Big Small Haus is a licensed Queensland builder, QBCC 15506005, and the authorised installer for Outhaus. We install and build granny flats across the Redlands: Capalaba, Alexandra Hills, Birkdale and Wellington Point, the canal estates at Raby Bay, south to Redland Bay and Mount Cotton, and over the water to the Southern Moreton Bay Islands.
Redland allows some of the biggest granny flats in SEQ. The size caps sit in a council guideline rather than the City Plan, which is why some pages still say there's no limit. There is.
| Rule | What it says |
|---|---|
| Maximum size | 85 m² GFA on lots under 1,000 m²; 112 m² on 1,000 m² or more; 160 m² in the Rural zone on 6,000 m² or more |
| Setbacks | Must meet the Queensland Development Code acceptable solutions |
| Minimum lot | None for a granny flat today |
| If you miss size or setbacks | Council is referred the building application before the certifier decides |
| Infrastructure charges | Only on granny flats over the size caps |
Canal estates
Raby Bay, Sovereign Waters and Aquatic Paradise carry extra setbacks from the revetment wall and canals. The pending amendment also proposes a 600 m² minimum lot and 15 m frontage there.
Coming: Amendment 02/25
Council asked the Planning Minister in July 2026 to approve a residential amendment that moves the same size caps into a new City Plan code. Going over the cap would then need a code assessable application. Not adopted yet.
Islands and rural lots
Overlays for bushfire, coastal, flood and storm tide, landslide and environmental values apply across the city. Rural lots in the Tingalpa Reservoir catchment have their own wastewater rules.
Rules that apply across Queensland
- You can rent a granny flat to anyone, not only family. The state removed the family-only test in September 2022. It still has to be secondary to the main house and can't be sold separately.
- You always need a building approval from a licensed certifier, and a plumbing approval from council.
- Queensland's new Housing Code started on 1 September 2026 with new setbacks. Each council keeps its current rules until it adopts the new code, by 1 September 2029 at the latest.
What we'd check on your block
The zone and the size cap, lot size, every overlay, where the sewer runs, the slope, and whether a truck and crane can get in. Send us the address and we'll tell you straight.
Getting a granny flat in on a Redland block
Water and sewer: Redland City Council
Redland runs its own water and sewer, so council owns the pipes as well as the planning rules. Its fact sheet on building near infrastructure lists secondary dwellings by name. No referral is needed if the granny flat sits at least 1.5 m from the centre of a manhole, 1.2 m from underground sewer, stormwater or water pipes, 1 m clear of all connection points in every direction, with 2.4 m of height clearance. Bigger mains, sewers over 225 mm and stormwater over 375 mm, need 3 m. Miss any of those and it's a concurrence agency referral to council, with a fee, RPEQ-certified drawings and the engineer's Form 15.
Council also says not to build over or plant big trees near connection points, and that sub-meters on an existing property need an assessment and a quote. By default a granny flat shares the house's connections with one bill; the Queensland Government confirms an owner can split them, at a connection charge.
Islands, canals and the bush
The Southern Moreton Bay Islands are a different game for wastewater. Council's septic page says most older island houses have separate septic and sullage systems, and every new house there needs a combined system, an all-purpose septic tank or a household sewerage treatment plant, and on an unsewered lot it recommends keeping footings at least 2 m from the disposal area on level ground or downhill, and 4 m when the trenches are uphill. On a small island lot, that disposal area can decide where the granny flat goes.
Canal estates at Raby Bay, Sovereign Waters and Aquatic Paradise carry extra setbacks from the revetment wall, and the bushfire, coastal, flood and storm tide overlays above apply across the city.
Crane access in the Redlands
On the mainland it's the usual mix: generous suburban lots in Alexandra Hills and Capalaba, tight canal streets at Raby Bay, and bush blocks with trees in all the wrong places at Mount Cotton. The islands are their own job. There's no bridge, so the truck, the crane and the barge all have to line up on the same day, along with the tides and the weather. It can be done, and it's worth planning in that order.
What an install costs in the Redlands
Most installs run $70,000 to $140,000 inc GST, on top of the price of the home. In the Redlands it climbs with an island delivery, where the barge and a crane on the island add to the transport line, an on-site wastewater system on an unsewered lot, which roughly doubles the plumbing line, a council main or manhole in the way, and crane work near a canal wall. A mainland lot with the sewer close and room for the crane sits at the lower end. Council only charges infrastructure charges on granny flats over the size caps.
Questions about granny flats in the Redlands
Is there a size limit on a Redland granny flat?
Yes. 85 m² on lots under 1,000 m², 112 m² on 1,000 m² or more, and 160 m² in the Rural zone on 6,000 m² or more. The caps sit in council's Amenity and Aesthetics Guideline, which is why some pages say there's no limit.
How close can a granny flat be to the sewer?
Without a referral: 1.5 m from the centre of a manhole, 1.2 m from the pipe, 1 m clear of connection points and 2.4 m of height clearance, or 3 m from sewers over 225 mm. Closer than that needs a concurrence agency referral to council.
I'm on Russell or Macleay Island with a septic. Can I add a granny flat?
Possibly, if the size, setbacks and wastewater all work. New houses on the islands need a combined septic or a household treatment plant, and council recommends footings 2 m from the disposal area on level ground, 4 m upslope.
Is the amendment law yet?
No. Council asked the Planning Minister in July 2026 to approve Amendment 02/25, which moves the size caps into a new City Plan code. Until it's adopted, the guideline caps apply.
Does Redland charge infrastructure charges?
Only on granny flats over the size caps.
Can I rent it out?
Yes, to anyone, since the state removed the family-only test in September 2022. It stays part of the house and can't be sold separately.
Read next
- Queensland granny flat rules, explained
- Owner builder or licensed builder on a modular home
- Renting out a granny flat
- What a granny flat costs in SEQ
- Free block check
- Granny flats in Brisbane
- Granny flats in Logan
- Granny flats in Gold Coast
- Our jobs, on the tools
- Redland Amenity and Aesthetics Guideline
- Redland, dual living and secondary dwellings
- Redland City Plan amendments
- Redland City Plan amendments list
- Queensland Government, secondary dwelling changes
- Ministerial statement, Queensland Housing Code
- Business Queensland, SEQ water and sewerage service providers
- Redland, building over or near relevant infrastructure fact sheet
- Redland, water and sewerage connections
- Redland, maintaining a septic system
- Queensland Parliament, Question on Notice 1574 (2023), secondary dwelling utilities and charges