Granny flat questions,
answered

Short answers to the questions we hear most.
Each one links to a longer guide if you want the detail.

Builder Licence 247388C

HIA member

HIA GreenSmart

In-house approvals, not outsourced

NSW Fair Trading

Can I build one?

Can I build a granny flat on my property?

Often, yes. On the fast approval path your lot needs to be at least 450 m² and in a residential zone. It also needs to be at least 12 m wide at the building line, for lots of 450 to 900 m². If your block misses one of those, a council DA may still work. The NSW granny flat rules page has every number, or check your block.

Can I build a granny flat on a block under 450 m²?

Not as complying development. 450 m² is the minimum for the fast path. On a smaller block you need a development application, and council decides on merit, so approval is not guaranteed.

How big can a granny flat be?

Up to 60 m² of floor area on most NSW blocks, unless another planning rule on your land allows more. Some councils, such as Canterbury-Bankstown, have a clause that lets a granny flat go bigger on a large enough property. Your council’s page on our site says if yours does.

Is there a limit on bedrooms?

Not in the state rules. Of the 17 council areas we have checked, 2 have a local 2-bedroom control: Penrith and the former Pittwater area of Northern Beaches. Both apply only to a development application.

Can I sell the granny flat separately?

No. The state rules do not allow the lot to be subdivided, so the granny flat stays on the same title as the house.

Approval

Do I need council approval to build a granny flat?

You need an approval, but not always from council. If your block meets the state standards, a private certifier approves it as complying development (a CDC). Council decides only when it goes as a development application (a DA). About 9 in 10 granny flats go the CDC way. We manage both in-house. How approvals work

What is the difference between a CDC and a DA?

A CDC is checked by a private certifier against a fixed state checklist and cannot be refused if you comply. A DA is assessed by your council on merit, against its own development control plan as well. A CDC usually takes 4 to 6 weeks. A DA typically takes 3 to 6 months. CDC or DA guide

Time

How long does it take to build a granny flat?

12 weeks to build, from slab to handover. Before that, approval takes 4 to 6 weeks on a CDC or 3 to 6 months on a DA, and the survey, reports and drawings come first. Our process

Can I live in the main house while you build?

Yes, in almost all cases. Part of the yard will be closed off and there will be noise, but the house stays liveable.

Cost

How much does a granny flat cost in Sydney?

With BlueGum, the base build costs:

Build	Price range
Studio	$118,990 to $140,000
1-bedroom	$125,000 to $160,000
2-bedroom	$134,990 to $174,000
3-bedroom	$145,000 to $186,000

Plans and approvals, council fees and non-standard site works are extra, usually $14,000 to $39,000. Cost guide

What is in the price?

The base build from slab to final clean, with the kitchen, bathroom and flooring. What is included

Is the price fixed?

Yes, once we have inspected your block. The quote lists what is included and what is not, line by line.

Renting it out

Can I rent out my granny flat?

Yes. In NSW a granny flat can be rented to anyone, including people who are not family. What you cannot do is subdivide it and sell it. Our guide to renting out your granny flat covers what landlords need to get right.

How much rent does a granny flat earn?

It depends on the suburb, the size and the finish. Each of our suburb pages gives an estimate for that area, and our rental yield guide shows how to work out a return.

Insurance

Is my granny flat build insured?

NSW law requires Home Building Compensation Fund (HBCF) cover on home building work over $20,000, including GST, before work starts or any payment is taken. It covers major defects for 6 years and other defects for 2 years, as a last resort if the builder cannot fix them. HBCF guide

Still have a question?

Check whether your block qualifies, or call BlueGum on 1300 060 651.

Check My Property Eligibility

Or call our team on 1300 060 651

Building granny flats since

Since 2012

Builder licence

247388C, verifiable through NSW Fair Trading

Industry body

Housing Industry Association member

MBA NSW Excellence in Housing Awards

Winner 2021, Winner 2023, Finalist 2020

Completed granny flats documented on this site

70+

Approvals

CDC and DA, both managed in-house

Pricing

Fixed price after a site assessment, 2-bedroom from $134,990