Parallel Strand Lumber
Parallam PSL (Parallel Strand Lumber) uses a process patented by Weyerhaeuser to bond together thin strands of wood typically 4-8 feet long. PSL manufacturing involves little waste, as almost all parts of a log are used in the product.
PSL is much more uniform than sawn timber or Glulam, as all defects such as knots are distributed uniformly in the glue matrix; this gives PSL one of the highest strengths of any engineered wood product. Due to its uniformity, PSL offers good connection strength and ductility - it is not prone to splitting failures at connections like sawn timber or Glulam. It also has strong insect resistance.