___ is used over joists to form a working platform.

___ is used over joists to form a working platform.

• A. Siding
• B. Plywood
• C. Decking
• D. Subflooring

Answer: (D)

Subflooring is the layer installed directly over the floor joists to create a flat, rigid working surface. It provides a solid base you can stand on and nail the finish floor to, and it helps distribute loads across the joists. Typical materials are plywood or OSB, but the term describes the function of that layer, not a specific material. Siding belongs on exterior walls, decking is used for outdoor platforms, and plywood is a common material used for subflooring but the correct label for the base layer is subflooring.

Subflooring is the layer installed directly over the floor joists to create a flat, rigid working surface. It provides a solid base you can stand on and nail the finish floor to, and it helps distribute loads across the joists. Typical materials are plywood or OSB, but the term describes the function of that layer, not a specific material. Siding belongs on exterior walls, decking is used for outdoor platforms, and plywood is a common material used for subflooring but the correct label for the base layer is subflooring.