Solar access and overshadowing: residential planning controls in AU
How solar access and overshadowing rules work in AU residential: ADG, ResCode, council DCPs, shadow diagrams, neighbour protection, gotchas.
Ask Chalkline about this →TL;DR
Solar access rules in residential planning work both ways. Your development must receive adequate sun, and it must not strip your neighbour’s existing solar access. The standard test: does the building cast shadow that reduces a neighbour’s sunlight to less than 2 hours (NSW Class 1) or 3 hours (VIC ResCode) on 21 June, the winter solstice? Shadow diagrams at 9am, 12 noon and 3pm on that date are the tool councils use to check. Get them prepared before DA lodgement. Finding out mid-assessment that your first-floor addition shadows the neighbour’s living room for the whole winter morning is an expensive discovery.
What this article is for
Cross-state primer on solar access and overshadowing as a residential planning control. Covers how the rules work, what shadow diagrams must show, NSW ADG standards for Class 2, VIC ResCode, WA R-Codes, and the practical traps. Use it alongside setbacks, building height controls, and the per-state structure articles.
The fundamental rule
Two obligations run in parallel on every residential DA:
- The proposed development must receive enough solar access to its own private open space and main living areas.
- The proposed development must not reduce a neighbour’s existing solar access below the minimum threshold.
The second obligation bites most often. A neighbour who already receives marginal sun has it protected. A new addition that takes an already-shaded living room from 2.5 hours to 1.5 hours will fail assessment, even if the addition itself is well-lit.
Neither obligation is absolute. Reducing a neighbour’s sun from 6 hours to 4 hours is generally acceptable. The controls protect floors, not ceilings.
The reference moment is the winter solstice (21 June), when shadows are longest. Every state that sets a specific date uses 21 June, except VIC’s open-space test which uses 22 September (spring equinox). The reference window is 9am to 3pm.
Shadow diagrams: what’s required
Most councils require a shadow diagram package for any DA likely to overshadow neighbouring properties. The standard requirement:
- Three snapshots: 9am, 12 noon and 3pm on 21 June.
- Two conditions: existing shadows (before) and proposed shadows (after), overlaid on the same drawing.
- Adjacent properties shown: include neighbouring private open space, living-room windows and north-facing habitable room windows within the shadow cone.
- Scale: per the council DCP (commonly 1:200 or 1:500).
Some councils have specific format requirements in their DCPs. Check the relevant DCP’s solar access chapter before commissioning the diagrams.
NSW Apartment Design Guide solar access
For Class 2 residential flat buildings in NSW, the design standard is set out in the Apartment Design Guide (ADG), which operates under the State Environmental Planning Policy (Housing) 2021.
The ADG solar access requirement (Sydney Metro, Newcastle, Wollongong):
| Metric | Standard |
|---|---|
| Apartments receiving 2+ hours direct sunlight (9am-3pm, 21 June) | 70% minimum |
| Apartments receiving zero direct sunlight | 15% maximum |
| Sunlight patch to count as “direct” | 1 m2 measured at 1 m above floor level, for at least 15 consecutive minutes |
In regional NSW, the threshold increases: 70% of apartments must receive a minimum of 3 hours (not 2 hours) of direct sunlight.
The ADG solar test applies to living rooms and private open spaces. Bedrooms and bathrooms are not counted in the denominator. An apartment that gets sun only to a bedroom window does not count toward the 70%.
Where a proposal cannot meet these standards due to site constraints, the consent authority may still approve if solar access is demonstrably optimised. The applicant carries the burden.
For Class 1 dwellings in NSW, solar access is managed through individual council DCPs. A common benchmark is that both the proposed dwelling and neighbouring dwellings retain at least 2-3 hours to principal private open space on 21 June. Camden Council DCP requires 3 hours to at least 50% of private open space for both the subject and adjoining properties. City of Sydney DCP requires 2 hours to living room windows and 50% of private open space.
Adjoining property protection
The neighbour protection rule comes in two forms.
Absolute floor: the development cannot reduce a neighbour’s solar access below X hours. Common NSW DCP threshold is 2 hours on 21 June. If the neighbour already receives less than 2 hours, no further reduction is permitted.
Proportional: at least Y% of the neighbour’s secluded private open space must still meet the minimum. This is the VIC ResCode approach: 75% or 40 m2 (whichever is lesser) of secluded POS must receive 5 hours on 22 September.
NSW DCPs use the floor form most often. Some councils stack both tests: floor on living room windows, proportional on open space.
The “no further reduction” clause catches additions in tight suburban streets. A neighbour’s living room receiving 1.5 hours on the solstice has exactly 1.5 hours protected. Any reduction fails, regardless of how small.
