Variations to Residential Building Contracts in the NT

What it is

The Northern Territory does not legislate variations to residential building contracts. There is no statutory writing requirement, no prescribed content for a variation document, no notice period and no provision barring a builder from recovering for an unwritten variation.

That is unusual enough to state plainly, because most Australian jurisdictions do regulate variations and builders arriving from the eastern states expect a section number to point at. In the Territory, a variation is whatever the contract says it is.

Confirming the absence

The Building Act 1993 (NT) contains no variations provision. Its building contractor Part runs sections 48B to 48F, covering the contract obligation, the builder's declaration and owner-builders. Nothing addresses changes to scope or price.

The Building Regulations 1993 (NT) use the word "variation" twice in a contract sense, and neither is about scope. Regulation 41H(g) refers to the parties agreeing to "a variation of the standard progress payments", and regulation 41HB(1)(b) requires a progress payment agreement to say so. Both are about the payment schedule. The only other use is regulation 40A, on registration conditions.

Regulation 41H, which lists the mandatory contents of a residential building contract, does not require a variations clause at all.

What fills the gap

Three things fill it. The general law of contract. A variation needs agreement and consideration like any other contract change. If the contract requires variations to be in writing and signed, that clause is the only writing rule that applies, and the usual waiver, estoppel and course of dealing arguments sit on top of it.

The Australian Consumer Law unfair contract terms regime, which applies to standard form consumer contracts and reaches a variation clause letting the builder change the price or the scope unilaterally.

The consumer guarantees in section 54B of the Building Act, which cannot be excluded by contract under section 54BA. Varied work is still building work, and it still has to be done in a workmanlike manner, with reasonable care and skill, in accordance with Territory law.

The trap the NT builds in anyway

The absence of a variations regime meets a rule that does exist.

Regulation 41H(d) requires the contract to specify the extent of the work and the total contracted price. Regulation 41H(f) requires it to specify the percentage of the total contracted price payable after each stage. Regulation 41HE(2)(b) then makes it an offence, carrying up to 50 penalty units, for a contractor to request or receive from the contracting owner more than the percentage of the total contracted price that is specified in or under the residential building contract.

Follow that through. The lawful invoice is a percentage of the total contracted price. A verbal instruction on site does not change that price, because the price is a term of a written contract. So the extra work has no percentage attached, and an invoice for it is not a claim for a percentage of the price specified in the contract.

The builder who does the work on a nod is exposed twice. Recovery for the variation depends on ordinary contract principles and on whatever writing clause the parties agreed, with no statutory relief to fall back on. And the invoice mechanics run into regulation 41HE(2) unless the total contracted price is adjusted in the contract document first. Regulation 41HE(5) lets a court that convicts order a refund of some or all of the amount paid.

No statutory relief means no safety net

In jurisdictions with a variations regime, the statute usually pairs the bar on recovery with a discretion to let the builder recover where it would be unjust not to. The NT has neither half: no bar, which sounds good for builders, and no relief, which is only comfortable while the contract is well drafted. The exposure is evidentiary: where the contract requires signed written variations and the builder did not get one, the builder is arguing waiver or estoppel against a written price term in a document the Regulations required to state that price.

What good practice looks like

Because the statute is silent, the contract has to do all the work. A variation document should record the change to the scope, the change to the total contracted price, the resulting new total contracted price, any change to the stage percentages, any effect on the date for completion, and be signed by both parties before the work starts.

If the variation shifts the payment structure rather than just the price, regulation 41HB is engaged and the progress payment agreement must be in the approved form.

NT Government guidance puts the practical point simply: if there are any changes or variations during construction, make sure these are in writing and the contract is changed as needed. That is guidance, not law. In the Territory it is the contract, not the statute, that decides whether the builder gets paid.