''Cicuta'' (water hemlock) **''Conium'', four species, of which ''maculatum'' is the only endemic outside of southern Africa; in history given to poison and execute p ...
, 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, many other Commonwealth nations and Ireland, the term ''
timber Lumber, also known as timber, is wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, sup ...
'' is used in both senses. (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 A resaw is a large band saw A bandsaw (also written band saw) is a power saw with a long, sharp blade consisting of a continuous band of toothed metal stretched between two or more wheels to cut material. They are used principally in woodwo ...
to create dimensions that are not usually processed by a primary
sawmill A sawmill (saw mill, saw-mill) or lumber mill is a facility where logs are cut into lumber Lumber, also known as timber, is wood Wood is a porous and fibrous structural tissue found in the Plant stem, stems and roots of trees and ...

sawmill
. Re-sawing is the splitting of
hardwood is a popular hardwood Hardwood is wood Wood is a porous and fibrous structural tissue found in the Plant stem, stems and roots of trees and other woody plants. It is an organic materiala natural composite material, composite of cellulos ...

hardwood
or
softwood Scots Pine, a typical and well-known softwood Softwood is wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or t ...
lumber into two or more thinner pieces of full-length boards. For example, splitting a long into two 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 Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forest A forest is an area of land dominated by tree In botany, a tree is a perennial plant with an elongated Plant stem, ste ...
industry. Blending fiberglass in plastic lumber enhances its strength, durability, and fire resistance. Plastic
fiberglass Fiberglass (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American Englis ...
structural lumber can have a "class 1
flame spreadFlame spread or surface burning characteristics rating is a ranking derived by laboratory standard test methodology of a material's propensity to burn rapidly and spread flame A flame (from Latin '' flamma'') is the visible, gaseous part of a fire ...
rating of 25 or less, when tested in accordance with
ASTM ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization ( ...
standard E 84," which means it burns more slowly than almost all treated wood lumber.


History


Conversion of wood logs

Logs are ''converted'' into timber by being sawn, hewn, or
split Split(s) or The Split may refer to: Places * Split, Croatia, the largest coastal city in Croatia * Split Island, Canada, an island in the Hudson Bay * Split Island, Falkland Islands * Split Island, Fiji, better known as Hạfliua Arts, entertainm ...
. Sawing with a
rip saw 300px, A rip saw A rip saw is a wood saw that is specially designed for making a rip cut, a cut made parallel to the direction of the wood grain. Design The cutting edge of each tooth has a flat front edge and it is angled backward by about 8°, ...
is the most common method, because sawing allows logs of lower quality, with irregular grain and large knots, to be used and is more economical. There are various types of sawing: * Plain sawn (flat sawn, through and through, bastard sawn) – A log sawn through without adjusting the position of the log and the grain runs across the width of the boards. * Quarter sawn and
rift sawnRift-sawing is a woodworking process that aims to produce lumber that is less vulnerable to distortion than flat sawn lumber. Rift-sawing may be done strictly along a log's radials—perpendicular to the annular growth ring orientation or wood grain ...
– These terms have been confused in history but generally mean lumber sawn so the annual rings are reasonably perpendicular to the sides (not edges) of the lumber. * Boxed heart – The
pith Pith, or medulla, is a tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a species of geometer moth found in North America * ''Triphosa d ...
remains within the piece with some allowance for exposure. * Heart center – the center core of a log. * Free of heart center (FOHC) – A side-cut timber without any pith. * Free of knots (FOK) – No knots are present.


Dimensional lumber

Dimensional lumber is lumber that is cut to standardized width and depth, often specified in
millimetre 330px, Different lengths as in respect to the Electromagnetic spectrum, measured by the Metre and its deriveds scales. The Microwave are in-between 1 meter to 1 millimeter. The millimetre (American and British English spelling differences#-re, - ...
s or
inch Measuring tape with inches The inch (symbol: in or ″) is a unit Unit may refer to: Arts and entertainment * UNIT Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television s ...
es.
Carpenters Carpenters in an Indian village Carpentry is a skilled trade A tradesman, skilled tradesman, or tradie refers to a skilled worker who specializes in a particular occupation that requires work experience, on-the-job training, and often fo ...

Carpenters
extensively use dimensional lumber in framing wooden buildings. Common sizes include ''2×4'' (pictured) (also ''two-by-four'' and other variants, such as ''four-by-two'' in Australia, New Zealand, and the UK), ''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, and twelve feet in length. In
Canada Canada is a country in the northern part of North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, ...

Canada
and the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

United States
, the standard lengths of lumber are . For wall framing, precut "stud" lengths are available, and are commonly used. For ceilings heights of , studs are available in , , and .


