Author: Rhys Brenton

I was called to this job to give advice for the removal of mould in the bathroom. The only health problems reported were from the occupant’s previous attempts to remove the mould using bleach.

Symptoms including headaches, dizziness, nausea, sore eyes, prolonged difficulty breathing during and after the cleaning process (go figure!). The owner could not bare putting himself through that exposure again. (good choice)

Bathroom condensation causing mould

The bathroom ceiling was black with evenly spread mould. Two small vents were located above the shower, one of which was mechanical and the other just an open vent into the roof cavity. The tiling and grout appeared free from mould staining and the plumbing and drainage all appeared of good integrity.

During inspection of the roof cavity, it was found that the mechanical vent did vent externally, however it was later revealed that it was not used by the occupants during bathroom use because it was ineffective and the basic open vent was covered over with thick insulation batts.

Mould was not visually present on the roof cavity side of the ceiling gyprock cladding, suggesting that the water damage was contained to the internal surfaces and this also reiterating the consequences of condensation.

The obvious conclusion in this case was seriously inadequate ventilation and therefore prolonged condensation issues with subsequent mould growth.

Recommendations included:

  • Remediation process to remove the effected gyprock ceiling and to treat all the other surfaces, for settled mould spores.
  • Installation of adequate, high volume mechanical ventilation and an encouraged change in behavioural patterns to ensure the habitual use of mechanical ventilation during bathroom use.

If you have any concerns, please contact a qualified Building Biologist – you can find one close to you here.

Always look for the ASBB logo – the ASBB checks the qualifications of all Building Biologist.