Many people will be familiar with the regular variety of lumber, also known as “dimensional lumber”, which is wood that has been processed into conventional beams, planks, or boards through a process that begins with logs that are cut down into various sizes. Engineered lumber—also known as engineered wood, mass timber, composite wood, man-made wood, or manufactured board—is any manufactured wood product in which the strands, particles, fibres, veneers, or boards of wood are bound or fixed together with adhesives or some other method of fixation to form a composite material. Engineered lumber products can be used to create joists and beams with enough strength to replace steel in many building projects, and mass timber as a group of building materials can be used to replace concrete assemblies.
Although engineered wood is sometimes referred to as “man-made wood”, this designation is something of a misnomer. Composite woods are often made out of the same hardwoods and softwoods that are also processed into conventional lumber, rather than synthetic products. It’s also possible to manufacture engineered lumber-adjacent products out of a variety of other plant materials, including bamboo and various vegetable fibres (such as rye straw, wheat straw, rice straw, hemp stalks, and sugarcane residue).
Engineered lumber products are used in a wide variety of ways, and have several advantages over traditional solid wood products. Firstly, as they are manufactured, engineered lumber solutions can be created in any configuration of size rather than being limited based on the dimensions of a potential source tree. Engineered lumber products are also available in a wide variety of thicknesses, sizes, grades, strengths, and exposure durability classifications, making them usable in multiple types of projects. Engineered lumber panels are easy to work with in a wide variety of applications using ordinary tools and basic skills. Finally, engineered lumber products make more efficient use of wood than traditional solid-wood products. They can be made from young timber rather than old-growth wood, wood that has defects, sawmill scraps and other wood waste, wood with defects, and wood taken from underutilized species of trees.
However, no material is without its limitations. Although engineered lumber can be superior to conventional solid-wood lumber products in versatility and strength, it requires more energy to manufacture engineered lumber products, and the adhesives used in some types of engineered lumber are toxic, meaning that individuals who work with them can be exposed to toxic compounds if they do not take the appropriate safety precautions. Some engineered lumber products, most notably those specified for interior use—such as particle and fibre-based products—may be more prone to absorbing moisture, which can lead to warping. Engineered wood is also often less aesthetically pleasing than solid wood products because of the visible texture of the particles used to make it, and as a material it can be much more expensive than dimensional lumber because of the complexity of its manufacturing process.