Termites cause more property damage in Australia than fire, flood, and storms combined. The CSIRO estimates one in five Australian homes will experience termite damage in its lifetime. In Queensland and northern NSW, that risk is closer to one in three.

If your pre-purchase building inspection finds termite evidence — or if you've already bought and just discovered some — the next question is always the same: how much is this going to cost?

The answer depends on five things.

Factor 1: Active vs Historical

Inspectors classify termite findings in two buckets:

Most pre-1990 Australian homes have SOME historical evidence somewhere — it's incredibly common. What matters is (a) is it active right now, and (b) is the damage structural or cosmetic.

Factor 2: Where the damage is

Termites attack timber. The cost-of-repair scales with what timber:

Cosmetic damage ($2,000–$8,000)

These are unsightly but don't threaten the house. A carpenter replaces the affected elements; a painter touches up the surrounding finish. Half a day's work for a competent tradie.

Sub-structural damage ($5,000–$15,000)

These need structural assessment — affected timber must be replaced with new (or sister-jointed where partial replacement is structurally adequate). A carpenter does the work; an engineer's sign-off is often required.

Major structural damage ($15,000–$35,000+)

This is the worst-case scenario. Replacement requires temporary support during work, an engineer's scope, potential matching building permits. On a heritage property it can easily push past $50,000 because replacement timber must match original species + section size + heritage spec.

Whole-house structural compromise ($50,000+)

Extreme cases — termites have travelled the entire framing system undetected for years. This is rare but happens, especially in:

At this end of the scale, demolition is sometimes more economical than rectification. Pre-purchase inspections aim to catch these before exchange — your inspector should specifically note timber sounding tests (light tapping reveals hollow-feeling damaged timber) and any restricted-access areas flagged for follow-up investigation.

Factor 3: Treatment vs damage repair

Two separate cost lines you need to budget:

1. Termite TREATMENT — stopping the colony

Treatment doesn't repair damage. It stops more from happening. AS3660 compliance is the minimum standard your pest controller should be quoting against.

2. Damage REPAIR — fixing what termites already chewed

This depends entirely on what was damaged (see Factor 2). The carpenter and pest controller work together — pest controller kills the colony first, carpenter repairs once the timber is certified clear.

Factor 4: Where in Australia you are

Termite pressure varies dramatically by region. The CSIRO maps risk in classes:

Brisbane / SE Queensland homes need ongoing termite management as a cost of ownership, not an optional extra. Melbourne homes can be more relaxed (still needs inspection, just less frequent treatment). Your suburb's class affects your forward 5-year capex forecast significantly.

Factor 5: Property age + construction type

The buyer's playbook when termites are found

  1. Get a specialist pest inspection(separate from your building inspector) by an AS3660-certified pest controller. Cost: $300–$500. They'll confirm active vs historical and identify the species.
  2. Get an engineering assessmentif the inspector noted structural damage. $1,500–$3,000 for a residential engineer's report. Necessary if any load-bearing timber is affected.
  3. Get treatment quotes from 2-3 pest controllers. Quotes should reference AS3660 + state the 5-year management plan.
  4. Get repair quotes from 2-3 carpenters once you know the damage scope. Itemise: cosmetic vs sub-structural vs structural.
  5. Negotiate off contract price using documented costs.Treatment + repair + your time + risk discount = your negotiation floor. See our negotiation guide for how to structure the ask.

What if you've already bought?

Three immediate actions:

The cost of NOT treating

Untreated active termite colonies double their consumption rate every 6–12 months as the colony grows. A "minor" finding ignored for 18 months can mean the difference between $5K repair and $35K repair. Don't kick this down the road.

What Report Decoded does with termite findings

When your AS4349.1 / AS4349.3 building + pest inspection mentions termites — past or active — we extract:

Then we plug it into the negotiation amount and the ready-to-send negotiation letter to the vendor's agent. Every claim cites the page in your inspector's PDF so the evidence is right there.

$59 per report. No subscription. Under 2 minutes.