A good mould test report tells you exactly which moulds are present, how much of each, what condition that puts the building in under the international IICRC S520 standard, and what needs to happen next. A poor one is a list of Latin names with no explanation. This article walks through a real Scaada NZ test report, line by line, so you know what each number means and what to do with it.
What is on your Scaada test report
Every sample analysed by our laboratory is reported against the same fixed set of fields. Below is an extract from a recent Scaada test report for a single surface sample — sample identifier S02, taken from a concrete wall:
An extract from a Scaada test report for a single surface sample. Every result appears in the same place on every report we produce.
Reading left to right, top to bottom:
- Sample identifier (S02: Concrete Wall) — the location reference. Cross-reference with the assessor's sampling map or photograph log to know exactly where on the property this sample was taken
- Analyst Notes — qualitative observations the analyst made under the microscope. In this example: a Celotape sample loaded with mineral debris and trace organics; among that debris field, hyphal networks, spores and reproductive structures of Acremonium. This text is the analyst's case-by-case interpretation and often tells you more than the numbers alone
- Debris Rating (1 — Trace) — a 1–4 scale describing how much non-fungal material is on the slide. High debris ratings can mask fungal structures and warrant a follow-up sample; low ratings mean the analyst could see clearly
- Mould Genera (highest to lowest) — the fungi identified, ordered by abundance. Here, Acremonium only. A multi-genus result would list every genus in descending order of count
- Total Fs/cm² (11,520) — "fungal structures per square centimetre" of the sampled surface. This is the core quantitative measure for tape-lift samples. 11,520 is a high count consistent with active colonisation
- LOR Fs/cm² (64) — the Limit of Reporting. Below this count, the lab cannot confidently distinguish background from signal. Always check LOR before drawing conclusions from low-count results
- Ecological Condition Rating (3 — Active Growth) — the IICRC S520 condition rating, the single most important field on the report. Explained in detail below
- Microscopy Image — the actual image the analyst used to identify the genus, with the magnification noted (600x in this example). Every Scaada surface result includes one
Two sampling methods: surface and air
Mould assessments combine two distinct sampling techniques, and the units on your report tell you which one was used.
Surface sampling (tape lifts). A Celotape, Bio-Tape, or similar adhesive lift is pressed against a building surface and analysed under microscopy. Results are reported as Fs/cm² — structures per square centimetre. Surface samples are the only way to confirm whether mould is actively growing on a substrate (versus settled from elsewhere): microscopy can directly observe hyphae, conidiophores and propagules, which together indicate colonisation, not just deposition. Taking one is straightforward, and our tape lift instruction sheet (PDF) covers it in eight steps.
Air sampling (spore traps). A calibrated pump draws a known volume of air through a sticky collection cassette, which is then examined under microscopy. Results are reported as Fs/m³ — structures per cubic metre of air. Air samples tell you what is currently airborne, what is respirable, and how indoor counts compare to outdoor reference. They are the appropriate test when occupants report symptoms but no visible growth is present.
Most full assessments use both. The two outputs complement each other: surface samples answer "is mould growing there?" and air samples answer "what is the occupant breathing?".
The indoor-vs-outdoor comparison: the most important part of the report
A single indoor count means very little on its own. The only way to know whether an indoor figure is elevated is to compare it against an outdoor reference sample taken on the same day. For this reason, most assessors collect at least one outdoor sample — both to compare indoor air against the external baseline and to check which types of mould are present, including the water-damage taxa that point to a moisture source. A good report uses the outdoor sample as the reference point for every indoor result.
The outdoor reference sample, collected on a calibrated spore trap on the same day as the indoor samples — the external baseline every indoor figure is read against
Below is an indoor-versus-outdoor air sample summary from a real report — six locations from one property:
Air sample composition across six locations in a single property — outdoor reference at 364 fs/m³ versus indoor counts ranging from 806 to 6,760 fs/m³. This summary chart is part of every Scaada multi-sample report
Three things to read from a chart like this:
- The outdoor baseline — here 364 fs/m³. This is the natural fungal background for that property on the sampling day. Every indoor figure should be read as a multiple of this number
- The indoor multiples — the subfloor at 6,760 fs/m³ is roughly 18× the outdoor reference. The kitchen at 2,652 fs/m³ is roughly 7×. Even the lowest indoor reading (entry stairs, 806) is over 2× outdoor. Where indoor exceeds outdoor by a meaningful multiple, an indoor source is driving the difference
- The composition by genus — not just the totals, but the colour mix. The light-blue band (Aspergillus / Penicillium-like) dominates every indoor sample and is essentially absent outdoors. This change in the mix of moulds is the clearest sign that moisture-loving moulds are growing indoors, and it is exactly the pattern we describe in our NZ lab observations
The IICRC S520 condition rating — what each one means
The ANSI/IICRC S520 (2024) standard is the internationally recognised framework for classifying mould contamination in buildings. Every Scaada surface and area result is assigned one of three condition ratings. This is the field on your report that determines what action is required.
Condition 1 — Normal Fungal Ecology
Spore counts are typical of a healthy indoor environment without water damage or humidity issues. Surface samples show low counts of common genera without active growth indicators (no hyphae, no spore-bearing structures). Air samples are consistent with or below outdoor levels. No remediation is required. This is the target condition for any building and the benchmark a Post-Remediation Verification confirms.
Condition 2 — Settled Spores
Elevated spore levels are present on surfaces, but microscopy shows settled spores rather than active growth — the contamination originated elsewhere (another room, the HVAC system, outdoor intrusion, or disturbance of an established colony nearby). The surface itself is not the source. Condition 2 areas typically need professional cleaning and an investigation of where the spores are coming from. They do not need full containment remediation, but they should not be ignored: a Condition 2 result means the spores are coming from a source elsewhere that still needs to be found.
Condition 3 — Active Growth
Confirmed mould colonisation with active growth on the substrate — hyphae, conidiophores, propagules visible under microscopy, and often visible growth on the surface. The example earlier in this article (sample S02, Acremonium, 11,520 fs/cm²) is a clear Condition 3 finding. This is the most serious rating and requires professional remediation by an IICRC-certified contractor with appropriate containment, HEPA filtration, removal of contaminated porous materials, and a Post-Remediation Verification at the end. Mould damage to porous materials (plasterboard, carpet, soft furnishings) is permanent — the fungal enzymes break down the substrate — so cleaning in place is not an option and removal is the usual scope.
What to do with your results
- All samples Condition 1: Your property has normal fungal ecology. No action required beyond maintaining good ventilation and managing humidity
- Condition 2 areas present: Investigate the source of the spore load. Improve ventilation, address any moisture issues, professionally clean affected surfaces. Re-test afterwards to confirm the problem is fixed
- Condition 3 areas present: Engage an IICRC-certified remediation contractor (WRT and AMRT credentials) and confirm the scope includes containment, HEPA, porous-material removal, and a PRV. The IICRC global locator at iicrc.org/iicrcgloballocator lists certified professionals. Independent sampling for the PRV confirms the job is finished and gives you (and any insurer) independent evidence that it worked
- Elevated Asp/Pen indoors but no Condition 3: Look at ventilation and humidity rather than hunting for visible mould. This pattern usually points to a problem with how the building is ventilated or heated. See our notes on modern NZ build ventilation patterns
- Hydrophilic genera identified (Stachybotrys, Chaetomium): Find and fix the moisture source before remediation begins. These genera require sustained, heavy moisture — remediation without source repair will see them return
And whatever the report says, it is worth pausing before reaching for the bleach bottle — the reasons are set out in why bleach (and vinegar) don't kill mould.