State variance
| State | Reference date | Minimum hours | What is protected | Key instrument |
|---|---|---|---|---|
| NSW (Class 2) | 21 June | 2 hrs (Sydney); 3 hrs (regional) for 70% of apartments | Living rooms, POS | Apartment Design Guide (SEPP Housing 2021) |
| NSW (Class 1) | 21 June | Typically 2-3 hrs per council DCP | Neighbour’s POS, living room windows | Council DCP |
| VIC (open space) | 22 September | 5 hrs to 75% or 40 m2 of secluded POS | Secluded private open space | ResCode Cl. 54 (A14) and Cl. 55 (B21) |
| VIC (north windows) | N/A (setback formula) | Height-based setback, not hours | Existing north-facing habitable room windows | ResCode Cl. 54 (A13), Cl. 55 |
| WA | 21 June (midday) | Shadow < 25% of adjoining site (R25); 35% (R30-R40); 50% (R40+) | Adjoining site area | R-Codes SPP 7.3 Vol. 1, Element 5.4.2 |
| QLD | Varies by council | No state-wide standard; local planning schemes set requirements | Varies | Council planning scheme (Brisbane City Plan, Gold Coast, etc.) |
| SA | N/A | 30-degree shadow plane from 3 m above southern boundary | Adjoining properties | Planning and Design Code residential zones |
| TAS | 21 June | 3 hrs (9am-3pm) | Habitable rooms, POS | State Planning Provisions |
| ACT | 21 June | Solar fence envelope (31-degree plane from fence height) | Adjoining properties | Territory Plan 2023 |
Three notes on the table:
VIC uses 22 September (equinox) not 21 June for its open space test, so shadows are shorter on the reference date than in NSW. VIC also protects north-facing windows through a height-based setback formula (Cl. 54 A13), not a hours-of-sunlight test. WA uses a shadow-area percentage at solar noon rather than a minimum hours count. QLD has no state-wide standard; solar access is an amenity issue in individual council planning schemes, expressed in subjective terms (“not unduly overshadow”) with no prescribed minimum hours.
What can go wrong
Shadow diagrams ordered too late. Commission a rough shadow study at concept design stage, before the full drawing set is prepared. Finding a fail after drawings are complete means redesigning and redrawing. A 3D sun study takes an hour and saves weeks.
Cantilever additions overlooked. A first-floor addition close to the southern boundary can shadow a neighbour’s living-room window for the entire morning at the solstice, even if it looks compliant on plan. Model it in 3D before committing to structure.
Neighbours objecting during DA notification. Solar access is one of the most common grounds for neighbour objections. A detailed objection with a competing shadow study can delay assessment by months. Sharing shadow diagrams with affected neighbours before lodgement is not required, but it often kills objections before they are filed.
Assuming the neighbour’s current situation isn’t protected. If a neighbour’s living room currently receives 1.8 hours of sun on 21 June, that 1.8 hours is protected. The absolute floor applies regardless of the fact that 1.8 hours is already below the 2-hour standard. No further reduction permitted means none.
Privacy screens casting additional shadow. Louvred or solid screens proposed for privacy compliance can themselves cast shadow on the neighbour’s open space or windows. Model screens in the shadow study. They also reduce solar gain to north-facing windows on your own building, which is a separate NatHERS energy compliance issue.
Reading the wrong state’s rules. VIC’s 22 September equinox reference date is different to every other state’s 21 June. If you’ve worked in NSW and you’re picking up a VIC permit, re-check the reference date. Five hours at the equinox is a fundamentally different test to two hours at the solstice.
How to use this with related articles
Setbacks and building height controls feed directly into shadow outcomes: setback determines how far the wall is from the boundary; height determines how far the shadow falls. Check both before committing to a design. DCPs contain the specific solar access thresholds and shadow diagram format requirements for each NSW council. SEPPs in NSW explains the hierarchy placing the ADG above DCP controls for Class 2. Privacy and sight lines covers the related issue of screening and overlooking controls.
References
- NSW Apartment Design Guide (2015, updated 2021), Part 3F Solar and Daylight Access, via planning.nsw.gov.au (verified 2026-05-23).
- State Environmental Planning Policy (Housing) 2021 (NSW), Schedule 4 (Apartment Design Guide), via legislation.nsw.gov.au (verified 2026-05-23).
- Victoria Planning Provisions Clause 54 (One Dwelling on a Lot) and Clause 55 (Two or More Dwellings on a Lot), standards A13-A14, B20-B21, via planning.vic.gov.au (verified 2026-05-23).
- State Planning Policy 7.3 Residential Design Codes Volume 1, Element 5.4.2 (WA), via dplh.wa.gov.au (verified 2026-05-23).
- Queensland Property Law Act 1974, s. 180, and overview of QLD planning scheme solar access approach, via ncchambers.com.au (verified 2026-05-23).
- Shadow diagram state comparison, via feasly.com.au (verified 2026-05-23).
- Camden Council DCP solar access controls, via dcp.camden.nsw.gov.au (verified 2026-05-23).
Related
- Setbacks: minimum distances from boundaries in AU residential planning
- Building height controls in AU residential planning
- Development Control Plans (DCPs) in NSW
- SEPPs in NSW: what they are and when they affect your project
- Privacy and sight lines in AU residential planning
- VIC planning scheme structure
- NSW planning scheme structure
See also
- LEPs in NSW: how to read them for a residential project
- Landscaped area and deep soil controls in AU residential planning
- Housing SEPP 2021 NSW: blanket override explained
- DCP (glossary)
- SEPP (glossary)
Last updated: 2026-05-23. Verified: 2026-05-23. Quarterly review for currency. State standards verified against primary planning portals and legislation on 2026-05-23.