What's a Microlam or LVL (Laminated Veneer Lumber)?

Microlam is a term you hear bandied around a lot when doing home renovations. Microlam, also known as Laminated Veneer Lumber or Weyerhauser's brand name of Glulam, is a fairly recent development in construction.

If you have an old house and you're lucky enough to be able to get in the crawlspace or basement, you'll have a good peek at the joists and carrying beams. Unless the home has been renovated recently, no doubt you will be viewing sizeable joists: two-by-eights or two-by-tens. Carrying beams, as the name infers, carry huge loads and are serious hunks of timber. In the past, size equated with strength.

But with newer advancements in lumber processing, manufacturers were able to produce lighter and smaller lumber with the same or even greater strength.

I think of microlam as "plywood on steroids." Like plywood, thin sheets of wood are sandwiched on top of each other, held together with super-strong glue. Each layer is perpendicular to the layers on either side of it. But unlike brittle plywood, microlam is very solid, heavy, and construction-grade.

Microlam is sometimes used for joists in new homes. For home renovation, microlam's high price tag doesn't make it effective for joists. If you've got saggy, mushy joists, consider sistering your existing joists. Microlam runs at least $6 per linear foot--and typically much more--so you'll find it's more effective if you use it for carrying beams or other uses where you need a high degree of strength. For example, if you're tearing out a sizable portion of an exterior wall to expand into an addition, you'll have to use a microlam beam to carry the weight that the wall formerly carried.