The short answer
A mould inspection looks for visible growth, hidden moisture and the conditions behind both. Readings from moisture meters, a thermal camera and a hygrometer are mapped room by room, so the report explains not just where mould is, but why it is there — the part that decides whether it comes back.
Who books this
- Owners with a musty smell, staining or growth that keeps returning
- Tenants and property managers who need an independent account of the cause
- Workplaces and strata committees investigating complaints
Methods used
- Visual survey
- Pin and non-invasive moisture meters
- Thermal imaging
- Relative humidity and dew point readings
Why the cause matters more than the patch
Mould needs moisture. Wiping or painting over a patch does nothing about the leak, the condensation or the blocked ventilation that let it grow, which is why the same corner of the same room keeps going black. The Queensland Government notes that mould that keeps coming back can be a sign of leaks or building problems rather than housekeeping.
An inspection is built around finding that moisture source. The usual suspects are a failed shower seal, a leaking roof flashing or gutter, a plumbing joint inside a wall, air-conditioning condensate, rising or penetrating damp at the base of a wall, and surface condensation on cold walls and windows.
What the instruments show (and what they don’t)
Moisture meters
Pin meters read moisture in timber and some building materials directly; non-invasive meters scan behind tiles and plasterboard without damage. Readings are compared against dry reference areas in the same building.
Thermal camera
A thermal image shows surface temperature, not water. A cool patch can be moisture evaporating, missing insulation or an air leak. Every thermal anomaly is checked with a meter before it goes in the report as damp.
Hygrometer
Relative humidity and surface temperature together give the dew point — whether a wall or ceiling is cold enough for condensation to form on it.
When an inspection needs samples as well
Plenty of inspections need no laboratory work: if growth is visible and the cause is clear, the report says so. Samples are worth adding when the question is whether there is hidden growth (air sampling), whether a stain is mould at all (surface sampling), or when a claim, dispute or sign-off needs results that someone else will scrutinise.
Example moisture map
Wall behind a shower, floor to 1.5 m · relative readings
Questions people ask
Is a mould inspection destructive?
No. Moisture meters, thermal imaging and air or surface samples are non-invasive. If a wall cavity needs opening to confirm a finding, that is recommended in the report and only done with the owner’s permission.
Will the inspection find the source of the moisture?
That is the main purpose. Where the source sits behind a wall or under a roof that cannot be reached safely, the report says where the readings point and which trade should investigate next.
Do I need air testing if I can already see mould?
Often not. The WHO guidelines on dampness and mould focus on finding and fixing persistent damp rather than measuring spores. Air sampling helps when growth is suspected but not visible, or when results are needed for a claim or dispute.
References
- [1]Mould and damp — Queensland Government
- [2]WHO guidelines for indoor air quality: dampness and mould (2009) — World Health Organization Regional Office for Europe
- [3]Condensation in buildings handbook — Australian Building Codes Board
Checked against these references on 2 November 2026.