An I-joist, also known as engineered wood I-beams, is a type of engineered wood product commonly used in residential and commercial construction for floor and roof framing. It consists of a combination of solid lumber flanges or chords, typically made of either laminated veneer lumber (LVL) or dimensional lumber, and a web made of oriented strand board (OSB) or plywood.
The I-joist design provides several advantages over traditional solid wood joists, including increased strength-to-weight ratio, dimensional stability, and resistance to warping, twisting, and shrinking. They are also designed to resist bending and deflection, making them suitable for longer spans than traditional joists.
I-joists offer versatility, strength, and cost-effectiveness, which have made them a popular choice in modern construction projects.