How to comply with the Apartment Design Guide

Even after calculating a rough yield, the real number of apartments is usually different, because the Apartment Design Guide decides what will actually fit. Three criteria decide most schemes, and they are the ones to test first: solar access, natural ventilation and communal open space.

Use the free buildable envelope tool below to see the apartment envelope for your address, or follow the compliance steps.

The one number Sydney designers get wrong here

On the Central Coast the solar criterion is 3 hours, not 2. The 2 hour figure everyone quotes is expressly limited to the Sydney Metropolitan Area and the Newcastle and Wollongong local government areas. We are in neither, so the ADG's "all other areas" criterion applies. If a scheme has been tested at 2 hours, it needs to be retested at 3.

The three criteria to check first

1. Solar access (Part 4A). Living rooms and private open spaces of at least 70% of apartments get a minimum of 3 hours direct sunlight between 9am and 3pm at mid winter, and a maximum of 15% of apartments may receive no direct sunlight at all.
2. Natural cross ventilation (Part 4B). At least 60% of apartments naturally cross ventilated in the first nine storeys. Cross through apartments are capped at 18m deep, glass line to glass line.
3. Communal open space (Part 3D). Minimum 25% of the site, with 50% of the principal usable part getting at least 2 hours of direct sunlight between 9am and 3pm on 21 June.

Test all three before the design develops, because they are geometry. Once the massing is settled they are extremely expensive to retrofit, and they are the criteria councils enforce most rigorously.

Minimum apartment sizes (Part 4D)

| Apartment | Minimum internal area | |---|---| | Studio | 35m² | | 1 bedroom | 50m² | | 2 bedroom | 70m² | | 3 bedroom | 90m² |

Those minimums include only one bathroom. Each additional bathroom raises the minimum by 5m², and a fourth bedroom and each one after that raises it by 12m². This is worth reading carefully, because it is commonly misquoted as a studio being 30m²: the 5m² is an addition to the minimum, not part of the base figure.

Apartment size (Part 4D) and ceiling heights (Part 4C) are non-discretionary standards under the Housing SEPP, which cuts both ways. Comply and council cannot demand more. Fall short and there is no argument available.

Ceiling heights (Part 4C)

Minimum 2.7m for habitable rooms and 2.4m for non-habitable. In mixed use areas the ground and first floor go to 3.3m to keep future uses open.

Then check again

1. Check the minimum areas for storage, living areas, private open space and bedrooms.
2. Recheck solar access, ventilation and communal open space once the design is resolved, because they move as the massing moves. Use solar access diagrams to demonstrate compliance to council.

Which projects this applies to

The ADG is picked up through Chapter 4 of the Housing SEPP, which replaced SEPP 65 in December 2023 (the term SEPP 65 is still what everyone says, but the instrument is the Housing SEPP now). It catches residential flat buildings, shop top housing and mixed use with a residential component, where the building is at least 3 storeys (not counting underground car parking storeys) and has at least 4 dwellings.

It does not apply to seniors housing, which has its own Seniors Housing Design Guide.

One nuance worth knowing: the Housing SEPP requires councils to consider the ADG, and then says explicitly that this does not require compliance with the design criteria. In practice the three big criteria are enforced hard, so design to them. On a genuinely constrained site, a well argued and well drawn variation is still worth putting to council.

If you want to know what your site will actually yield under these rules before you commit to it, send me the address.