Termite inspection zone
The termite inspection zone is the minimum 75mm of exposed slab edge AS 3660.1 requires so termite mud tubes bridging the barrier stay visible. Banking over it voids it.
Ask Chalkline about this →The termite inspection zone is the strip of exposed slab edge, a minimum of 75 mm, that must be kept clear at the building perimeter so termite mud (shelter) tubes bridging the termite barrier can be seen. It is required under AS 3660.1 for perimeter termite management systems and is roughly the height of one house brick (verified 2026-05-25, AS 3660.1 industry guidance).
How it is formed: the damp-proof membrane or vapour barrier turns up to the outside perimeter slab edge and finishes at ground, landscaping, or paving level, leaving at least 75 mm of slab edge exposed above the finished surface.
What it does: the inspection zone is not a barrier itself. Termites can still build a shelter tube up the slab edge, but across an exposed 75 mm strip that tube is out in the open and easy to spot at a routine inspection. Conceal the strip and the tube is hidden, which is the whole problem the zone exists to prevent. Early detection of mud trails is the point, before termites reach the frame.
For a builder:
- Keep the 75 mm clear. Soil, garden beds, mulch, or paving banked above the inspection line voids the visual inspection function and creates a concealed bridging path. This is a common defect and a handover risk.
- Brief the client and the landscaper. The zone is frequently undone after handover when gardens or paving are added against the wall. Flag it at handover so it is not buried.
- It works with, not instead of, the barrier. The chemical or physical barrier resists entry; the inspection zone makes any breach visible.
Also known as: inspection zone, slab edge exposure, 75mm inspection zone.
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Last updated: 2026-05-25. Verified: 2026-05-25. Quarterly review for currency.