Building: Two storey mixed use alteration: Class 5 consulting suites and Class 9b studios on the ground floor, two new Class 2 apartments above
Location: Gippsland, Victoria
NCC edition: NCC 2022, Volume One
Area of NCC requirements: D1P1 access for people with a disability; D4D2, D4D3, D4D4; AS 1428.1 clause 11.1 stairways
Raised by: The relevant building surveyor, in a request for further information
Year: 2026
The challenge
The two new apartments are reached only by an existing internal stair between fire rated, load bearing masonry walls. AS 1428.1 requires 1000 mm clear between handrails. Measured at four points and allowing 80 mm for one handrail, the stair is 875 mm at its narrowest point, the two step mid landing, and 890 to 995 mm elsewhere. Widening it would mean rebuilding fire rated structural walls and losing floor area.
The performance solution
Expert judgement and comparison with the Deemed to Satisfy Provisions, applying the affected part principle from the Premises Standards guidelines to an existing building:
the shortfall is 125 mm (12.5%) at one point, not along the whole flight
widening means demolishing fire separating, load bearing walls, which is out of proportion to the gain
the stair serves only two apartments reached by stair alone, so the residual risk falls mainly on ambulant people with a mobility impairment
The conditions target that group: a continuous handrail to AS 1428.1 and D3D22 for the full flight with returns at each landing, luminance contrasting nosings, slip resistant treads, and better stair lighting. The 80 mm handrail allowance is to be checked against the handrail actually chosen, and the solution reassessed if the installed clear width differs.
Outcome
Final report issued in August 2026 and successfully accepted by the relevant building surveyor.
Lesson for owners of older buildings
When an existing stair falls short of current access widths, measure it at several points before assuming the whole stair must be rebuilt. The narrowest point sets the question, and targeted upgrades often answer it.
Related: Access performance solutions | Performance solution report
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