What is the required minimum slope of the ground adjacent to a building foundation?

The correct response indicates that the required minimum slope of the ground adjacent to a building foundation is 1:20. This standard is in place to ensure proper drainage away from the foundation, which is vital for preventing water accumulation that can lead to structural issues such as erosion, settling, or even basement flooding.

A slope of 1:20 means that for every 20 units of horizontal distance, the ground should drop by at least 1 unit vertically. This gradient facilitates effective rainwater runoff, directing it away from the building and maintaining the integrity of the foundation over time.

Appropriate drainage is crucial to minimize moisture intrusion and ensure a long-lasting structure. It is important for building inspectors to verify this slope during inspections, as overlooking proper grading can lead to significant long-term challenges for the property.