Received your mould test results and overwhelmed by technical jargon, spore counts, and species names? Understanding what these results mean helps you make informed decisions about your home and health.
As IICRC-certified specialists who interpret test results daily, we’ll help you decode the common terms, understand what numbers mean, and determine appropriate next steps.
Types of Mould Testing
Air Sampling
What it measures: Airborne mould spore concentrations
How it’s done: Air pumped through collection device
Results show: Spore counts per cubic meter, species identified
Surface Sampling
What it measures: Mould growing on surfaces
Methods: Swab, tape lift, or bulk sample
Results show: Species present on specific surfaces
Understanding Your Report
Key Terms Explained
Spores/m³ (Spores per Cubic Meter):
- Concentration of mould spores in air
- Higher numbers = more contamination
- Compare indoor to outdoor baseline
CFU (Colony Forming Units):
- Number of viable (living) mould colonies
- Used in some laboratory reporting methods
Total Spore Count:
- Combined count of all mould types detected
- Gives overall contamination picture
Interpreting Spore Counts
General guidelines (not absolute rules):
- < 200 spores/m³: Typically normal background levels
- 200-1,000 spores/m³: May indicate problem if species composition different from outdoor
- 1,000-10,000 spores/m³: Moderate contamination, investigation warranted
- > 10,000 spores/m³: Significant contamination, remediation needed
Important: Numbers alone don’t tell full story. Species type and indoor/outdoor comparison matter more than raw numbers.
Indoor vs Outdoor Comparison
Why it matters:
- Some mould naturally present outdoors
- Indoor should be similar or lower than outdoor
- Different species indoors suggests growth inside
Red flags:
- Indoor counts significantly higher than outdoor
- Indoor species not found in outdoor sample
- Water-damage associated species present
Common Mould Species in Results
Species You Might See
Cladosporium:
- Most common indoor and outdoor
- Often on fabrics, wood, painted surfaces
- Usually not concerning unless very high levels
Aspergillus:
- Common allergen
- Various species with different characteristics
- Some species more concerning than others
Penicillium:
- Often associated with water damage
- Blue-green appearance
- Spreads quickly
Stachybotrys (“black mould”):
- Associated with chronic water damage
- Requires constant moisture
- Presence indicates significant water problem
For detailed information on these species, see our article on types of mould in NSW homes.
What Results Mean for You
If Results Show Elevated Levels
Immediate steps:
- Identify and fix moisture source
- Schedule professional remediation if extensive
- Consider health impacts if family members symptomatic
Don’t panic but take seriously:
- Elevated levels indicate problem needing attention
- Professional remediation prevents worsening
- Addressing now prevents expensive future repairs
If Results Are Normal
Possible explanations:
- No significant mould problem
- Mould is hidden (not releasing spores during sampling)
- Sampling timing or location didn’t capture problem area
If you still have concerns:
- Persistent musty odor suggests hidden mould
- Consider additional sampling in different locations
- Visual inspection may reveal issues not captured by air sampling
Next Steps Based on Results
For Moderate Contamination
- Identify moisture source
- Fix water intrusion, leaks, ventilation
- Assess if DIY or professional remediation appropriate
- Implement prevention measures
For Significant Contamination
- Professional remediation essential
- IICRC-certified specialists following S520 Standard
- Address moisture causes simultaneously
- Post-remediation verification testing
Questions to Ask Your Assessor
- How do my results compare to typical homes?
- What moisture sources might explain these results?
- Is remediation necessary or can I address through prevention?
- What’s the recommended timeline for action?
- Should I retest after remediation?
Limitations of Mould Testing
Testing cannot:
- Determine health impacts (that’s for medical professionals)
- Guarantee to find all mould (depends on sampling locations)
- Replace thorough visual inspection
- Predict future mould growth
Testing is most valuable when:
- Combined with thorough inspection
- Used to verify successful remediation
- Documenting for insurance or legal purposes
- Investigating health concerns
Central Coast & Newcastle Considerations
Coastal baseline typically higher:
- High ambient humidity means more outdoor spores
- Comparison to outdoor sample especially important
- Certain species more common in coastal environments
Conclusion
Mould test results provide valuable information when interpreted correctly. Rather than focusing solely on numbers, consider species types, indoor/outdoor comparisons, and physical inspection findings together.
If your results show elevated levels or concerning species, don’t delay addressing the problem. Contact MouldSafe for expert interpretation of results and appropriate remediation planning.
Need help understanding your mould test results? Contact MouldSafe for expert interpretation and guidance.