Mould testing: what it tells you and when it is worth doing

Testing is not always necessary. When it is, it is the difference between an opinion and a documented position.

Air versus surface sampling

Air sampling measures what occupants are breathing, compares indoor spore counts against an outdoor control, and detects hidden growth. Surface sampling identifies what a specific patch is. Air sampling answers the health question; surface sampling answers the identification question.

When testing is worth it

• Occupants are reporting symptoms and you need to establish whether the building is a factor.
• Insurance, WHS or accreditation requires documentation.
• A tenancy or strata dispute is live and evidence matters.
• There is a smell but nothing visible.
• You want a baseline so treatment can be measured rather than assumed.

When it is not

If mould is plainly visible, the source is known, and nobody needs documentation, testing can be an expensive way to confirm what you already know. In that case the money is better spent on treating it.