Shadow Diagrams in Australia: Complete Developer's Guide to Solar Access & Yield Impact

Shadow diagrams may represent one of the most significant yet underappreciated constraints on Australian property development yield. These technical planning documents illustrate how proposed buildings cast shadows throughout the day, and they could fundamentally shape what can realistically be built on a site—often more restrictively than height limits or floor space ratio controls alone.

Research from the Reserve Bank of Australia suggests that height restrictions driven by overshadowing controls may add an estimated $399,000–$489,000 to Sydney apartment costs, representing approximately 85% above marginal construction costs. For developers, shadow compliance requirements could routinely reduce achievable yield by 30–50% compared to theoretical maximums permitted under LEP controls.

This comprehensive guide covers shadow diagram requirements across all Australian states and territories, from fundamental concepts through to advanced yield optimisation strategies. Whether you’re undertaking your first development or seeking to maximise returns on a complex urban site, understanding shadow compliance is typically considered essential for project success.

What shadow diagrams are and why they matter for development feasibility

A shadow diagram is generally understood as a visual representation showing the length, direction, and movement of shadows cast by a proposed structure at specific times throughout the day. Planning authorities across Australia typically mandate these diagrams to protect solar access for neighbouring properties, ensuring habitable rooms and private open spaces may receive adequate sunlight—particularly during winter months when shadows are longest.

Shadow diagrams are usually prepared using 3D modelling software and must typically show shadow impacts at multiple times, most commonly 9am, 12 noon, and 3pm on specific reference dates that vary by jurisdiction. The diagrams are generally required to be drawn to true north (not magnetic north) and prepared at scales of 1:100 or 1:200 in accordance with a registered surveyor’s feature and level survey.

The distinction between overshadowing and solar access analysis

Two related but distinct concepts may apply to development applications. Overshadowing analysis typically maps shadows cast by a proposed development onto neighbouring properties, showing the extent and duration of new shadow impacts. Solar access analysis, by contrast, generally calculates natural light received by existing buildings and quantifies any reduction in daylight hours that may result from the proposed development.

Both analyses are commonly required for comprehensive DA submissions, particularly for multi-dwelling developments or buildings that may affect residential neighbours.

Why shadow controls often prove more limiting than height controls

Many developers discover that shadow requirements could be more restrictive than LEP height limits. A site may have theoretical permission for 15 storeys under the LEP, but shadow impacts on southern neighbours might effectively limit achievable height to 8–10 storeys. This interaction between shadow controls and building envelopes is typically considered one of the most significant factors affecting development yield.

Example scenario: A 1,000-square-metre site with 21-metre LEP height limit might theoretically accommodate a 6-storey building. However, if shadow analysis reveals that a 6-storey building would cause non-compliant overshadowing of a southern neighbour’s private open space, the achievable height might be reduced to 4 storeys—potentially representing a 30% reduction in gross floor area and corresponding revenue.

State-by-state shadow diagram requirements

Australian jurisdictions take markedly different approaches to shadow regulation, creating complexity for developers operating across multiple states. The most significant variations typically involve reference dates (when shadows are measured), minimum sunlight hours required, and assessment methodologies.

New South Wales

NSW generally applies the most detailed apartment standards through the Apartment Design Guide (ADG), which has been consolidated into Housing SEPP Chapter 4. The framework establishes specific numeric thresholds that developments should typically aim to achieve.

Key requirements under the ADG may include:

• Living rooms and private open spaces of at least 70% of apartments should receive minimum 2 hours direct sunlight between 9am and 3pm on 21 June (winter solstice) in Sydney Metro, Newcastle, and Wollongong
• Regional NSW developments may need to achieve 3 hours minimum sunlight for the 70% threshold
• A maximum of 15% of apartments should receive zero direct sunlight
• Sunlight must generally form a usable 1-square-metre patch measured at 1 metre above floor level for at least 15 consecutive minutes to count toward the requirement
• Shadow diagrams typically need to show impacts at 9am, 12 noon, and 3pm on 21 June

For developments that may overshadow existing apartments, the ADG generally requires demonstration that overshadowing of neighbouring properties is minimised during mid-winter. Where existing buildings already receive less than compliant solar access, new development should typically not make the situation worse.

