Retaining Walls: Why They Fail (and How to Build Them Right)

Image and Retaining Wall by South Central Landscapes LLC

The Takeaways:

• Drainage is Key: Most failures come from trapped water behind the wall (hydrostatic pressure).

• Proper Base Prep: A strong wall starts with a solid foundation.

• Engineering Matters: There's more to structural integrity than just stacking blocks.

Retaining walls have a tough job: holding back thousands of pounds of soil. When done right, a wall can outlast a person's lifetime. Done wrong, and signs of shifting, leaning or total failure can occur within just a few years.

The #1 culprit? Water. If it can't drain through or around the wall, water builds up hydrostatic pressure. This invisible force pushes against the wall, and over time, that pressure wins. That's why every wall should be built with drainage in mind – usually including clean stone backfill, interior drain tile and sometimes face drains. 

The #2 cause: A bad foundation. Without a properly excavated and compacted base, walls will shift and settle unevenly. Retaining walls shouldn't be built to sit directly on top of soil.

The #3 cause: Inadequate engineering. Many walls require stepped-back construction or interior reinforcement, like geogrid or tie-backs. Plus, it's important to use retaining wall block, rather than non-structural garden wall block, like what's available a big box retailers. Many DIY and low-bid projects skip these considerations, and the wall's structural integrity suffers. 

Pro tip: Choose the right material for the wall's purpose. Garden wall block is never appropriate for structural retaining purposes. Natural stone looks beautiful, but can be harder to engineer for taller heights. Manufactured, segmental retaining wall blocks are designed to lock together and work with reinforcement systems – they work in virtually any situation. 

Bottom line: A retaining wall isn't just landscaping – it's a structural feature. Treat it like one, and it'll stand tall for decades. 

About South Central Landscapes LLC:

We're a landscape contractor serving the greater Madison, Wisconsin area with a specialty focus on hardscapes & outdoor living – including retaining walls, seating walls, and structural features in the landscape. 

Need a pro evaluation on a retaining wall? Our experts have the experience and know-how to get the job done right. Learn more about us and request a quote here: www.sclandscapeswi.com/virtualquote