12 questions to ask any granny flat builder before you sign

The questions below are not about catching anyone out. They are about making 2 quotes comparable, because most of the difference between granny flat quotes is scope rather than price. Ask all 12 of every builder you are considering, and write the answers down.

The most useful ones are questions 3, 7 and 12.

A licensed builder will give you the number without hesitation. You can check it yourself on the NSW Fair Trading licence check. Verify the licence is current, held by the entity named on your contract, and covers the class of work.

BlueGum’s licence number is 247388C.

A good answer: the number, immediately, and an invitation to check it.

HBCF insurance is required for most residential building work in NSW over $20,000 including GST. The builder must have the cover in place before starting work or taking any payment, including a deposit.

A good answer: yes, and here is the certificate before you pay a deposit.

The most important question on this list. Every builder will say the price is fixed. The useful part is the second half of the question.

A good answer: names the specific circumstances, usually variations you request and genuinely unforeseeable site conditions, and confirms everything else is locked.

A poor answer: “it’s fixed” with no qualification, or a vague reference to site conditions with no detail.

Site costs are the biggest variable in any granny flat quote, and they cannot be priced properly without a look at the block.

A good answer: yes, and here is what we found and how it is priced.

A provisional sum is an allowance, not a price. If the real cost is higher, you pay the difference. They are legitimate, but you need to know where they are.

A good answer: a specific list, with how each was estimated.

Every quote has exclusions. The question is whether the builder will tell you.

A good answer: a written list, without hesitation.

Use a checklist and go through it. Floor coverings, window furnishings, driveway, paths, fencing, clothesline, letterbox, landscaping, air conditioning, insect screens, connections for water, sewer, power and NBN.

Take that table to every builder and fill it in. It will tell you more than the totals do.

Some builders quote the build only. Others manage approval as well. Both are valid, but you cannot compare the prices until you know which you are looking at.

A good answer: states whether approval is in scope, which pathway your block qualifies for, and what the approval costs.

Not just the construction time. The whole thing, including design, documentation and approval.

A good answer: a stage by stage timeline with the approval pathway identified.

On a small build it is easy for a project to fall between people.

A good answer: a named contact and a clear answer about site supervision.

You should know when money is due and what has to be complete before each payment. If you are using a construction loan, these stages need to line up with your lender’s drawdown schedule.

A good answer: a written schedule tied to completed stages, not to dates.

Every build has a few defects. What matters is the process for dealing with them.

A good answer: a defects liability period, a clear process for reporting and rectifying, and a straight answer about statutory warranties.

Write them down for each builder, then compare side by side. Patterns show up quickly.

The builder with the lowest headline price and the longest exclusion list is often not the cheapest once you finish the job. The builder who answers question 3 with specifics is usually the one whose price will hold.