IN SHORT
- Mould needs moisture and food. Removing growth matters, but the moisture decides what happens next.
- Aim for indoor relative humidity of 30–50%, and keep it below 60%.
- Sprays and bleach don't physically remove mould. Physical removal is the standard.
- Porous materials with visible growth are often replaced, not cleaned.
What mould needs
Mould spores are a natural part of the air, indoors and out. The problem starts when moisture gives them somewhere to grow. Mould needs two things: moisture and food. The food is usually cellulose, found in plasterboard paper, timber and wallpaper backing. The moisture is the trigger.
If a patch returns after cleaning, it's a sign the moisture behind it is still there. In Australian homes that is often high humidity, condensation, a slow leak or a damp subfloor.
Keep indoor humidity in range
Aim to keep indoor relative humidity between 30% and 50%, and below 60%. A simple digital humidity meter shows you where your home sits.
- Run exhaust fans that vent outside, not into the roof space.
- Use a dehumidifier in rooms that stay damp.
- Open up cross-ventilation when the weather allows.
- Pay attention to subfloor ventilation in older and coastal homes.
Why cleaning alone isn't enough
Many people try to kill mould with sprays or bleach. Even when the mould dies, its particles stay on the surface, which is why the industry standard focuses on physical removal.
On non-porous surfaces such as tiles, glass and metal, thorough cleaning may be enough. On porous materials with visible growth, such as plasterboard, carpet or untreated timber, replacement is often recommended. In industry terms, that level of growth is Condition 3.
The bottom line
Mould is a moisture problem first. Remove the growth properly and deal with the moisture, and you give it far less reason to return.
WHERE DRYSAFE FITS
Mould needs moisture, so we take readings and understand where the moisture could potentially be to help you take the right steps to prevent it from reoccurring. Then we remove growth with a HEPA vacuum and apply a TGA-listed antimicrobial.