What Is Floor Joist

After joists are installed plywood subflooring and or drywall are fastened to the joists to complete the structural floor or ceiling.

What is floor joist.

Floor joists installed on second or third or higher levels double as ceiling joists for the level below. In many countries the fabrication and installation of all framing members including joists must meet building code standards. The floor sheeting is also engineered to provide a solid floor. They are covered with subflooring panels of plywood or oriented strandboard osb to complete the floor s structural assembly and create the solid continuous platform on which you install tile carpet or other finish flooring.

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. Floor joists are an important part of the supportive structure of a floor. 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. In building constructions the term joist refers to a horizontal framing member that is the primary structural element of a floor or ceiling frame.

True floor joist span calculations can only be made by a structural engineer or contractor. 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. This size is no longer acceptable when framing a structure. The rim joist fig.

Each type of wood has a specific span and spacing requirement. Joists must exhibit the strength to support the anticipated load over a long period of time. In buildings with basements the first level of floor joists serves the same purpose. 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.

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. The floor joist is nailed to the plate material and spans the open area under the floor. Joists are spaced at regular intervals much like the studs in a wall frame. In the past 2x4s or 2x6s were sometimes used as floor joists.

The floor sheeting is usually made from 3 4 or thicker sheets of plywood or osb. Floor joist spacing is the distance a floor joist board can be separated from an adjacent floor joist.