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Mould Remediation Standards

IICRC S520 containment, HEPA filtration, and post-remediation verification protocols

≥0.03 PaContainment Pressure
99.97%HEPA Efficiency
1,000+Mould Species (AUS)
IICRC S520Standard

Mould Remediation Standards

Professional mould remediation follows IICRC S520 standards[10], requiring negative-pressure containment at ≥0.03 Pa, HEPA-filtered air scrubbing, and antimicrobial treatment of affected materials. Mould can begin growing within 24–48 hours when relative humidity exceeds 60%. The World Health Organisation[10] links indoor mould exposure to respiratory illness in 21% of asthma cases. Australian remediation must address both visible mould and the underlying moisture source.

Technical Standards & Science

Mould remediation is governed by IICRC S520 — Standard for Professional Mould Remediation[10]. Unlike surface cleaning, professional remediation addresses the root cause (moisture), contains the contamination, and verifies successful treatment.

The Remediation Process

  • Assessment — Qualified assessors identify mould species, contamination extent, and moisture source using air sampling, surface sampling, and moisture mapping.
  • Containment — Affected areas are sealed with polyethylene sheeting and negative air pressure (≥0.03 Pa) to prevent cross-contamination to unaffected areas.
  • HEPA Filtration — Air scrubbers with HEPA filters (99.97% efficiency at 0.3μm) run continuously to capture airborne spores during remediation.
  • Removal — All porous materials with mould penetration (drywall, carpet, insulation) are removed and disposed of as contaminated waste.
  • Treatment — Non-porous and semi-porous surfaces are treated with registered antimicrobial agents and physically cleaned.
  • Verification — Post-remediation air testing confirms spore counts return to normal background levels before containment is removed.
Why DIY Mould Removal FailsSpraying bleach on visible mould only kills surface growth — it does not address root systems (hyphae) penetrating porous materials or airborne spores throughout the property. Without containment, disturbing mould colonies spreads millions of spores into the air, potentially contaminating previously clean areas.

Common Australian Mould Species

Over 1,000 mould species are common in Australian buildings[10]. The three most prevalent genera — Aspergillus, Penicillium, and Cladosporium — represent approximately 80% of indoor fungal ecology. Some species produce mycotoxins (toxic metabolites) that pose serious health risks even at low concentrations.

Legal & Insurance Framework

Landlord and Tenant Obligations

Under Australian residential tenancy legislation, landlords must maintain rental properties in a reasonable state of repair, including addressing mould caused by structural defects or inadequate ventilation. Tenants must maintain reasonable ventilation and report mould promptly. Failure by either party can result in tribunal orders for remediation or compensation.

Work Health and Safety (WHS) Act

Commercial property owners and employers have duties under WHS legislation to maintain safe workplaces free from biological hazards including mould. Employees exposed to mould may be entitled to workers compensation claims.

Strata and Body CorporateIn strata properties, responsibility for mould remediation depends on whether the moisture source is within the lot (owner responsibility) or common property (body corporate responsibility). The Strata Schemes Management Act 2015 (NSW) and equivalent legislation in other states governs this distinction.

Insurance Coverage for Mould

Most Australian insurance policies cover mould remediation when it results from a sudden, insured event (e.g., burst pipe, storm damage). Gradual mould from poor maintenance, condensation, or rising damp is typically excluded. Check your PDS for specific terms.

Why Choose a Vetted Contractor?

Mould Remediation: Vetted vs Unvetted Contractors

NRPG-Vetted Contractor
  • IICRC S520 certified with containment and HEPA protocols
  • Pre- and post-remediation air testing for verification
  • Identifies and resolves the moisture source — not just symptoms
  • Registered antimicrobial agents used per manufacturer specifications
  • Detailed remediation report for insurance and legal records
  • Warranty on workmanship with post-treatment monitoring
Unvetted Contractor
  • Surface-only treatment — bleach kills surface mould but not root systems
  • No containment — disturbing mould spreads spores to clean areas
  • No moisture source investigation — mould returns within weeks
  • Unregistered chemicals that may not be effective or safe
  • No documentation — no proof of remediation for resale or insurance
  • No verification testing — no way to confirm remediation was successful

Frequently Asked Questions

How long does professional mould remediation take?

Small-scale remediation (single room, <3m²) typically takes 1–3 days. Medium jobs (multiple rooms or wall cavities) take 3–5 days. Large-scale remediation with extensive contamination can take 1–2 weeks. Post-remediation verification adds 1–2 days for laboratory results.

Is mould dangerous to health?

Yes. The World Health Organisation identifies indoor mould exposure as a cause of respiratory symptoms, asthma exacerbation, and allergic reactions. Some mould species produce mycotoxins that can cause more serious health effects. Children, elderly people, and those with respiratory conditions are particularly vulnerable.

What causes mould in Australian homes?

The most common causes are water leaks (burst pipes, roof leaks), poor ventilation (especially in bathrooms and laundries), condensation on cold surfaces, flood damage, and rising damp. Australia's humid climate zones (particularly coastal QLD, NSW, and northern regions) are naturally prone to mould growth.

Can I remove mould myself?

Small areas of surface mould (<1m²) on hard, non-porous surfaces can be cleaned with appropriate products. However, any mould affecting porous materials, wall cavities, HVAC systems, or areas larger than 1m² should be professionally remediated to prevent cross-contamination and ensure complete removal.

Does insurance cover mould removal in Australia?

Insurance typically covers mould remediation when caused by a sudden, insured event such as a burst pipe or storm damage. Pre-existing mould, gradual deterioration, poor maintenance, and condensation-related mould are generally excluded. Always check your Product Disclosure Statement for specific terms.

How do I prevent mould returning after remediation?

Maintain indoor relative humidity below 60% using ventilation and dehumidification. Fix all water leaks promptly. Ensure adequate ventilation in bathrooms, laundries, and kitchens with exhaust fans. Monitor moisture levels in high-risk areas. Address condensation by improving insulation on cold surfaces.

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IICRC S520 containment, HEPA filtration, and post-remediation verification protocols

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