Pre-construction termite barriers in the NT.
Every new home in the NT requires a termite management system to AS 3660.1 under the National Construction Code. The certifier won’t sign the Form 21 occupation certificate without the Form 16 Termite Management Certificate. Three options, very different costs, very different maintenance profiles. Here’s what the builder choice means for you 20 years in.
The three barrier types.
1. Chemical soil barrier (Termidor SC).
Fipronil-based liquid sprayed under and around the slab perimeter before pour. Creates a treated soil envelope. ~$2,400–$3,600 installed on a typical 200m² build. Service life 8–10 years before re-treatment required.
2. Physical barrier (Termimesh, Kordon TMB).
Stainless steel mesh (Termimesh) or laminated chemical layer (Kordon) installed at every slab penetration (pipe, conduit) and around the perimeter under the slab. Lifetime — doesn’t require re-treatment. ~$3,400–$4,800 installed. Preferred for premium builds.
3. Combined system (barrier + bait).
Physical barrier at construction PLUS in-ground bait stations installed around the perimeter at handover. Belt and braces. ~$5,800–$7,400 plus $380–$560/yr ongoing monitoring. Top-tier protection.
Where 90% of termite entry happens.
A continuous chemical or physical barrier around the slab perimeter is straightforward. The hard part is the dozens of slab penetrations for plumbing, electrical conduits, and sub-floor services. Every penetration is a potential entry route.
AS 3660.1 requires every penetration to be:
- Wrapped in a Termimesh stainless collar where pipes pass through the slab
- Sealed with proprietary mastic at the slab-pipe interface
- OR an alternative engineered detail (Kordon, Trithor) approved by the system manufacturer
The cheap version of this is “chemical only” without penetration treatment. It looks compliant on paper. In practice, termites find the unprotected pipe penetrations within 5–10 years.
The Certificate of Termite Protection (CoTP).
After installation, the licensed termite installer issues a Certificate of Termite Protection that:
- Identifies the system type and brand
- Describes the installation extent
- Specifies the warranty (and any conditions)
- States the next inspection due date
You must receive a CoTP at handover — it’s part of the completion documents. Without it, the builder hasn’t completed the work to NCC standard. Keep it forever — needed for the AS 3660.2 annual inspection and for insurance.
Honest recommendation.
Standard new build, cost-sensitive: Chemical (Termidor) + proper penetration treatment. Cheapest, works, requires 8-year retreatment.
Premium new build, forever-home: Physical (Termimesh or Kordon) + annual inspections. Lifetime barrier, no retreatment cost, preferred by insurers.
High-risk area or bushland surrounds (Howard Springs, Humpty Doo, Berry Springs — Litchfield acreage and bushland-boundary blocks): Combined barrier + bait system. Maximum protection.
Slab-on-ground with no perimeter access (e.g. terraced into a hillside): Physical barrier mandatory — you can’t retreat the soil later.
The retrofit option (existing homes).
If your home was built without a barrier or the barrier is past its warranty:
- Chemical retrofit: Trench-and-rod chemical injection around perimeter. $2,800–$5,400. Same warranty as new-build chemical.
- Baiting retrofit: Install bait stations around perimeter. $2,400–$4,200. Annual monitoring continues.
- Physical barrier retrofit: Not practical — physical barriers go under slab at construction. Use chemical or baiting for retrofit.
Where we work.
Building new? We work with builders.
Pre-construction barrier installation, Certificate of Termite Protection at handover.