R503.2.2

Section R503.2.2 is titled 'Allowable spans' and covers requirements for the installation of wood structural panels on floor joists. A cross-reference to other tables in this code and another standard which list allowable spans of wood structural panels used as subflooring, combination subfloor underlayment, and sanded combination subfloor underlayment is established. The purpose of this section is to prevent structural failure.

The model shows 2 partial floor sections. The 1st section shows 1/2" subfloor sheathing installed on floor joists spaced 16" o.c. Since the sheathing is not tongue-and-groove, and it is not intended to install an underlayment or other covering listed in footnote j to table 503.2.1.1(1), blocking has been installed to support the edges of the sheathing in accordance with footnote j. The 2nd section shows 1/2" subfloor sheathing installed on floor joists spaced 24" o.c. with 3/4" wood finish flooring being installed perpendicular to the floor joists. The finish flooring allows for the span to be increased to 24" per footnote h of table 503.2.1.1(1), and either the tongue-and-groove sheathing or the finish flooring allows for not using edge blocking, per footnote j. Should permits be required for finished flooring⸮