Glossary Letter I

I-joist

Manufactured structural building component resembling the letter "I". Used as floor joists and rafters. I-joists include two key parts:flangesandwebs. Theflangeof the I joist may be made of laminated veneer lumber or dimensional lumber, usually formed into a 1 ½" width. Thewebor center of the I-joist is commonly made of plywood or oriented strand board (OSB). Large holes can be cut in the web to accommodate duct work and plumbing waste lines. I-joists are available in lengths up to 60 feet long