The house at Albion Park was five years old and the owners had done everything right on paper. Slab-on-ground, reputable builder, chemical management zone under and around the slab, and a durable notice screwed to the inside of the meter box with the product, the date and the next inspection due. They found it for me before I'd even asked. Very organised people.
They also had termites in the wall behind the kitchen.
It took twenty minutes and a shovel to work out why. Two summers earlier they'd put in a raised garden bed along the northern wall, sleepers and about 300mm of good soil and mulch, running the full length of the house. Lovely bit of landscaping. It had buried the slab edge under a foot of damp organic material, and the termites had come up through the soil, over the top of the treated zone, and straight into the frame without ever crossing a millimetre of treated ground.
The barrier hadn't failed. It had been walked around.
What the barrier is actually for
This is the bit that gets lost, and it's worth being blunt about it: a pre-construction termite management system does not kill termites and it isn't meant to. It's a management zone. Its whole job is to make sure that if termites want into your house, they have to come up somewhere you can see them.
That's why the exposed slab edge matters so much. Leave 75mm of bare concrete visible between the finished ground level and the bottom of the wall cladding, and any mud lead has to build itself right across that gap in plain view. Anyone with a torch can find it on an annual inspection. Bury that edge and the same termites make the same journey inside the soil, hidden, and the first anyone knows is when a skirting sounds hollow.
Physical or chemical, and who chose
There are two families of system and most people never get told which one they got.
A physical barrier is a material termites can't chew through or fit past. Stainless steel mesh laid under the slab and turned up at the perimeter, graded crushed stone sized so they can't squeeze between the particles, collars around every pipe penetration. It doesn't wear out. It also can't be repaired easily once the concrete's over it, which is why the installation photos matter.
A chemical zone is a termiticide applied to the soil under the slab and around the perimeter before the concrete goes down, sometimes with a reticulation pipe loop cast in so it can be recharged from a couple of access points years later. Modern products are non-repellent, meaning termites walk into treated soil without detecting it and carry it back with them. It has an expected service life, and that life is a number on a page, not a guarantee. Ask what it is.
Both are done to AS 3660.1, which is the new-build half of the standard. Part 2 is the remedial work you do on a house that's already standing, and we've covered what that costs and how it differs separately. The NCC's termite risk management provisions set out what's required and what the durable notice has to carry. The Illawarra is termite territory across the board, so this isn't optional here.
If you're building and nobody has told you which system is going in, that's a question for the builder before the slab is poured, not after.
The notice in the meter box
Every properly finished job leaves paperwork: a durable notice fixed somewhere permanent, usually the meter box or inside a cupboard door, stating the system used, the date, its expected life, and when it needs looking at again.
Get it. Photograph it. If you buy an established house, go and look for it before you go looking for anything else, because its absence tells you something. And if you're mid-purchase, the pest half of the inspection is where this gets checked properly, which is a different job to the building inspection and I've written about why the two aren't interchangeable.
One more thing on the paperwork. Whoever applied the chemical needs a current pest management technician licence from the NSW EPA. That licence belongs to the person, not the company, and on a new build it's often a subcontractor you never met. You're entitled to ask which one.
Six ways homeowners undo it
Nearly every breached barrier I find was created by someone who owned the house and had no idea they were doing anything.
Raised garden beds and mulch against the wall, like Albion Park. Rendering carried down past the slab edge to the ground, which looks tidier and hides the one thing you needed to see. A concrete path or paving poured level with or above the slab edge. A deck built hard against the wall with no clearance underneath to inspect. An air conditioner installer drilling a new penetration through the slab or the wall years later and foaming the hole without telling anyone. And the quiet one: a leaking hot water overflow or a downpipe discharging next to the footing, keeping a patch of soil permanently wet, which is an invitation regardless of what's in the ground.
None of those are dramatic. They're all Saturday afternoon jobs. That's exactly the problem.
Owner-builders and small developers
If you're running the build yourself, treat the termite work as two staged visits rather than one line item. Part A goes in before the slab pour and it has a narrow window, because once the concrete truck is booked nobody is waiting on you. Part B is the perimeter completion after the external works are done.
Miss the coordination and you end up paying for a full remedial treatment on a house that hasn't had anyone live in it yet, which is a conversation I've had more than once. Get the scope, the system type and the certificate written into the contract at the start. The NSW Fair Trading guidance on quotes and contracts is worth a read if this is your first build.
Warranties still need the annual
Every new-build system I've come across carries a warranty that's conditional on an annual inspection by a licensed technician. Skip two years because nothing seems wrong and the protection you paid for at construction quietly stops being protection, usually right when you'd want to lean on it.
The inspection is also the only way anyone finds a breach like the garden bed before it costs money. Five minutes with a shovel at the northern wall would have caught that one in year three.
August is the window
Slabs are going down across Albion Park, Kiama and the Shellharbour estates right now, and the flight season starts in a few weeks. Warm, humid evening after rain, usually October through December, and the alates come out looking for somewhere to start. A house with an exposed slab edge and a current inspection is a bad prospect for them. A house with a garden bed over the edge is not.
If you're building, ring us before the pour and we'll tell you what needs to happen and when. If you've already got a house with a barrier in it and you've since landscaped, decked or rendered, book a look at what a timber pest inspection covers and we'll check whether the thing you paid for is still doing its job. Either way, give us a call and describe the site.
Need a hand with this in your home? Get a free quote or call 0430 007 651.