Defect type
High · 2–4/5
Inadequate Subfloor Ventilation Creating Termite-Conducive Moisture
I inspected the subfloor and found the wall vents blocked, too few for the floor area, or poorly distributed - airflow is restricted and the space is persistently humid with damp soil beneath suspended timber floors. In my experience this moisture load supports subterranean termite foraging, fungal decay, and borer activity in bearers, joists, and flooring, and is a recognised conducive condition I record against AS 3660.2. Common in older Perth and Sydney cottages where garden beds or additions now cover the original vents.
Causes
- Original terracotta or metal vents blocked by mortar, paint, soil, or garden beds
- Insufficient vent count or poor cross-flow distribution for the floor area
- Ground level built up against external walls, partially burying vents
Symptoms to look for
- Musty or earthy smell at floor registers and wall bases
- Visibly damp soil, fungal growth, or condensation in the subfloor
- Cupped floorboards, sticking doors, or corroding metal fixings in the subfloor
Remedies
- Clear obstructions from existing vents and lower garden bed levels where needed
- Install additional passive vents to improve cross-ventilation (reference NCC Volume Two Part 3.1.3)
- Consider powered subfloor ventilation where passive airflow cannot be achieved
Critical
Get an inspector through this property.
Findings in this category skew high severity. If you are under contract, we can usually book inside the cooling-off window. Every inspection includes 12 months of free advice.
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