Trade education and workforce development are two initiatives we value highly here at Dunn Lumber, so it should come as no surprise that we have close ties with Seattle Central College's Wood Technology Center (WTC). With roots dating back to the early 1900s, WTC's history intersects with ours at Dunn Lumber at various points (our very own Ed Dunn Jr. took some classes at Edison), and we're proud to be connected with such an exemplary educational institution.
Throughout the episodes in this series, we'll be speaking with Dave Borgatti, a long-time faculty member at the WTC, about the center's history, program offering, and various topics in woodworking education. Dave got his start in woodworking as a boat builder in Portland, Oregon, for Schooner Creek Boat Works, and ended up at WTC as an instructor in 1992. Since then, Dave has helped countless students—from boat builders to carpenters and cabinetmakers—learn the woodworking craft.
In this episode, we're talking all about engineered lumber. Watch the video above or read on for a recap of our discussion.
A sustainable wood product
At Dunn, we know wood is our greatest renewable resource, which is why engineered lumber is such an important product. Engineered lumber has become popular for several reasons, but topping our list is its sustainability. In short, engineering lumber stretches our timber supply. While wood is renewable, it takes several decades to grow into a harvestable product. Engineered wood products can be made with younger, smaller trees and scrap wood pieces by slicing them up and gluing them together in different ways. The result is high-performing building materials made with processes that use a greater percentage of the raw log than at any time in our history.
Other reasons to consider engineered lumber
Like any manufactured product, engineered lumber is designed to meet standards that can be hard to find in nature. The glues and machinery used in the engineering process can often create building materials that are just as strong and durable as old-growth trees, without the 120-year timeline or hefty price tag. And, while dimensional lumber is limited to the size of the tree it's cut from, engineered lumber can be made to just about any size because it's not cut from a single tree.
Types of engineered lumber
There are all sorts of engineered wood products designed for various structural and decorative uses. Finger-jointed lumber is engineered by joining small pieces of solid wood together (you'll often see this method used with interior and exterior trim products), while plywood (the original engineered wood product) is made by laminating sheets of wood veneer in alternating directions.
One of the most popular engineered lumber products is laminated veneer lumber, or LVL. These composite lumber products are made by bonding several layers of veneer together so the grain of each layer runs parallel to the longest side. LVL beams are available in much greater lengths than conventional lumber, and are commonly used for headers and beams, hip and valley rafters, scaffold planking, and as flange material for prefabricated wood I-joists.
Cross-laminated timber (CLT), is a sort of "super plywood" made by stacking several layers (usually three to seven) of kiln-dried lumber together in alternating directions. The layers are then bonded together with structural adhesives and pressed to create straight, solid boards.
CLT panels—which are typically two- to 10-feet wide and up to 60 feet long—have become popular in sustainable multifamily and commercial construction for several reasons. They offer more design flexibility than traditional building materials like concrete, masonry, or steel, and are easier to install. They're lightweight yet strong and have excellent acoustic, fire, seismic, and thermal performance. Further, they generate almost no waste onsite.
These are just a few of the most popular products out there—there are so many more innovative engineered wood products on the market, and more are being developed all the time. We're lucky to have knowledgeable people like Dave to help us better understand the materials at our disposal.