Retaining walls play a vital role in keeping your landscape functional and beautiful. Among the most popular choices are interlocking block retaining walls — strong, attractive, and relatively easy to install. But over time, even these walls can start to show problems like shifting, leaning, or bulging. If you’ve noticed your interlocking block retaining wall starting to move out of place, don’t panic — it can often be repaired effectively.
Let’s discuss how to fix a shifting or bulging interlocking block retaining wall step by step, and what you can expect during the repair process.
Why Do Interlocking Block Retaining Walls Shift or Bulge?
Before you jump into repairs, it helps to understand the cause of the problem. Interlocking block walls rely on precise placement and gravity to hold back soil. But certain conditions can disrupt this balance. Some common reasons your wall might be moving include:
- Poor drainage behind the wall, leading to hydrostatic pressure.
- Settling or erosion of the soil base.
- Inadequate backfill material.
- Improper installation or skipped steps during construction.
Knowing the root cause of the issue will help you or your contractor repair the wall properly so it doesn’t happen again.
Signs Your Wall Needs Immediate Attention
You might be wondering: how do you know when your wall really needs repair? Here are some clear warning signs:
- Visible bulging or bowing outward.
- Cracks between blocks or in the blocks themselves.
- Gaps between sections of the wall.
- Blocks that have shifted, tilted, or sunk.
- Soil and water seeping through the wall excessively.
If you notice any of these, it’s best to act quickly. Waiting too long could lead to a full collapse, which is much more expensive to fix.
First Step: Assess the Damage
The first thing a professional (or you, if it’s a DIY project) will do is inspect the wall carefully. Is the damage localized to one section, or is it happening along the entire wall? Is the base still stable? Are drainage pipes clogged? These answers will help determine the best repair method.
If the damage is minor and limited to one area, you might not need to rebuild the entire wall. But if the base has failed or drainage is completely blocked, a more extensive repair may be required.
Remove the Problem Area
For most shifting or bulging walls, the next step is to disassemble the affected section. The blocks are carefully removed, stacked to the side, and any damaged ones are replaced. This also allows access to the base and the backfill material behind the wall.
During this step, you might discover saturated, muddy soil, clogged drainage pipes, or uneven gravel base material. All of these contribute to the wall failure and must be addressed before rebuilding.
Improve the Base and Drainage
Here’s where a lot of repairs succeed or fail: fixing the base and drainage. Let’s discuss why this is so important. The base of your wall needs to be level, compacted, and made of proper crushed gravel or stone to prevent settling. If it’s uneven or weak, your wall will continue to shift over time.
Similarly, drainage is key. Without proper water flow behind the wall, hydrostatic pressure builds up and pushes the wall outward. Make sure there’s a perforated drain pipe (also called a French drain) installed behind the base, wrapped in landscape fabric, with clean gravel for water to flow through easily.
Rebuild the Wall
Once the base is level and drainage issues are fixed, the wall can be rebuilt. Start with the bottom course of interlocking blocks, ensuring each block is perfectly level side-to-side and front-to-back. Use a rubber mallet and a level to adjust as you go.
Subsequent courses of blocks should be staggered (like a brick pattern) for stability. Some walls also use special pins or lips on the blocks to help lock them into place. As each row is added, backfill with clean gravel and compact it behind the wall to support the structure.
Continue adding rows and backfill until the wall is rebuilt to its original height.
Finishing Touches
When the wall is fully rebuilt, give it a final inspection. Are the blocks aligned neatly? Is the capstone (if your wall has one) secured properly with landscape adhesive? Check the drainage pipe outlet to ensure water can escape freely.
Many homeowners also choose to add a layer of topsoil and plantings behind the wall for aesthetics and erosion control.
When to Call a Professional
You may be wondering: is this a DIY-friendly project? The answer depends on the size and severity of the problem. Small, localized repairs on a low wall can often be handled by a skilled homeowner. But if the wall is tall, extensively damaged, or sits on a slope, it’s wise to call in a professional. They have the expertise, tools, and manpower to handle complex repairs safely and correctly.
We highly recommend rainierrockeries.com for anyone looking for reliable and skilled help with retaining walls in Kent, WA — their team delivers quality work and great service. Many homeowners in the area trust them for durable and attractive solutions when it comes to retaining walls in Kent, WA, and the results speak for themselves.
Preventing Future Problems
Once your wall is repaired, you’ll want to keep it looking good for years to come. Here are some simple tips to prevent shifting and bulging in the future:
- Keep drainage outlets clear of debris.
- Don’t plant large trees close to the wall — roots can disturb the base.
- Avoid overloading the top of the wall with heavy soil or structures.
- Check the wall each spring for signs of movement and fix issues early.
Final Thoughts: Don’t Wait Too Long
If you’ve noticed your interlocking block retaining wall starting to bulge or shift, don’t ignore it. These problems only get worse over time, and what starts as a small repair can turn into a major rebuild if left unchecked. The good news is that with the right approach, most walls can be repaired and restored to their full strength and beauty.
So — are you ready to fix your retaining wall? Whether you tackle it yourself or call in the pros, understanding the process helps you make informed decisions and achieve great results. Let’s discuss your next step: will you repair it yourself or hire an expert? Either way, your landscape will thank you.