Is your retaining wall failing? 7 warning signs to catch early
A retaining wall does a quiet job. It holds back tonnes of soil every single day and asks for nothing in return. So when it starts to go, most people don't notice until it's leaning into the driveway. The good news is that walls almost always warn you first. Catch the signs early and a repair is straightforward. Ignore them and you're looking at a full rebuild, often after the wall has taken out a fence, a patio, or a chunk of the yard with it.
Here are the seven signs we get called out for most often around Surrey and the Lower Mainland, and what each one usually means.
1. The wall is leaning or tilting forward
A wall that's tipping away from the slope is the clearest red flag there is. A small, even lean that's been there for years and hasn't moved might be cosmetic. A lean that's getting worse, or one that's uneven along the length of the wall, means the soil behind it is winning. Stand at one end and sight down the face. If the top course is bowing out past the bottom, the wall is rotating, and that doesn't fix itself.
2. Cracks that keep getting wider
Hairline cracks in a concrete or block wall aren't always serious. The thing to track is movement. Mark the end of a crack with a pencil and a date. If it grows over a few weeks or months, the wall is under stress it can't handle. Stair-step cracks running diagonally through block joints are a classic sign of uneven settlement underneath.
3. A bulge or a bowed-out belly
When a section in the middle of the wall pushes out further than the top and bottom, that's a bulge. It usually means water and soil pressure are concentrated at one spot, often because the drainage failed right there. Bulges are a late-stage symptom. Once a wall is bellying out, it's typically past a simple patch.
4. The wall is wet, mossy, or streaked with white
Water is the enemy of every retaining wall, so any sign that water is moving through the face matters. Constant damp patches, moss, or chalky white streaks (that's efflorescence, mineral salts left behind as water evaporates) all tell you the same thing: water is getting trapped behind the wall instead of draining away. The wall might look fine today, but the pressure building behind it is the problem.
5. Soil or gravel washing out from behind
If you're finding fans of dirt or fine gravel at the base of the wall after heavy rain, the backfill is escaping through gaps or failed drainage. Every bit that washes out is a void behind the wall, and voids turn into sinkholes and settlement.
6. Gaps opening between blocks or at the ends
Separation between units, or a gap opening up where the wall meets a set of stairs or a corner, means different parts of the wall are moving at different rates. On segmental block walls, watch the cap stones. If they're shifting or you can rock them by hand, the courses below are moving too.
7. The ground behind the wall is sinking
A dip, a low spot, or a crack in the lawn or patio a foot or two back from the wall is easy to miss. It's also one of the earliest signs of trouble, because it shows the soil the wall is supposed to hold is already settling into voids. If a fence post or a section of paving behind the wall has started to tilt, treat the wall itself as suspect.
One mild, stable sign is worth keeping an eye on. Two or more, or anything that's actively getting worse, is worth a look from someone who builds walls for a living. A 20-minute site visit tells you whether you're looking at a quick fix, a partial rebuild, or a wall that needs to come down before winter.
When we assess a failing wall, we're not just looking at the face. We check the drainage behind it, the base it's sitting on, the soil type, and what's loading it from above. Nine times out of ten the real cause is hidden: a drainage layer that was skipped, geogrid that was never installed, or a base that was never compacted. Fix the wall without fixing the cause and you'll be doing it again in a few years.
