Building: Specialist Disability Accommodation (SDA) shared house, approved as Class 3
Location: Inner north west Melbourne
NCC edition: NCC 2022, Volume One
Area of NCC requirements: F7P2 sound transmission and insulation; F7D4 and F7D6 walls between sole occupancy units
Raised by: The relevant building surveyor
Year: 2026
The challenge
An SDA dwelling is approved as Class 3, so each bedroom is treated as a sole occupancy unit. Under F7D4 and F7D6 that means rated airborne and impact sound insulation in every wall between bedrooms. For a shared home designed around residents living together with a live in carer, that adds cost and construction without matching how the building is actually used.
The performance solution
Expert judgement and comparison with the Deemed to Satisfy Provisions. The report looked at how the building operates rather than only its label:
The NDIS describes SDA as a home that maximises independence within contemporary housing, not an institution.
Day to day, residents share the house like a Class 1b boarding house or hostel, and the occupant numbers sit within the Class 1b limit in A6G2(b)(i)(A).
In a Deemed to Satisfy Class 1b building the whole dwelling is one sole occupancy unit, and Part 10.7 of the Housing Provisions does not require sound insulation between bedrooms in the same dwelling.
The building is sprinklered, which allows concession S5C10, so bedroom walls do not need fire separation either. That supports treating the bedrooms as rooms in one home rather than separate units.
The report weighed the function, location and users of the building, the presence of staff, and the nature and frequency of use, and found F7P2 met without detriment to residents' amenity.
Outcome
Final report issued in August 2026, peer reviewed, and successfully accepted by the relevant building surveyor.
Lesson for SDA developers
Class 3 rules written for residential care do not always fit a shared SDA home. Raise sound insulation with your building surveyor early, before wall types are locked in.
Related: Performance solution report | Access performance solutions
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