How many inches of minimum coverage is required for concrete placed against dirt or earth?

The requirement for a minimum coverage of concrete placed against dirt or earth is specifically set at 3 inches. This standard ensures that the concrete is adequately protected from moisture and soil movement that can compromise its structural integrity over time. By having a coverage of at least 3 inches, it allows for a sufficient barrier to mitigate issues such as soil erosion and groundwater seepage, both of which can lead to cracking or settling of the concrete. This guideline helps to ensure that the concrete remains stable and durable, optimizing its performance and extending its lifespan in relation to the foundation or structure being supported.