Retaining Wall Drainage Repair for Large Stair-Stepped Planters

Two-story home with deck and built-in pool. Large stair-stepped planters (12x7 ft) form access. One 2x6/4x4 wall is bowing, leaking soil. Owner plans to excavate, reset posts plumb, and refill. Needs backfill material and drainage to prevent recurrence.

Comprehensive Repair Protocol

1. Apply 6-10 mil waterproof plastic membrane to back of wall, stapled above soil line
2. Install French drain at base behind wall, daylighting to lower yard or through wall base
3. Backfill with consistent 6-12 inches of gravel against wall, then soil
4. Compact in lifts with plate compactor or hand tamper
5. Drill 1.5-2 inch weep holes every 18-24 inches along wall base for backup drainage

This system manages hydrostatic pressure—the root cause of wall failure.

Sean Murphy