stylistic:style_transfer, information:classification, quality:correction, stylistic:tone
Upper floor construction

Floors in wood-frame homes are usually constructed with joists centered no more than 16 inches (41 centimeters) apart, according to most building codes. Heavy floors, such as those made of stone, require more closely spaced joists. If the span between load-bearing walls is too long for joists to safely support, then a heavy crossbeam (thick or laminated wood, or a metal I-beam or H-beam) may be used. A "subfloor" of plywood or waferboard is then laid over the joists.