Engineered wood is a buzzword among green builders and conservationists, but a mystery to many homeowners. What is engineered wood, how do you apply it properly in construction, and what makes it a renewable building material? I consulted with some experts in the field of engineered wood composites and asked them about everything from new developments in technology to classic problems with application. What follows is a pretty thorough overview, which I suggest you read if you are considering building with wood products.
What are engineered wood composites?
There are two primary types of engineered wood composites commonly used in residential construction: oriented strand board and laminated strand lumber, known as OSB and LSL, respectively. Oriented strand board is a panel; laminated strand lumber is a structural lumber substitute. Both of these products are made of particles of wood that are bound together with an adhesive.
How do engineered wood composite beams with fiber reinforcement compare to milled lumber? According to Professor Douglas Gardner of the Wood Science and Technology School of Forest Resources at the University of Maine, engineered wood has a higher load-bearing capacity. Gardner said, “If you test it to failure, typically [milled] wood will break in the tension zone and propagate. Usually what happens in the tension zone with reinforced wood is the failure tends to become more of a shear failure, and the beam actually becomes more ductile because the fiber reinforced plate creates a much stronger composite.
“Thus, the failure mechanisms for these beams are different. And that could be a good thing, because that basically means that the failure might not be as catastrophic if you test to failure: The beam doesn’t fly apart. It basically crushes and it holds together because of the fiber reinforced plate on the bottom.”