The "Double Whammy": When a Leak and High Humidity Combine in a West Ryde Bathroom

It started with a call for our free mould inspection. A homeowner in West Ryde was battling a stubborn and recurring mould problem on their bathroom ceiling and wasn't sure of the cause. This case study shows how our initial free assessment led to a deeper, scientific investigation that uncovered a 'double whammy'—a slow roof leak combined with a failing ventilation system—and how we used an advanced, data-driven process to solve it for good.

Step 1: The Free Inspection - Identifying the Obvious Clues

The homeowner took advantage of our obligation-free inspection service. Our certified inspector attended the West Ryde property and quickly identified the first culprit. Using a Flir thermal imaging camera, we detected a clear moisture signature on the ceiling, tracing it back to a slow leak from the roof space above. However, the widespread nature of the mould suggested there might be more to the story.

Step 2: The Scientific Diagnosis - Using Data to Isolate the Problem

To determine if the bathroom's own environment was contributing to the problem, we needed objective data. We set up professional Protimeter BLE data loggers in several locations: one in the affected bathroom and others in different rooms of the house to act as a baseline 'control'.

After seven days, we collected the loggers and analyzed the data. The results were striking. While the other rooms showed normal, healthy humidity levels, the bathroom's data revealed a chronic problem, with humidity spiking to 100% saturation after every shower. This scientifically proved that the bathroom's faulty extractor fan was creating a separate, ongoing moisture problem.

Step 3: The Remediation – A Meticulous, Multi-Stage Process

With our data confirming two distinct problems, our IICRC certified team began the physical remediation inside a fully contained and controlled negative air environment.

1. Source Removal: We performed a careful strip-out of the contaminated plaster ceiling, which was safely bagged and disposed of, exposing the timber structure underneath.

2. Structural Cleaning: The exposed timber frames were decontaminated using abrasive cleaning (sanding and wire brushing) to physically remove all visible mould. For tight areas like butt joints, we performed a low-pressure chemical flush using Actichem Percide with a booster.

3. Specialised Treatment: For structurally critical areas that were inaccessible for manual cleaning, we applied IAQ 6000, a premium mould encapsulation membrane, to permanently seal and isolate any residual mould.

Step 4: A Scientific Approach to Structural Drying

Once the structure was hygienically clean, the final step before rebuilding was to ensure it was completely dry. For this, we established a closed-loop drying system, fully containing the bathroom to create a controlled 'drying chamber'.

Inside the chamber, we installed our Drymatic thermal targeting heat drying system. Critically, all air fed into the Drymatic system is pre-filtered through a standalone HEPA air scrubber. This guarantees that only pure, spore-free air is used for drying, preventing any possibility of re-contamination.

This is not a 'set and forget' process. To monitor the drying with scientific accuracy, we used two separate Protimeter BLE data loggers:

• One logger with direct pins was inserted into the timber framing, giving us a real-time moisture content reading every 60 minutes.

• A second logger continuously monitored the chamber's ambient temperature and humidity.

This constant stream of data allows us to calculate the evaporation potential and make micro-adjustments to the Drymatic system and our Ecor Pro desiccant dehumidifiers, ensuring the fastest possible drying time while protecting the home's materials.

Step 5: Final Verification and Recommendations

Once our data confirmed the structure was back to a dry standard, the job concluded when an independent hygienist performed the Post-Remediation Verification (PRV), providing a clearance certificate. We also provided the homeowner with a clear report on the ventilation issue, recommending they have a licensed electrician upgrade their faulty extractor fan to prevent the high humidity problem from recurring.

Photos from this mould removal job site in West Ryde

photo if mould on the ceiling of the bathroom as a result of water ingress from roof and high humidity

heavy mould growth on walls and ceilings

A Holistic Approach to a Healthy Home

This West Ryde project is a perfect example of why a thorough, scientific investigation is crucial. By not just stopping at the obvious leak, but using data to diagnose the underlying environmental issue, we were able to provide a truly permanent solution and give the client the confidence that their mould problem would not return.

If you are dealing with a persistent bathroom mould problem in the Ryde area, contact our team for a comprehensive mould inspection that finds all the contributing causes.

About the Author

Michael Nguyen is the founder of AAA Mould Removal and a leading expert in mould remediation and building science. His mission is to help Sydney residents maintain healthy indoor environments through scientifically-backed, professional remediation services.

With a unique combination of hands-on and academic expertise, Michael's qualifications are extensive:

• IICRC Certified: Water Damage Restoration, Applied Microbial Remediation & Applied Structural Drying.

• Microbiology: Completed specialised study in Microbiology at RMIT University.

• Licensed Builder & Carpenter with a Diploma in Building & Construction.

• Current University Studies: Double Bachelor’s degree in Medical Science and Environmental Science at Macquarie University.

This deep understanding of building structures, environmental science, and microbiology allows Michael to diagnose the root cause of mould problems, not just treat the symptoms. He specialises in residential and commercial mould removal, black mould treatment, and water damage restoration.

Need a true expert to assess your property? Contact AAA Mould Removal today for a comprehensive mould inspection.