Hiring a builder: what to sort out before anyone swings a hammer

What a builder actually takes on

A builder manages and delivers construction work: removing structural walls, renovations, extensions, second storeys and new builds. They quote the whole job, engage and schedule the subcontractors — electricians, plumbers, plasterers, tilers — handle materials, and carry responsibility for the finished result meeting the Building Code.

You need a builder, rather than individual trades, when the work is structural or spans multiple trades that need sequencing. Knocking out a load-bearing wall, anything touching footings or the roof structure, and any project where one trade's work depends on another's are builder territory. A single-trade job — a repaint, a new fence — doesn't need one.

Making sense of the numbers

Builder pricing spans an enormous range because the work does: small structural jobs commonly land in the four-to-low-five-figure zone, major renovations run to tens of thousands, and extensions or second storeys reach well into six figures. Under the hood, quotes are built from labour, materials, subcontractors and a margin.

The comparison trap is provisional sums — placeholder allowances for tiles, fittings or excavation. A quote can look cheap because its allowances are unrealistic, then grow to match reality once you choose actual products. Compare quotes line by line, and treat every figure as indicative until the scope is nailed down in writing.

Checking a builder properly

Building is a licensed or registered trade in every state for work above modest thresholds, so start there: check the licence or registration is current, in the builder's name, and covers the class of work you're doing. Ask about home warranty insurance too — it's mandatory above a value threshold in most states and protects you if the builder can't finish the job.

Beyond paperwork, good builders show rather than tell. Recent jobs you can look at or call about, a written fixed-price contract with a detailed scope, a realistic start date rather than a flattering one, and straight answers about who's on site day to day. A builder who resists a written contract on a big job has answered your real question.

Mistakes to avoid

Building disputes almost never start with bad workmanship — they start with vague scopes, thin contracts and payment schedules that got ahead of the work.

• Signing a vague quote instead of a fixed-price contract with a detailed scope
• Skipping the licence and home warranty insurance checks because the builder seemed nice
• Ignoring low provisional sums that make a quote look cheaper than it will be
• Agreeing to payments tied to dates rather than completed stages of work
• Choosing the cheapest of three quotes without asking what it excludes
• Starting without agreeing how variations get priced and approved in writing