North American softwoods

The length of a unit of dimensional lumber is limited by the height and girth of the tree it is milled from. In general the maximum length is . Engineered wood products, manufactured by binding the strands, particles, fibers, or veneers of wood, together with adhesives, to form composite materials, offer more flexibility and greater structural strength than typical wood building materials. Pre-cut studs save a framer much time, because they are pre-cut by the manufacturer for use in 8-, 9-, and 10-foot ceiling applications, which means the manufacturer has removed a few inches or centimetres of the piece to allow for the sill plate and the double top plate with no additional sizing necessary. In the
Americas The Americas (also collectively called America) is a landmass comprising the totality of North America, North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

Americas
, ''two-bys'' (2×4s, 2×6s, 2×8s, 2×10s, and 2×12s), named for traditional board thickness in inches, along with the 4×4 (), are common lumber sizes used in modern construction. They are the basic building blocks for such common structures as
balloon-frame File:Salarom Sabah Frame-of-a-new-house-01.jpg, upright=1.35, The erection of a wooden frame in Sabah, Sabah, Malaysia Framing, in construction, is the fitting together of pieces to give a structure support and shape. Framing materials are usua ...
or platform-frame housing. Dimensional lumber made from
softwood Scots Pine, a typical and well-known softwood Softwood is wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or t ...
is typically used for construction, while
hardwood is a popular hardwood Hardwood is wood Wood is a porous and fibrous structural tissue found in the Plant stem, stems and roots of trees and other woody plants. It is an organic materiala natural composite material, composite of cellulos ...

hardwood
boards are more commonly used for making cabinets or
furniture Furniture refers to movable objects intended to support various human activities such as seating (e.g., chairs, stools, and sofas), eating (table (furniture), tables), and sleeping (e.g., beds). Furniture is also used to hold objects at a con ...

furniture
. Lumber's
''nominal'' dimensions
''nominal'' dimensions
are larger than the actual standard dimensions of finished lumber. Historically, the nominal dimensions were the size of the green (not dried), rough (unfinished) boards that eventually became smaller finished lumber through drying and planing (to smooth the wood). Today, the standards specify the final finished dimensions and the mill cuts the logs to whatever size it needs to achieve those final dimensions. 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 . After drying and planing, it would be smaller by a nonstandard amount. Today, a "2×4" board starts out as something smaller than 2 inches by 4 inches and not specified by standards, and after drying and planing is minimally . As previously noted, less wood is needed to produce a given finished size than when standards called for the green lumber to be the full nominal dimension. However, even the dimensions for finished lumber of a given nominal size have changed over time. In 1910, a typical finished board was . In 1928, that was reduced by 4%, and yet again by 4% in 1956. In 1961, at a meeting in Scottsdale, Arizona, the Committee on Grade Simplification and Standardization agreed to what is now the current U.S. standard: in part, the dressed size of a 1-inch (nominal) board was fixed at  inch; while the dressed size of 2 inch (nominal) lumber was ''reduced'' from  inch to the current  inch. Dimensional lumber is available in green, unfinished state, and for that kind of lumber, the nominal dimensions are the actual dimensions.


Grades and standards

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 the 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 U.S. Secretary of Commerce. Design values for most species and grades of visually graded structural products are determined in accordance with
ASTM ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization ( ...
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 The United States Department of Agriculture (USDA), also known as the Agriculture Department, is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, ...
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. 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 forest An old-growth forest – also termed primary forest, virgin forest, late seral forest or primeval forest – is a forest that has attained great age without significant disturbance and thereby exhibits unique ecological features and might be cl ...

virgin forest
s common over a century ago to the fast-growing
plantations A plantation is an agricultural estate, generally centered on a plantation house, meant for farming that specializes in cash crops, usually mainly planted with a single crop, with perhaps ancillary areas for vegetables for eating and so on. The c ...
now common in today's commercial forests. Resulting declines in lumber quality have been of concern to both the
lumber industry The wood industry or lumber industry is the industry Industry may refer to: Economics * Industry (economics) In macroeconomics, an industry is a branch of an economy that produces a closely related set of raw materials, goods, or servic ...
and consumers and have caused increased use of alternative construction products. Machine stress-rated and machine-evaluated lumber are readily available for end-uses where high strength is critical, such as
truss A truss is an assembly of ''members'' such as beams, connected by ''nodes'', that creates a rigid structure. In engineering, a truss is a structure A structure is an arrangement and organization of interrelated elements in a material object ...

