Engineered timbers are a category that includes Glulam beams and Parallel Strand Lumber (PSL). Made from the same material as natural timbers, engineered timbers can be customized to allow for a cost effective beam with an increased structural load and longer spans.
Glued laminated timber, also called glulam, is a type of structural timber product comprising a number of layers of dimensioned timber bonded together with durable, moisture-resistant structural adhesives.
Glulam optimizes the structural values of a renewable resource wood. Because of their composition, large glulam members can be manufactured from a variety of smaller trees harvested from second- and third-growth forests and plantations. Glulam provides the strength and versatility of large wood members without relying on the old growth-dependent solid-sawn timbers. As with other engineered wood products, it reduces the overall amount of wood used when compared to solid sawn timbers by diminishing the negative impact of knots and other small defects in each component board.
Glulam has much lower embodied energy than reinforced concrete and steel, although of course it does entail more embodied energy than solid timber.