Case Study: Investigating Unexplained Health Symptoms with ERMI Testing

 An example of FLIR thermography mapping a sub-surface moisture anomaly. The dark blue zones represent evaporative cooling (registering here down to 21.2°C), which creates the exact type of damp microclimate required for the ERMI Group 1 mould species identified in this case study.

When our client contacted us, reporting persistent health symptoms they believed were linked to their indoor environment, we were asked to move beyond speculation and identify what was actually happening inside the property.

Surface cleaning and visual inspections had already been attempted, yet the problem kept returning. This is a common pattern in moisture-related properties: the visible mould is only the symptom, not the source.

To understand the full picture, we needed environmental data—not assumptions.

Findings and Decision-Making

Following the physical inspection and subsequent laboratory analysis, the findings provided a clear, evidence-based picture of the property's indoor environment.

To move beyond surface observations, dust samples were collected from ten separate locations throughout the home and submitted for ERMI Testing (Environmental Relative Moldiness Index) analysis. This type of testing acts as a long-term biological record of the indoor environment, identifying mould species commonly associated with water-damaged buildings.

Laboratory Findings

The ERMI analysis returned a score of 42.7, indicating an elevated relative mould burden when compared with typical indoor environments.

In addition, the HERTSMI-2 score of 40.0 reflected a significantly increased presence of mould species commonly associated with chronic moisture and water-damaged building materials.

The laboratory analysis identified elevated concentrations of several Group 1 species associated with moisture-damaged environments, including:

• Cladosporium sphaerospermum

• Aspergillus fumigatus

• Eurotium amstelodami

• Aspergillus versicolor

• Trace levels of Stachybotrys chartarum

• 
  

These findings, when considered alongside the physical inspection, were consistent with long-term moisture-related conditions within the property rather than isolated surface contamination.

ERMI laboratory analysis identified elevated levels of mould species commonly associated with water-damaged indoor environments, including several Group 1 indicator species.

Correlation with Physical Inspection

While laboratory analysis provides biological evidence, identifying the source of moisture requires a physical investigation.

During our inspection, thermal imaging and moisture mapping identified chronic moisture intrusion affecting sections of the external walls and areas around deteriorating window seals. Elevated moisture readings confirmed that parts of the building envelope were retaining excessive moisture, creating conditions favourable for continued mould growth.

The laboratory findings and physical inspection results supported one another, allowing us to move from speculation to evidence-based conclusions.

Executive summary integrating laboratory analysis with physical inspection findings to provide an evidence-based assessment of the property's indoor environment.

A Real-World Indicator

While awaiting the laboratory results, the occupants hosted a visitor known to have a high sensitivity to mould. Shortly after arriving, the individual experienced symptoms that prompted concern regarding the indoor environment.

Although anecdotal observations cannot establish causation, they served as a practical indicator that further investigation was warranted. The subsequent inspection and laboratory analysis provided objective information that allowed informed decisions to be made.

Remediation and Monitoring Strategy

Despite the report recommending consideration of relocation, the occupants elected to remain in the property. As conditions moved into the drier summer months, the strategy focused on immediate remediation combined with long-term risk management.

Professional Remediation

A specialist remediation company was engaged to perform a comprehensive treatment programme using professional-grade mould remediation products and fogging techniques to reduce existing contamination.

Building Envelope Maintenance

The inspection identified moisture intrusion associated with porous exterior walls and deteriorating window seals. Corrective maintenance was recommended to address these defects before the return of the wetter winter season.

Verification Through Monitoring

Remediation is only one part of the process. Long-term success depends on confirming that the moisture source has been eliminated.

Comparative moisture measurements will be taken at the end of summer and again during winter to determine whether the building envelope repairs have successfully prevented moisture accumulation and reduced the risk of recurrence.

Key Takeaway

Remediation is only half the battle. Our protocol mandates follow-up testing and moisture mapping to ensure that building envelope repairs have successfully eliminated the source of the mould.

Before any remediation begins, we perform a comprehensive Property Inspection to identify these underlying moisture pathways, ensuring the root cause is resolved alongside the visible growth.

By combining physical building diagnostics with laboratory analysis, it is possible to identify not only the presence of moisture-related mould species, but also the conditions allowing them to persist. Lasting remediation depends on correcting those conditions and verifying that the building environment no longer supports mould growth.

Note: Where health concerns persist, we always advise clients to consult with a medical professional regarding potential exposure to mould-related compounds. Our role is to identify and resolve the environmental source of the problem, ensuring a safer living environment through empirical evidence and strategic maintenance.