Last reviewed: August 2026
The questions below are not about catching anyone out. They are about making two quotes comparable, because most of the difference between granny flat quotes is scope rather than price. Ask all twelve of every builder you are considering, and write the answers down.
The most useful ones are questions 3, 7 and 12.
The licence and insurance questions
1. What is your builder licence number, and can I verify it?
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.
2. Will you provide Home Building Compensation cover?
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 price questions
3. Is this a fixed price, and what specifically can change it?
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.
4. Has anyone inspected my block before producing this number?
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.
5. Which items are provisional sums?
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.
6. Can I have the exclusions in writing?
Every quote has exclusions. The question is whether the builder will tell you.
A good answer: a written list, without hesitation.
The scope questions
7. Walk me through what is included, item by item.
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.
| Item | Included | Excluded | Provisional |
| Floor coverings throughout | |||
| Window furnishings | |||
| Driveway and paths | |||
| Fencing | |||
| Landscaping and turf | |||
| Air conditioning | |||
| Utility connections | |||
| Site works and excavation | |||
| Approval fees |
Take that table to every builder and fill it in. It will tell you more than the totals do.
8. Are approvals included, and which pathway am I on?
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.
The delivery questions
9. What is the realistic timeline, from today to handover?
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.
10. Who is my point of contact, and who supervises the site?
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.
11. What are the progress payment stages?
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.
12. What happens after handover if something is wrong?
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.
What to do with the answers
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.
Frequently asked questions
How do I check a builder’s licence in NSW?
NSW Fair Trading provides a public licence check. Search the licence number or the business name, and confirm the licence is current and held by the entity that will sign your contract.
Is HBCF cover always required?
It is required for most residential building work over $20,000 including GST, unless the project is exempt. The builder must have it before starting work or taking any payment, including a deposit.
How many quotes should I get?
At least two, and preferably three, quoted against the same written scope. Quotes for different scopes cannot be compared no matter how many you collect.
Should I always choose the cheapest quote?
Compare total delivered cost for the same scope, not headline prices. Once you add back the items one builder excluded, the ranking often changes.
What if a builder will not answer these questions?
That is an answer in itself. These are reasonable questions about a six figure purchase, and a builder who is uncomfortable with them is telling you something useful.
Ask us all twelve
We would rather answer these before you sign than have you find out afterwards.
Call BlueGum on 1300 060 651, or book a site assessment.
BlueGum Granny Flats is a licensed NSW builder, licence number 247388C, and a member of the Housing Industry Association. HBCF details in this article are drawn from icare NSW as at August 2026. This article is general guidance and not legal advice.
