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Planter Box Leak Mould Removal and Structural Drying in a Lane Cove Unit
By Michael Nguyen | Indoor Environmental Professional (IEP) | IICRC WRT, AMRT, ASD (69486970) | Mould Testing Technician (NAT10913005) | Licensed Builder NSW 392154C (Supervisor, KBL+RENO)
Water does not always come in through the roof or the plumbing. In this Lane Cove apartment, the waterproofing in an outdoor planter box had failed, and water from the soil was soaking through the wall into the lounge room. By the time we were called, the paint was flaking along the bottom of the wall and mould was growing behind and above the skirting.
Here is how we removed the mould, set up HEPA air filtration and dried the wall with a targeted heat drying system, following IICRC standards.
What We Found
The lounge room wall backed onto a planter box on the outside of the building. Planter boxes hold wet soil against the wall all year round, so once the waterproofing membrane fails, water seeps into the masonry every time the plants are watered or it rains.
Inside, the paint had bubbled and flaked along the base of the wall, the skirting boards were damp, and there was mould on the wall surface. Moisture readings confirmed the wall was wet well beyond the visible damage. If you are seeing similar signs, a mould and moisture inspection is the best place to start.
Our Mould Remediation and Drying Process
Step 1: Removing Damaged Paint and Skirting
We cleaned off the damaged, flaking paint from the affected section of wall and removed the skirting boards. Taking off the skirting lets us see and treat the bottom of the wall, where water and mould collect, and stops the timber trapping moisture against the wall during drying.
Step 2: Mould Clean-Up and HEPA Air Filtration
The mould-affected surfaces were cleaned using the HEPA sandwich method (HEPA vacuum, damp wipe, HEPA vacuum again), following the IICRC S520 Standard for professional mould remediation. We ran HEPA air filtration in the room throughout the job to capture airborne mould spores and dust, which matters in an apartment where people are still living in the home.
Step 3: Drymatic Thermal Targeted Drying
Masonry walls hold water deep inside, so air movers alone are slow. We set up the Drymatic thermal targeted drying system: a heat unit sends warm air through ducting into insulated drying mats laid along the base of the wall, with a booster fan to keep the airflow moving. Heating the wall drives moisture out of the masonry to the surface, where it can be removed, and targeting the heat means we dry only the wet section rather than heating the whole apartment.
[PHOTO: Drymatic heat unit and drying mats along the base of the lounge room wall]
How Long It Took and What It Cost
The drying took about 3 weeks. We monitored moisture readings at the same points on each visit and only signed the wall off once it reached its drying goal. Repainting or refitting skirting too early is one of the most common reasons mould comes back.
The total cost of this job was about $6,000, covering mould removal, skirting removal, HEPA air filtration, the Drymatic drying system and moisture monitoring over the 3 weeks. Every job is different: the price depends mainly on how much of the wall is wet, what it is made of and how long it takes to dry.
Fix the Planter Box First
Drying and mould removal only last if the water source is fixed. The planter box needs to be emptied and its waterproofing repaired or replaced, otherwise the wall will get wet again. In apartment buildings, planter boxes can be common property, so the owners corporation may be responsible for the repair. Our report documents the cause so the owner, strata manager and insurer can sort out who fixes what.
Signs a Planter Box Is Leaking Into Your Home
Flaking or bubbling paint on an inside wall behind an outdoor planter or garden bed
Damp, swollen or stained skirting boards
Tide marks or white salt deposits low on the wall
A musty smell in the room
Mould that comes back after cleaning
Mould Removal and Water Damage Drying in Lane Cove
AAA Mould Removal provides mould remediation and water damage restoration in Lane Cove and across the Lower North Shore. For another wall drying job, see our bathroom leak and targeted heat drying job in Campsie. Once drying is complete, we can carry out post-remediation mould testing to confirm the area is clean.
Frequently Asked Questions
Can a planter box cause mould inside my home?
Yes. If the planter box waterproofing fails, water from the soil soaks through the wall and causes damp, flaking paint and mould on the inside.
Why remove the skirting boards?
Water and mould collect at the bottom of the wall. Removing the skirting lets us clean and dry that area properly, and stops the timber holding moisture against the wall.
What does HEPA air filtration do?
A HEPA air scrubber filters the air in the room, capturing mould spores and fine dust released during the work so they don't spread through the home.
How long does it take to dry a wet masonry wall?
It depends on how wet the wall is and what it is made of. This wall took about 3 weeks with targeted heat drying.
How much does mould removal and structural drying cost?
This job cost about $6,000. Smaller jobs cost less and larger ones more, depending on the area affected and the drying time. We give a written quote after inspecting.
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
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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