Wooden joist systems, or timber floor systems, are horizontal structural members used in buildings to support floors and ceilings. They are laid in parallel series and supported by larger beams, walls, or foundations. The three main types of wooden joist systems are solid lumber, I-joists, and open-web floor trusses.

Solid lumber joists

Solid lumber joists are the traditional and most affordable type of wood joist. They are sawn from a single piece of timber and are often used in residential construction.

Engineered wood I-joists

I-joists are engineered wood products shaped like a capital "I" to maximize strength while minimizing material usage. They consist of solid or laminated veneer lumber (LVL) flanges and a vertical web made of oriented strand board (OSB) or plywood

Open-web floor trusses (Posi-Joists)

Open-web trusses combine timber chords with a steel web, creating an open design. This makes it a popular option for projects where HVAC, plumbing, and wiring need to be run through the floor structure.