Rooftop solar PV · NCC Part J9
NCC 2025 asks for solar PV on the roof area that isn't excluded, or a minimum output per square metre of conditioned space. Shading, plant and terraces decide which roof counts, and the surveyor will ask how you measured it. We model the shading, map the eligible area and coordinate with your Section J.
Send us your roof plan and site context.
[Why it matters]
NCC 2025 moved J9D5 from "leave room for solar" to "install solar". For Class 3 and 5–9 buildings, PV must cover the roof area except areas shaded for more than 25% of annual daylight hours, plus other listed exclusions. The alternative is to meet a minimum peak output per m² of conditioned space. Shading therefore sets your compliance obligation. We model the roof, map the shaded area against the 25% test, and document the PV area and exclusions for your Section J report.
And you install panels that won't perform.
And the building surveyor asks for evidence you don't have.
[What does NCC 2025 J9D5 require?]
PV covering 100% of the roof area, excluding areas that are shaded for more than 25% of annual daylight hours; pitched over 45°; awnings, car parks, roof gardens or occupied terraces; roof lights and translucent roofing; trafficable, height safety and maintenance access paths, or paths of travel to an exit; plant and services areas; above exhaust air flows; or impractical for panel size or mounting.
Or a minimum peak PV output per m² of conditioned space (Table J9D5a). For climate zones 2–7 this is 65 W/m² for Class 5, 6 and 7, and 40 W/m² for Class 3 and 9. Buildings using gas need additional PV capacity (Table J9D5b); those panels must not be shaded for more than 25% of daylight hours or pitched over 45°. The requirement doesn't apply where 100% of the effective roof area is shaded for more than 70% of annual daylight hours, or where equivalent on-site renewable generation is provided.
Switchboard: at least 2 empty three-phase breaker slots and 4 labelled DIN rail spaces for a future battery. This doesn't apply if a battery is installed.
Still current where NCC 2025 isn't yet adopted. Same switchboard provisions. At least 20% of the roof area must be kept clear for future PV. The exemptions include where the whole roof is shaded for more than 70% of daylight hours.
Since Amendment VC267 (in operation 31 March 2025), Clause 55.05-2 (Overshadowing domestic solar energy systems), Standard B5-2, sets setbacks for new buildings next to an existing solar system on an adjoining lot. It applies where the existing solar system is on a building in a Township, General Residential or Neighbourhood Residential Zone.
[What you receive]
Your building, plant, parapets, lift overruns and neighbouring buildings.
Of the roof in daylight-hour terms, mapped against the 25% and 70% thresholds.
Each J9D5(2) exclusion marked up on the roof plan.
The area-based layout compared with the Table J9D5a W/m² alternative.
The additional Table J9D5b capacity, with its panel siting checked.
Included in or appended to the Section J report.
An overshadowing check against neighbouring rooftop solar for Victorian Clause 55 proposals.
Roof plan, elevations, services layout and site context.
[When do you need it?]
Any Class 3 or 5–9 building using the NCC 2025 J9D5 Deemed-to-Satisfy provisions. NCC 2025 applies in Victoria from 1 May 2026, and in WA and the ACT from 1 May 2026 with a 12-month transition. Projects claiming a J9D5 shading exemption under NCC 2022 or 2025, and Victorian townhouse proposals next to existing rooftop solar, need it too. NSW has a state variation to J9D1. Check variations for your project.
NCC 2025 adoption: 1 May 2026, no transition period.
NCC 2025 adoption: 1 May 2026, 12-month transition.
NCC 2025 adoption: 1 May 2027.
NCC 2025 adoption: 1 May 2027 (temporarily adopted 1 May–4 June 2026).
We give you a shading map and an exclusion schedule they can check.
We quantify which areas are over 25% and test the W/m² alternative.
We confirm which edition applies and what J9D5 now requires.
[How it works]
Roof plan, elevations, services layout and site context.
Fast-track timeframes are available case by case; timeframes are confirmed at quote.
Shading model, eligible area, PV layout and the alternative pathway check.
A J9D5 compliance report for the building surveyor, coordinated with the Section J assessment.
For Class 3 and 5–9 buildings using the Deemed-to-Satisfy route, yes, subject to the exclusions and the W/m² alternative. It doesn't apply where the whole effective roof is shaded for more than 70% of daylight hours, or where equivalent on-site renewables are provided.
It depends on the state and the application date. NCC 2025 took effect in VIC, WA and the ACT on 1 May 2026 (WA and the ACT with a 12-month transition), and takes effect in NSW, QLD and TAS on 1 May 2027.
The test is the proportion of annual daylight hours an area is shaded. That's why we model the full year, not a single winter-solstice snapshot.
No. Occupied terraces, roof gardens, plant areas, maintenance access and several other areas are excluded.
No. J9D5 is about your own building. In Victoria, existing domestic rooftop solar on adjoining lots is addressed through the Clause 55 planning standards.
Not under J9D5. The switchboard must have spaces reserved for one, unless a battery is installed.
[Why Makao]
The model behind your Section J and daylight work covers PV, so roof decisions are tested once.
Reviewed by Kelvin Mureithi, Founder, Makao · Green Star Accredited Professional, ISAP, Engineers Australia member.
