What fire separation is required for my secondary residence?
The fire-separation requirements for a secondary residence depend on how close it is to the main dwelling, other buildings and the property boundaries.
Under the NCC, fire-resisting construction is generally required where a Class 1 building is less than 900 mm from a property boundary (other than a boundary adjoining a road or public space), or less than 1.8 m from another building on the same block, subject to the applicable exceptions.
Where a wall is required to be fire-resisting, the NCC provides compliant construction methods, including walls achieving an FRL of at least 60/60/60 or specified masonry construction.
If the secondary residence is attached to another Class 1 dwelling, additional requirements for separating walls may apply.
The exact fire-separation requirements should be confirmed by the building certifier based on the particular design and the version of the NCC being used for the Building Approval.
Reference: National Construction Code – Volume Two, Part H3 Fire Safety; ABCB Housing Provisions, Part 9.2 Fire Separation of External Walls & Part 9.3 Fire Protection of Separating Walls and Floors – https://ncc.abcb.gov.au/editions/ncc-2022/adopted/volume-two/h-class-1-and-10-buildings/part-h3-fire-safety?utm_source
Short Answer
Fire separation depends on the location and design of the secondary residence. Generally, fire-resisting construction may be required where a Class 1 building is less than 900 mm from a property boundary or less than 1.8 m from another building on the same block. Additional fire-separation requirements may apply where dwellings are attached.
Detailed Explanation
Fire separation for a secondary residence is determined under the National Construction Code (NCC) according to the classification, location and configuration of the buildings.
For Class 1 buildings, fire-resisting construction is generally required where an external wall is less than 900 mm from an allotment boundary (other than a boundary adjoining a road or public space), or less than 1.8 m from another building on the same allotment, subject to the applicable NCC exceptions.
Where fire-resisting construction is required, the NCC specifies compliant construction methods, which may include walls achieving an FRL of not less than 60/60/60 or prescribed masonry construction. Where Class 1 dwellings are attached, additional requirements relating to separating walls may apply.
The specific requirements must be determined from the building classification and proposed design under the applicable NCC edition used for Building Approval.
No minimum block size does not remove the need for planning assessment.
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