Does Insulation Prevent Mould — Or Make It Worse?

Insulation is often recommended to prevent mould, but poorly installed insulation can actually create mould problems. Understanding the relationship is critical before any retrofit.

How Insulation Helps

Insulation raises the temperature of internal wall and ceiling surfaces, reducing condensation. When the wall surface stays above the dew point, moisture doesn’t form — and mould can’t grow. This is why insulated homes generally have fewer mould problems than uninsulated ones.

How Insulation Can Backfire

If insulation is installed without addressing existing moisture problems (rising damp, leaks, inadequate ventilation), it traps moisture inside wall cavities. The insulation gets wet, loses its thermal performance, and creates a hidden mould paradise between the insulation and the wall lining.

Adelaide Retrofit Warning

Many Adelaide homeowners in Burnside, Norwood, and Unley are retrofitting insulation into heritage homes. If the walls have rising damp — common in stone homes — adding cavity insulation without first treating the damp will make things significantly worse.

Always get a moisture assessment before insulating older Adelaide homes. Get professional advice.