Below grade floors in a building are designated as what?

The correct designation for below grade floors in a building is "Subfloor division 1, 2, 3." This terminology is used in architectural and construction practices to categorize different levels or sections of the building that are located below the main ground level.

The term "subfloor" specifically refers to layers of flooring that are installed under the final floor finish, and the divisions indicate different sections or types of subfloors that may be required for various purposes, such as structural support or accommodating mechanical systems. Highlighting these divisions helps in planning and executing the construction or renovation of lower levels, ensuring clarity in building documentation and compliance with building codes.

Other options may not be specific or clear enough in referring to below grade levels. Terms like "Basement divisions" or "Ground divisions" lack the technical specificity that "Subfloor division" provides, and while they may be used in casual conversation, they do not accurately reflect the structured understanding of building classifications.