Mold inspection — and who is paying the inspector

Interview before instruments

Any inspector worth the fee starts by asking about the building’s history — past leaks, renovation dates, which rooms feel damp, whether it is seasonal, how the bathroom and kitchen are ventilated, and when the last roof or plumbing work happened. That narrative directs everything that follows.

Watch for: An inspector who walks in and starts pumping air samples without asking a single question about the building. Sampling without a hypothesis produces a number nobody can interpret, and it is the fastest route to a report that says very little at length.

Visual survey of the wet-prone assemblies

Under sinks and behind kick plates, around tub and shower surrounds, at window and door heads, ceiling below bathrooms, exterior wall bases, the attic sheathing, the crawl space, and anywhere water is delivered or discharged. Growth follows water, so the survey follows water.

Watch for: An inspection that never leaves the finished rooms. If nobody puts a head into the attic or the crawl space, half the plausible sources were not looked at.

Moisture readings, mapped rather than sampled

Pin and pinless meters read walls, floors, framing and subfloor. The useful output is a comparison: this wall against an equivalent dry wall in the same building, and a boundary showing where the wet area stops. That is what tells a remediator where to cut.

Watch for: A single reading with no dry-material comparison. Meter numbers mean little in isolation; the value is the difference between an affected area and an unaffected one of the same material.

Thermal imaging and borescope, used as pointers

An infrared camera shows temperature differences, which often correspond to evaporative cooling from damp material — it does not see mould. A borescope through a small drilled hole lets an inspector look inside a cavity without demolishing the wall.

Watch for: Thermal images presented as proof of mould. The camera detects thermal patterns, and a cold spot can equally be missing insulation, a stud, or a draught. Anything the camera flags should then be confirmed with a meter or a look inside.

Sampling — only where it will change something

Air sampling draws a volume of air onto a cassette read by a laboratory; surface sampling lifts material with tape or a swab. Samples answer narrow questions: is there growth in a cavity we cannot see, does this area compare differently to an unaffected area, is this stain biological at all.

Watch for: Sampling sold as the product. If the growth is visible and the source is known, the lab result usually does not change the scope of removal — extent and moisture do. Ask directly: what decision changes depending on this result?

A report that names the source

The deliverable should identify the moisture mechanism, the extent, the materials affected, and what needs doing — in language a contractor can price and you can argue from. Photographs, meter readings and locations, not adjectives.

Watch for: A report that is mostly boilerplate about mould in general with two site photos. You are paying for findings about your building, not a brochure with your address on the cover.

Handover to remediation — at arm’s length

The inspection scope becomes the remediation scope, and the contractor prices against it. Because the scope was written by someone who is not doing the removal, it is a scope you can put to more than one bidder on identical terms.

Watch for: An inspector who produces a finding and a same-day quote to fix it. That is one party writing both the diagnosis and the invoice, and the incentive runs one way.