Identifying mould · 1 min read
How to identify mould in a commercial building
What to look for, where to look, and why the absence of visible growth does not mean the absence of a problem.
Visible mould is the easy part. It appears as spots, patches or fuzzy growth in black, green, grey, white or pink, usually on a surface that has been damp. The harder part is the mould you cannot see — behind linings, above ceilings, inside ductwork and, most importantly, in the air.
Where to look
- Wet areas: bathrooms, kitchens, laundries, plant rooms.
- Corners and junctions: where walls meet floors and ceilings, behind furniture against external walls.
- Above and behind: ceiling tiles, joinery, wall linings near known leaks.
- Mechanical: supply and return grilles, filters, condensate trays.
- Below grade: basements, car parks, lower floors after heavy rain.
The signs that are not mould
A musty smell. Condensation on windows. Staining on ceilings. Peeling paint. Warped skirting. None of these is mould — all of them are the conditions that produce it.
When looking is not enough
A clean-looking room can carry a high airborne mould count. If people are reporting symptoms, or there has been a water event, an assessment with readings will tell you what a walkthrough cannot.