Townhouse Development — Parramatta NSW

The Situation

The homeowners had been dealing with recurring black mould in their master bedroom, ensuite, and wardrobe for three years. Each year, they’d clean it off — and each winter, it came back. A building inspector found no leak or structural issue. The problem was purely moisture in the air.

Their home was a well-built 2010 townhouse — airtight and energy-efficient, but without any mechanical ventilation. Bathroom exhaust fans were the only extraction — and they weren’t running consistently enough to make a difference to the overall indoor humidity level.

Our Approach

We recommended the combined MVHR + ducted dehumidification solution — appropriate for a coastal home in Wollongong’s climate, where extended summer humidity regularly pushes indoor conditions to over 80% RH even in well-ventilated spaces.

The MVHR system was retrofitted through the existing ceiling cavity over two days. The dehumidifier was installed in the roof space and connected via short duct runs to three high-humidity zones: the master suite, ensuite, and laundry corridor. The whole installation was completed with two small access hatches — no damage to lining or painting required.

The Outcome

Within the first four weeks, the homeowners noticed condensation on windows had stopped. By the end of the first winter season, there was no mould recurrence. Indoor humidity — previously regularly exceeding 75% — now holds between 49–54% year-round, even during Wollongong’s humid summer months.