Which component provides the base for finished flooring and is installed directly over the joists?

Which component provides the base for finished flooring and is installed directly over the joists?

• A. Joists
• B. Subflooring
• C. Rim board
• D. Decking

Answer: (B)

Subflooring provides the base for finished flooring and is installed directly over the joists. It creates a flat, solid surface that ties the joists together, distributes loads, and gives a stable nailing surface for the final floor. Typical materials are plywood or OSB sheets laid across the joists and fastened in place, with small gaps to allow for expansion and Moisture movement. The finished floor—whether hardwood, laminate, carpet, or tile—then sits on top of this subfloor. The joists are the structural support running beneath, rim board forms the outer edge of the floor framing, and decking is used for exterior or outdoor surfaces, not the interior base for finished flooring.

Subflooring provides the base for finished flooring and is installed directly over the joists. It creates a flat, solid surface that ties the joists together, distributes loads, and gives a stable nailing surface for the final floor. Typical materials are plywood or OSB sheets laid across the joists and fastened in place, with small gaps to allow for expansion and Moisture movement. The finished floor—whether hardwood, laminate, carpet, or tile—then sits on top of this subfloor. The joists are the structural support running beneath, rim board forms the outer edge of the floor framing, and decking is used for exterior or outdoor surfaces, not the interior base for finished flooring.