truss
es,
rafter Image:Photograph of the Roof Framing in the Bequet-Ribault House in Ste Genevieve MO.png, A ''double roof'' (using a Norman truss), ''common rafters'' supported by ''principal rafters'' (''top chords'' in this case) and an unusual extra layer of c ...
s, laminating stock,
I-beams An I-beam, also known as H-beam (for universal column, UC), w-beam (for "wide flange"), universal beam (UB), rolled steel joist (RSJ), or double-T (especially in Polish language, Polish, Bulgarian language, Bulgarian, Spanish language, Spanish, ...
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 Flexural strength, also known as modulus of rupture, or bend strength, or transverse rupture strength is a material property, defined as the stress in a material just before it yields in a flexure test. The transverse bending test is most freque ...
. 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 rectangular sawn timber (both softwood and hardwood) is done according to EN-14081 and commonly sorted into classes defined by EN-338. For softwoods, the common classes are (in increasing strength) C16, C18, C24, and C30. There are also classes specifically for hardwoods and those in most common use (in increasing strength) are D24, D30, D40, D50, D60, and D70. For these classes, the number refers to the required 5th percentile bending strength in newtons per square millimetre. There are other strength classes, including T-classes based on tension intended for use in
glulam Glued laminated timber, also abbreviated glulam, is a type of structural engineered wood Engineered wood, also called mass timber, composite wood, man-made wood, or manufactured board, includes a range of derivative wood Wood is a porous ...

glulam
. * C14, used for
scaffolding Scaffolding, also called scaffold or staging, is a temporary structure used to support a work crew and materials to aid in the construction, maintenance and repair of buildings, bridges and all other man-made structures. Scaffolds are widely us ...

scaffolding
and
formwork Placing a formwork component Formwork is temporary or permanent molds into which concrete File:Pantheon cupola.jpg, Interior of the Pantheon dome, seen from beneath. The concrete for the coffered dome was laid on moulds, mounted on temp ...
* C16 and C24, general construction * C30, prefab roof trusses and where design requires somewhat stronger
joist A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members. When incorporated into a floor A floor is the bottom surface of a room or vehicle. Fl ...

joist
s than C24 can offer. TR26 is also a common trussed rafter strength class in long standing use in the UK. * C40, usually seen in
glulam Glued laminated timber, also abbreviated glulam, is a type of structural engineered wood Engineered wood, also called mass timber, composite wood, man-made wood, or manufactured board, includes a range of derivative wood Wood is a porous ...

glulam
Grading rules for African and South American sawn timber have been developed by ATIBT according to the rules of the Sciages Avivés Tropicaux Africains (SATA) and is based on clear cuttings – established by the percentage of the clear surface.


North American hardwoods

In North America, market practices for dimensional lumber made from hardwoods varies significantly from the regularized ''standardized ' dimension lumber' sizes'' used for sales and specification of softwoods – hardwood boards are often sold totally rough cut, or machine planed only on the two (broader) face sides. When hardwood boards are also supplied with planed faces, it is usually both by random widths of a specified thickness (normally matching milling of softwood dimensional lumbers) and somewhat random lengths. But besides those older (traditional and normal) situations, in recent years some product lines have been widened to also market boards in standard stock sizes; these usually retail in
big-box store A big-box store (also hyperstore, supercenter, superstore, or megastore) is a physically large retail establishment, usually part of a chain Image:Kettenvergleich.jpg, Roller chains A chain is a wikt:series#Noun, serial assembly of connecte ...
s and using only a relatively small set of specified lengths; in all cases hardwoods are sold to the consumer by the board-foot (), whereas that measure is not used for softwoods at the retailer (to the cognizance of the buyer). Also in North America, hardwood lumber is commonly sold in a "quarter" system, when referring to thickness; 4/4 (four quarter) refers to a board, 8/4 (eight quarter) is a board, etc. This "quarter" system is rarely used for softwood lumber; although softwood decking is sometimes sold as 5/4, even though it is actually one-inch thick (from milling off each side in a motorized
planing
planing
step of production). The "quarter" system of reference is a traditional North American lumber industry nomenclature used specifically to indicate the thickness of rough sawn hardwood lumber. In rough-sawn lumber it immediately clarifies that the lumber is not yet milled, avoiding confusion with milled dimension lumber which is measured as actual thickness after machining. Examples – -inch, 19 mm, or 1x. In recent years architects, designers, and builders have begun to use the "quarter" system in specifications as a vogue of insider knowledge, though the materials being specified are finished lumber, thus conflating the separate systems and causing confusion. Hardwoods cut for furniture are cut in the fall and winter, after the sap has stopped running in the trees. If hardwoods are cut in the spring or summer the sap ruins the natural color of the timber and decreases the value of the timber for furniture.


