Avoid costs. Remain compliant. Retaining wall waterproofing
Avoid costly structural damage and meet building compliance standards. Address water leaking retaining walls early to protect property, tenants, and budget.
Why do retaining walls leak?
Retaining walls play a crucial role in landscaping and construction by holding back soil and preventing erosion. These below-ground structures are particularly vulnerable to water ingress due to constant ground pressure, changing weather conditions, and substandard waterproofing.
Poor or blocked drainage
Without proper drainage, hydrostatic pressure builds up behind retaining walls, forcing water through cracks and weak points. In Melbourne’s wet climate, even minor drainage issues can quickly lead to significant water ingress.
Inadequate or failed waterproofing membranes
Many older retaining walls were built with little or no waterproofing, or membranes have since deteriorated. Over time, exposure to moisture, soil pressure, and temperature fluctuations causes these systems to break down, allowing water to seep through.
Cracks and structural movement
Retaining walls naturally degrade with age, especially if built with porous materials like concrete block or rendered brick. Melbourne’s clay soils and shifting foundations also cause retaining walls to crack or move over time. This creates new water entry points.
High water tables
Water tables can rise temporarily in Melbourne during wet periods. Below-ground retaining walls can leak when high water tables create constant hydrostatic pressure that overwhelms inadequate waterproofing or drainage.
The lifespan of a retaining wall’s waterproofing system and membrane depends on several factors. Liquid applied membranes typically last 10-15 years, however bituminous or sheet membranes can last up to 25 years.
Why you should care
Ignoring retaining wall leaks puts your property at risk. Acting early protects your investment, ensures safety, and keeps maintenance costs low.
Structural safety risks
Leaking retaining walls can weaken over time due to water pressure, leading to cracking, bowing, or even collapse. This poses serious safety hazards to buildings, tenants, and nearby structures.
Legal and liability exposure
If a leaking retaining wall leads to injury, property damage, or mould-related health issues, property managers and owners may face legal claims and insurancec complications.
Damage to internal spaces
Water from leaking retaining walls can migrate into basements, car parks, or lower-level commercial areas, damaging flooring, electrical systems, and tenant assets—impacting building value and functionality.
Expensive repairs if ignored
What starts as minor water ingress can escalate into major structural damage, requiring costly reconstruction. Addressing leaks early is far more cost-effective than dealing with failed retaining walls later.
Spot the warning signs
Addressing retaining wall waterproofing issues early is critical. Watch for these common signs of retaining wall leaks:
Damp or stained surfaces: Dark patches, green algae, or moss growth on wall faces or nearby surfaces indicate prolonged moisture exposure.
Efflorescence and mineral deposits: White, chalky salt deposits on concrete or brick show that water is moving through the wall and leaving mineral traces behind.
Cracks or bulging: Visible horizontal, vertical, or step-pattern cracks are signs of potential water infiltration and retaining wall water ingress.
Concrete-specific signs: Spalling concrete, porous-looking concrete surfaces, visible gaps or deterioration along cold joints between concrete pours, are all water damage signs to look out for.
Additional signs to watch for: Peeling or blistering paint/render, rust staining or exposed reinforcement bars, mould or musty odours, soft or eroding soil at the base, or water seepage after rainfall.
Early detection of these signs allows for preventive repairs before structural damage occurs.
The Schaefer solution
Trust Schaefer Waterproofing to detect, fix, and prevent water leaks in retaining walls. If we can’t access the soil-facing side of the wall (the positive side), we can waterproof the wall from the inside (the negative side). This stops water from entering an occupied space, however the structural integrity of the retaining wall could still be compromised.
1.
Assessment and solution design
We conduct a detailed site inspection to identify moisture ingress points, drainage issues, and structural concerns. If the positive side (soil-facing side) of the wall is not accessible, a negative side waterproofing system will be recommended.
2.
Waterproofing membrane selection
Recommendations will be made based on wall type, condition, budget and access. Positive-side waterproofing recommendations include long-lasting sheet membranes (butyl rubber, torch on), or liquid-applied membranes (liquid rubber) that are durable and resistant to hydrostatic pressure. Negative-side waterproofing systems may include polyurethane injection, waterstops, and cementitious membranes.
3.
Surface preparation
We prepare the retaining wall surface by grinding and removing damaged render, old waterproofing, efflorescence, and contaminants like oil, dirt, and dust. Sharp objects are eliminated, and any cracks, holes, or voids are repaired using suitable mortars. This ensures a clean, stable surface for effective and long-lasting waterproofing adhesion.
4.
Waterproofing system installation
Certified technicians apply the waterproofing system according to the manufacturer's specifications. Photographic evidence of detailing and installation is provided for every step.
5.
Protection board installation
We use a number of protection options including Armour Blue peel and stick or protection sheet (cuspated) in conjunction with a geo fabric. This is applied on top of the waterproofing membrane to prevent damage during backfill. This barrier ensures long-term performance in high-pressure and below-ground conditions.
6.
Testing
The retaining wall is flood tested after the membrane is applied and the AGI (Above Ground Inlet) drain has been installed. This ensures the membrane doesn’t have any breaches. Third-party leak testing is available to verify waterproofing success.
7.
Project handover
We manage your project end-to-end and coordinate other trades, for peace of mind. All work is documented, and warranty provided. We return in 6-12 months after waterproofing system installation to ensure effectiveness.
Think your retaining wall might be leaking? Let’s talk
Don’t let minor retaining wall leaks escalate into injury, property damage, or mould-related health issues. Protect your building, tenants and internal dwellings with Schaefer Waterproofing. Book a call for a chat with our team.
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