R502.2.2

Section R502.2.2 is titled 'Blocking and subflooring' and covers requirements for floor construction. The requirement to use a minimum grade of lumber and wood structural panels for structural blocking and subflooring, respectively, and the allowance for fireblocking to be any grade of lumber is established. The purpose of this section is to prevent structural failure and to slow the spread of fire.

The model shows a partial floor assembly with highlighted structural blocking, subflooring, and fireblocking.