Engineered wood 276504 225735924 2008-07-15T03:56:25Z Ekotekk 2272624 revert vandalism and remove advertising [[Image:PDX1966PGEplant.jpg|thumb|right|This [[1966]] photo shows wood waste being burned for fuel in [[Oregon]].]] [[Image:Holz_kabache_werte_verfall_trostlos.jpg|thumb|right|75 Unit [[Apartment]] [[building]], made largely of wood, in [[Mission, British Columbia]].]] '''Engineered wood''', also called '''composite wood''', "man made wood" or "manufactured wood", includes a range of derivative [[wood]] products which are manufactured by binding together the strands, particles, [[wood fibre|fibers]], or [[wood veneer|veneers]] of wood, together with [[adhesive]]s, to form [[composite material]]s. These products are [[engineering|engineered]] to precise design specifications which are tested to meet national or international standards. Typically, engineered wood products are made from the same [[hardwood]]s and [[softwood]]s used to manufacture [[lumber]]. [[Sawmill]] scraps and other wood waste can be used for engineered wood composed of wood particles or fibers, but whole logs are usually used for veneers, such as [[plywood]]. Alternatively, it is also possible to manufacture similar engineered [[cellulose|cellulosic]] products from other [[lignin]]-containing materials such as [[rye]] straw, [[wheat]] straw, [[rice]] straw, [[hemp]] stalks, [[kenaf]] stalks, or [[sugar cane]] residue, in which case they contain no actual wood but rather [[vegetable]] fibers. ==Characteristics== Engineered wood products are used in a variety of ways, often in applications similar to [[solid wood]] products. Engineered wood products may be preferred over solid wood in some applications due to certain comparative advantages: * Because engineered wood is man-made, it can be designed to meet application-specific performance requirements. * Large panels of engineered wood may be manufactured from fibres from small diameter [[tree]]s. * Small pieces of wood, and wood that has defects, can be used in many engineered wood products, especially particle and fiber-based boards. * Engineered wood products are often stronger and less prone to [[humidity]]-induced warping than equivalent solid woods, although most particle and fiber-based boards readily soak up water unless they are treated with sealant or [[paint]]. Engineered wood products also have some disadvantages: * They require more primary energy for their manufacture than solid lumber. * The required [[adhesive]]s may be toxic. A concern with some resins is the release of formaldehyde in the finished product, often seen with urea-formaldehyde bonded products. * Cutting and otherwise working with engineered wood products can expose workers to toxic constituents. The types of adhesives used in engineered wood include: *[[Urea-formaldehyde]] resins, (UF), most common and cheapest, not waterproof. *[[Phenol]]-formaldehyde resins, (PF), a yellow-brown adhesive commonly used for exterior exposure products. *[[Melamine]]-formaldehyde resin, (MF) a white, heat and water resistant resin, often used in exposed surfaces in more costly designs. *[[Methylene diphenyl diisocyanate]] (MDI) or [[polyurethane]] resins which are expensive and generally waterproof do not contain formaldehyde. A more inclusive term is "structural composites". For example, [[fiber cement siding]] is made of cement and wood fiber, while cement board is a low density cement panel, often with added resin, faced with fiberglass mesh. Plastic extrusion mixes of wood fiber and thermoplastic, such as polyproplyene, has given rise to decking and railing material resistant to weather and is steadily replacing rot resistant wood. ==Types== [[Image:Wood plastic composite.JPG|right|thumb|[[Wood-plastic composite]] is a type of engineered wood.]] [[Image:Wood plastic composite 2.jpg|right|thumb|Another picture of [http://www.newtechwood.com/ NewTech] brand WPC.]] *[[I-joist]] *[[Glued laminated timber]] *[[Multilaminar Veneer]] *[[Wood veneer|Veneer]]-based **[[Plywood]] **[[Laminated veneer lumber]] (LVL) **[[Stamina wood]] *[[Parallam]] *[[Oriented strand board|Parallel strand lumber]] *Particle-based **[[Oriented strand board]] (OSB) **[[Waferboard]] **[[Particleboard]] (chipboard) *[[Fiberboard]] **[[Insulation board]] **[[Homasote]] (1909) **[[Masonite]] (1924) **[[Medium-density fiberboard]] (MDF) **[[Hardboard]] *[[Mineral]]-bonded particleboard and fiberboard **[[Cement board]] **[[Fiber cement siding]] **[[Gypsum board]] **[[Papercrete]] *[[Strawboard]] *[[Wood-plastic composite]] [[Category:Engineered wood]] [[Category:Composite materials]] [[Category:Building materials]] {{Unreferenced|date=January 2008}} [[pt:Derivados da madeira]] [[zh:人造板]] Realated subjects are[[Hardwood]] and [[Softwood]] which are on this site