It is common to classify wood as either softwood or hardwood. The wood from conifers (e.g. pine) is called softwood, and the wood from dicotyledons (usually broad-leaved trees, e.g. oak) is called hardwood. These names are a bit misleading, as hardwoods are not necessarily hard, and softwoods are not necessarily soft. The well-known balsa (a hardwood) is actually softer than any commercial softwood. Conversely, some softwoods (e.g. yew) are harder than most hardwoods.

Engineered wood products have properties that usually differ from those of natural timbers.

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Different qualities in terms of thickness, panel size, strength, and rigidity can be imparted to the OSB by changes in the manufacturing process. OSB panels have no internal gaps or voids, and are water-resistant, although they do require additional membranes to achieve impermeability to water and are not recommended for exterior use. The finished product has similar properties to plywood, but is uniform and cheaper. It has replaced plywood in many environments, especially the North American structural panel market. The most common uses are as sheathing in walls, floors, and roofs.

While OSB does not have a continuous grain like a natural wood, it does have a specific axis of strength. This can be seen by observing the alignment of the surface wood chips. The most accurate method for determining the axis of strength is to examine the ink stamps placed on the wood by the manufacturer.

All wood-based structural use panels can be cut and installed with the same ease and types of equipment used with solid wood. In 2001, 19.4 million m³ of OSB panel was produced in the US. The US is Canada’s largest OSB market, receiving 98% of its export product in 2005.

Some manufacturers may treat the wood chips with various borate compounds which are toxic to termites, wood boring beetles, molds, and fungus but not mammals in applied doses. Buyers are recommended to seek borate modified wood products for construction, particularly in warm moist climates.

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Typically, engineered wood products are made from the same hardwoods and softwoods 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 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.

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• Particle-based
            o Oriented strand board (OSB)
            o Laminated strand lumber (LSL)
            o Waferboard
            o Particleboard (chipboard)
• Fiberboard
            o Insulation board
            o SyrocoWood
            o Homasote (1909)
            o Masonite (1924)
            o Medium-density fiberboard (MDF)
            o Hardboard
• Mineral-bonded particleboard and fiberboard
            o Cement board
            o Fiber cement siding
            o Gypsum board
            o Papercrete
• Strawboard
• Wood-plastic composite

• 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 trees.
• 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 adhesives 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.

Source: Wikipedia

Fiberboard is also used in the auto industry to create free-form shapes such as dashboards, rear parcel shelves, and inner door shells. These pieces are usually covered with a skin, foil, or fabric such as cloth, suede, leather, or polyvinyl chloride, often referred to as vinyl or PVC. PVC can be stamped with a pattern to resemble leather, and is often cheaper than leather, which makes it an ideal candidate for use.

Urea-formaldehyde (UF) resins are dominantly used in the medium density fiberboard (MDF) industry because of their low cost and fast curing characteristics. However, pressures on the use of UF resins are mounting steadily due to potential problems associated with formaldehyde emission. On the other hand, phenol-formaldehyde (PF) resins are more durable and do not emit formaldehyde after cure. But the Industry has traditionally shied away from using PF resins due primarily to their huge cost and much slower curing rate than UF resins. However, the press times PF-bonded fiberboard can be substantially reduced by manipulating the fiber mat temperatures, molecular weight distribution of PE resins and pressing parameters. As a result, the press times for PF-bonded fiberboard can be made comparable to those for UF-bonded fiberboard. Also, the resin content required for PF-bonded fiberboard is less than 5% to achieve a good board quickly. This is considerably lower than that required for UF-bonded fiberboard.

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By laminating several smaller pieces of wood, a single large, strong, structural member can be manufactured from smaller lumber. These structural members are used as vertical columns or horizontal beams, as well as curved, arching shapes. Connections are usually made with bolts and steel plates.

Glued laminated timber, like other engineered wood products, represent an efficient use of available timber. With an increased demand for lumber worldwide, the amount of solid timber available has steadily declined. Gluelam structural members thus make use of smaller and less desirable dimensions of timber, yet are engineered to be stronger than similarly sized members comprised of solid wood. Gluelam structural members are also an environmentally friendly alternative to concrete and steel members as they have a lower embodied energy in comparison.

The first use of glued laminated timber was in Germany in 1890 by Otto Hetzer. The technology arrived in North America in 1934 when Max Hanisch, Sr., who had worked with Hetzer at the turn of the century, formed a firm in Peshtigo, Wisconsin to manufacture structural glued laminated timber.

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It differs from particle board in that the bonding of the wood fibers requires no additional materials, although resin is often added. Unlike particleboard, it will not split or crack. It is used in construction and furniture. Hardboard is produced in either a wet or dry process, which produce a panel called S1S or S2S respectively. The wet process leaves only one smooth side, but dry processed hardboard is smooth on both sides.

Unlike solid wood, hardboard is very homogeneous with no grain. A wood veneer can be glued onto it to give the appearance of solid wood. Other overlays include formica, laminated papers and vinyl. It has many uses, such as a substrate. It is used in construction, furniture, home appliances, automobiles and cabinetry, and is popular among acrylic and oil painters as a painting surface due to its economical price (though it must be coated with gesso or canvas before use). It is also used as the final layer in many skateboard ramps and the half-pipe.

Tempered hardboard is hardboard that has been coated with a thin film of linseed oil and then baked; this gives it more water resistance, impact resistance, hardness, rigidity and tensile strength. An earlier tempering process involved immersing the board in linseed oil or tung oil until it was 5 to 6 percent saturated, and heating to 170° C (340° F). Tempered hardboard is used in construction siding.

Perforated hardboard, also called pegboard, is tempered hardboard that has rows of ¼" holes in it, into which hooks can be placed for hanging tools.

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Particleboard is cheaper, denser and more uniform than conventional wood and plywood and is substituted for them when appearance and strength are less important than cost. However, particleboard can be made more attractive by painting or the use of wood veneers that are glued onto surfaces that will be visible. Though it is denser than conventional wood, it is the lightest and weakest type of fiberboard, except for insulation board. Medium-density fibreboard and hardboard, also called high-density fiberboard, are stronger and denser than particleboard.

A major disadvantage of particleboard is that it is very prone to expansion and discoloration due to moisture, particularly when it is not covered with paint or another sealer. Therefore, it is rarely used outdoors or places that have high levels of moisture, with the exception of some bathrooms, kitchens and laundries, where it is commonly used as an underlayment beneath a continuous sheet of vinyl floor covering. In such an installation the edges must be properly covered upward against the wall and joints and non-covered edges must be properly sealed against moisture penetration. A higher quality material not subject to expansion is underlayment-grade plywood, which is constructed without interior voids in its layers to better resist the high local pressure from objects such as stiletto heels.

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