Our sloping Canberra block makes a step-free entry very hard. The certifier mentioned the livable housing provisions have an out for exactly this. When is step-free entry required and what relief exists?

The certifier is right that there is an out, but it is narrower than "the block is steep". Under NCC 2025 the exemption needs two things to be true at once, and even when it applies it only switches off the step-free access path. The rest of the livable housing requirements still apply. [2]

First, check which edition you are on. The ACT is on NCC 2022 today, and until 30 April 2027 building work can elect NCC 2025 instead, with one edition nominated at lodgement and no mixing of provisions. The provisions below are the NCC 2025 ones. If your project is on NCC 2022, have your certifier confirm the 2022 wording rather than assuming it is identical.

What step-free entry requires. A Class 1a dwelling must comply with the ABCB Standard for Livable Housing Design. [2] The access part of that requires a continuous path to a dwelling entrance door from one of: [1] [3]

• the pedestrian entry at the allotment boundary;
• an appurtenant Class 10a garage or carport; or
• a car parking space on the allotment for the exclusive use of the occupants.

The path must have no steps, a maximum gradient of 1:14 in the direction of travel, crossfall no steeper than 1:40, and a minimum width of 1000 mm. [3] Ramping is capped: the aggregate ramp length (excluding landings) must not exceed 9 m at 1:14 or 15 m at 1:20, interpolated in between, with a landing at least 1200 mm long at each end of a ramp. [3] One step ramp is allowed, up to 190 mm high, no steeper than 1:10 and no longer than 1900 mm. [3]

Those ramp caps are what bite on a sloping block. 9 m at 1:14 climbs only about 640 mm, and 15 m at 1:20 climbs 750 mm. Past that, a complying ramp is not available.

The relief: H8D2(2). Clause 1.1 of the Standard (the step-free access path) need not be complied with if both of these apply: [2]

• (a) step-free access via an appurtenant garage, carport or parking space is not provided; and
• (b) one or more of these conditions exists:
  • (i) the average slope of the ground on which the access path would be constructed is steeper than 1:14;
  • (ii) an external step-free path would need ramping beyond the length and gradient limits above;
  • (iii) there is not enough space on the allotment for a complying path; or
  • (iv) the level difference from the pedestrian entry or parking space to the entrance door floor level would need ramping beyond those limits.

For (iv), the level is measured from the floor at the entrance door, or, if an attached deck or balcony gives a step-free connection to the door, from the lowest point of that deck or balcony above the surface beneath. [2]

The two traps.

• Slope alone is not enough. The explanatory information under H8D2 is explicit that the exemption applies only if both (a) and (b) apply, not just one or the other. [2] A step-free route from the garage, carport or parking space is itself a compliance route. So on many sloping blocks the question is whether that route can be designed in, not whether the front path is too steep.
• The exemption is partial. Even if Clause 1.1 is not complied with, all other relevant provisions of the Standard must still be complied with. [2] A steep block gets you out of the path, not out of livable housing.

Practical next step. Before relying on the exemption, get the designer to document which (b) condition applies, with levels, and why step-free access from the garage, carport or parking space is not provided. That is the evidence the certifier will need to sign off on the out they have mentioned.