A Hidden Defect: Tracing a Newtown Mould Problem to Its Source

What looks like a small water mark under a window can often be the tip of the iceberg, pointing to a much larger, hidden problem. Our team was recently called to a townhouse in Newtown where the owner had noticed exactly that. This case study details how our rapid, scientific approach uncovered a serious building defect and the meticulous process required to make the home safe again.

Step 1: Same-Day Inspection to Uncover the Truth

We received the call and our certified mould inspector was on-site the very same day. Using a thermal imaging camera, we immediately saw that the entire area under the window was wet, far beyond the visible stains. A follow-up check with a pin moisture meter confirmed that the plaster, the internal timber frames, and even the yellow tongue flooring under the carpet were saturated. To confirm the root cause, we cut a small, neat inspection section, which revealed the problem: the window had been installed with no protective flashing, allowing water to freely enter the wall cavity.

Step 2: A Clear Plan & Protecting Possessions

With the cause identified, we created a detailed scope of work and a quote on the spot. The client accepted, and we scheduled the work to begin just two days later. Our first on-site action was to carefully bubble wrap and box all contents in the affected area. These items were then transported to our North Rocks warehouse to be assessed and treated by our dedicated content remediation specialist team, ensuring they were kept safe and free from contamination.

Step 3: Creating a Safe Work Zone in the Home

On Day 1, our IICRC certified team focused entirely on safety and containment. We used the Zipwall® dust barrier system to construct a fully sealed work zone around the affected area. To prevent cross-contamination to the rest of the townhouse, we established negative air pressure with our Husqvarna A 2000 HEPA air scrubbers. We take great care in this setup, using professional painter's tape to ensure no secondary damage is done to the client's walls.

Step 4: A Multi-Stage Approach to Mould Remediation

With all staff in full PPE, the source mould removal began on Day 2.

• Strip-Out: All contaminated plaster, flooring, and timber was carefully cut out, placed into 200um disposal bags, and 'goose-neck' sealed before being moved through a decontamination area and taken out to a waiting truck.

• The 4-Step Clean: All remaining structural timber underwent our meticulous cleaning process: first, aggressive sanding to remove all visible mould, followed by a chemical wash with Actichem Percide and its booster. We then use a high-pressure, low-water wash. For areas we cannot sand, we perform a chemical flush to ensure 100% treatment.

  
  

Step 5: Advanced Structural Drying

This is a critical step, as any delay can cause mould to regrow. We immediately set up our Drymatic thermal targeting drying equipment. This system applies controlled heat directly to the materials, which we combine with an ECOR PRO EPD200-PRO Desiccant Dehumidifier to rapidly and thoroughly dry the entire structure.

Step 6: Final Cleaning and In-House Verification

After drying, we performed another full round of HEPA vacuuming and damp wiping using the 'sandwich method' for a final deep clean. Before dismantling the containment, we carried out our own preliminary quality check using Air-O-Cell® cassettes and surface tape lift sampling. This internal check ensures the environment is clean and ready for the final, independent clearance test by a hygienist.

This Newtown project highlights how a seemingly small issue can point to a major building defect. By using a rapid, scientific, and meticulous process, we were able to diagnose the cause, protect the client's belongings, and restore their home to a safe, dry, and mould-free state, ready for rebuilding.

Photos from this mould removal job site in Newtown

strip out section of plaster under the windows. Carpet has also remove for disposal

the second bedroom was also sustained water damage and has mould contaminated in a number of different areas

If you suspect a building defect is causing mould in your Inner West home, contact our expert team for a detailed mould inspection.

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 inspection.