Engineered lumber

Engineered lumber Engineered wood, also called mass timber, composite wood, man-made wood, or manufactured board, includes a range of derivative wood products which are manufactured by binding or fixing the strands, particles, fibres, or wood veneer, veneers or b ...
is lumber created by a manufacturer and designed for a certain structural purpose. The main categories of engineered lumber are: * Laminated veneer lumber (LVL) – LVL comes in inch thicknesses with depths such as , , 14, 16, 18, and 24 inches, and are often doubled or tripled up. They function as beams to provide support over large spans, such as removed support walls and garage door openings, places where dimensional lumber is insufficient, and also in areas where a heavy load is bearing from a floor, wall or roof above on a somewhat short span where dimensional lumber is impractical. This type of lumber is compromised if it is altered by holes or notches anywhere within the span or at the ends, but nails can be driven into it wherever necessary to anchor the beam or to add hangers for I-joists or dimensional lumber joists that terminate at an LVL beam. * Wooden I-joists – sometimes called "TJI", "Trus Joists" or "BCI", all of which are brands of wooden I-joists, they are used for floor joists on upper floors and also in first floor conventional foundation construction on piers as opposed to slab floor construction. They are engineered for long spans and are doubled up in places where a wall will be aligned over them, and sometimes tripled where heavy roof-loaded support walls are placed above them. They consist of a top and bottom chord or flange made from dimensional lumber with a webbing in-between made from oriented strand board (OSB) (or, latterly, steel mesh forms which allow passage of services without cutting). The webbing can be removed up to certain sizes or shapes according to the manufacturer's or engineer's specifications, but for small holes, wooden I-joists come with "knockouts", which are perforated, pre-cut areas where holes can be made easily, typically without engineering approval. When large holes are needed, they can typically be made in the webbing only and only in the center third of the span; the top and bottom chords lose their integrity if cut. Sizes and shapes of the hole, and typically the placing of a hole itself, must be approved by an engineer prior to the cutting of the hole and in many areas, a sheet showing the calculations made by the engineer must be provided to the building inspection authorities before the hole will be approved. Some I-joists are made with W-style webbing like a truss to eliminate cutting and to allow ductwork to pass through. * Finger-jointed lumber – solid dimensional lumber lengths typically are limited to lengths of 22 to 24 feet, but can be made longer by the technique of "finger-jointing" by using small solid pieces, usually 18 to 24 inches long, and joining them together using finger joints and glue to produce lengths that can be up to 36 feet long in 2×6 size. Finger-jointing also is predominant in precut wall studs. It is also an affordable alternative for non-structural hardwood that will be painted (staining would leave the finger-joints visible). Care is taken during construction to avoid nailing directly into a glued joint as stud breakage can occur. * Glulam beams – created from 2×4 or 2×6 stock by gluing the faces together to create beams such as 4×12 or 6×16. As such, a beam acts as one larger piece of lumber – thus eliminating the need to harvest larger, older trees for the same size beam. *
Manufactured trusses
Manufactured trusses
– trusses are used in home construction as a pre-fabricated replacement for roof rafters and ceiling joists (stick-framing). It is seen as an easier installation and a better solution for supporting roofs than the use of dimensional lumber's struts and purlins as bracing. In the southern U.S. and elsewhere, stick-framing with dimensional lumber roof support is still predominant. The main drawbacks of trusses are reduced attic space, time required for engineering and ordering, and a cost higher than the dimensional lumber needed if the same project were conventionally framed. The advantages are significantly reduced labor costs (installation is faster than conventional framing), consistency, and overall schedule savings.


Various pieces and cuts

* Square and rectangular forms:
Plank Plank may refer to: *Plank (wood), flat, elongated, and rectangular timber with parallel faces *Plank (exercise), an isometric exercise for the abdominal muscles *Martins Creek (Kentucky), the location of Plank post office *The Plank (1967 film), ' ...
, slat,
batten A batten is most commonly a strip of solid material, historically wood but can also be of plastic, metal, or fiberglass. Battens are variously used in construction, sailing, and other fields. In the lighting industry, battens refer to linear ...
,
board Board or Boards may refer to: Flat surface * Lumber, or other rigid material, milled or sawn flat ** Plank (wood) ** Cutting board ** Sounding board, of a musical instrument * Cardboard (paper product) * Paperboard *Corrugated fiberboard *Fiberbo ...
,
lath A lath or slat is a thin, narrow strip of straight-grain A grain is a small, hard, dry seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warn ...

lath
, ''strapping'' (typically ), ''cant'' (A partially sawn log such as sawn on two sides or squared to a large size and later resawn into lumber. A ''flitch'' is a type of cant with wane on one or both sides). Various pieces are also known by their uses such as
post Post or POST commonly refers to: *Mail The mail or post is a system for physically transporting postcards, letters, and parcels. A postal service can be private or public, though many governments place restrictions on private systems. Since ...
,
beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized group ...
, (
girt In architecture or structural engineering, a girt, also known as a sheeting rail, is a horizontal structural member in a framed wall. Girts provide lateral support to the wall panel, primarily, to resist wind loads. A comparable element in roof c ...
),
stud Stud may refer to: * Stud (animal) 280px, Stud Murray Grey cows receiving supplementary feeding during a drought, Graman, NSW. A stud animal is a registered animal retained for breeding. The terms for the male of a given animal species (stallion (h ...
,
rafter Image:Photograph of the Roof Framing in the Bequet-Ribault House in Ste Genevieve MO.png, A ''double roof'' (using a Norman truss), ''common rafters'' supported by ''principal rafters'' (''top chords'' in this case) and an unusual extra layer of c ...
,
joist A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members. When incorporated into a floor A floor is the bottom surface of a room or vehicle. Fl ...

