End of the black roof? The overhaul coming to Sydney’s heat-trapping suburbs

Developers could soon be required to abandon heat-absorbing materials such as dark rooftops when building new homes under a sweeping overhaul of NSW planning laws aimed at tackling rising temperatures and the urban heat island effect in fast-growing suburbs.

Proposed alterations to the state’s climate change and natural hazards planning policy would, for the first time, formally recognise extreme heat as a planning hazard alongside floods, bushfires and coastal erosion – a shift experts say could reshape how new communities are designed across the state.

The move represents a significant change in planning policy and responds to modelling warning that natural-disaster damage to the built environment could cost the state $9.1 billion a year by 2060 if no mitigation measures are taken.

It also comes as NSW faces pressure to deliver 377,000 new dwellings by 2029 under the National Housing Accord, prompting concern within the development industry that additional planning requirements could increase costs and slow approvals.

The draft policy would require planners, councils and developers to assess how new projects affect local temperatures, with measures such as increased tree canopy, reflective building materials and improved street orientation expected to become standard considerations for some developments.

The rules are expected to apply mainly in urban zones – including residential, mixed-use, employment and recreational areas – with the aim of reducing the urban heat island effect, where dense concentrations of concrete, asphalt and dark surfaces trap heat and push temperatures higher in built-up suburbs.

Planning Minister Paul Scully said the policy was designed to ensure homes were built in the “right locations” while still maintaining the pace of housing delivery.

“The changes streamline the system rather than add new layers, helping us to keep communities safe,” a government spokeswoman said.

The reforms are underpinned by climate modelling forecasting sharp increases in extreme heat across the state. Under high-emissions scenarios, Penrith could experience an additional 26 days each year above 35 degrees by 2090, while regional centres may face even greater extremes, with Dubbo projected to endure 56 extra days of extreme heat annually by the end of the century.

Dr Ehsan Noroozinejad, a housing researcher at Western Sydney University, said formally recognising heat within planning policy represented a major shift.

“It recognises heat as a planning issue, not just a weather issue,” he said.

“It encourages practical responses – more shade, more trees, cooler building materials and smarter neighbourhood design. If implemented well, it can significantly improve liveability and reduce cooling costs.”

Large areas of western Sydney are dominated by “black-roofed” housing estates, where dark tiles, wide roads and limited tree cover intensify summer heat. Without intervention, cooling costs for households in western Sydney could rise by as much as 370 per cent by 2079.

Blacktown Mayor Brad Bunting, who is also president of the Western Sydney Regional Organisation of Councils, said: “Increased housing supply should not come at the cost of housing quality and healthy living.

“Well-designed homes and suburbs are about more than just comfort. It can reduce cost of living, deliver better health outcomes and support life safety in extreme events.”

The proposed planning changes would also require councils and developers to consider future climate scenarios when assessing major developments with smaller projects typically assessed against lower-emissions projections over a 50-year time frame, while major developments – including rezonings and state-significant projects – would be tested against more severe 100-year emissions scenarios.

Central to the approach is the concept of “tolerable risk”, which the government describes as an acknowledgement that eliminating climate hazards entirely is unrealistic.

Rather than banning development in high-risk areas outright, planners would assess whether risks associated with a project can be managed through design or resilience measures.

Professor Chris Pettit, director of the City Futures Research Centre at UNSW, said the approach did not clearly rule out growth in high-risk areas.

“Surely there are certain areas which should be a no-go zone for future urban growth because the risks are too great,” he said.

Others say the reforms may overlook a key contributor to rising urban temperatures – the exemption of small-scale developments – typically renovations and minor extensions, which the government has excluded to avoid adding costs for households.

Macquarie University Professor Peter Davies said such projects often lead to the loss of tree canopy and the spread of hard surfaces in established suburbs.

The reforms also address rebuilding after disasters. Under the proposed changes, rebuilding could require stronger resilience measures.

Coastal engineer Angus Gordon pointed to 2022 floods in Lismore as a warning about the long-term consequences of poor planning decisions.

“Yes we need more housing, but if we build homes in inappropriate locations it will end up costing the state a fortune in the long run,” he said.

The Insurance Council of Australia has broadly supported the proposed reforms.

“If homes are constructed to higher resilience standards in appropriate locations, that will be reflected in pricing.”

Property industry groups remain cautious, warning the state must balance climate resilience with housing supply.

Western Sydney Leadership Dialogue chief executive Adam Leto said addressing urban heat was necessary but must not create new barriers to building homes.

“It’s vital that any new policy is workable and supported by councils and industry – particularly given our housing crisis – and the need to limit planning and development impediments so that more homes can be built, and built fast,” he said.

The reforms follow a 2025 parliamentary inquiry that recommended stronger integration of climate risk into the planning system, amid warnings that extreme heat already contributes to more than 1000 deaths each year among Australians aged over 65.

Macquarie University’s Centre for Environmental Law lecturer Paul Govind said the reforms were unlikely to dramatically change where housing could be built but could influence how developments were designed.

The proposals remain in draft form, with feedback from councils, industry and the public expected to shape the final policy before it is introduced.

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