Minimum Concrete Cover for Foundations – ACI & Eurocode Standards

The foundations minimum concrete cover values depend on how the reinforcement is placed. For instance, ACI 318 specifies a minimum of 75 mm (3″) when concrete is cast directly against soil. However, when cast against formwork, this requirement is reduced to 40 mm (1.5″). Similarly, Eurocode 2 sets cover values between 30 mm and 50 mm, depending on exposure class, bar diameter, and required fire resistance.

To maintain proper cover, place durable plastic spacers under bottom bars and along vertical edges. For example, spacers should be positioned every 1.0 m and at key points such as corners and near column dowels. In contrast, avoid using steel chairs, since they may corrode over time and reduce the protective cover’s effectiveness.

Concrete cover plays a critical role in foundation performance. It prevents direct contact between reinforcement and aggressive soil, thereby reducing the risk of corrosion. In addition, adequate cover improves anchorage, enhances long-term durability, and supports structural integrity. Therefore, using the correct cover depth is not only a good practice—it is essential for code compliance and service life.