StandAId › NCC explained › How far a shed or garage (Class 10a) has to be from the house and other sheds
A shed, garage or carport is a Class 10a building, and the NCC treats it as a fire risk to the house next to it. The rules come down to distances and fire-rated walls: a Class 10a building generally needs to be a set distance from the allotment boundary, from the house, and from other Class 10a buildings — or the wall facing them needs a fire-resistance level (FRL).
The number people ask about most is the 1.8 m: where two or more Class 10a buildings sit between different houses on the same block, they need to be at least 1.8 m apart or built with FRL walls. There are separate provisions for carports, which get an exemption if they're open enough.
Below are the core Part 9.2 clauses. Western Australia has its own Part 9.6 for roofed outdoor areas (patios, alfrescos) — see the separate WA page.
This page is a plain-English guide written by StandAId, followed by the actual NCC 2025 clause text. It is not professional advice and StandAId is not endorsed by the ABCB — always check the current edition on ncc.abcb.gov.au and your state's requirements.
(1) An external wall (including a gable) required to be fire-resisting (referred to in 9.2.1 or 9.2.4) must—
(a) commence at the footings or ground slab, except where the external wall commences above a separating wall complying with 9.3.1 (see Figure 9.2.2e); and
(b) extend to—
(i) the underside of a non-combustible roof covering, except that a wall may terminate not more than 200 mm from the underside of a non-combustible roof covering, where the area between the external wall and underside of the roof covering is sealed with a non-combustible fascia, gutter or flashing; or
(ii) the underside of a non-combustible eaves lining (See Figures 9.2.3a and b); and
(c) be constructed in accordance with (2).
(2) A wall required by (1) must—
(a) have an FRL of not less than 60/60/60 when tested from the outside; or
(b) be of masonry-veneer construction in which the external masonry veneer is not less than 90 mm thick; or
(c) be of masonry construction not less than 90 mm thick.
(3) Openings in external walls required to be fire-resisting (referred to in 9.2.1 or 9.2.4) must be protected by—
(a) non-openable fire windows or other construction with an FRL of not less than –/60/–; or
(b) self-closing solid core doors not less than 35 mm thick.
(4) The requirements of (3) do not apply to a window in a non-habitable room that is located adjacent to and not less than 600 mm from the boundary of an adjoining allotment or 1.2 m from another building on the same allotment provided that—
(a) in a bathroom, laundry or toilet, the opening has an area of not more than 1.2 m2; or
(b) in a room other than one referred to in (a), the opening has an area of not more than 0.54 m2 and—
(i) the window is steel-framed, there are no opening sashes and it is glazed in wired glass; or
(ii) the opening is enclosed with translucent hollow glass blocks.
(5) Subfloor vents, roof vents, weepholes, control joints, construction joints and penetrations for pipes, conduits and the like need not comply with (3).
[See Figure 9.2.3a — Typical construction of external walls]
[See Figure 9.2.3b — Typical construction of external walls — attached Class 1 buildings on the same allotment]
Explanatory information: • A Performance Solution must be used where an external wall required to be fire-resisting does not commence in accordance with 9.2.3(1)(a). • The intent of the typical construction details shown in Figures 9.2.3a and b are to ensure that combustible materials (external or internal) are not directly exposed to fire at the junction of the wall and non-combustible roof, eaves lining, guttering and the like. Other forms of construction may also be acceptable provided that they achieve this intent. • See Figure 9.2.2a and clause 10.7.3 for internal separating wall construction under one common roof.
Figures referenced (view on the ABCB site — images aren't reproduced here):
(1) The following methods are acceptable for the protection of a Class 1 building where a Class 10a building is located between or adjacent to a Class 1 building and a boundary alignment that is not a boundary with a road alignment or other public space:
(a) The Class 10a building is not less than 900 mm from the allotment boundary, other than the boundary adjoining a road alignment or other public space, as shown in Figure 9.2.5a.
(b) An external wall of the Class 10a building which is less than 900 mm from an allotment boundary, other than the boundary adjoining a road alignment or other public space, complies with 9.2.3 as shown in Figure 9.2.5b.
