Understanding Different Types of Mould and What Your Testing Results Mean

Most people recognise mould when they see dark spots on walls or smell that distinctive musty odour. But surface cleaning is rarely enough - visible mould represents only part of the problem. Mould is a complex organism, and dealing with it effectively requires more than just a visual inspection.

Mould Assessment vs. Visual Inspection

While anyone can spot visible mould growth, microscopic spores colonise hidden areas within walls, ceiling cavities and ductwork. Professional assessments employ specialised tools like moisture meters and thermal cameras to detect hidden dampness and identify moisture sources. The key difference: systematic professional evaluation versus guesswork.

Different Types of Mould: Why Specifics Matter

Not all mould presents equal risk. Stachybotrys chartarum ("black mould") is particularly concerning due to mycotoxin production. Other common types include Aspergillus and Penicillium, which trigger allergic reactions. Identifying specific genera informs remediation protocols - treatment for Cladosporium differs substantially from addressing Stachybotrys colonies.

Professional Testing Methods

Our laboratory uses three primary testing approaches:

• Air Sampling: Specialised pumps collect airborne spores for laboratory analysis, compared against outdoor control samples
• Surface Sampling: Tape lifts or swabs identify specific mould species on affected surfaces
• Bulk Sampling: Material pieces are analysed to determine colonisation depth, particularly useful for porous materials

Decoding Laboratory Reports

Our reports typically include:

• Mould genera identified in samples
• Spore count/concentration assessment
• Guidance and interpretation sections for understanding your results

It's important to understand that zero mould is unrealistic - mould spores are naturally present everywhere. The goal is to determine if the indoor environment has an unnaturally high concentration compared to outdoor conditions.

New Zealand Context

New Zealand's temperate maritime climate - with high humidity and temperature fluctuations - creates favourable mould conditions year-round. From Auckland's subtropical humidity to Wellington's notorious dampness, understanding local moisture challenges is essential for effective mould management.