Can 2x8 floor joists spaced at 16 inches span 16 feet?
Selection of floor joists depends on several factors including wood species, lumber grade, floor covering, and room designation. The 2003 International Residential Code (IRC) differentiates between rooms designated as sleeping areas (30 psf live load) and living areas (40 psf live load). Moreover, where heavy floor coverings are used including ceramic tile or slate maximum allowable spans are reduced to account for the additional weight. For living areas with carpet covering, SPF #2 2x8 joists spaced at 16 inches can only span 12 feet and three inches. SPF #2 2x12 or Southern Pine #2 2x10 spaced at 16 inches should be specified for a 16-foot floor span for the given conditions. Tables R502.3.1(1) and R502.3.1(2) of the 2003 IRC provide information for various floor joist options.