Internal Defects & Finishes

Mould & Moisture Damage

Mould growth in Class 2 buildings is a significant health concern and is increasingly the subject of strata disputes and litigation. Mould requires moisture, a food source (building materials) and warmth to grow. In apartment buildings, the primary moisture sources driving mould are water ingress from external envelope defects, condensation from inadequate insulation and ventilation, and moisture from internal sources such as bathrooms and kitchens without adequate exhaust. Visible mould is the final indicator — by the time it appears on surfaces, the underlying building materials are likely already significantly contaminated.

Common Signs

Visible mould growth on walls, ceilings and around windows
Musty or earthy smell in affected rooms
Condensation on windows and cold external walls
Paint peeling and blistering in wet or cold areas
Black staining in grout joints in bathrooms
Residents experiencing respiratory symptoms, allergies or asthma
Discolouration of plasterboard near external walls

Common Causes

Water ingress from failed waterproofing, flashings or sealants
Inadequate exhaust ventilation in bathrooms, laundries and kitchens
Thermal bridging at cold external walls creating condensation surfaces
Absence of ceiling insulation causing condensation on ceiling plasterboard
Inadequate make-up air allowing humidity to build up in sealed apartments
Wet building materials from construction moisture not dried before enclosure
Failed or unvented dryer exhausting moisture into the building

Risk of Neglect

Health risks including respiratory illness, allergic reactions and asthma from mould spore exposure
Progressive contamination of building materials requiring full strip-out and replacement
Structural damage to timber framing and plasterboard from prolonged mould
Significant strata liability for health impacts on occupants
Disputes and potential litigation if the moisture source is common property
Difficulty in selling or renting affected lots
Insurance claims and dispute resolution costs

Inspection Requirements

Download Inspection Checklist

Identify all visible mould growth and map locations relative to potential moisture sources.
Measure relative humidity in affected rooms — sustained RH above 70% supports mould growth.
Use a moisture meter to assess moisture content of affected walls, ceilings and floors.
Inspect the external envelope at locations corresponding to internal mould — check for waterproofing, flashing or sealant failure.
Inspect exhaust ventilation outlets for blockage and confirm they exhaust directly outside the building.
Assess the insulation levels in external walls and ceilings adjacent to mould zones.
Engage a mould assessor to conduct spore sampling where health impacts are reported.
Confirm whether the moisture source is external ingress or internal condensation before specifying treatment.

Start Inspection Checklist

Create a project inspection record, add defect locations, upload photos, and save notes for scope writing.

Typical Repair Methodology

01.Address the moisture source first — mould treatment without source rectification will result in recurrence.
02.Engage a licensed mould remediation contractor where mould coverage exceeds 1 sqm or where health impacts are reported.
03.Establish containment and negative pressure in affected areas before mould removal commences.
04.Remove all mould-affected plasterboard, insulation and framing that cannot be effectively cleaned.
05.Apply a biocidal mould treatment to all affected and adjacent surfaces, allowing adequate dwell time.
06.HEPA vacuum all treated surfaces and dispose of contaminated materials as regulated waste.
07.Allow the area to dry fully before re-lining.
08.Re-line with moisture-resistant plasterboard in high-risk zones.
09.Install additional mechanical ventilation where condensation is a recurring source.
10.Apply a mould-resistant paint system throughout the remediated areas.
11.Conduct a post-remediation verification inspection before reoccupation.

Related Repair Systems

Mould remediation and containment systems
Moisture source rectification systems
Mechanical ventilation upgrade systems
Mould-resistant lining and coating systems
Post-remediation verification and air quality testing

Open Repair Systems →