What is the purpose of a leveling course under concrete?

• A. Creates a smooth, uniform substrate and corrects minor irregularities before pouring.
• B. Provides structural support.
• C. Acts as final wearing surface.
• D. Adds insulation between the slab and soil.

Answer: (A)

A leveling course is a thin, preparatory layer used to create a smooth, flat, uniform base before pouring the main concrete slab. It fills small dips and minor irregularities in the subgrade so the subsequent slab sits evenly, with consistent thickness and a good surface for bonding. This helps prevent voids, uneven finishes, and cracking that can happen if the main pour were placed directly onto an uneven surface. It is not meant to carry structural loads or serve as the final wearing surface, and it doesn’t provide insulation; those roles belong to the main slab and other design features.