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.
Floor joist and wall.
How joists support floors and ceilings joists the horizontal members that span two walls and or beams have to carry the weight of the walls people furniture appliances and other stuff we place on them.
Joists and beams are two types of structural elements that have similar and related functions in home construction.
Normal spacing is 16 inches on center from center to center though some floors may have joists on 12 inch or 24 inch centers.
After joists are installed plywood subflooring and or drywall are fastened to the joists to complete the structural floor or ceiling.
In building constructions the term joist refers to a horizontal framing member that is the primary structural element of a floor or ceiling frame.
Floor joists spaced on regular intervals span the areas between supports such as walls foundations girders and beams.
Joists are spaced at regular intervals much like the studs in a wall frame.
Joists span across the tops of load bearing walls and may be supported at mid span by a beam or other member.
This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction.