This refers to a method of construction where structural supports, specifically joists, are placed 16 inches apart, measured from the center of one joist to the center of the next. A calculator, often in the form of a table or software, is then used to determine the maximum distance these joists can span, based on factors like the type of wood, the load they need to bear, and building codes. For instance, a span table might indicate that a specific type of joist, spaced 16 inches on center, can safely span 12 feet while supporting a standard residential floor load.
Utilizing this method is critical in building construction to ensure structural integrity and safety. Proper spacing and span determination prevents floors from sagging, ceilings from cracking, and, in extreme cases, structural failure. Historically, these calculations were done manually using complex formulas. The development of calculators and pre-calculated span tables simplifies the process, reducing the risk of errors and saving time during the design and construction phases. Accurate span determination also optimizes material usage, preventing over-engineering (which increases costs) and under-engineering (which compromises safety).