What's with the dirt and water that is regularly flushed out of the gap next to your retaining wall? Does it mean that your retaining wall is about to lose its ability to retain anything and that a collapse is imminent? Should that gap even be there? Retaining walls are deceptive in their simplicity, and though the idea is basic enough, there's a significant amount of design and construction that goes into a wall capable of bracing so much weight behind it. If a seam has been left next to the wall, creating a small gap, this would have been done by design. But why is this the case? And should the loss of soil and water via this gap be something to worry about?
A Deliberate Choice
A narrow seam can sometimes be left when a retaining wall connects to an adjacent structure, such as your home, or even another wall. This choice is based on the wall's capacity for minor movement, and a small gap prevents the wall from placing too much pressure on the exterior of the adjacent structure. Despite its narrow nature, it's possible for a small amount of soil to escape from this seam and to be messily deposited onto the ground beneath the retaining wall. But how much is too much?
You might argue that any mud or dirt that is unceremoniously dumped onto your lawn or driveway is too much. This doesn't mean that there's an issue with the structural integrity of the wall, and its ability to drain off this excess weight contributes to your retaining wall actually retaining its structural integrity. However, when too much dirt is lost, the wall can become compromised as it gradually becomes a freestanding structure without the weight of the dirt behind it.
When a significant amount of soil begins passing through the retaining wall's seam, it's a sign that a simple yet crucial part of the wall's lining has broken down to the point where it has lost its effectiveness or was mistakenly deemed to be unnecessary when the wall was constructed. Landscape fabric is a fine mesh made from durable plastic and should be lining the seam, allowing moisture to escape while holding the soil. Some excavation work will be required to remove enough soil to allow the installation or replacement of landscape fabric. This is a labour-intensive job, and the wall might need to be braced while the soil is removed, so it can be wise to call in professional assistance for this maintenance.
That seam can comfortably expel any moisture and a small amount of soil without any issue, but when a lot of soil is being lost, it's a sign that the seam is lacking a lining.
If you have any questions about retaining walls, contact a contractor near you.