The City of Sydney Development Control Plan 2012 explicitly states that new development must not create any additional overshadowing where solar access is already less than two hours.

A significant 2023 Land and Environment Court decision confirmed that the ADG operates as performance-based rather than requiring rigid numeric compliance. Where site constraints may make 70% compliance difficult or impossible (such as CBD sites with existing surrounding shadows), developments could potentially achieve approval through optimisation strategies including dual-aspect apartments, shallow floor plate layouts, and strategic orientation of habitable rooms.

Victoria

Victoria uses a fundamentally different reference date—22 September (spring equinox)—under ResCode Clauses 54 and 55. The approach and numerical standards differ significantly from NSW.

Key requirements under Victorian planning provisions may include:

• Standard B21 typically requires that 75% or 40 square metres (whichever is lesser) of existing secluded private open space should receive minimum 5 hours sunlight between 9am and 3pm on 22 September
• Amendment VC243 (September 2023) codified these standards, establishing that if numerical requirements are met, developments are generally deemed to comply
• VCAT decisions have confirmed that meeting the equinox standard may prevent council refusal arguments based on winter overshadowing

The Victorian approach through Planning Practice Note 27 provides detailed guidance on calculating overshadowing impacts, including setback requirements that graduate based on wall height.

Setback requirements under ResCode typically include:

• 1-metre base setback from side and rear boundaries
• Additional 0.6 metres for every metre of wall height between 3.6 metres and 6.9 metres
• Additional 1 metre for every metre of wall height above 6.9 metres

Queensland

Queensland has no state-wide solar access mandate for residential development. The Queensland Development Code MP1.2 includes performance criteria that buildings should not overshadow adjoining houses, but prescribes no specific hours or reference dates.

Requirements are determined entirely by individual council planning schemes:

• Brisbane City Plan 2014 establishes local requirements for the Brisbane local government area
• Gold Coast City Plan and Sunshine Coast Planning Scheme each set their own standards
• Queensland’s subtropical latitude (approximately 27.5°S for Brisbane) results in higher sun angles and shorter shadows year-round, which may partly explain the less prescriptive state-wide approach

Developers working in Queensland should typically consult the specific planning scheme for their local government area to understand applicable requirements.

South Australia

South Australia replaced all individual council development plans with the unified Planning and Design Code in March 2021, creating a standardised approach across the state.

Key provisions may include:

• Buildings must generally be constructed within a building envelope provided by a 30-degree plane grading north, measured from 3 metres above natural ground level at southern boundaries in residential zones
• The Code uses Deemed-to-Satisfy pathways where numerical compliance may provide automatic approval
• Building envelope plans are available for certain areas, potentially modifying standard envelope requirements

The Guide to the Planning and Design Code provides detailed explanations of how shadow and building envelope requirements are assessed.

Western Australia

Western Australia regulates shadow impacts through the Residential Design Codes (R-Codes) SPP 7.3, with requirements varying based on site density coding.

Key standards may include:

• Shadow cast at midday on 21 June should not exceed 25% of adjoining site area for R25-coded properties
• Shadow limits increase to 35% for R30-R40 coded sites and 50% for sites coded higher than R40
• Where adjoining sites are R40 or lower, developments should typically maintain 4 hours per day solar access on 21 June for existing solar collectors
• For apartments, 70% of dwellings should generally receive at least 2 hours direct sunlight between 9am and 3pm on 21 June

The R-Codes Volume 2 provides additional guidance for apartment developments, with requirements that may closely align with NSW standards for multi-dwelling projects.

Tasmania

Tasmania operates under the Tasmanian Planning Scheme with State Planning Provisions that establish shadow requirements.

Key provisions typically include:

• Buildings should not cause overshadowing that reduces sunlight to habitable rooms and private open space below 3 hours between 9am and 3pm (or 9am and 5pm in some zones) on 21 June
• Tasmania’s southern latitude (approximately 42°S for Hobart) creates the longest shadows in Australia, making solar access protection particularly critical but also challenging to achieve

The extreme shadow lengths at Tasmanian latitudes mean that even modest building heights could create substantial overshadowing impacts, potentially requiring careful design consideration from early feasibility stages.

