What is the term used for the covering of plywood sheets nailed directly to the floor joists?

The term for the covering of plywood sheets nailed directly to the floor joists is "sub flooring." Sub flooring is an essential part of a flooring system and provides structural support for the finished flooring material that will be installed on top. It creates a flat and even surface, ensuring that the flooring is stable and durable.

Sub flooring typically consists of plywood or OSB (oriented strand board) sheets that are laid over the joists, allowing for a solid base that prevents movement or squeaking. This layer also aids in distributing the load from the flooring above, improving the overall strength of the floor system.

Understanding the role of sub flooring is crucial in carpentry, as it affects the overall integrity, durability, and performance of the finished floor. In contrast, terms like floor joists, plywood covering, or floor sheeting refer to different aspects or components of the flooring system and do not specifically denote the layer that serves as the base for flooring finishes.