Engineered Wood/Lumber Products
In the past, the primary source of structural beams, timbers, joists, and other weight-bearing lumber was old-growth trees. These trees, which need many decades to mature, are tall and thick and can produce a large amount of high-quality, tight-grained lumber.
The development of wood laminating techniques by lumber producers has permitted the use of younger-growth trees in the production of structural building materials. These materials are given the general classification of engineered lumber products.
Classifications of Engineered Lumber Products
Engineered lumber products fall into the following general classifications: laminated veneer lumber (LVL), parallel strand lumber (PSL), laminated strand lumber (glulam). These materials provide several benefits:

• They can be made from younger, more abundant trees.
• They can increase the yield from a tree by 30 percent to 50 percent.
• They are stronger than the same size of structural lumber.
• Greater strength allows the engineered lumber to span a greater distance
• A length of engineered wood is lighter than the same length of solid lumber. It is therefore easier to handle.
• They are dimensionally accurate and do not warp, crown, or twist.