What Is Floor Joist

The floor sheeting is usually made from 3 4 or thicker sheets of plywood or osb.

What is floor joist.

In building constructions the term joist refers to a horizontal framing member that is the primary structural element of a floor or ceiling frame. In buildings with basements the first level of floor joists serves the same purpose. Each type of wood has a specific span and spacing requirement. The floor joist is nailed to the plate material and spans the open area under the floor.

The floor sheeting is also engineered to provide a solid floor. After joists are installed plywood subflooring and or drywall are fastened to the joists to complete the structural floor or ceiling. Floor joists are an important part of the supportive structure of a floor. The rim joist fig.

Floor joists installed on second or third or higher levels double as ceiling joists for the level below. True floor joist span calculations can only be made by a structural engineer or contractor. This spacing is combined with a floor joist span to determine the maximum capacity load of a floor. This size is no longer acceptable when framing a structure.

They hold up the weight of a building absorb impacts on the floor and create structural support so that the floor will be stable and secure. Joists span across the tops of load bearing walls and may be supported at mid span by a beam or other member. B the framing member that runs around the perimeter of your house and that the floor joists butt into often gets riddled with large holes this space is the logical exit point for dryer and furnace vents big electrical service wires and fireplace fresh air intakes. Joists must exhibit the strength to support the anticipated load over a long period of time.

The width of a board is an important factor in determining the distance a floor joist can span playing a much larger role than the thickness. Considering the cross section of a typical joist the overall depth of the joist is critical in establishing a safe and stable floor or ceiling system. Floor joist spacing is the distance a floor joist board can be separated from an adjacent floor joist. In the past 2x4s or 2x6s were sometimes used as floor joists.

Joists are spaced at regular intervals much like the studs in a wall frame. For example if you double the thickness or number of joists in a floor the distance the boards can span will increase by approximately 25.