Subfloor ventilation in Ipswich houses

Rising Damp Ipswich arranges damp assessments across Ipswich and the western corridor.

Why a Queenslander needs air, not a barrier

A house on stumps is designed to have air moving under the floor, carrying moisture out from under the building before it reaches the timber. When that airflow stops, the ground under the house stays wet, the humidity underneath climbs, and the floor structure takes it up. There is no wall for water to climb, so a chemical damp course has nothing to do here.

What stops the airflow

• Building in underneath, which walls in what used to be open air.
• Garden beds, paving and concrete raised against the perimeter, covering vents.
• Screening or lattice added around the base for appearance.
• Ground under the house that has never been graded, holding water after rain.
• Air conditioning condensate and hot water overflows discharging underneath.

What the work involves

Usually additional vents, and clearing whatever is blocking the existing ones. Where a house has been built in underneath and passive airflow is no longer possible, powered extraction on a humidistat does the same job actively. Getting water away from the perimeter matters as much as the vents themselves.

What it will not fix

A masonry wall with no damp course and wet ground against it. Ventilation reduces the humidity in a space; it does not stop water climbing through brick. Where both conditions exist - and on a built-in-under Queenslander they often do - both need addressing.

Areas we cover

We take enquiries across the Ipswich local government area and the western corridor.