Negative grade
Ground that slopes toward a building rather than away from it, directing surface water at the foundation.
What is Negative grade?
What is Negative grade?
Negative grade is the specific condition behind a large share of wet basements and damp crawl spaces. It arises from original construction, from settlement of backfill around the foundation over time, or from later landscaping, patios and additions that changed the drainage. It frequently accompanies downspouts that discharge directly at the foundation. Because regrading and extending downspouts are inexpensive compared with interior drainage systems or exterior excavation, inspectors normally recommend correcting surface drainage first and reassessing before any client commits to major waterproofing work.