Most patios and carports in South East Queensland need only a building approval from a private certifier. Overlays are what change that. An overlay is a map in the council’s planning scheme marking land with a hazard or something to protect, and if your lot sits in one, extra rules apply even to a small roof.
Flood
Councils map flood hazard areas and set a defined flood level for each lot. Inside the flood overlay, a carport or patio that would normally be accepted picks up mandatory requirements, and a design that cannot meet them goes to council.
- Open structures are judged on whether they block flood water, so walls and solid screens are the usual problem.
- Materials must handle getting wet, and posts must be anchored against floating debris and flow.
- In Logan’s high and moderate flood areas, a carport roof has to sit above the defined flood level unless an engineer certifies it for the flood loads, and only a fence is accepted in a mapped high-flow area.
Bushfire (BAL)
In a bushfire prone area the build gets a bushfire attack level (BAL), worked out from the vegetation type, the slope and the distance to it, under AS 3959. The ratings run BAL-12.5, 19, 29, 40 and flame zone, and the construction gets stricter at each step.
- A carport, patio or deck attached to the house, or within 6 m of it, must meet the same bushfire standard as the house unless it is fire separated.
- Freestanding and further away, it usually escapes the construction standard, so where you put it can be the cheapest fix.
- Steel framing and Colorbond roofing suit bushfire areas well; the details (gaps, gutters, screens) are what the BAL controls.
Landslide and steep land
On mapped steep or landslide land, the ground itself is assessed. Expect a geotechnical report before the design is accepted, and footings designed by an engineer rather than standard ones.
- In Logan, slopes of 12% or more need a site specific geotechnical report showing a factor of safety above 1.5, and cut and fill is held to 40 m³.
- Stormwater is designed at the same time, because concentrated runoff is what moves slopes.
Heritage and character
Heritage and character overlays control how a place looks, not just how it is built. A carport visible from the street can need approval before anything else, while a patio at the back is often fine. In Brisbane, pre-1947 homes in the traditional building character overlay restrict structures in front of the house, and Logan makes any building work in its heritage overlay code assessable.
Vegetation
Clearing for a slab, footings or a trench counts as clearing. In a vegetation overlay, or under Brisbane’s natural assets local law, a permit can be needed before any site work. Designing around the trees is usually faster than applying to remove them.
Easements and pipes
A registered easement for sewer, water, stormwater or power gives the owner of that service a say over anything built on or near it, even if no pipe was ever laid. See our guide to building near a sewer for the distances.
What is changing
- Queensland’s new draft State Planning Policy proposes one statewide method for flood mapping.
- Logan’s temporary flood rules (TLPI 1/2024) expire on 6 March 2027 unless replaced sooner.
- Brisbane is updating its bushfire hazard policy in amendment package S.
How to check your lot
Each council has an online map showing the overlays on your property. You can also see setbacks, overlays and sewer lines on one site plan with RapidSitePlan. Or simply ask us: we check every overlay before we quote, so there are no surprises at approval time.