Australian Capital Territory

The ACT introduced a unique solar fence system under the Territory Plan 2023, establishing a distinctive approach to shadow regulation.

Key features may include:

• Buildings must generally sit within a solar building envelope formed by planes projected at 31 degrees from solar fence heights
• Solar fence heights are typically 3 metres for primary building zones and 2.3 metres for rear zones
• The September 2024 final Territory Plan simplified requirements from location-specific calculations to a standardised 31-degree angle (reflecting Canberra’s approximate noon winter solstice sun angle)

The solar fence concept effectively creates a three-dimensional building envelope that developments must fit within, potentially providing more predictable compliance outcomes than shadow diagram analysis alone.

Northern Territory

The Northern Territory has minimal shadow regulation due to Darwin’s tropical latitude (approximately 12.5°S). The NT Planning Scheme 2020 requires only that development not have significant impact on existing and future amenity—no specific hours or reference dates typically apply.

High sun angles year-round mean overshadowing concerns are substantially reduced compared to southern states. A building in Darwin may cast shadows approximately 70% of its height at noon on winter solstice, compared to over 200% in Hobart.

How shadow compliance affects development yield

Understanding the relationship between shadow controls and development yield is typically considered essential for accurate feasibility analysis. Shadow constraints could significantly reduce achievable floor area compared to theoretical LEP maximums.

The building envelope constraint

Shadow requirements frequently create what might be called a shadow building envelope that sits within—and is often more restrictive than—the LEP building envelope. This shadow envelope is determined by:

• The location and sensitivity of neighbouring properties (particularly properties to the south)
• Existing solar access levels of neighbouring habitable rooms and private open spaces
• The reference date and minimum sunlight hours required by the relevant planning framework
• Sun angles at the site’s specific latitude

Example scenario: Consider a 600-square-metre site in Sydney with R3 Medium Density zoning permitting 12-metre height and 0.9:1 FSR. Theoretical yield under LEP controls might be 540 square metres GFA. However, if the southern neighbour has a north-facing living room window and 30 square metres of private open space currently receiving 3 hours of winter sunlight, shadow analysis might reveal that any building over 7.5 metres would reduce this below the 2-hour ADG threshold. The achievable building envelope could therefore be substantially smaller than LEP controls suggest.

Quantifying yield reduction

Research and industry experience suggest that shadow constraints may typically reduce achievable development yield by:

• 10–20% on sites with favourable orientation (narrow street frontage, neighbours to east/west rather than south)
• 20–35% on standard suburban sites with residential neighbours to the south
• 35–50% on constrained sites with multiple sensitive receivers or existing marginal solar access

These reductions flow directly through to project feasibility. With Feasly’s feasibility software, you can model different building envelope scenarios based on shadow constraints to understand the true yield potential of a site before committing to acquisition.

Strategic approaches to yield optimisation

Developers may employ several strategies to maximise yield within shadow constraints:

Orientation and apartment mix: The 70% minimum threshold in NSW creates design flexibility. Compliant north-facing apartments could potentially subsidise south-facing units within the 15% non-complying allowance, rewarding sophisticated orientation strategies that maximise north-facing dwellings.

Stepped building forms: Upper-level setbacks can maintain street-level bulk while reducing shadow length cast onto southern neighbours. A building might achieve 6 storeys at the street frontage while stepping down to 4 storeys at the southern boundary.

Podium-tower configurations: Positioning height where existing shadows already fall (such as within existing CBD shadow patterns) could utilise neighbouring building shadows rather than creating new impacts on sensitive receivers.

Dual-aspect apartments: Units with windows on multiple facades may achieve solar access compliance more easily than single-aspect apartments, potentially allowing higher density while meeting ADG thresholds.

Shallow floor plates: Narrower building depths typically allow more apartments to achieve north-facing orientation, though this must be balanced against construction efficiency and per-square-metre costs.

Technical fundamentals: Sun angles and shadow calculations

Understanding the underlying geometry may help explain why requirements differ between jurisdictions and how shadow lengths are calculated.

