How to Fix a Bulging Retaining Wall

A bulging retaining wall needs immediate attention and typically requires rebuilding the affected section with proper drainage and reinforcement to prevent soil pressure buildup.

  1. Measure the damage first. Stop using the area immediately and keep people away from the wall. Look for cracks, tilting, or gaps between blocks. Measure how far the wall has moved using a string line or level. If the bulge is severe or the wall is over 4 feet tall, call a structural engineer before proceeding.
  2. Relieve the pressure. Dig out the soil behind the bulging section, working from the top down. Remove soil to at least 12 inches behind the wall face. This relieves pressure and gives you access to see what caused the failure. Watch for poor drainage, roots, or missing backfill material.
  3. Strip to the base. Take apart the bulging portion of the wall, starting from the top course and working down. Number or photograph each block to help with reassembly. Clean mortar off blocks if you plan to reuse them. Check the foundation for damage or settling.
  4. Install drainage first. Level and compact the foundation base, adding gravel if needed. Install a perforated drain pipe at the base, sloped toward an outlet. Cover the pipe with gravel and filter fabric. This prevents water from building pressure behind the wall.
  5. Reconstruct with precision. Reconstruct the wall using proper techniques for your wall type. For block walls, ensure each course is level and properly aligned. For stone walls, select well-fitting stones and maintain consistent batter. Check alignment frequently with a string line.
  6. Layer the backfill correctly. Use graded gravel for the first 12 inches behind the wall, then transition to soil. Compact in 6-inch lifts, but avoid heavy compaction directly against the wall. Install filter fabric between gravel and soil to prevent clogging of the drainage system.
  7. Reinforce for permanence. For walls over 3 feet or in problem soils, install geogrid reinforcement every 2-3 courses. The grid extends back into the soil at least as far as the wall is tall. This creates a reinforced soil mass that won't push against the wall.