Retaining wall bulging or leaning

Symptoms

• Wall visibly bulging outward or leaning away from the slope it holds back
• Cracks forming in the wall, especially horizontal ones
• Soil or mulch appearing to sink or crack on the uphill side

Likely causes

• CommonPoor or blocked drainage behind the wallWater building up behind the wall adds significant pressure it wasn't designed to resist alone.
• CommonWall not originally built with adequate drainage or reinforcementMany older or DIY-built walls lack proper drainage gravel, weep holes, or geogrid reinforcement for their height.
• PossibleWall height exceeding what its design or materials can safely supportTaller walls need engineering considerations that shorter walls don't.

What to do

1. Look for weep holes or drainage outlets in the wall face and check whether they're clear or blocked.
2. Check the uphill side for signs of water pooling or soil sinking, which suggests trapped water pressure.
3. Clear visible drainage outlets of debris if that's an easy first step.
4. Avoid adding heavy loads, like a new patio, shed, or excess soil, near the top of a bulging wall.
5. Photograph and measure the bulge or lean, noting the date, and monitor for changes over the following weeks and months.
6. Get a structural or geotechnical evaluation for any wall over about 3–4 feet tall that shows bulging, leaning, or cracking.
7. Follow the recommended repair, which may involve rebuilding with proper drainage and reinforcement rather than a surface patch.

Tools and parts

• Camera
• Tape measure

When to call a pro

Call a structural or geotechnical engineer for taller or clearly failing walls, and a landscaping or masonry contractor for the rebuild.

Safety