The wood boards used as floor joists generally range in size from no smaller than 2-by-4 inches to no larger than 2-by-12 inches. two-by-6 inches is a joist size frequently used in both indoor floors and as deck joists.. Joists are the repeated structural members that are used to build a deck frame. the minimum size joist to be used in deck construction depends on the number of footings and beams that will be installed. in general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches.. Though there is no standard joist size for the ceilings in all buildings, most average homes use ceiling joists in a board size of 2-by-6 inches. the range of joist sizes used in homes varies though, between 2-by-4 inches and 2-by-12 inches..
Designing with floor joist span tables part 2 of residential structural design. looking at this table you will see there is a choice in the size of floor joist (2 x 6, 2 x 8, 2 x 10 or 2 x 12) and there is a choice in the joist spacing (12", 16" or 14"). the floor joist spacing is the distance between the centers of any two installed joists.. Floor joist construction floor joists are usually wood 2x’s. the size depends on the type of wood, the span (length between supports), and the anticipated load they will carry. spans for various species and grades of wood can be found in published span tables.. Choosing the correct floor joist size depends on your building application, joist spacing, and several other factors.these include the length of the span as well as the type and grade of the lumber being used. common joist spacings are 12 inches (304.8 mm), 16 inches (406.4 mm), and 24 inches (609.6 mm)..
