Engineered Timber for Low-Carbon Buildings

About this course.

Engineered timber products are structural elements made by bonding together smaller pieces of wood — boards, veneers or laminations — with adhesives (and sometimes mechanical fasteners) to form larger, stronger and more dimensionally reliable components than a single piece of sawn timber could provide. Traditional sawn timber is cut directly from a log into beams, joists or boards, so its size is limited by the tree and its properties vary with natural features such as knots and grain. Engineered timber, by contrast, is manufactured to designed specifications, which gives more consistent and predictable structural performance and allows much larger spans and taller structures. "Mass timber" is the umbrella term for the large, solid engineered timber panels and beams used as primary structure.

Cross-laminated timber (CLT) is one of the best-known mass timber products. It is made from layers of timber boards stacked in alternating directions — each layer laid at right angles to the one below — and bonded together into large, solid panels. This cross-lamination is the key idea: because the grain runs in two directions, the panel is strong and stable in both directions and resists the shrinking, swelling and warping that can affect solid timber. CLT panels can be very large, and they are typically used as walls, floors and roofs, functioning rather like precast concrete panels but in timber. Their two-way strength and stiffness are what make timber floor plates and shear walls practical at scale.