Why Is My Retaining Wall Leaning? 8 Common Causes and Solutions

Retaining walls are important in landscaping, ensuring the structural integrity of outdoor spaces. They prevent erosion and create level areas on sloped properties. However, one of the most common problems many Brisbane homeowners face when it comes to their retaining walls is the tendency for them to bulge or lean. This issue, if not addressed promptly, can lead to significant issues such as structural damage and safety concerns. A leaning retaining wall not only affects the appearance of your landscape but can also pose a safety hazard, leading to a complete wall failure and costly repairs. Understanding the common reasons behind these problems is the first step to ensure that your retaining wall remains sturdy and functional. In this blog post, we’ll explore seven common causes of leaning retaining walls and provide solutions to prevent and correct these issues.

Cause 1: Poor Drainage

install drainage pipes to prevent water accumulation

Water accumulation behind a retaining wall can increase pressure, causing the wall to lean or bulge. Brisbane experiences heavy rainfall and regular summer storms which can worsen this issue if proper drainage is not in place. When water is trapped behind the wall without an escape route, the pressure builds up and pushes against the wall’s structure.

To prevent this from happening, ensure that your retaining wall has effective drainage systems. This includes weep holes, drainage pipes, and a gravel backfill. Weep holes allow water to escape from behind the wall, reducing the pressure from behind. Installing a drainage pipe at the base of the wall helps drive water away from the structure. Gravel backfill behind the wall enables water movement and prevents buildup and pressure on the wall. During heavy rainfalls, make sure that the drainage systems are clear of debris and working properly. Regular maintenance is needed to ensure that they’re still effective, especially during Brisbane’s summer storm season. 

Cause 2: Inadequate Foundation

A strong foundation is the cornerstone of any stable retaining wall. If the foundation is weak or improperly constructed, it can fail to support the wall’s weight, leading to leaning or bulging. Inadequate foundations often result from poor soil conditions, insufficient depth, or the use of substandard materials. To prevent this issue, it is crucial to build a solid foundation with the appropriate materials and techniques, taking into account the soil type and the load the wall needs to bear. By ensuring a robust foundation, you can significantly enhance the stability and longevity of your retaining wall, preventing future structural problems.

Cause 3: Incorrect Construction Techniques

follow best construction practices for your retaining walls

Using incorrect construction or building techniques can compromise the stability of your retaining wall. Some might have used substandard materials like low-grade pine, not adding necessary reinforcements like not digging post holes deep enough, and improper backfilling like not using drainage gravel as mentioned previously. Following the best practices when it comes to constructing retaining walls is important for its strength and durability. Choose the right materials, ensure proper reinforcement, and follow design specifications. Hiring professional Brisbane retaining wall builders can prevent costly mistakes and ensure a durable structure. They will also ensure that your retaining walls comply with local building codes and standards.

Cause 4: Soil Movement

use geogrid to prevent soil movement

Soil movement is fairly common in Brisbane due to heavy rainfalls and is also a reason why retaining walls lean. When soil becomes waterlogged, it shifts and exerts uneven pressure on the retaining wall. To prevent this, the soil must be properly compacted during construction to make it dense and stable. You should also use geogrid reinforcement to stabilise the topsoil. You may also plant small shrubs and ground cover plants above the wall to further help stabilise the soil and prevent movement.

Cause 5: Overloading

Excessive weight from structures, vehicles, or large trees near the retaining wall can push the wall outwards. Overloading is a common issue when the wall is not designed to support additional weight beyond the soil it retains. If your retaining wall will be subjected to additional weight from a vehicle or another building then it will require approval from Brisbane City Council. If you want your retaining wall to support additional loads than just the soil behind the wall it’s best to consult a professional retaining wall builder as it will require engineering to ensure that it can support the load safely.

Cause 6: Tree Roots

If there are trees near the retaining walls, their roots might grow into or near them. These can exert pressure, causing it to lean. As the roots continue to grow, they can push against the wall which ultimately leads to cracks and instability. Avoid planting large trees close to the retaining walls to prevent the roots from growing into them. If there is any existing vegetation, you can trim them regularly to prevent them from latching onto the wall’s structure and causing damage. Monitor the area for root growth regularly and take necessary measures to maintain the wall’s integrity. 

Cause 7: Erosion

implement soil erosion control measures

Soil erosion behind or beneath the retaining wall can weaken its support which leads to leaning. This is very common in areas with heavy rainfall or poor soil conditions. Implementing soil erosion control measures is important. You can use retaining wall fabrics to hold soil in place while allowing water to pass through. Proper grading is also needed to ensure that water flows away from the wall rather than accumulating behind it. You must regularly inspect the wall and surrounding areas for any sign of erosion and take necessary actions immediately.

Protect the Integrity of Your Retaining Walls

Leaning retaining walls are a serious concern that can lead to further structural problems if not addressed. To prevent these issues, it is crucial to design and build retaining walls with proper planning and attention to detail. Consider the local climate and soil conditions in Brisbane when planning and constructing to ensure their longevity and effectiveness. Using high-quality materials, following best practices, and seeking professional advice can significantly reduce the risk of leaning issues. You also need to practise regular maintenance and inspection to catch potential problems early, allowing for timely repairs.

If your retaining wall is showing signs of leaning, you need an expert in retaining walls to prevent the issue from escalating. Ensure the longevity and stability of your retaining walls with our professional expertise. Contact us today for a free consultation and quote to protect the integrity of your retaining walls.

concrete sleeper retaining wall in Mango Hill

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