Foundation Drainage: Why Berms Are Wrong and French Drains Are Right

Fixing Basement Seepage: Grading vs. Drainage

Adding soil (berm) against a block foundation worsens seepage. You need less soil contact, not more.

Correct Approach

1. Diagnose source – Roof runoff? High water table? Surface slope?
2. Install French drain – Perforated pipe in gravel trench at footing level, sloped to daylight/sump.
3. Ensure positive grading – Soil slopes 6" in first 10 ft away from foundation.
4. Gutters/downspouts – Extend 6-10 ft out; critical first step.

Why Berms Fail

• Increase hydrostatic pressure on wall.
• Trapped water has nowhere to go.
• Only useful as flood barrier (temporary).

Depth & Width of French Drain

• Deep (at footing) for high water table.
• Shallow (12-18") for surface water only.
• Width: 12-18" trench; 4" pipe; gravel to 6" below grade.

Start with gutters and grading. If seepage persists, French drain is the permanent fix.