Save Your Retaining Wall: Expert Tips to Avoid Costly Collapses

When we were in the market for a new home a few years ago, we were looking in a hilly town. We noticed that many of the properties had bulging retaining walls. We learned that it was due to the area’s geology and soil composition, and unfortunately, it made many homes undesirable. A local engineer told us it could cost many thousands of dollars to prevent or fix a retaining wall collapse.

Luckily, that price tag isn’t universal. Depending on the size of your wall and what’s causing it to fail, fixing a retaining wall isn’t always too expensive.

“But if the whole thing’s come down, or it’s no longer stable, you’re probably looking at rebuilding it,” says Hayden Slack, owner of G.L. Hunt Foundation Repair. “Rebuilding is more expensive, so catching problems early is the best-case scenario.”

If you’re worried or wondering about your retaining wall, here’s what to know about its potential demise and what to do about it.

What Is a Retaining Wall?

A retaining wall is a structure that holds soil in place to prevent erosion and movement.

“You’ll see them a lot around properties with hills, slopes or where the land’s been cut and graded for a house or driveway,” says Slack. “It’s there to stop soil from washing away or collapsing in places where the natural grade has been altered.”

Retaining walls vary in design, and can be made from concrete blocks, stone, brick, wood or even boulders. Some are built into a cut-slope or backfilled to create usable space behind.

“Depending on the type of soil to be supported, height of planned wall and any anticipated surcharge loads, a wall may extend two times deeper into the earth than is visible at the surface, or even include horizontal tiebacks for enhanced stability,” says Jakob Walter, founder and principal engineer of haushepherd.

Why Retaining Walls Collapse

The main reason retaining walls collapse is because of improper drainage, aka water trapped behind the wall, which causes pressure buildup and pushes the wall outward.

When making a retaining wall, “A lot of people skip proper drainage or backfill, but it adds up over time,” says Slack. “Sometimes folks build them without really thinking about how heavy wet soil can get.”

Sometimes homeowners also end up overloading a wall by parking vehicles or building additional structures on top of it.

“In colder climates, even freezing water can create pressure enough to damage the walls,” says contractor Yaeir Moinzadeh. “Using the right materials and design for your specific soil conditions is crucial.”

How To Prevent a Retaining Wall Collapse

When building a retaining wall, it’s vital to set up proper drainage systems to ensure water can escape. Depending on your situation, these could include weep holes or gravel backfill. Also, make sure the soil underneath the wall is properly compacted, and don’t park or build heavy objects close to the edge.

“Bring in a structural engineer who can figure out the load requirements,” says Slack. “You’re also going to want to keep an eye on it after it’s built, or if it’s been there for a long time. If it’s cracked or leaning, get it checked out.”

How To Fix a Collapsing Retaining Wall

“In a lot of cases, repairs are possible, but it really depends on how far gone it is,” says Slack. Depending on your situation, a few solutions could include:

• Adding supports or braces, which can fix a small amount of leaning.
• Fixing the drainage by digging out the soil behind it, then reinforcing the wall with tiebacks or piers. “But you need a specialist for that,” says Slack.
• Deepening the wall footing, aka underpinning.

“Installation of a French drain behind the wall, if not present, is also an excellent mitigation measure to reduce the possibility of groundwater induced failure,” says Walter.

FAQ

Does homeowners’ insurance cover a retaining wall collapse?

Not usually. “Basically, they consider it normal wear and tear or classify it as ‘earth movement,’ thus, it is excluded,” says Nick Schrader, owner of Texas General Insurance. “However, coverage could be applicable to specific cases, like vehicle damage to the wall.”

About the Experts

• Hayden Slack is owner and general manager of G.L. Hunt Foundation Repair in Fort Worth, Texas, and has a decade of hands-on foundation experience.
• Jakob Walter, PE, is founder and principal engineer of haushepherd, a residential engineering and design firm based in San Francisco, which helps homeowners stabilize existing foundations, repair and build new retaining walls and develop drainage designs.
• Yaeir Moinzadeh is an MHIC licensed contractor and owner of Blue Rise Baltimore Roofing in Maryland.
• Nick Schrader is owner of Texas General Insurance. He has more than eight years of experience in the insurance industry.

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