Inspection zone or building protection: what’s the difference?
An inspection zone is the most common termite measure on Queensland slabs, and the most misunderstood. It shows you termites after they arrive. It doesn’t stop them. A deltamethrin-impregnated sheet barrier does: it repels and kills termites at the entry point, which protects the building and reduces the need to spray chemicals against live termites later.
Written for builders, developers and specifiers. It isn’t legal advice: your certifier makes the call on each project.
The short answer
- An inspection zone is a clear space, usually 75 mm, that termites have to cross in the open to get into a building.
- It detects. It does not repel, block or kill.
- It only works if someone inspects it, and if nothing is built over it.
- A deltamethrin-impregnated sheet barrier, such as JH Termite Barrier, is both. It has an inspection zone, and it kills and repels termites, which is what protects the building.
- Stopping termites at the barrier reduces the chance of a live infestation, and with it the need for chemical sprays around an occupied building later.
What an inspection zone is
AS 3660.1 refers to a 75 mm inspection zone between the edge of the termite management system and the finished ground level. Termites crossing it have to build mud tubes over an exposed surface, which a trained inspector can see.
The simplest version is an exposed slab edge: 75 mm of the concrete slab left visible around the building.
What it doesn’t do
The QBCC’s notes for builders are direct about this. An exposed slab edge will not stop termites getting into the building. It brings them into the open, where they can be noticed, and then baiting or treatment follows.
That leaves three weak points:
- Someone has to look. If the annual inspection is skipped, the zone does nothing.
- It is easily covered. The QBCC warns that garden beds, paths, pergolas and render can bridge it.
- Treatment comes after entry. By the time termites are seen, chemicals have to be brought in anyway.
The industry code of practice (AEPMA) lists exposed slab edges among the “minimal protection” measures that too often fail to prevent unobserved entry.
Detection or protection
| Exposed slab edge alone | Untreated physical barrier | Deltamethrin-impregnated sheet barrier (JH Termite Barrier) | |
|---|---|---|---|
| Inspection zone | Yes | Yes | Yes |
| Building protection | No | Blocks only: no repellent or lethal effect | Yes: kills and repels |
| What stops termites | Nothing | Blocks them where it is installed | Blocks, repels and kills on contact |
| Size of the inspection zone | 75 mm | As set out in the system’s manual | 75 mm, reduced at concrete and paving (25 mm for JH) |
| If termites get in | Baiting or chemical treatment | Baiting or chemical treatment | Baiting or chemical treatment, but less likely to be needed |
| Annual inspection | Required | Required | Required |
Why a deltamethrin barrier protects the building
- It works without anyone watching. The barrier repels and kills termites at the entry point, every day between inspections.
- The chemical is sealed inside the sheet. A measured amount of deltamethrin is encapsulated between plastic layers and installed once, during construction. Nothing is sprayed onto soil.
- It reduces the need for sprays later. With an inspection zone alone, the answer to termites is baiting or chemical treatment of a finished, occupied building. A barrier that turns termites away at the slab makes that less likely.
- It lasts. JH Termite Barrier carries a 50 Year Product Warranty.
- It is still inspected. The inspection zone stays as a second check, so you get detection and protection.
It doesn’t cost more to do it properly
A deltamethrin-impregnated sheet is flexible, so it is cut and fitted on site to suit each penetration, joint and perimeter detail. Our indicative rates are $15 per service penetration, $12 per metre of construction joint and $12 per metre of perimeter, excluding GST.
In our experience, this is far more economical than a stainless steel mesh system on the same slab.
Our view
It is common in Queensland to treat an inspection zone as an adequate termite management strategy. We disagree.
An inspection zone tells you termites have arrived, and the answer is then to bait or spray a finished building. A deltamethrin-impregnated barrier stops them at the entry point. For protecting a building, it is the better system.
What to specify
- Specify a deltamethrin-impregnated sheet barrier at the perimeter, penetrations and joints, not an exposed slab edge alone.
- Keep the inspection zone as well, and show it on the drawings so landscaping and paving don’t cover it.
- Give the owner the inspection requirements at handover.
What is a termite inspection zone?
A clear band, usually 75 mm, around a building’s perimeter or subfloor that termites must cross in the open, so their mud tubes can be seen.
Does an inspection zone stop termites?
No. It makes them visible. They still have to be found at an inspection and then treated.
Is an exposed slab edge enough in Queensland?
It is an accepted method under AS 3660.1. It detects termites and does not stop them, so we recommend a deltamethrin-impregnated barrier that repels and kills as well.
Does a deltamethrin barrier reduce chemical use later?
That is the aim. The deltamethrin is sealed inside the sheet and installed once, during construction. Because the barrier repels and kills termites at the entry point, a live infestation that needs baiting or chemical spraying of the finished building is less likely.
Is JH Termite Barrier an inspection zone or building protection?
Both. It keeps the inspection zone, 25 mm at concrete and paving and 75 mm elsewhere, and the barrier itself kills and repels termites.
Sources
Official and manufacturer sources used for this page. Rules change: confirm the current requirements with your certifier.
Building in Queensland?
Send us your drawings and we’ll price the termite management system your certifier will ask for.