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Condition 2 Mould Explained: What It Means and How We Clean It
By Michael Nguyen | Indoor Environmental Professional (IEP) | IICRC WRT, AMRT, ASD (69486970) | Mould Testing Technician (NAT10913005) | Licensed Builder NSW 392154C (Supervisor, KBL+RENO)
When we inspect a home for mould, we don't just ask "is there mould?" We work out what condition each area is in. The IICRC S520 standard for professional mould remediation uses three conditions, and the one that applies decides how a room is cleaned.
The Three Mould Conditions in IICRC S520
Condition 1 (normal fungal ecology): the normal mix and level of mould spores you would expect in that environment. No remediation is needed.
Condition 2 (settled spores): an area contaminated with mould spores or fragments that have settled from a nearby Condition 3 area. There may be no visible growth, but the surfaces are not normal.
Condition 3 (actual growth): active or visible mould growth, including growth hidden inside building materials.
The goal of mould remediation is to bring every affected area back to Condition 1.
Where Condition 2 Shows Up
Condition 2 is common in rooms next to a mouldy bathroom, wardrobe, ceiling or subfloor. Spores settle on furniture, skirting boards, door frames, shelving and contents. It can also be created during mould removal if the work area isn't contained, which is why we set up containment first.
How We Clean a Condition 2 Area
Containment where needed, so spores aren't spread into clean rooms
HEPA vacuuming of surfaces and contents
Damp wiping with a suitable cleaning solution
A second HEPA vacuum pass (a HEPA sandwich clean)
HEPA air filtration running during the work
Because Condition 2 is settled spores rather than growth, it usually doesn't need building materials removed. Condition 3 is different: porous materials with mould growth, such as plasterboard, often need to be removed.
Watch: Condition 2 Surface Cleans From Our Recent Jobs
These short clips are from Condition 2 surface cleans on recent jobs in Willoughby, Mosman and Rose Bay.
How Do You Know If a Room Is Condition 2?
Often you can't tell by looking. Common signs are a musty smell, dust settling on surfaces near a known mould problem, or a room that always feels stuffy. A professional inspection, with air sampling and surface testing where needed, can confirm the condition of each area.
Our mould inspection and quote are free. If you need a professional moisture and mould report, for example for a landlord, strata or insurer, reports start from $500 + GST. Learn more about our mould removal service.
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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
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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