Rear
Ventilated
Waterproofing
Systems
(RGV I & RGV II)
Advanced Moisture Engineering & Substrate Protection
Those innovative systems were specifically designed to address challenges faced by five flat roofs that experienced extensive water damage and dampness due to failed waterproofing applications. The original installations suffered from poor workmanship, resulting in leaks, damp ceilings, and walls–compounded by thermal bridging.
Why RGV?
Standard waterproofing applications trap existing structural dampness underneath the membrane, leading to bubbling, blistering, and recurring failures.
Our innovative Rear Ventilated Waterproofing Systems introduce a passive air insulation layer between the existing structure and the new system. This engineered gap allows standing water and deep substrate moisture to constantly evaporate through natural, continuous ventilation—permanently protecting your property’s structural integrity, improving thermal efficiency, and ending the cycle of failed repairs.
Problem Overview: Why Traditional Systems Fail
Most clients contact us after experiencing a recurring cycle of failed repairs. Understanding the root cause of these failures is essential before undertaking any corrective work:
1. Initial Failure & Water Infiltration: Poorly executed initial waterproofing allows water to penetrate the building envelope. This moisture becomes deeply trapped within the concrete screed and masonry walls.
2. Thermal Bridging & Condensation: Traditional flat roof designs often suffer from thermal bridges. These bridges allow unwanted heat transfer, drastically increasing energy inefficiency and creating high risks of internal condensation and mold growth.
3. Superficial “Patch” Repairs: Standard contractors often apply superficial patches over damp substrates. These patches address the symptoms temporarily but fail to resolve the underlying moisture problem. This results in severe, hidden degradation of the screed and plaster, drastically weakening their compressive strength over time.
4. Long-Term Structural Risks: Left unaddressed, trapped moisture accelerates structural damage through concrete carbonation, rebar corrosion, and constant water saturation—ultimately threatening the entire architectural integrity of the building.
The Solution: Active Rear Ventilation
Our RGV systems are custom-engineered to address immediate water ingress while eliminating long-term structural moisture risks simultaneously.
1. Engineered Air Insulation Layer
Introduced seamlessly between the existing substrate and the newly installed system.Mitigates condensation, controls moisture transit, and can be paired with high-performance insulation beneath the waterproofing layers for enhanced efficiency.
2. Dynamic Continuous Airflow
Trapped moisture and vapor evaporate naturally and continuously through dedicated ventilation paths, ensuring the underlying structure dries out and stays dry.
3. Passive Thermal Benefits
Provides distinct, seasonal climate advantages for luxury homes:
Winter: Enhanced heat retention minimizes energy loss through the roof envelope.
Summer: Passive cooling via the ventilation layer minimizes solar heat gain.
4. Long-Term Durability
Drastically reduces heating and cooling costs by optimizing the home’s thermal insulation.
Protects core structural elements from future water exposure, degradation, and aging.
Verified Success & Technical Documentation
We back our engineering with hard scientific data, not guesswork.
Thermal Imaging & Diagnostics: Every completed RGV installation is verified using advanced thermal scans and independent, third-party leak detection to confirm the roof ecosystem is 100% dry and functioning perfectly.
Architectural Detailing: The system is prepared for premium final touches, including custom German RHEIN ZINK parapet flashings precisely detailed and installed by master craftsmen.
Execution, Components & Compliance
Application Process
Efficient & All-Weather: Our specialized installation methodology allows for secure application even in adverse, unpredictable Cape Town weather conditions, minimizing open-roof exposure.
Core System Components
Rear-Ventilated Parapets: Custom-fabricated profiles that maintain consistent, weather-protected airflow between the old substrate and the new waterproofing membrane.
Integrated Window Flashings: Seamless aluminum window flashing systems integrated directly into the waterproofing boundaries to eliminate traditional weak points.
Inspection & Rigorous Industry Approval
To ensure absolute compliance with global and local standards, our systems are inspected, tested, and fully approved by:
Leading Waterproofing Material Suppliers
Double-Glazing Window Specialists
Premium Sealant & Repair Mortar Importers
Consulting Architects & Structural Engineers
All installations adhere strictly to South African Building Regulations (SANS).
Comprehensive Long-Term Warranties
Because we use the finest materials available and execute the torch-on applications ourselves with master-level precision, we provide unmatched warranty peace of mind:
Workmanship Warranty: 3 Years (Fully insurance-backed directly by The German Roofer).
Materials Warranty: 10 Years (Fully backed by the premium waterproofing manufacturing supplier and independent insurance).
Advantages at a Glance
| Feature | Direct Benefit to Property Owners |
| Energy Efficiency | Reduces heat transfer through the building envelope, minimizing reliance on high-cost HVAC systems. |
| Moisture Control | Eliminates interstitial condensation risks, preventing toxic mold growth and material degradation. |
| Structural Durability | Provides permanent, long-term protection for your concrete screed, plaster, and underlying structural elements. |
| Seasonal Comfort | Maintains optimized, balanced indoor living temperatures all year round. |
Acknowledgments
A special thank you to our clients, premium suppliers, and the dedicated team at “The German Roofers” for bringing these highly innovative, permanent architectural solutions to life with true craftsmanship and technical expertise.