Solar position and shadow length

The sun’s position is determined by solar altitude (height above horizon, measured in degrees from 0–90°) and solar azimuth (compass direction). Shadow length equals object height divided by the tangent of the altitude angle—a lower sun creates proportionally longer shadows.

At winter solstice (21 June), the sun reaches maximum altitude at solar noon of approximately:

These multipliers represent noon shadows on winter solstice. Morning and afternoon shadows are typically longer due to the lower sun angle.

Why winter solstice is the reference date in most jurisdictions

The winter solstice represents worst-case overshadowing because the sun travels its lowest and shortest path across the northern sky. If a development passes solar access requirements on 21 June, it should typically comply year-round. Victoria’s choice of the equinox as reference date provides a less restrictive standard, partially offset by requiring 5 hours rather than NSW’s 2–3 hours.

Time intervals and measurement methodology

Most jurisdictions require shadow diagrams at three time intervals—9am, 12 noon, and 3pm—representing morning, midday, and afternoon conditions. Some councils may request additional times (such as 10am and 2pm) for sensitive sites.

The NSW ADG specifies that sunlight must form a 1-square-metre patch sustained for at least 15 consecutive minutes to count toward compliance. This prevents developers from claiming compliance through brief moments of sunlight through small windows or at extreme angles.

Who prepares shadow diagrams and what they cost

Shadow diagrams are typically prepared by architects as part of DA documentation packages, though specialist consultants may be engaged for complex sites or where independent certification is required.

Preparation options

Architect-prepared diagrams: Most architectural practices include basic shadow diagrams within their DA documentation scope. However, the quality and detail may vary, and architects may not always be familiar with the specific requirements of different council areas.

Specialist consultants: Firms such as Shadow Diagrams and Certified Energy offer dedicated shadow diagram services with expertise across different jurisdictions and council requirements.

Software tools: Programs including SketchUp (most common for residential projects), Autodesk Revit (larger commercial projects), and specialist plugins may be used to generate compliant shadow diagrams. Platforms like Archistar offer early-stage sunlight analysis capabilities.

Typical costs

Professional shadow diagram preparation costs may typically range from:

• Standard plan shadows (three times on winter solstice): $350–$450
• Elevation shadows: $350–$450 additional
• 3D perspective views: $350–$400 additional
• Complex sites with multiple neighbours: $150–$250 additional
• Registered architect certification: $150–$200 additional
• Expedited service (2-day turnaround): Premium rates may apply

Total costs for a comprehensive shadow analysis package on a moderately complex site might typically range from $800–$1,500, depending on the level of detail required and whether certification is needed.

Shadow diagrams are typically not included in base architectural fees and represent additional project costs that should be budgeted in feasibility analysis.

Turnaround times

Standard turnaround is generally 5–10 business days from receipt of survey and design information. Expedited 2-day service may be available from specialist providers at premium rates.

Common mistakes that delay or derail applications

Understanding common errors may help developers avoid costly delays in the approval process.

Technical errors

Incorrect reference dates: Using NSW’s 21 June requirement for a Victorian application (which should use 22 September), or vice versa, is a common error that may require complete redrawing of diagrams.

Failing to distinguish existing and proposed shadows: Shadow diagrams should typically show existing conditions (current shadows) separately from proposed conditions (new shadows) to enable assessment of additional impact.

Omitting required time intervals: Most jurisdictions require shadows at 9am, 12 noon, and 3pm. Submitting diagrams at only one or two times could result in requests for additional information.

Including tree shadows: Shadow diagrams generally should not include shadows from trees, as vegetation is typically considered temporary and may be removed. Only building and permanent structure shadows are usually relevant.

Using magnetic north instead of true north: Shadow diagrams must typically be oriented to true north. The difference between magnetic and true north varies across Australia and could result in inaccurate shadow positioning.

Documentation errors

Not identifying affected rooms: Shadow diagrams should typically identify the room uses of neighbouring windows affected (living room, bedroom, etc.) as different standards may apply.

Missing private open space calculations: The total square metres of neighbouring private open space affected should generally be calculated and documented.

