Granitgard: the graded-stone termite barrier

Granitgard is a non-toxic, graded-stone termite barrier: a precisely sized crushed-stone aggregate laid as a continuous physical barrier so termites cannot get through it undetected. It is a chemical-free alternative to a soil treatment like bifenthrin, and it is one of the recognised physical termite management systems for Australian residential work. Developed over about 15 years with the CSIRO and used in more than 150,000 buildings, it is CodeMark-certified under AS 3660.1 and carries a 50-year warranty (verified 2026-05-25, Granitgard / Flick Anticimex).

How a graded-stone barrier works

The whole system depends on the stone being graded to a tight particle size, 1.5 mm to 5 mm, with each batch tested in a NATA-registered laboratory for compliance (verified 2026-05-25). At that grading the barrier stops termites three ways at once:

Too hard to chew. The particles are stone, not timber or foam, so termites cannot eat through them.
Too big to move. Individual particles are too large for a termite to pick up and carry out of the way.
Packed too tight to pass. The graded particles sit closely together, so the gaps between them are too small for a termite to squeeze through.

Get any one of those wrong, finer stone they can move, coarser stone with gaps they can pass, and the barrier fails. That is why the grading and the batch testing matter, and why a barrier has to be the certified product, not just any crushed rock from the quarry.

Like every compliant termite barrier, Granitgard is not claimed to kill termites. It blocks the concealed entry paths and forces any termite trying to get in out into the open, where it has to build a visible mud tube over the barrier and can be spotted at a routine inspection. The barrier buys visibility, not eradication.

Where it is installed

Granitgard is laid as a continuous barrier at the points where termites would otherwise get concealed access to the building:

Around and beneath the slab perimeter, as a continuous bed to the certified design.
As collars around every service penetration (pipes, conduits) that passes through the slab, because penetrations are the classic concealed entry point.
At service entries and other gaps in the slab edge.

The barrier has to be continuous. A graded-stone barrier with a break at a penetration or a gap in the perimeter is exactly the untreated path a termite will find, the same logic that applies to a repellent chemical barrier.

Certification and standards

AS 3660.1. Termite management for new building work is governed by AS 3660.1, and a physical barrier has to be installed to a system that meets it.
CodeMark. Granitgard is nationally certified under the CodeMark scheme, the ABCB’s product-certification framework, as complying with the Building Code of Australia (verified 2026-05-25, ABCB CodeMark scheme). CodeMark certification is what lets a certifier accept the product as a deemed-to-satisfy solution without re-assessing it.
NATA-tested batches. The grading is verified per batch in registered laboratories, which is the quality-control step behind the certification.

The 50-year warranty and its catch

Granitgard carries a 50-year warranty, which is far longer than a chemical soil treatment (a bifenthrin barrier runs to about a 10-year label). The stone does not break down, so the barrier itself does not have an expiry the way a chemical does.

The catch is in the word undisturbed. A graded-stone barrier only works while the stone bed is intact and correctly graded. Anything that digs into, mixes, or removes the stone breaks it:

A plumber trenching through the perimeter to add or repair a service.
A landscaper excavating a garden bed or footing against the wall.
An owner laying paving or a path over the barrier line.

When the barrier is disturbed, it must be reinstated by an accredited installer to the certified detail, or the protection (and the warranty) is void at that point. This is the single biggest practical difference between a stone barrier and a chemical one on a live site: the stone is permanent but physically fragile to later trades.

Granitgard versus the other barriers

	Granitgard (graded stone)	Chemical soil (e.g. bifenthrin)	Stainless mesh (e.g. TermiMesh)
Type	Physical, particle	Chemical, repellent or non-repellent	Physical, mechanical
Chemicals	None	Yes	None
Typical life	50-year warranty (undisturbed)	~10-year label	Long, material-dependent
Main weakness	Disturbance by later trades	Chemical ages out; gaps in repellent barriers	Damage or poor termination detail
Reinstatement	By accredited installer if disturbed	Re-treat at label intervals	Repair the mesh

None is automatically best. The choice depends on the site, the client’s preference (a chemical-free option appeals to many owners), the budget, and the design. What matters for the builder is understanding the trade-off each one brings to the program.

For a builder

Book it into the slab sequence. A perimeter-and-penetration stone barrier is installed at a specific point in the slab works; coordinate the installer rather than leaving it to chance.
Protect it from your own trades. Once the barrier is down, brief the plumber, the landscaper, and the concreter that the stone bed is a certified barrier, not spoil to be dug through.
Plan reinstatement. If a later service has to cross the barrier, build in the accredited installer’s reinstatement, do not let the trench get backfilled with ordinary soil.
Keep the durable notice. As with any termite system, the installed barrier, its date, and the inspection regime go on the durable notice fixed in the building, and the homeowner still needs ongoing annual inspections.
Keep the inspection zone clear. The barrier forces termites into the open; that only helps if the slab edge stays visible.

How a graded-stone barrier works

Where it is installed

Certification and standards

The 50-year warranty and its catch

Granitgard versus the other barriers

For a builder

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