You’ve noticed something growing on your wall, but it’s not black — it’s green, or white, or even pink. So what type of mould is it, and does it matter? The truth is, Australian homes can harbour dozens of different mould species, each with distinct characteristics, health risks, and removal requirements. Understanding what you’re dealing with is the first step toward protecting your home and family.
The Most Common Mould Species in Australian Homes
Australia’s varied climate zones — from tropical Queensland to cool, humid Tasmania — create conditions suitable for many mould species. The most frequently encountered include Aspergillus (common in dust and HVAC systems), Cladosporium (often found on fabrics and wood), Penicillium (blue-green mould on food and building materials), Stachybotrys (black mould), and Alternaria (dark-coloured, found in damp areas). Each species behaves differently and poses unique health concerns.
If you need help identifying what’s growing in your home, bathroom mould removal can target the specific areas where mould commonly takes hold, particularly in wet rooms.
Identifying Mould by Colour
While colour alone cannot definitively identify a mould species, it provides useful initial clues. Black mould is often Stachybotrys or Aspergillus niger. Green mould typically indicates Aspergillus, Cladosporium, or Penicillium. White mould can be early-stage growth of several species or sometimes confused with efflorescence (mineral deposits). Pink growth in bathrooms is usually the bacterium Serratia marcescens. For a deeper dive into visual identification, see our guide on how to identify mould.
Health Risks by Mould Type
Not all moulds are equally dangerous, but none should be ignored. Aspergillus species can cause aspergillosis in immunocompromised individuals. Stachybotrys produces mycotoxins linked to respiratory illness. Cladosporium is a potent allergen triggering hay fever and asthma. Penicillium can cause allergic reactions and respiratory infections. The key takeaway: any visible mould growth warrants attention and action.
Understanding what causes mould in houses helps explain why every mould species should be taken seriously, regardless of colour.
Where Different Moulds Grow
Mould species have preferences for specific surfaces and conditions. Stachybotrys prefers continuously wet cellulose-rich materials — gyprock, cardboard, timber. Aspergillus thrives in dust, HVAC ducts, and insulation. Cladosporium colonises fabrics, carpets, and wood surfaces. Penicillium favours food, wallpaper, and insulation. Alternaria appears around windows, showers, and below leaking sinks. Knowing where to look means catching problems early.
When to Get Professional Help
If mould covers more than one square metre, if it’s growing behind walls or in HVAC systems, or if occupants are experiencing health symptoms, professional mould removal is the safest course of action. Professionals use air sampling and surface testing to identify exact species and determine the appropriate remediation protocol. Use our mould removal cost calculator to understand potential costs before booking a consultation.
Prevention Is Universal
Regardless of species, all mould needs three things: moisture, a food source, and warmth. Control moisture through ventilation, dehumidification, and prompt leak repair, and you’ll create an environment hostile to every type of mould. Hobart homes benefit from particular attention to winter condensation management, given the city’s cold, damp conditions from May through September.
Need Professional Help?
If you’re dealing with mould in your home, don’t wait for it to get worse. Our Hobart-based mould removal specialists are ready to help you reclaim a safe, healthy living environment. Take our free mould risk assessment to understand the severity of your situation, or contact us directly for a no-obligation consultation.