“[Our concept] takes a fresh look at the complex challenges of city living, and uncovering new urban design approaches that will make our cities more productive, prosperous and liveable,” he said.

HASSELL had a presence in the three cities in the study “so we know them well”, but in Tickle’s view, the effect of rapid urbanisation on housing in each is a common thread. The different models – the Sydney “McMansion”, the Shanghai laneway house and the London estate – each had a response to housing demand in their time, “but failed in some way”, he said. Therefore, all had potential “for transformation for better social, environmental, lifestyle outcomes”.

In Sydney, for instance, the study proposes that a typical suburb of walk-up apartments would be transformed to create greater density and diversity of housing. “Looking at a cluster of three buildings, two are demolished to create a consolidated lot for development, which then can accommodate a range of new homes – from large terrace house to smaller apartments, as well as the potential for other uses such as retail, offices and community rooms,” Tickle said.

Comparatively speaking, this renewal delivered a doubling of dwelling numbers, as well as open space, he added. “The proposal would yield 5,000 new apartments and 77,000 square metres of new green space for the suburb of Auburn, and the same concept could be applied to many more suburbs to address Sydney’s current affordability crisis,” he said.

In London the subject was a clutch of 19th-century row houses with small private back gardens, a model that represents 23 per cent of London’s housing stock. “The focus on Harringay Ladder (north of London city) was addressing London’s critical housing shortage – the worst since the second world war – through the quick delivery of new homes,” Tickle said. The consolidation of existing backyards into a single open space created a second entry into each home, allowing their subdivision into two or three dwellings. New self-contained studio apartments could be prefabricated and craned in – “the fastest means of getting homes on the ground”, he said.

“Applied to just 10 per cent of London’s row houses,” Tickle said, “this proposal would generate the potential for more than 100,000 new homes and 30,000 new garden allotments, significantly reducing the lengthy waiting lists for both.”

The Shanghai study examined a typical cluster of six- to eight-storey xincun (new village) apartment blocks within the city’s middle ring. It acknowledged the government’s intent to move away from public housing towards quality private living space, and increasing the amount and accessibility of open space, Shanghai-based HASSELL principal Richard Mullane said. Such research, he added, could be replicated to improve standards of living across many of mainland China’s booming cities.

The studied neighbourhood is a typical hotch-potch of slab-box units built for workers in state-run factories, newer housing blocks in place of old industrial buildings, and some existing schools and community buildings.

Its layout was “disorganised and confusing”, with little open space, Mullane said. Yet as would be the case in many Chinese cities with a history of tearing down their past, there were social sensibilities to consider. Not everyone wanted to leave their old neighbourhood. The study aimed to find ways “to house them better”, and maintain the continuous narrative of the city.

HASSELL’s proposal involves a mix of retention and renewal: removing former industrial buildings that remain near schools and community facilities, replacing them with taller, modern residential towers, and creating new “neighbourhood cells” focused around green open space. Mixed-use towers would be built along major road corridors, and a surface-level transport loop (either light rail or bus) would link people with the parks, and back to the metro station.

In Shanghai’s middle ring alone, Mullane said, the research had identified 29 locations where such a transformation could take place. “This would place more than 1.8 million people in higher quality, better connected and more sustainable communities,” he said. “It would also contribute significantly to the government’s plan to green the city, delivering more than 200 hectares of new green space.”

Tickle said the concepts were not proposed as finite solutions, “rather as conversation starters for wider exploration, scrutiny and development”.