Detailed permit guide
Why fire safety is checked separately from boundary setbacks—and what it can change in a design.
A structure can be acceptable under the setback rules and still need a separate fire-safety response.
The National Construction Code (NCC) is concerned with limiting fire spread between a property boundary, a home and other buildings. It looks at more than distance: walls, openings, roof construction, materials, attachment and the arrangement of buildings can all affect the outcome.
Do not stop at the setback
Both checks matter near a boundary, but they answer different questions.
Victorian Building Regulations
These rules address where a building sits, including side and rear setbacks, boundary walls and open carports. They also deal with neighbourhood and adjoining-property amenity.
Read the setback guideNational Construction Code
These provisions address the risk of fire spreading to or from a boundary, a Class 1 home and relevant Class 10a buildings. Construction can matter as much as position.
Start the assessment early
The NCC contains several building arrangements, but these distances are useful signals that a detailed fire check is needed.
900 mm
Boundary check
NCC Housing Provisions Part 9.2 includes acceptable arrangements where a Class 10a building sits between or beside a Class 1 home and a boundary. When the relevant building or wall is less than 900 mm from that boundary, fire-resisting construction or another listed arrangement may be needed. Boundaries adjoining a road or public space are treated differently.
1.8 m
Building-to-building check
The 1.8 metre distance appears in several NCC arrangements involving a Class 10a building, a Class 1 home and another building on the same allotment. The exact compliant option depends on which buildings are associated, their relative positions and which wall provides the required protection.
Treat these numbers as prompts for assessment, not pass-or-fail shortcuts. The NCC provides multiple configurations, and measurements are taken to the relevant walls and features—not simply to the fence as it appears on site.
Design responses
When separation alone does not provide the required protection, the construction details become part of the solution.
A wall within the affected area may need a specified Fire Resistance Level (FRL) and construction that continues to the required height or roof junction.
Windows, doors and service penetrations can undermine a fire-resisting barrier. Their location, protection or removal may form part of the compliant design.
Roof coverings, ceilings, soffits, wall cladding and infill at a shared roof space can affect the available pathway, particularly for open carports and attached structures.
Where a standard Deemed-to-Satisfy arrangement does not suit the design, a suitably qualified specialist may need to prepare a Performance Solution for assessment.
Our approach
Fire separation is specialist territory. We bring it into the process at the right time so you are not left trying to interpret it alone.
We consider boundaries, the home and nearby buildings while the layout can still be adjusted.
The permit team obtains the drawings, product information or specialist input needed for the chosen pathway.
The Registered Building Surveyor reviews the proposed construction as part of the building-permit documentation.
We follow the approved plans and details on site, including any required fire-separation construction.
FAQs
Plain-English answers to common design questions.
No. Victorian siting rules and the NCC fire provisions are separate checks. A structure can meet its siting setback and still need a fire-separation response because of its relationship to a boundary, the home or another building.
Not in exactly the same way. The NCC provides several acceptable arrangements and specific provisions for Class 10a buildings and open carports. The answer depends on the structure, its openness, the nearby house or buildings, roof and wall construction, and the boundary involved.
Yes. The NCC includes a specific open-carport concession where conditions for openness, roof and lining materials, structural support and roof-space separation are met. Being called a carport is not enough by itself; the detailed design must satisfy the provision.
It can. Attachment points, shared roof spaces, nearby walls and the way a structure sits between the house and a boundary all need to be considered as part of the complete fire-separation assessment.
The Registered Building Surveyor assesses the building-permit documentation. Depending on the design, supporting details may also be prepared by the designer, engineer, product supplier or another appropriately qualified fire specialist.
Prepared by 2L Constructions and reviewed September 2026. Always use the current NCC requirements for a live project.
NCC Housing Provisions — Part 9.2Start Your Project
Talk to us before fixing the layout. We can coordinate the right checks and help turn the requirements into a practical buildable design.