Inadequate survey information: Shadow diagrams should be based on accurate survey data showing existing building heights and window positions of neighbouring properties.

Practical guidance for the development process {#practical}

Shadow analysis should ideally occur during feasibility and site selection, not after design development has commenced.

Pre-acquisition due diligence

Before committing to a site, developers may benefit from preliminary shadow analysis to understand realistic development potential. This typically involves:

• Identifying sensitive receivers (neighbouring properties with habitable rooms or private open space that could be affected)
• Assessing existing solar access levels of neighbouring properties
• Modelling preliminary building envelopes against shadow constraints
• Comparing shadow-constrained yield against theoretical LEP yield

Feasly’s feasibility software enables developers to model different building envelope scenarios based on shadow constraints, helping to determine realistic yield potential before site acquisition.

Pre-DA consultation

Pre-DA consultation with councils is generally considered valuable for shadow-sensitive sites. Early engagement could identify potential issues before substantial design investment, though formal pre-lodgement meetings vary in availability by council.

When preparing for pre-DA consultation, developers may wish to:

• Prepare preliminary shadow diagrams showing proposed impacts
• Document existing solar access conditions of affected neighbours
• Identify any design modifications that could reduce impacts
• Understand the council’s assessment approach and any local policies

Responding to objections

When shadow-related objections arise during assessment, responses typically focus on:

• Demonstrating compliance with applicable numeric standards
• Showing optimisation efforts where full compliance may not be achievable
• Proposing design modifications that could reduce impacts (additional setbacks, reduced height on sensitive elevations)
• Providing context about existing shadows from other sources

In some cases, direct negotiation with affected neighbours about minor design modifications may prove more effective than council negotiation alone.

Recent reforms and emerging trends

Shadow diagram requirements continue to evolve across Australian jurisdictions.

NSW Housing SEPP consolidation

The December 2023 consolidation of SEPP 65 provisions into Housing SEPP Chapter 4 did not change solar access standards but reorganised the regulatory framework. The Low and Mid-Rise Housing Policy (Stage 2, February 2025) permits new dwelling types within 800 metres of 171 town centres across Greater Sydney, though affected developments must still comply with ADG requirements where the 3+ storey/4+ dwelling threshold is triggered.

Victorian codification

Victoria’s Amendment VC243 (September 2023) codified ResCode standards, establishing that if numerical requirements are met, developments are generally deemed to comply and councils may not exercise further discretion. This could provide greater certainty for developers but may also limit flexibility for site-specific considerations.

Solar panel considerations

The increasing prevalence of rooftop solar installations (now on over 30% of Australian dwellings) has elevated solar access protection from amenity concern to economic necessity. WA’s R-Codes already require 4 hours daily solar access maintenance for existing solar collectors; other jurisdictions may follow as solar panels become standard infrastructure.

Key takeaways for development feasibility

Shadow diagram compliance represents a critical constraint that could significantly affect development yield and project viability. Key considerations may include:

Analyse shadow constraints early: Shadow analysis should typically occur at feasibility stage, not DA preparation. Sites should be evaluated against realistic developable envelopes considering shadow constraints, not theoretical LEP maximums.

Understand jurisdictional variations: NSW’s winter solstice standard differs substantially from Victoria’s equinox approach. Queensland’s council-by-council system requires local research. The ACT’s solar fence concept is unique nationally.

Budget for professional preparation: Shadow diagram preparation typically costs $800–$1,500 for comprehensive analysis and is generally not included in base architectural fees.

Consider yield optimisation strategies: The 70%/15% structure in NSW creates design flexibility. Stepped building forms, podium-tower configurations, and strategic apartment orientation could potentially maximise yield within shadow constraints.

Engage early with councils: Pre-DA consultation may identify issues before substantial design investment and could inform negotiation strategies where full compliance may not be achievable.

Document existing conditions thoroughly: Understanding current solar access levels of neighbouring properties is typically essential for demonstrating that new development does not cause unacceptable additional impacts.

Shadow compliance is commonly considered one of the most technically complex aspects of Australian development assessment, but understanding the requirements across different jurisdictions may provide significant competitive advantage for developers seeking to maximise site potential while achieving approval.