Innovation with lumber treatment helps meet special demands of tall wood buildings

Friday, April 26, 2013

As builders and developers seek cost-effective ways to meet the demand, many are turning to wood framing for four- and five-story buildings-and even up to six stories in Canada. However, wood shrinkage can be an issue. Laminated strand lumber (LSL) provides an effective means of dealing with shrinkage in wall plates.

LSL is created from a mixture of hardwoods. The raw logs are debarked, cut into strands, blended with waterproof adhesives that contain no formaldehyde, and formed into dense mats. A massive steam injection press then uses steam and pressure to convert the mats into billets. The final product typically has moisture content around 7% to 8%, less than the equalized framing in most enclosed structures. Wall plate shrinkage is then minimal or nonexistent because the moisture content of LSL is so close to the moisture equilibrium of the building.