(c) An external wall of the Class 10a building, which is less than 900 mm from the Class 1 building, complies with 9.2.3 as shown in Figure 9.2.5c.
(d) The Class 1 building is not less than 900 mm from the Class 10a building, as shown in Figure 9.2.5d.
(e) An external wall of the Class 1 building, which is less than 900 mm from the Class 10a building, complies with 9.2.3, as shown in Figure 9.2.5e.
(f) An external wall of the Class 10a building which is less than 900 mm from an allotment boundary other than the boundary adjoining a road alignment or other public space, complies with 9.2.3, as shown in Figure 9.2.5f.
(g) An external wall of the Class 10a building, which is less than 900 mm from the external wall of the Class 1 building, complies with 9.2.3, as shown in Figure 9.2.5g.
(h) An external wall of the Class 1 building, which is less than 900 mm from a Class 10a building that is situated less than 900 mm from an allotment boundary, complies with 9.2.3, as shown in Figure 9.2.5h.
(i) The external wall of the Class 1 and Class 10a building which are less than 900 mm from an allotment boundary, other than the boundary adjoining a road alignment or other public space, complies with 9.2.3 as shown in Figure 9.2.5i.
[See Figure 9.2.5a — Class 10a building 900 mm from allotment boundary]
[See Figure 9.2.5b — External wall to Class 10a building with FRL (method 1)]
[See Figure 9.2.5c — External wall to Class 10a building with FRL (method 2)]
[See Figure 9.2.5d — 900 mm separation between buildings]
[See Figure 9.2.5e — Class 1 building with FRL to external wall]
[See Figure 9.2.5f — External wall of adjacent Class 10a building with FRL (method 1)]
[See Figure 9.2.5g — External wall of adjacent Class 10a building with FRL (method 2)]
[See Figure 9.2.5h — Class 1 building with FRL to external wall]
[See Figure 9.2.5i — External wall to Class 10 building with FRL]
Figures referenced (view on the ABCB site — images aren't reproduced here):
(1) The following methods are acceptable for the protection of a Class 1 building where a Class 10a building is located between or adjacent to a Class 1 building it is associated with and another building on the same allotment:
(a) The Class 10a building is not less than 1.8 m from the other building, as shown in Figure 9.2.6a.
(b) An external wall of the Class 10a building, which is less than 1.8 m from the other building, complies with 9.2.3, as shown in Figure 9.2.6b.
(c) An e xternal wall of the Class 10a building, which is less than 1.8 m from the Class 1 building, complies with 9.2.3, as shown in Figure 9.2.6c.
(d) The Class 1 building is not less than 1.8 m from the Class 10a building, as shown in Figure 9.2.6d.
(e) An external wall of the Class 1 building, which is less than 1.8 m from the Class 10a building, complies with 9.2.3, as shown in Figure 9.2.6e.
(f) An external wall of the Class 10a building, which is less than 1.8 m from the external wall of the other building, complies with 9.2.3, as shown in Figure 9.2.6f.
(g) An external wall of the Class 10a building, which is less than 1.8 m from the external wall of the Class 1 building, complies with 9.2.3, as shown in Figure 9.2.6g.
(h) An external wall of the Class 1 and 10a building, which is less than 1.8 m from the external wall of the other building, complies with 9.2.3, as shown in Figure 9.2.6h.
[See Figure 9.2.6a — Class 10a building 1.8 m from other building on allotment]
[See Figure 9.2.6b — External wall to Class 10a building with FRL (method 1)]
[See Figure 9.2.6c — External wall to Class 10a building with FRL (method 2)]
[See Figure 9.2.6d — 1.8 m separation between Class 1 and 10a]
[See Figure 9.2.6e — Class 1 building with FRL to external wall]
[See Figure 9.2.6f — External wall of adjacent Class 10a building with FRL (method 1)]
[See Figure 9.2.6g — External wall of adjacent Class 10a building with FRL (method 2)]
[See Figure 9.2.6h — Class 1 and 10 building with FRL to external wall]
Figures referenced (view on the ABCB site — images aren't reproduced here):
(1) The following methods are acceptable for the protection of a Class 1 building where two or more Class 10a buildings on the same allotment are located between and are associated with different Class 1 buildings:
(a) Each Class 10a building must be separated from each other by a distance of not less than 1.8 m, as shown in Figure 9.2.7a.
