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Water Main Leak in a Balmain Bedroom Wall: Mould Strip-Out, Clearance and Full Rebuild
By Michael Nguyen | Indoor Environmental Professional (IEP) | IICRC WRT, AMRT, ASD (69486970) | Mould Testing Technician (NAT10913005) | Licensed Builder NSW 392154C (Supervisor, KBL+RENO)
In August 2026 we remediated and rebuilt a bedroom and part of a hallway in Balmain, in Sydney's Inner West. A leaking water main had been letting water into the wall cavity, wetting the bottom of the walls and the timber framing behind the plasterboard.
The job took 10 days from strip-out to a finished room and cost $7,500 + GST. This post covers what we removed, why the rebuild waited for an independent clearance test, and what went back in.
The Job
Because the leak was inside the wall cavity, the damage was hidden behind the plasterboard at the bottom of the walls. The insurer's plumber fixed the leak. We handled everything inside the bedroom and hallway:
Set up containment to keep the work area separate from the rest of the home
Strip out the wet and mould-affected lower section of plasterboard
Clean up the wall cavity and framing
Replace the lower section of the timber frame, including noggins and bottom plates
Independent post-remediation verification by a building biologist
Reinstall plasterboard, paint, the wardrobe and timber flooring
Why the Rebuild Waited for Clearance
We cut the plasterboard out above the wet line so the framing could be cleaned, dried and checked. Closing the wall straight away would have sealed any remaining mould and moisture inside it.
An independent building biologist carried out post-remediation verification (a clearance check) before any new plasterboard went up. We don't sign off our own remediation work.
The Rebuild
Once clearance passed, our trades rebuilt the room: new plasterboard on the lower walls, set and painted, the wardrobe reinstalled, and new timber flooring laid over the existing tiles.
All building work was carried out under NSW builder's licence 392154C.
Outcome
Leak repaired by the insurer's plumber
Wet plasterboard removed; lower framing, noggins and bottom plates replaced
Independent post-remediation verification passed before the rebuild
Bedroom and part of the hallway finished with plasterboard, paint, wardrobe and timber flooring in 10 days
What It Costs
This job cost $7,500 + GST, covering the strip-out, clean-up, framing repairs, plasterboard, painting, wardrobe and timber flooring. Our mould inspection and quote are free, and professional moisture and mould reports start from $500 + GST.
See more examples on our Building Repairs page.
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About the Author
Michael Nguyen is the director of AAA Mould Removal and leads our water damage and mould remediation work across Sydney. His qualifications include:
Indoor Environmental Professional (IEP) – Testing Water-Damaged Buildings, Australian College of Environmental Studies (RTO 21740), 2026. Includes nationally recognised units NAT11429003 Conduct a comprehensive mould and moisture assessment and NAT11429007 Conduct post remediation verification mould testing (11429NAT Advanced Diploma of Building Biology)
IICRC Water Damage Restoration Technician (WRT)
IICRC Applied Microbial Remediation Technician (AMRT)
IICRC Applied Structural Drying (ASD), IICRC no. 69486970
Mould Testing Technician (NAT10913005)
Licensed Builder NSW 392154C (Supervisor, Kitchen, Bathroom & Laundry and Renovation)
Carpentry Licence
AAA Mould Removal is an IICRC Certified Firm. Michael is also completing a double degree in Medical Science and Environmental Science at Macquarie University.
Worried About Mould or Water Damage?
Call AAA Mould Removal on 1300 739 783 or contact us online. We will find the moisture, remove the mould properly and dry your home to IICRC standards.
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