Engineered wood products have been around for years, particularly in the form of plywood, glu-lam beams, and metal-plate-connected wood trusses. I-joists are more recent, as are LVLs (laminated veneer lumber), PSLs (parallel strand lumber), and LSLs (laminated strand lumber).
It is not the intent of this chapter to explain everything there is to know about engineered wood products, but rather to make you familiar with this category of materials, and give you a sense of what to look out for when you are working with them.
Engineered wood products (EWP) fit into two general categories, engineered panel products (EPP) and engineered lumber products (ELP). The
first group includes plywood, oriented strand board (OSB), waferboard, and composite and structural particleboard.
The second group includes I-joists, glu-lam beams, metal-plate-connected wood trusses, and structural composite lumber (LVLs, PSLs, and LSLs).
Engineered panel products are so common that their uses are defined in the building codes.
Specific applications vary from job to job, and from manufacturer to manufacturer.
Oriented Strand Board & Waferboard
Most building codes recognize oriented strand board and waferboard for the same uses as plywood, as long as the thicknesses match.
Working with Engineered Panel Products
When working with any engineered panel products, keep the following guidelines in mind:
1. On floors and roofs, run the face grain perpendicular to the supports (except with particleboard, which has no grain). See “Using Engineered Panel Products" illustration.
2. Do not use any piece that does not span at least two supports for floors and roofs.
3. Allow a gap of at least Vs" on all edges, and a gap of more than 1/s" if the piece will be exposed to a lot of moisture before the siding is installed. Note that this also applies to walls.
4. Follow manufacturers’ recommended installation directions.