joist
,
sill plate A sill plate or sole plate in construction Construction is a general term meaning the art and science to form Physical object, objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Editi ...
,
wall plate A wall is a structure and a surface that defines an area; carries a load; provides security Security is freedom from, or resilience against, potential harm (or other unwanted Coercion, coercive change) caused by others. Beneficiaries (technica ...
. *Rod forms:
pole Pole may refer to: Astronomy *Celestial pole, the projection of the planet Earth's axis of rotation onto the celestial sphere; also applies to the axis of rotation of other planets *Pole star, a visible star that is approximately aligned with the ...

pole
, (
dowel A dowel is a cylindrical wikt:rod, rod, usually made of wood, plastic, or metal. In its original manufactured form, a dowel is called a ''dowel rod''. Dowel rods are often cut into short lengths called dowel pins. Dowels are commonly used as struc ...
), stick (staff, baton)


Timber piles

In the United States,
piling , United States. , Florida Florida is a U.S. state, state located in the Southeastern United States, Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the nort ...

piling
s are mainly cut from
southern yellow pine In ecology and forestry, yellow pine refers to a number of pinophyta, conifer species that tend to grow in similar plant communities and yield similar strong wood. In the Western United States, yellow pine refers to Jeffrey pine or Pinus ponderos ...
s and
Douglas fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who ...
s. Treated pilings are available in
Chromated copper arsenateChromated copper arsenate (CCA) is a wood preservative containing compounds of chromium, copper, and arsenic, in various proportions. It is used to impregnate timber and other wood products, especially those intended for outdoor use, in order to pro ...
retentions of 0.60, 0.80 and 2.50 pounds per cubic foot (, and ) if treatment is required.


Historical Chinese construction

Under the prescription of the '' Method of Construction'' (營造法式) issued by the
Song dynasty The Song dynasty (; ; 960–1279) was an imperial dynasty of China that began in 960 and lasted until 1279. The dynasty was founded by Emperor Taizu of Song Emperor Taizu of Song (21 March 927 – 14 November 976), personal name Zhao Kua ...
government in the early 12th century, timbers were standardized to eight cross-sectional dimensions. Regardless of the actual dimensions of the timber, the ratio between width and height was maintained at 1:1.5. Units are in Song Dynasty inches (31.2 mm). Timber smaller than the 8th class were called "unclassed" (等外). The width of a timber is referred to as one "timber" (材), and the dimensions of other structural components were quoted in multiples of "timber"; thus, as the width of the actual timber varied, the dimensions of other components were easily calculated, without resorting to specific figures for each scale. The dimensions of timbers in similar applications show a gradual diminution from the Sui Dyansty (580–618) to the modern era; a 1st class timber during the Sui was reconstructed as 15×10 (Sui Dynasty inches, or 29.4 mm).


Defects in lumber

Defects occurring in lumber are grouped into the following four divisions:


Conversion

During the process of converting timber to commercial form the following defects may occur: * Chip mark: this defect is indicated by the marks or signs placed by chips on the finished surface of timber * Diagonal grain: improper sawing of timber * Torn grain: when a small dent is made on the finished surface due to falling of some tool * Wane: presence of original rounded surface in the finished product


Defects due to fungi and animals

Fungi attack timber when these conditions are all present: * The timber moisture content is above 25% on a dry-weight basis * The environment is sufficiently warm * Oxygen (O2) is present Wood with less than 25% moisture (dry weight basis) can remain free of decay for centuries. Similarly, wood submerged in water may not be attacked by fungi if the amount of oxygen is inadequate. Fungi timber defects: * Blue stain * Brown rot *
Dry rot Dry rot is wood decay A wood-decay or xylophagous fungus is any species of fungus that digests moist wood, causing it to decomposition, rot. Some species of wood-decay fungi attack dead wood, such as brown rot, and some, such as ''Armillaria ...
*
Heart rotimage:Fistulina hepatica.JPG, 300px, The bracket fungus ''Fistulina hepatica'' is one of many that cause heart rot. In trees, heart rot is a fungal disease that causes the wood decay, decay of wood at the center of the Trunk (botany), trunk and branc ...
* Sap stain *
Wet rot Wet rot is a generic term Trademark distinctiveness is an important concept in the law governing trademark A trademark (also written trade mark or trade-markThe styling of ''trademark'' as a single word is predominantly used in the Unit ...
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White rot A wood-decay or xylophagous fungus is any species of fungus that digests moist wood Wood is a porous and fibrous structural tissue found in the Plant stem, stems and roots of trees and other woody plants. It is an organic materiala natural ...
Following are the
insects Insects (from Latin ') are pancrustacean Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, Thorax (ins ...

insects
and
molluscs Mollusca is the second-largest phylum In biology, a phylum (; plural The plural (sometimes list of glossing abbreviations, abbreviated ), in many languages, is one of the values of the grammatical number, grammatical category of number ...

molluscs
which are usually responsible for the decay of timber: *
Woodboring beetle The term woodboring beetle encompasses many species and families of beetles Beetles are a group of insect Insects or Insecta (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the ...
s * Marine borers ( Barnea similis) * Teredos (
Teredo navalis ''Teredo navalis'', commonly called the naval shipworm or turu, is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A spec ...

