Last reviewed: August 2026
Most Sydney blocks that are at least 450m², in a residential zone, with 12m of frontage and enough room to keep the required setbacks will qualify for a granny flat through the fast approval pathway. The things that most often disqualify a block are size, frontage, heritage listing, flooding and bush fire.
Here is how to check yours, in order, starting with the questions that rule blocks out fastest.
Step 1: How big is your lot, really?
You need at least 450m² for complying development.
Check the figure on your title or survey, not a real estate listing.
Two traps here:
- Battle-axe blocks. The access handle is excluded from the calculation. A 500m² title with a long driveway strip can land under 450m² once that strip comes out.
- Rounded numbers. A block described as “about 450” is not a block that is at least 450m². The threshold is not negotiable.
If you are under 450m², complying development is off the table. A development application to council is still possible, and is assessed on merit.
Step 2: What is your zoning?
Granny flats are permitted with consent in residential zones R1, R2, R3, R4 and R5.
For the fast complying development pathway, R5 Large Lot Residential is excluded. If you are on an R5 block, a granny flat is still allowed, but through a development application.
Your zoning is on the NSW Planning Portal, or on your council’s mapping tool.
Step 3: How wide is your frontage?
Measured at the building line, and it steps up with lot size.
| Lot area | Minimum frontage |
| 450m² to 900m² | 12m |
| Over 900m² to 1,500m² | 15m |
| Over 1,500m² | 18m |
Older subdivided blocks in the inner and middle suburbs are the ones that most often fail here. A deep, narrow block can easily be over 450m² and still be under 12m wide.
Step 4: Is there room left after the setbacks?
This is the step people skip, and it is the one that decides whether the building actually fits.
Work out your required setbacks for your lot size band, then draw what is left.
| Lot area | Side | Rear (single storey under 3.8m) |
| 450m² to 900m² | 0.9m | 3m |
| Over 900m² to 1,500m² | 1.5m | 5m |
| Over 1,500m² | 2.5m | 10m |
Then subtract:
- Your existing house and any structures staying
- Required landscaped area, which is 20% to 45% depending on lot size, with at least half behind the building line
- Driveway and access to the granny flat
- Any tree with a protection zone
- Sewer or stormwater lines you cannot build over
What is left is your building envelope. If a 60m² rectangle does not fit inside it with room for eaves, the answer is a smaller granny flat or a different position, not a bigger one.
Anything over 3.8m tall increases the setbacks, so a taller design shrinks the envelope further.
Step 5: Is there anything on your land that changes the rules?
Any one of these moves you off the fast pathway.
| Constraint | Effect |
| Heritage item or conservation area | Excluded from complying development |
| Environmentally sensitive land | Excluded from complying development |
| Flood control lot | Additional standards apply, often a DA |
| Bush fire prone land | Additional construction standards, higher ratings usually mean a DA |
| Easement across the building area | You generally cannot build over it |
| Sewer main under the proposed build | Needs a build-over application or a diversion |
| Existing second dwelling on the lot | Only one secondary dwelling is permitted |
None of these are automatic no answers. They are all reasons to take the DA path or to move the building.
Step 6: What is the block physically like?
These do not affect whether you are allowed to build. They affect what it costs.
- Slope, which brings cut and fill and retaining
- Rock, the most common budget blowout
- Soil classification, which sets how heavy the slab needs to be
- Access for a truck and excavator
- Distance to the sewer and stormwater connection points
- Trees requiring removal or protection
The short version
| Question | Qualifies for fast approval |
| Lot at least 450m², excluding any battle-axe handle | Yes |
| Residential zone, not R5 | Yes |
| Frontage meets the band for your lot size | Yes |
| A 60m² footprint fits after setbacks and landscaping | Yes |
| No heritage, flood, bush fire or sensitive land issue | Yes |
| Only one existing dwelling on the lot | Yes |
All six yes, and you are almost certainly on the complying development pathway. Any no, and you are looking at a development application or a redesign.
What if your block does not qualify?
You have more options than people assume.
- A development application. Council assesses on merit and can approve things the fixed checklist cannot.
- A smaller granny flat. If the envelope is tight, a 45m² two bedroom often fits where a 60m² will not.
- Moving the building, or removing a structure that is in the way.
- An internal conversion. A secondary dwelling inside the existing house has a different and simpler set of requirements, with no external alterations beyond one added entrance.
Frequently asked questions
My block is 440m². Is there any way around it?
Not through complying development. 450m² is a threshold, not a guideline. A development application is still open to you and council assesses it on merit, so it is worth asking rather than assuming the answer is no.
Does a pool or shed count against me?
They take up space in your building envelope and count toward site coverage, so they can affect whether a granny flat fits. They do not disqualify you outright. Removing a shed is a common way to free up an envelope.
Can I build a granny flat if I still have a mortgage?
Yes. You will usually need to tell your lender, and if you are borrowing against the property to fund it they will be involved anyway. It is not a planning issue.
How do I find out if my land is flood or bush fire affected?
A planning certificate, often called a 10.7 certificate, from your council lists the constraints applying to your land. It is the document a builder or certifier will ask for.
Can I do this check myself or do I need a professional?
You can do steps 1 to 3 yourself from your title and the planning portal. Step 4 onward really needs someone who can read a survey and knows how the setbacks stack. That is what a site assessment is for.
Have your block checked properly
The six questions above will tell you quickly whether you are likely to qualify. Confirming it takes a look at your survey, your title and your planning certificate.
Check your block, or call BlueGum on 1300 060 651 to book a site assessment.
BlueGum Granny Flats is a licensed NSW builder, licence number 247388C. This article summarises the State Environmental Planning Policy (Housing) 2021 as in force in August 2026 and is general information, not planning advice. Confirm the requirements for your block with a certifier or your council.
