Reviewed and updated 7 October 2026 by Nick Roth, Mould Remediation Specialist, AllAces Cleaning & Restoration
A mould inspection report should tell you three things: where the water is coming from, how far the mould has spread, and what it will take to fix. If yours only has photos of the patch you already found, it hasn’t done its job.
This guide walks through what an inspector actually checks, what belongs in the report, how to read the condition ratings, and when lab testing is worth paying for.
It’s written for homeowners, renters, buyers and property managers who want to know what they’re getting before they book.
Key takeaways
- The report is the product. A walk-through with no written findings isn't an inspection.
- Moisture first, mould second. Every good report names the water source, not just the growth.
- Look for a condition rating. AS-IICRC S520:2025 rates spaces as Condition 1, 2 or 3.
- Lab testing is often optional. NSW Health says testing is generally not needed when mould is visible.
- A building inspection isn't a mould inspection. Pre-purchase reports are mostly visual.
- Don't clean before the visit. Wiping the patch removes the evidence the inspector needs.
What happens during a mould inspection
Short answer: the inspector looks, measures, and traces the water. Sampling only comes in if the first three steps leave questions.
- History: when you first noticed it, recent leaks, smells, and who in the house is unwell.
- Visual check: every room, plus wet areas, ceilings, subfloor access and roof space where it’s safe to reach.
- Moisture mapping: moisture meters on walls, floors and joinery to find wet material behind the surface.
- Thermal imaging: cold spots that often line up with leaks, condensation or missing insulation.
- Humidity readings: relative humidity indoors and out, to see if the air itself is feeding growth.
- Sampling, if needed: surface swabs, tape lifts or air samples sent to a laboratory.
- Written report: findings, photos, readings, a condition rating and a recommended scope.
Mould inspection methods compared
| Method | What it finds | Limits |
|---|---|---|
| Visual inspection | Visible growth, staining, water marks, damaged finishes | Misses anything inside walls, ceilings or under floors |
| Moisture meter | Wet material behind paint, tiles and timber | Shows moisture, not mould itself |
| Thermal imaging camera | Temperature patterns that point to leaks and condensation | Needs a temperature difference to work well |
| Hygrometer | Indoor relative humidity and dew point | A snapshot of one day, not the whole season |
| Surface swab or tape lift | What type of mould is on a surface | Only tells you about the spot sampled |
| Air sampling | Airborne spore levels compared with an outdoor control | Results swing with weather, activity and timing |
What a good mould inspection report includes
Short answer: enough detail that a different contractor could quote the job from it.
- Property details and scope: which areas were inspected, and which weren't and why
- Moisture readings with locations, ideally marked on a floor plan or photo
- Photos of growth, staining and the likely water source
- The cause: leak, condensation, rising damp, ventilation or a past flood
- A condition rating for each affected area (see below)
- Lab results, if samples were taken, with a plain-English summary
- A recommended scope: what should be removed, cleaned, dried and repaired
- Clearance criteria: how you'll know the job is finished
Reading the condition rating
Under the IICRC S520 standard, adopted in Australia as AS-IICRC S520:2025, each area gets one of three ratings. It’s the most useful line in the report, because it decides what happens next.
Condition 1: normal
Normal fungal ecology. Spores are present at levels you'd expect in a similar clean space. No remediation needed.
Condition 2: settled spores
Spores have settled from a nearby growth area, with perhaps traces of growth. Usually needs cleaning, not removal.
Condition 3: actual growth
Active or dormant growth, visible or hidden. Needs containment and remediation, then a check that it's back to Condition 1.
Do you need air or swab testing?
Short answer: usually not if you can see the mould. NSW Health says that since most mould is visible, testing in the home is generally not necessary.
Testing earns its cost in a few situations:
- You can smell it but can't find it, and suspect it's inside a wall or ceiling
- Someone in the house has unexplained symptoms
- There's a dispute with a landlord, builder, buyer or insurer
- You need proof the job is finished, known as clearance or post-remediation verification
If you do test, the sample needs a comparison. Air results mean little without an outdoor control taken at the same time.
Our mould inspection and testing service covers on-site readings first, with swabs, air sampling and lab analysis added only when they’ll change the answer.
Pre-purchase and rental inspections
Short answer: a standard building inspection is a visual check of the building’s condition. It may flag damp or visible mould, but it isn’t designed to map moisture inside walls or sample the air.