Teredo navalis
) *
Termites Termites are s that are classified at the of Isoptera, or alternatively as Termitoidae, within the order (along with es). Termites were once classified in a separate from cockroaches, but recent studies indicate that they evolved from c ...

Termites
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Carpenter ants
Carpenter ants
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Carpenter bee Carpenter bees are species in the genus ''Xylocopa'' of the subfamily Xylocopinae. The genus includes some 500 bees in 31 subgenera. The common name "carpenter bee" derives from their nesting behavior; nearly all species burrow into hard plant ma ...

Carpenter bee
s


Natural forces

There are two main natural forces responsible for causing defects in timber: abnormal growth and rupture of tissues. Rupture of tissue includes cracks or splits in the wood called "shakes". "Ring shake", "wind shake", or "ring failure" is when the wood grain separates around the growth rings either while standing or during felling. Shakes may reduce the strength of a timber and the appearance thus reduce lumber grade and may capture moisture, promoting decay.
Eastern hemlock ''Tsuga canadensis'', also known as eastern hemlock, eastern hemlock-spruce, or Canadian hemlock, and in the French-speaking regions of Canada as ''pruche du Canada'', is a coniferous tree native to eastern North America. It is the state tree ...

Eastern hemlock
is known for having ring shake.U. S. Department of Agriculture. "Shake", ''The Encyclopedia of Wood''. New York: Skyhorse Pub., 2007. Print. A "check" is a crack on the surface of the wood caused by the outside of a timber shrinking as it seasons. Checks may extend to the
pith Pith, or medulla, is a tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a species of geometer moth found in North America * ''Triphosa d ...
and follow the grain. Like shakes, checks can hold water promoting rot. A "split" goes all the way through a timber. Checks and splits occur more frequently at the ends of lumber because of the more rapid drying in these locations.


Seasoning

The Wood drying, seasoning of lumber is typically either kiln- or air-dried. Defects due to seasoning are the main cause of splits, bowing and honeycombing. Seasoning is the process of drying timber to remove the bound moisture contained in the walls of the wood cells to produce seasoned timber.


Durability and service life

Under proper conditions, wood provides excellent, lasting performance. However, it also faces several potential threats to service life, including fungal activity and insect damage – which can be avoided in numerous ways. Section 2304.11 of the International Building Code addresses protection against decay and termites. This section provides requirements for non-residential construction applications, such as wood used above ground (e.g., for framing, decks, stairs, etc.), as well as other applications. There are four recommended methods to protect wood-frame structures against durability hazards and thus provide maximum service life for the building. All require proper design and construction: * Controlling moisture using design techniques to avoid decay * Providing effective control of termites and other insects * Using durable materials such as pressure-treated or naturally durable species of wood where appropriate * Providing quality assurance during design and construction and throughout the building's service life using appropriate maintenance practices


Moisture control

Wood is a Hygroscopy, hygroscopic material, which means it naturally absorbs and releases water to balance its internal moisture content with the surrounding environment. The moisture content of wood is measured by the weight of water as a percentage of the oven-dry weight of the wood fiber. The key to controlling decay is controlling moisture. Once decay fungi are established, the minimum moisture content for decay to propagate is 22 to 24 percent, so building experts recommend 19 percent as the maximum safe moisture content for untreated wood in service. Water by itself does not harm the wood, but rather, wood with consistently high moisture content enables fungal organisms to grow. The primary objective when addressing moisture loads is to keep water from entering the building envelope in the first place and to balance the moisture content within the building itself. Moisture control by means of accepted design and construction details is a simple and practical method of protecting a Timber framing, wood-frame building against decay. For applications with a high risk of staying wet, designers specify durable materials such as naturally decay-resistant species or wood that has been treated with preservatives. Cladding (construction), Cladding, Shake (shingle), shingles,
sill plate A sill plate or sole plate in construction Construction is a general term meaning the art and science to form Physical object, objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Editi ...
s and exposed timbers or Glued laminated timber, glulam beams are examples of potential applications for treated wood.


