What is the minimum slope requirement for ground adjacent to the foundation to drain water?

The minimum slope requirement for ground adjacent to a foundation to effectively drain water is generally considered to be 5 percent for a distance of 10 feet. This means that for every 10 units of horizontal distance from the foundation, the ground should drop 0.5 units vertically. This slope helps ensure that water flows away from the foundation, reducing the risk of water pooling near the structure, which can lead to issues such as flooding, erosion, or damage to the foundation.

The rationale for a 5 percent slope over a distance of 10 feet is based on best practices for drainage in construction. This standard is recognized in various building codes and guidelines, emphasizing the importance of proper drainage in preventing structural problems. A longer distance with the same slope assists in ensuring that the drainage is effective over a larger area, which contributes to the longevity and integrity of the foundation.

In comparison, other options either propose a slope that is either too steep or not steep enough for adequate drainage over the specified distance. Therefore, the choice of a 5 percent slope over 10 feet is the most suitable requirement for effective ground drainage adjacent to a foundation.