What term is used for additional cushioning placed underneath carpet?

The term used for additional cushioning placed underneath carpet is padding. Padding serves several essential functions, including providing comfort underfoot, extending the life of the carpet, and enhancing sound absorption and insulation. It acts as a protective layer that helps to absorb impact and reduce wear on the carpet fibers, making it an integral part of a carpet installation.

In interior design and flooring terminology, padding is often considered a crucial component that contributes significantly to the overall feel and durability of the carpeted area. While underlayment is a term used in various flooring installations, it does not specifically refer to the cushioning under carpet. Insulation typically pertains to materials used to control temperature and sound within a building but does not directly apply to carpet installation. Subflooring is the structural layer beneath the flooring material, which also does not pertain to the cushioning provided for carpet.