Controlling termites and other insects

For buildings in termite zones, basic protection practices addressed in current building codes include (but are not limited to) the following: * Grading the building site away from the foundation to provide proper drainage * Covering exposed ground in any crawl spaces with 6-mil polyethylene film and maintaining at least of clearance between the ground and the bottom of framing members above (12 inches to beams or girders, 18 inches to joists or plank flooring members) * Supporting post columns by concrete piers so that there is at least of clear space between the wood and exposed earth * Installing wood framing and sheathing in exterior walls at least eight inches above exposed earth; locating siding at least six inches from the finished grade * Where appropriate, ventilating crawl spaces according to local building codes * Removing building material scraps from the job site before backfilling. * If allowed by local regulation, treating the soil around the foundation with an approved termiticide to provide protection against subterranean termites


Preservatives

To avoid decay and termite infestation, untreated wood is separated from the ground and other sources of moisture. These separations are required by many building codes and are considered necessary to maintain wood elements in permanent structures at a safe moisture content for decay protection. When it is not possible to separate wood from the sources of moisture, designers often rely on preservative-treated wood. Wood can be treated with a preservative that improves service life under severe conditions without altering its basic characteristics. It can also be pressure-impregnated with fire-retardant chemicals that improve its performance in a fire. One of the early treatments to "fireproof lumber", which retard fires, was developed in 1936 by the Protexol Corporation, in which lumber is heavily treated with salt. Wood does not deteriorate simply because it gets wet. When wood breaks down, it is because an organism is eating it. Preservatives work by making the food source inedible to these organisms. Properly preservative-treated wood can have 5 to 10 times the service life of untreated wood. Preserved wood is used most often for railroad ties, utility poles, marine piles, decks, fences and other outdoor applications. Various treatment methods and types of chemicals are available, depending on the attributes required in the particular application and the level of protection needed. There are two basic methods of treating: with and without pressure. Non-pressure methods are the application of preservatives by brushing, spraying, or dipping the piece to be treated. Deeper, more thorough penetration is achieved by driving the preservative into the wood cells with pressure. Various combinations of pressure and vacuum are used to force adequate levels of chemical into the wood. Pressure-treating preservatives consist of chemicals carried in a solvent. Chromated copper arsenate, once the most commonly used wood preservative in North America began being phased out of most residential applications in 2004. Replacing it are amine copper quat and copper azole. All wood preservatives used in the United States and Canada are registered and regularly re-examined for safety by the U.S. Environmental Protection Agency and Health Canada's Pest Management and Regulatory Agency, respectively.


Timber framing

''Timber framing'' is a style of construction that uses heavier framing elements than modern Framing (construction), stick framing, which uses dimensional lumber. The timbers originally were tree Bole (botany), boles squared with a broadaxe or adze and joined together with joinery without nails. Modern timber framing has been growing in popularity in the United States since the 1970s.


Environmental effects of lumber

Green building minimizes the impact or "environmental footprint" of a building. Wood is a major building material that is renewable and replenishable in a continuous cycle. Studies show manufacturing wood uses less energy and results in less air and water pollution than steel and concrete. However, demand for lumber is blamed for deforestation.


Residual wood

The conversion from coal to biomass power is a growing trend in the United States. The United Kingdom, Uzbekistan, Kazakhstan, Australia, Fiji, Madagascar, Mongolia, Russia, Denmark, Switzerland, and Swaziland governments all support an increased role for energy derived from biomass, which are organic materials available on a renewable basis and include residues and/or byproducts of the logging, saw milling and paper-making processes. In particular, they view it as a way to lower greenhouse gas emissions by reducing the consumption of oil and gas while supporting the growth of forestry, agriculture and rural economies. Studies by the U.S. government have found the country's combined forest and agriculture land resources have the power to sustainably supply more than one-third of its current petroleum consumption. Biomass is already an important source of energy for the North American forest products industry. It is common for companies to have cogeneration facilities, also known as combined heat and power, which convert some of the biomass that results from wood and paper manufacturing to electrical and thermal energy in the form of steam. The electricity is used to, among other things, dry lumber and supply heat to the dryers used in paper-making.


Environmental impacts

Lumber is a sustainable and environmentally friendly construction material that could replace traditional building materials (e.g. concrete and steel). Its structural performance, capacity to fixate CO2 and low energy demand during the manufacturing process make lumber an interesting material. Substituting lumber for concrete or steel avoids the carbon emissions of those materials. Cement and concrete manufacture is responsible for around 8% of global GHG emissions while the iron and steel industry is responsible for another 5% (half a ton of CO2 is emitted to manufacture a ton of concrete; two tons of CO2  are emitted in the manufacture of a ton of steel). Advantages of lumber: * Fire performance: In the case of fire, the outer layer of mass timber will tend to char in a predictable way that effectively self-extinguishes and shields the interior, allowing it to retain structural integrity for several hours, even in an intense fire. * Reduction of carbon emissions: Building materials and construction make up 11% of global greenhouse gas emissions. Though the exact amount will depend on tree species, forestry practices, transportation costs, and several other factors, that one cubic meter of lumber sequesters roughly one tonne of CO2. * Natural insulation: lumber is a natural insulator which makes it particularly good for windows and doors. * Less construction time, labor costs, and waste: it is easy to manufacture prefabricated lumber, from which pieces can be assembled simultaneously (with relatively little labor). This reduces material waste, avoids massive on-site inventory, and minimizes on-site disruption. According to the softwood lumber industry, “Mass timber buildings are roughly 25% faster to construct than concrete buildings and require 90% less construction traffic".


