Retaining walls are commonly used around Sydney properties to create level platforms, stabilize slopes and define boundaries. Over time, retaining walls can begin leaning or bulging outwards due to soil pressure behind them. If left unchecked, leaning walls become structurally unsound and can collapse. As experienced Sydney building inspectors, Local Property Inspections provides tips on assessing and rectifying leaning retaining walls.
Causes of Leaning Retaining Walls
There are several common reasons retaining walls start to lean:
- Insufficient foundations allowing the wall to subside or sink unevenly.
- Poor drainage and hydrostatic pressure buildup behind the wall pushing it forward.
- Inadequate construction using the wrong materials or techniques.
- Excessive outward soil force applied if the slope behind is overly steep.
- Tree roots growing under the wall, lifting it out of alignment.
- Continuous heavy vehicle loads on adjoining roads vibrating the wall.
- General deterioration of mortar joints and masonry over decades of weathering.
Signs to Look For
How do you spot a leaning retaining wall needing repair? Warning signs include:
- Visible leaning, tilting or bulging of the wall face.
- Vertical cracking through wall sections.
- Mortar erosion and dislodged bricks indicating wall movement.
- Soil subsidence, slipping or pooling behind the wall.
- Cracking, rising pavers or soil retention failure in front of the wall.
- Leaning or warped fencing on top of the wall.
- Water pooling at the wall’s base during rains.
Safety is Critical
Severely leaning walls are structurally dangerous. Before attempting repairs:
- Prevent access near the affected wall with safety barriers.
- Stake out the danger zone equal to the wall’s height.
- Engage structural engineers to design remedial works.
- Shore up leaning sections with acro props to stabilize the wall temporarily.
Repair Options
Here are some common methods for fixing leaning retaining walls:
Rebuilding Sections – Dismantling damaged portions and rebuilding with proper foundations and drainage.
Concrete Buttressing – Pouring concrete braces against the tilting face to reinforce it.
Soil Anchors – Drilling and grouting long soil anchors through the wall into stable ground behind.
Geogrid Reinforcement – Excavating behind and installing geogrid sheets to tie-back the wall before backfilling.
Releveling – Lifting wall sections back into alignment using hydraulic jacks on top of new concrete footings.
Drainage Improvement – Installing agricultural drainage pipes and gravel trenches behind to reduce soil water pressure.
Partial Replacement – Removing severely compromised sections and replacing with new reinforced masonry.
The optimal solution depends on the wall’s extent of deterioration and budget. Severe leaning requires rebuilding while minor cases may only need realigning.
Expert Assistance
Repairing retaining walls is complex and requires engineering input. For experienced guidance, get Inner West Property Inspections to inspect leaning walls and provide tailored fixing recommendations. Their structural assessments help determine the safest repair approach. Don’t delay in tackling leaning retaining walls.
Conclusion
Catching wall leaning early and taking prompt remedial action prevents full-blown collapses. Monitor for warning signs and have deterioration assessed by industry experts. Walls over 1m in height require a structural engineer to asses for integrity. With the right repairs, leaning retaining walls can be restored to structurally sound condition.