Which are major interior floor coverings and their typical installation substrates?

• A. Carpet on pad over a subfloor; hardwood on plywood or OSB; ceramic tile on cement backer board or concrete; vinyl on concrete or wood subfloors.
• B. Carpet on concrete only; hardwood on asphalt; ceramic tile on glass.
• C. Laminate on metal; vinyl on waterproof membranes.
• D. Bamboo on steel; cork on ceramic.

Answer: (A)

The idea here is matching common interior floor coverings with substrates that give them the stability, flatness, and moisture control they need to perform well.

Carpet is installed with a padded underlayment over a subfloor, which cushions the feel and helps with sound; the subfloor is typically plywood or OSB. Hardwood needs a solid, relatively stiff base to hold fasteners and minimize movement, so it’s laid over a plywood or OSB subfloor. Ceramic tile requires a rigid, non-flexing surface to prevent cracking, so it goes on cement backer board or directly on a concrete slab that’s properly prepared. Vinyl can be laid over either concrete or wood subfloors, usually with an appropriate underlayment or adhesive system to create a smooth, stable base.

These substrates reflect standard practice because they provide the necessary rigidity, compatibility with the flooring material, and moisture considerations. The other options suggest substrates that aren’t typically used with those coverings (for example, tile on glass or hardwood on asphalt), which wouldn’t give the necessary stability or durability.