Planning & Budget

Bathroom Ventilation and Mould Prevention in Melbourne Homes

VicWide Renovations Team
2025-11-07
Updated: November 29, 2025
6 min read

Mould thrives in poorly ventilated Melbourne bathrooms. This guide covers exhaust fan sizing, ducting best practices, natural ventilation tactics and moisture management to prevent recurring mould issues.

Bathroom Ventilation and Mould Prevention in Melbourne Homes

Exhaust Fan Sizing

Minimum 25L/s for standard bathrooms. Larger ensuites need 30-40L/s. Calculate: bathroom volume x 8 air changes/hour.

Ducting Requirements

Rigid ducting outperforms flexible. Shortest run to exterior. Avoid 90-degree bends. Terminate above roof or through wall with flap damper.

Natural Ventilation

Openable windows (600x600mm minimum) supplement mechanical exhaust. Cross-ventilation ideal but rare in bathrooms. Louvred doors aid airflow.

Moisture Management

Run exhaust 10-15 minutes post-shower (timer switch). Squeegee glass screens. Wipe condensation from tiles. Address leaks immediately.

Mould Remediation

Surface mould: vinegar or dilute bleach. Recurring mould indicates ventilation failure or waterproofing breach. Investigate before repainting.

Key Takeaways

  • Size exhaust to 8 air changes per hour
  • Rigid ducting prevents airflow loss
  • Timer switches ensure adequate post-shower extraction
  • Windows supplement mechanical ventilation
  • Recurring mould signals systemic failure

Ready to Start?

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