End-of-Life

An EPA study shows the typical End-of-Life scenario for wood waste from municipal solid waste (MSW), wood packaging, and other miscellaneous wood products in the US. Based on the 2018 data, about 67% of wood waste was landfilled, 16% incinerated with energy recovery, and 17% recycled. A study conducted by Edinburgh Napier University demonstrated the proportional waste stream of recovered lumber in the UK shows that timber from municipal solid waste and packaging waste make up 13 and 26% of waste collected. Construction and demolition waste make up the biggest bulk of waste collectively at 52%, with the remaining 10% coming from industry.Insights in Timber Recycling and Demolition by Marlene Cramer
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Lumber in the circular economy

Ellen MacArthur Foundation, The Ellen MacArthur Foundation defines the circular economy as: “based on the principles of designing out waste and pollution, keeping products and materials in use, and regenerating natural systems.” The circular economy can be considered as a model that aims to eliminate waste by targeting materials, and products at their maximum value of utility and time. In short, it is a whole new model of production and consumption that ensures sustainable development over time. It is related to the reuse of materials, components, and products over a longer life cycle. Wood is among the most demanding materials which makes it important to come up with a model of the circular economy. The lumber industry creates a lot of waste, especially in its manufacturing process. From log debarking to finished products, there are several stages of processing that generate a considerable volume of waste, which includes solid wood waste, harmful gases, and residual water. Therefore it is important to identify and apply measures to reduce environmental contamination, giving a financial return to the industries (e.g., selling the waste to wood chippings manufacturers) and maintaining a healthy relationship between the environment and industries. Wood waste can be recycled at its EoL to make new products. Recycled chips can be used to make wood panels, which is beneficial for both the environment and industry. Such practice reduces the use of virgin raw materials, eliminating emissions that would have otherwise been emitted in its manufacturing. One of the studies conducted in Hong Kong was done using Life-cycle assessment, Life Cycle Assessment (LCA). The study aimed to assess and compare the environmental impacts of wood waste management from building construction activities using different alternative management scenarios in Hong Kong. Despite various advantages of lumber and its waste, the contribution to the study of the circular economy of lumber is still very small. Some areas where improvements can be made to improve the circularity of lumber is as follows: # First, regulations to support recycled lumber use. For example, establishing grading standards and enforcing penalties for improper disposal, especially in sectors that produce big quantities of wood waste, such as the construction and demolition sector. # Second, creating a stronger supply force. This can be achieved by improving demolition protocol and technology and enhancing the secondary raw materials market through circular business models. # Third, increase demand by introducing incentives to the construction sector and new homeowners to use recycled lumber. This can be in the form of reduced taxes for the construction of the new build.


Lumber as "secondary raw material"

The term Raw material, secondary raw material denotes waste material that has been recycled and injected back into use as productive material. Lumber has a high potential to be used as a secondary raw material at various stages, as listed below: * Recovery of branches and leaves for use as fertilisers: Timber undergo multiple processing stages before lumber of desired shapes, size, and standards are achieved for commercial use. The process generates a lot of waste which in most cases is disregarded. But being an organic waste, the positive aspect of such waste is that it can be used as a fertiliser or to protect the soil in severe weather conditions. * Recovery of Woodchips, wood chips for thermal energy generation: Waste generated during the manufacturing of lumber products can be used to produce thermal energy. Lumber products after their end-of-life can be Downcycling, downcycled into chips and be used a
biomass to produce thermal energy
It is very beneficial for industries that need thermal energy. Circular economy practices offer effective solutions concerning waste. It targets its unnecessary generation through waste reduction, reuse, and recycling. There is no clear explicit evidence of circular economy in the wood panel industry. However, based on the circular economy concept and its characteristics, there are opportunities present in the wood panel industry from the raw material extraction phase to its end-of-life. Therefore, there lies a gap yet to be explored.


See also

* Cubic ton * Deck (building) * Engineered wood * Hardwood timber production * List of woods * Logging * Lumber room * Lumberjack * Non-timber forest product * Recycling timber * Table of Wood and Bamboo Mechanical and Agricultural Properties * Timber treatment * Wood economy * Woodworking


Notes


References


Further reading

*


External links


National Hardwood Lumber Association
(Rules for Grading Hardwood Lumber – Inspector Training School)
Timber Development Association of NSW
– Australia
TDA: Timber Decking Association
– UK
TRADA: Timber Research And Development Association

The Forest Products Laboratory. U.S. main wood products research lab. Madison, WI (E)

WCTE, World Conference on Timber Engineering
June 20–24, 2010, Riva del Garda, Trentino, Italy
Forest Products data in Canada since 1990
{{Authority control Forestry Timber industry Wood products Woodworking