PERTHTermite barriers for new builds under AS 3660.1
Termite management for new WA homes under AS 3660.1: physical vs chemical barriers, why timing before the slab pour is critical
In Perth's termite-prone environment, a new home has to be built with a termite management system, and the time to get it right is before the slab is poured, because after that the main options are gone. If you are building, or buying a newish home, here is what the standard requires and what paperwork should exist.
Why new builds need a system
Termite management for new building work is governed by AS 3660.1, and compliance with it is how a new build satisfies the termite requirement in the National Construction Code. It applies to Class 1 homes and Class 10 structures like garages and sheds. The standard is realistic about what it can achieve: it does not claim to make a building termite-proof. What it does is deter concealed entry — forcing termites, if they come, to travel where they can be seen rather than tunnelling up hidden inside a wall.
That word, concealed, is the key. Termites do their worst damage precisely because they get in unseen. A management system's job is to remove the hidden path.
Physical and chemical barriers
AS 3660.1 allows physical systems, chemical systems, or a combination, and they work differently.
A physical barrier is a built-in obstacle termites cannot pass or must expose themselves to cross — stainless steel mesh with a weave too fine to penetrate, graded stone particles sized so termites cannot move through them, or the concrete slab itself detailed as a barrier. It is installed during construction, around service penetrations, construction joints and the perimeter, before the slab is poured. Its appeal is permanence: it does not degrade and need re-treatment the way a chemical does.
A chemical barrier is a treated zone — a termiticide applied to the soil or as a treated sheet, using products registered with the national pesticides authority. It is effective, but it has a service life and eventually needs renewal.
Many builds combine them: a physical barrier across the slab with chemical treatment at the penetrations and pipes a physical barrier alone cannot fully close.
The timing trap
This is the part that catches people. Once the slab is poured, the physical barrier options that go under and through it are gone — you cannot retrofit an under-slab system into a finished slab. So the termite system has to be planned and installed at the right point in the build sequence, and it has to be on the building application drawings from the start. A system treated as an afterthought is a system with its best options already closed off.
The paperwork, and why it matters at sale
When the system is installed and certified, two documents should result: a certificate confirming the work was done to AS 3660.1, and a durable notice fixed in the building, typically near the meter box, stating what system was installed and who to contact for future inspection and maintenance. That notice is not decoration — it tells the next owner, and their inspector, what protects the house.
On a Perth build, soil matters too: the sandy coastal soils and limestone affect which system suits, part of the same soil-varies-by-location story that runs through footing design.
What this means for a buyer
If you are buying a newish home, ask for the termite system certificate and look for the durable notice. Their presence tells you the house was protected to the standard and gives you what you need to maintain it. And whatever system is installed, the standard's own logic holds: it deters concealed entry so that termites can be found by inspection, which means annual inspection is still essential. That is the ongoing job a building and timber pest inspection does, and it is covered more broadly in our guide on the termite management standards.
Why a barrier is a system, not a product
It is tempting to think of a termite barrier as a single thing installed once, but on a new build it is better understood as a system that has to be designed, installed correctly, and then maintained for the life of the building. The barrier does not kill a colony or make a house termite-proof; what it does is manage the ways termites can get from the soil, where they live, into the timber of the house, where they feed. Subterranean termites travel from their nest to their food and cannot survive long in the open, so they build concealed routes, and a barrier system works by making those routes either impossible or detectable, forcing the termites into the open where their activity can be seen. That only works if the whole system is intact, which is why a barrier is a chain of measures rather than a single line of defence.
This matters because a barrier with a gap is a barrier the termites will find. Termites are relentless and patient in seeking a way in, and a single unprotected penetration, a service pipe, a joint, a bridging point where soil or a garden bed has been built up over the barrier, is all they need. A barrier that was installed well but then compromised, by later landscaping, an added path, a garden bed banked against the wall, is a barrier that no longer does its job at that point. Understanding the barrier as a system that has to stay intact is what explains why both the installation and the ongoing maintenance matter, and why so many termite problems in relatively new houses trace back to a barrier that was breached rather than one that was never there.
The timing trap on a new build
The most common way a termite barrier goes wrong on a new build is timing, because much of the barrier system has to be installed at particular points in the construction sequence, and once those points pass, doing it properly becomes difficult or impossible. Parts of the barrier, particularly the under-slab and perimeter elements, have to go in before the slab is poured or at specific stages of the build, when the relevant parts of the structure are accessible. Miss the window, and installing that part of the barrier later means working around finished construction, which is harder, more expensive, and often less effective. This is why the barrier is not something to leave to the end; it has to be planned into the construction sequence and installed at the right stages.
This ties the termite barrier directly to staged inspection, because the stages at which the barrier is installed are exactly the stages, pre-slab and early construction, where a staged inspection can confirm it went in and went in properly, while it is still visible. Once the slab is down and the house is up, the under-slab barrier is buried and can only be inferred from the documentation. A staged inspection that checks the barrier at the point of installation, combined with the paperwork that records what system was installed and where, is how an owner gets confidence that the barrier system is actually there and complete rather than assumed.
The paperwork, and what it means at sale
A termite barrier system on a new build should generate documentation: a record of what system was installed, where, by whom, and what maintenance and inspection it requires. This paperwork matters more than owners often realise, because it is the evidence the barrier exists and the guide to keeping it effective, and because it becomes relevant when the house is sold. A buyer of a relatively new house who asks about the termite barrier and receives clear documentation, the system, its installation, its maintenance requirements, its inspection history, is in a very different position from one who is told there is a barrier but shown nothing.
For a buyer, the barrier documentation is part of the due diligence on a newer home, and its absence is worth noting. A house whose barrier system is documented and has been maintained and periodically inspected is a house whose termite protection is a known quantity. A house where nobody can say what barrier was installed, whether it is intact, or when it was last checked is a house where the protection is uncertain, and in Perth, which sits in one of the higher termite-pressure regions in the country, that uncertainty is worth resolving. An inspection assesses the house for evidence of termite activity and for the conditions that invite termites, and the barrier documentation, obtained through the seller, completes the picture of how well the house is protected.
Common questions
What standard covers termite protection for a new home?
AS 3660.1, termite management for new building work. Compliance with it satisfies the termite requirement in the National Construction Code for Class 1 homes and Class 10 structures. It deters concealed entry rather than making a home termite-proof.
What is the difference between a physical and chemical termite barrier?
A physical barrier — stainless mesh, graded stone, or the slab detailed as a barrier — is a permanent built-in obstacle installed before the slab pour. A chemical barrier is a treated soil zone using registered termiticide that has a service life and needs renewal. Many builds combine them.
Why does termite barrier timing matter?
Once the slab is poured, under-slab physical barrier options are gone and cannot be retrofitted. The system must be planned and on the building drawings from the start, installed at the right point in the build sequence.
This comes up on every building & timber pest inspection and building stage inspections we carry out.
Read next: the 25mm gap that decides whether your termite barrier works and reactive-clay footing movement.
Sources
Read rather than recalled. Summarised here; the documents themselves are Crown copyright and are linked rather than reproduced.