What Is Engineered Wood?

Engineered wood sounds like it comes from a bio-lab, but rest easy — there’s no genetic modification involved. The term refers to real wood modified into different forms that are stronger and longer-lasting than the raw materials they’re made from.

You might not realize it, but there’s probably engineered wood all around you as you read this. If you’re inside a building, the roof, walls and floors incorporate engineered wood. So could the table and chair you work at. There’s probably also engineered wood in the cabinets and shelves of your kitchen and bathroom.

Plywood is an example of engineered wood, first developed in the 1920s. Today, engineered wood is considered a green building source partly because it’s often made from recycled materials. It’s one way the construction industry kept itself sustainable in the face of dwindling lumber resources.

What Is Engineered Wood?

Put simply, engineered wood products (EWPs) are fabricated from raw wood combined with resins or adhesives. The wood can be cut or sliced from tree trunks or recovered from sawmills as sawdust and wood chips. The resins are usually synthetic. The engineering process utilizes heat and pressure to compress the mixture into a usable form.

Some people refer to engineered wood as man-made wood, manufactured board or composite wood. Most EWPs retain many of the qualities of solid wood, including workability, resilience and thermal insulation. In many ways, it improves on it.

The Engineered Wood Association, founded in 1933 as the American Plywood Association (it’s still known by the APA acronym), is devoted to the promotion and development of EWPs. Its web site details the multiple ways engineered wood is used in construction. There are many other common applications for this versatile product.

What Are the Types of Engineered Wood?

Plywood is the original and arguably most common example of engineered wood. But there are many other types of engineered construction panels, structural members and cabinetry materials.

• Plywood: Manufacturers make plywood by slicing thin sheets from softwood trees like Douglas fir, pine and spruce and laminating them together in criss-crossing layers held together by a strong adhesive. Originally manufactured for door panels and automobile running boards in the 1920s, plywood came into its own with the development of waterproof adhesives in 1934. It became an essential war material, and its production skyrocketed during the post-war building boom.
• Laminated veneer lumber (LVL): Fabricated by a process similar to plywood, LVL boards are thick enough to substitute for dimensional lumber. LVL boards are used for I-joists, headers, rim boards, beams and trusses. They’re also found in skateboards and truck bed liners.
• Oriented strand board (OSB): Manufacturers fabricate OSB by gluing together strands of wood under pressure. OSB comes in the same size sheets as plywood. It’s structurally stable enough for subfloors, as well as for wall and roof sheathing.
• Glue laminated (Glulam) timber: Thicker pieces of wood are glued together to form dimensioned lumber. Glulam dimensional members like beams and joists are another engineered staple in the construction industry. The Glulam process provides thick structural lumber with minimal wood waste.
• Particleboard: It’s made by compressing sawmill waste (mainly sawdust and wood chips) into plywood-like sheets. Particleboard lacks the structural integrity of plywood or OSB, but it’s a common cabinet material as well as a common substrate for plastic laminate countertops.
• Composite boards: Like particleboard, composite boards are made by compressing wood chips with resins and plastic. They have a higher concentration of synthetic materials, suitable for exterior projects like decks and fences.
• Medium density fiberboard (MDF): Like particleboard, MDF is made from wood waste. But the wood particles are broken down into fibers before combining with wax and resins under pressure and fashioned into sheets. Denser than plywood or particleboard, MDF is commonly seen in cabinets and shelving.
• Engineered flooring: Manufactured with a top layer of solid wood and a plywood or MDF core, engineered wood flooring boards look like solid wood. Because the top layer is thin — from 1/8- to 3/16-in. — it can be made from exotic hardwoods that would be prohibitively expensive if milled into solid wood boards.

Features of Engineered Wood

The manufacturing process and the inclusion of synthetic resins gives engineered wood these advantages over the real thing:

• Dimensional stability: EWPs manufactured in criss-crossing layers are stronger than real wood. They resist warping, thermal expansion and splitting.
• Sustainability: Engineered wood helps preserve raw forest products.
• Size availability: Because it’s fabricated and not cut from actual trees, engineered wood is available in more sizes than solid wood products.

EWPs cost about the same as real wood, but some products like LVL can be more expensive. Drawbacks to EWPs include:

• Extra weight: Some products, especially MDF and composites, are heavier than wood.
• Unattractive: OSB, particleboard and lower grades of plywood don’t look as good as real wood.
• Variable moisture resistance: Some EWPs, primarily particleboard and MDF, deteriorate quickly when exposed to moisture. Early versions of composite boards swelled after prolonged exposure to the elements, but later versions compare favorable to wood for weather resistance.
• Variable workability: While all EWPs can be cut with woodworking tools, they can’t all be shaped or sanded. And neither particleboard nor MDF can hold nails.

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