A retaining wall holds back thousands of pounds of soil. When it starts to fail, the consequences can be sudden and severe — property damage, flooding, and safety hazards. In Northern Illinois, freeze-thaw cycles and heavy spring rains accelerate retaining wall deterioration faster than most homeowners realize.
RCC Masonry & Concrete has repaired and rebuilt retaining walls across McHenry County and Lake County for over 15 years. Here are the danger signs we tell every homeowner to watch for.
1. The Wall Is Leaning Forward
The most obvious sign of failure is a wall that's tilting away from the retained soil. Stand at one end and sight along the face — any visible lean means the wall is being pushed by soil pressure beyond its design capacity. Even a 1-inch lean that wasn't there before indicates active movement that will worsen over time, especially during spring thaw when soil is saturated.
2. Horizontal Cracks Along the Wall
Horizontal cracks indicate the wall is bowing under lateral soil pressure. In block or concrete walls, these cracks typically appear at the midpoint of the wall height. In stone walls, you'll see individual stones shifting or gaps opening between courses. Horizontal cracking is a structural failure mode — it won't heal itself and progressively weakens the wall.
3. Water Seeping Through the Wall Face
All properly built retaining walls have drainage behind them — typically crushed stone backfill and a perforated drain pipe at the base. If you see water seeping through the wall face, staining, or weep holes running constantly, the drainage system has failed. Without drainage, hydrostatic pressure builds against the back of the wall, which is the number one cause of retaining wall failure.
4. Soil Settling or Separating Behind the Wall
Check the area behind the top of the wall. If you see a gap between the soil and the wall, or if the ground has settled (dropped) within a few feet of the wall, soil is washing out through cracks or failed joints. This creates a vicious cycle — settling soil increases the load angle on the wall, accelerating its failure.
5. The Wall Is Bowing or Bulging in the Middle
A bulge in the center of the wall (when viewed from the side) means the soil pressure at the center exceeds the wall's strength. This is common in walls that were built too thin for their height, walls without adequate reinforcement, or walls where frost heaving has pushed against the back face repeatedly over many winters.
6. Crumbling Mortar or Deteriorated Block
For mortared stone or block retaining walls, the mortar joints are the weak link. If mortar is crumbling, missing, or popping out, the wall is losing its structural integrity one joint at a time. In Northern Illinois, freeze-thaw cycles accelerate mortar deterioration, especially on the exposed face where moisture contact is constant.
What to Do If You Spot These Signs
Don't wait for a collapse. A retaining wall that shows signs of failure needs professional evaluation. RCC Masonry & Concrete will assess the wall's condition, determine the cause of failure, and recommend the most cost-effective solution — whether that's drainage repair, reinforcement, partial rebuild, or full replacement. Call (224) 441-5284 for a free assessment.