Ten questions to ask any granny flat supplier before you sign

1. Is that the total, or the box?

Ask for one written number that includes the home, freight, delivery, craneage or on-site build, foundations, water, wastewater and power connections, hot water, the PIM and paperwork, and council development contributions. If any of those are missing, add them yourself before comparing prices. They can be a third of the total.

2. Who does the site work, and is it in the price?

Some suppliers deliver to the kerb and leave you to find a crane crew, a plumber, a drainlayer and an electrician. Ask exactly who turns up on site, who books them, and whose price they are on.

3. Does my design qualify for the 70m² exemption on my section?

Not just does the product qualify in principle. Ask whether it qualifies on your site, with your boundaries, your hazards and your construction type, and who checks that before you commit.

4. What about the council charges?

Development contributions and, in Auckland, the Watercare growth charge arrive whether or not a building consent is needed. Ask whether they are in the quote and how they were calculated for your address.

5. Who is the licensed building practitioner on my job?

Restricted building work must be done or supervised by an LBP, and you will need their record of work at the end. Ask for the name and licence number of the person who will sign it.

6. What documents do I get at handover?

With no council inspection there is no code compliance certificate, so the document pack is your proof. You should receive final plans, records of work, a certificate of work from the designer, and the electrical and gas certificates. Ask to see a sample pack.

7. Does it meet the current insulation standard?

The Building Code applies in full to exempt work, including H1 energy efficiency. Ask for the R-values and whether the design has been checked against the current H1 requirements for your climate zone.

8. What is the warranty, and who honours it?

Ask for the structural and fixtures warranty in writing, and who you call if the supplier is an importer and the factory is overseas.

9. When do I pay, and how much?

Deposit, progress payments and final payment should line up with milestones you can see: order, arrival, install, handover. Be cautious of paying the full balance before the home has reached your section.

10. Can I see one, and talk to someone who has one?

A finished home and a customer who will take a call are worth more than any brochure. If a supplier has neither, ask why.

We answer all ten in writing as part of every quote. If a supplier will not, that is an answer too.