If the house has a musty smell, fresh paint in odd places, or a history of leaks, a separate mould inspection before you sign is cheap insurance. The NSW Government’s guide to inspecting a property before you buy covers the other reports worth ordering.
- Buyers: book it inside the cooling-off or finance period, and ask for the report in writing
- Renters: photos plus a moisture-backed report make a repair request much harder to dismiss
- Landlords and property managers: a report that names the cause shows whether it's a building fault or a ventilation issue
- Strata: it helps settle whether the source is in a lot or common property
Renting in Queensland? Our guide to black mould in rental properties explains who’s responsible.
Which type of inspection do you need?
| Type | Best for | What you get | Watch out for |
|---|---|---|---|
| Pre-purchase building inspection | Buying any property | A visual report on the building overall | Mould is a side note, not the focus |
| Visual mould inspection with moisture mapping | Most homes with a visible problem | Cause, extent, condition rating and scope | Hidden growth is inferred from readings |
| Inspection plus lab sampling | Hidden mould, health concerns, disputes | The above plus species and spore data | Adds cost and a wait for results |
| Independent hygienist assessment | Workplaces, schools, legal or insurance disputes | Assessor separate from the remover | Overkill for a single bathroom |
Benefits of getting it inspected properly
You fix the cause, not the stain
Moisture mapping finds the leak or condensation that keeps bringing it back.
Quotes you can compare
A written scope means every contractor is pricing the same job.
Evidence that holds up
Readings and photos are what insurers, landlords and tribunals ask for.
No paying for what you don't need
A good inspector tells you when the answer is a small DIY clean.
Safety before and during the inspection
Short answer: leave it alone, close it off, and keep vulnerable people away until it’s been assessed.
- Don't clean or paint over it first. You'll spread spores and remove the evidence.
- Close the door and turn off fans or air conditioning that moves air through the room.
- Keep children, pets and anyone with asthma out of the affected area.
- Know the one square metre line. WorkSafe Queensland says areas of about one square metre or more should be handled by professionals.
Red flags in an inspection report
- No moisture readings at all
- No cause named, just “mould present”
- Lab testing sold as essential when the mould is plainly visible
- A remediation price on the same page with no scope behind it
- Areas marked “not inspected” with no reason given
Choosing who does the work after the report? Our guide on how to choose a mould remediation company covers the checks worth making.
What an inspection costs
Price depends on property size, access, and whether lab samples are taken. Visual inspections with moisture mapping sit at the lower end; every lab sample adds to it.
Our mould removal cost guide explains what moves the price for inspections and the work that follows.
Why people book AllAces for inspections
35+ years on the tools
Restoration work across three states, including major flood events in Queensland, NSW and Victoria.
IICRC Certified Firm
Inspections and reports written to AS-IICRC S520:2025.
Readings on every visit
Moisture and humidity readings are standard, not an upgrade.
Testing only when it helps
Swabs, air sampling and lab analysis are added when they'll change the answer.
A report you can use
Extent, risk level, cause and a recommended strategy, in writing.
Same team fixes it
If remediation is needed, the people who diagnosed it carry it out.
FAQs
Should I clean the mould before the inspector arrives?
No. Cleaning spreads spores and removes the evidence the inspector needs to judge how bad it is and where it came from. Close the room off and leave it as it is.
Can an inspector find mould behind walls without opening them?
Often, yes. Moisture meters and thermal imaging show where material is wet, which is where hidden mould grows. Confirming it may need a small inspection hole or a cavity sample.
Will a building and pest inspection pick up mould?
Only what’s visible on the day. A building inspection looks at the whole property, so it isn’t set up to map moisture inside walls or sample the air.
What does Condition 3 mean on my report?
It means actual mould growth, active or dormant, visible or hidden. That area needs containment and remediation, then a check that it’s back to normal.
The bottom line
A mould inspection is only as good as its report. Ask for moisture readings, a named cause, a condition rating and a written scope, and skip lab tests unless they’ll change the decision.
If you’re on the east coast, book mould inspection and testing with AllAces. If the report shows growth, here’s how our mould removal and remediation team handles it.
This guide is reviewed every three to six months. Next review due January 2027.
About the author
Nick Roth, Mould Remediation Specialist, AllAces Cleaning & Restoration
Nick has been with AllAces for more than six years and is our most experienced mould remediation specialist. He completed Decon Systems’ Mould Remediation for Technicians course in August 2021. Technicians in every state we work in call on him for the hardest mould testing and remediation jobs, including work with specialised equipment such as Hydroxyl machines.
