What to Do About Mould (and When Not to DIY)

🌱 Mould isn’t a cleaning problem first — it’s a moisture problem, and knowing the difference matters.

 

Mould in the home is common, but it shouldn’t be ignored.

Left untreated, mould can spread, damage surfaces, and affect indoor air quality.
But just as importantly, not all mould situations should be treated the same way — and not all of them should be DIY’d.

This guide explains:

• What mould actually is
• Why identifying it matters
• When DIY cleaning is appropriate
• When professional help is the safer option

 

What Mould Is (and Why It Keeps Coming Back)

Mould is a type of fungus that grows where moisture, warmth, and poor ventilation exist.

Bathrooms, laundries, kitchens, basements, and water-damaged areas are common problem zones — not because they’re dirty, but because they stay damp.

If moisture isn’t addressed, mould will return no matter what cleaner is used.

 

There Are Many Types of Mould (Not Just “Black Mould”)

Homes can host many different types of mould, each behaving differently and affecting surfaces and people in different ways.

Common mould types found in homes include:

• Alternaria
• Aspergillus
• Aureobasidium
• Cladosporium
• Penicillium
• Fusarium
• Stachybotrys chartarum (often referred to as “black mould”)

Some moulds thrive in warm, humid spaces.
Others grow in cool areas or on water-damaged materials like carpet, drywall, timber, and insulation.

For a detailed breakdown of common mould types and where they are typically found, see:
👉 Mold Types Found in Homes – Mold Advisor
https://www.mold-advisor.com/mold-types.html

Understanding that mould varies is important — because what you can safely deal with yourself depends on what you’re dealing with and where it’s growing.

 

Why “Scrubbing It Off” Can Make Things Worse

Visible mould is only part of the problem.

Scrubbing mould without understanding:

• the moisture source
• the surface type
• the extent of growth

can disturb spores and spread them further through the home.

This is why mould remediation is treated differently to everyday cleaning.

 

When DIY Mould Cleaning Is Not Recommended

DIY mould removal is not appropriate when:

• Mould covers a large area
• Mould keeps returning quickly
• There is mould on walls, ceilings, or porous materials
• The area smells persistently musty
• There has been flooding or ongoing leaks
• Anyone in the home has respiratory sensitivities

In these cases, professional assessment is the safest option.

Mould specialists use:

• Containment methods
• HEPA filtration
• Moisture detection tools

These tools help remove spores without spreading them — something standard household cleaning can’t reliably do.

 

A Note on Commercial Mould Killers

Many commercial mould and mildew products rely on chlorine-based ingredients, such as sodium hypochlorite.

While these products may:

• Whiten surfaces
• Remove visible staining

They also:

• Produce strong fumes
• Require heavy ventilation
• Can irritate lungs, eyes, and skin

Mixing chlorine-based products with other cleaners (especially ammonia-containing products) can create dangerous gases — a common household risk.

 

What You Can Do Safely

For small, surface-level mould in well-ventilated areas, focus on:

• Drying the area thoroughly
• Improving airflow
• Reducing condensation
• Preventing ongoing moisture
• Cleaning should always come after moisture control.

If you’re unsure whether mould is superficial or established, it’s better to pause and seek advice rather than experiment.

 

Prevention Is Always More Effective Than Removal

Mould prevention is about removing what mould needs to survive.

Focus on:

• Ventilating bathrooms and laundries
• Drying wet surfaces after use
• Fixing leaks promptly
• Reducing indoor humidity
• Allowing airflow into enclosed spaces

A dry surface is an inhospitable surface for mould.