(b) Each Class 10a building must be separated from each other by external walls complying with 9.2.3, as shown in Figure 9.2.7b.
(c) Each Class 10a building must be separated from each Class 1 building by a distance of not less than 900 mm, as shown in Figure 9.2.7c.
(d) Each Class 10a building must be separated from each Class 1 building by external walls complying with 9.2.3, as shown in Figure 9.2.7d.
(e) Each Class 10a building must be separated by a wall complying with 9.3.1, as shown in Figure 9.2.7e.
(f) Each Class 10a building must be separated from each other by external walls complying with 9.2.3, as shown in Figure 9.2.7f.
(g) Each Class 10a building must be separated from each Class 1 building by external walls complying with 9.2.3, as shown in Figure 9.2.7g.
(h) Each Class 10a building must be separated by a wall complying with 9.3.1, as shown in Figure 9.2.7h.
[See Figure 9.2.7a — 1.8m separation between Class 10a buildings]
[See Figure 9.2.7b — External wall to Class 10a building with FRL (method 1)]
[See Figure 9.2.7c — 900 mm separation between Class 10a and Class 1 buildings]
[See Figure 9.2.7d — External wall to a Class 10a buildings with FRL (method 2)]
[See Figure 9.2.7e — Class 10a buildings with FRL to separating wall (method 1)]
[See Figure 9.2.7f — External wall to adjacent Class 10a buildings with FRL (method 1)]
[See Figure 9.2.7g — External wall to adjacent Class 10a buildings with FRL (method 2)]
[See Figure 9.2.7h — Class 10a buildings with FRL to separating wall (method 2)]
Figures referenced (view on the ABCB site — images aren't reproduced here):
(1) A Class 10a carport is exempt from complying with 9.2.4(1) if—
(a) it has two or more sides open and not less than one third of its perimeter open; and
(b) for the purposes of (a), a side is considered to be open if the roof covering adjacent to that side is not less than 500 mm from another building on the same allotment or allotment boundary; and
(c) it has a polycarbonate or non-combustible roof covering; and
(d) any ceiling lining and wall cladding, including gables, is non-combustible (see Figure 9.2.8a); and
(e) it does not provide direct vertical support to any part of the Class 1 building; and
(f) in the case where it has a common roof structure with the Class 1 building and the carport does not have a ceiling (See Figure 9.2.8b), the opening between the top of the wall of the Class 1 building and the underside of the roof covering is infilled with—
(i) a non-combustible material; or
(ii) construction clad with non-combustible material on the carport side.
[See Figure 9.2.8a — Identifying an open carport]
[See Figure 9.2.8b — Requirements for non-combustible infill panels to carport]
Explanatory information: A side of a carport enclosed by a vehicle access door is not considered to be an open side.
Figures referenced (view on the ABCB site — images aren't reproduced here):
State variation: this clause is varied in South Australia. Check the state schedule on the ABCB site, or set your state in StandAId to get the right version.
Got a follow-up? StandAId answers questions on the text of the NCC 2025 — Volumes One, Two, Three and the Housing Provisions — with the clause linked. Free account, 3 questions a day; upload your own standards for more.
Ask the NCC in StandAId — free, 3 questions a dayUnder the Housing Provisions a Class 10a building's external wall generally needs to be at least 900 mm from the allotment boundary or have the required FRL — read 9.2.5 and 9.2.6 for the conditions.
Where two or more Class 10a buildings are between and associated with different Class 1 houses on the same allotment, they must be at least 1.8 m apart or separated by walls with the required FRL. See 9.2.7.
No — an open carport can be exempt from some fire separation requirements if it meets the openness conditions in 9.2.8.
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