When your city is hemmed in by mountains or ocean on all sides, finding space to put an extra 725,150 homes is challenging.

Yet according to the most recent population and household projections from the Department of Planning and Environment, the Sydney Metropolitan area will need this many new houses and multi-residential dwellings to cater for an additional 682,350 households between 2016 and 2036. That will take the city’s overall housing stock from 1.845 million to 2.566 million – an increase of 40 percent. Given the aforementioned limitations, finding space will be hard.

Toward this end, the Greater Sydney Commission last year released a draft plan to reimagine the entire metropolitan area as ‘three great cities’ by 2056 – the Eastern Harbour city (the traditional ‘city’ area now), a Central Parramatta River City and a Western City around the new airport.

Whilst the Eastern Harbour City will remain the powerhouse of the economy, the Plan said space limitations and affordability considerations dictate a need to look west for further development. In terms of urban infill, the Commission outlined a vision for growth in the Greater Parramatta to Olympic Park corridor and the ‘String of Pearls’ areas centred around the new Western Sydney Airport and the existing areas of Camden, Campbelltown, Liverpool and Penrith.

So where should the new houses go?

Speaking firstly of infill opportunities, Jenny Rudolph, President of Planning Institute of Australia NSW, said a number of factors should influence where growth takes place. Access to transport and employment was critical, she said. So too was looking at opportunities to leverage off existing projects through development of nearby area and thinking about the feasibility of what could be created based on issues such as land prices and land parcel sizes.

Local setting is also important. It is crucial to look at localised issues such as environmental or heritage related constraints, the level of open space and urban amenity and the potential or otherwise for redevelopment of any existing stock which may be aging and deteriorating, Rudolph says.

Finally, Rudolph says it is important to look at the profile of area, with one of the elements being land ownership. Where existing ownership was fragmented or the older strata titled residential flat buildings areas exist, she says, obtaining necessary agreement of existing owners for urban renewal projects is more complicated.

In terms of specific locations, Rudolph agrees with the GSC that the Greater Parramatta to Olympic area with its transport links, jobs and Homebush Stadium is a standout and says many planners also like the idea of the previous Planning of Minister Rob Stokes to pursue precinct style developments in ‘missing middle’ suburbs such as Ashfield or Marrickville.

Beyond that, she says it is important to consider opportunities at the sub-market level and the type of housing development which could be targeted to meet  specific demographic needs within smaller markets.

In terms of greenfield areas, Rudolph says there are opportunities in the south-west areas such as Leppington and north-west areas such as Schofields and Marsden Park, where she says a degree of capacity remains. She said critical considerations within these areas revolved around orderly growth with a supply of affordable housing and an ability to get adequate levels of infrastructure in place within a reasonable timeframe. Obviously, as well, there were areas in an around the second airport at Badgerys Creek.

One point of caution with the south-west and areas in and around Leppington, she said, was a high fragmentation of land ownership. This, Rudolph said, could complicate planning as the parcels were much smaller providing  difficulty to accommodate the diversity of uses, especially  the community and recreation facilities. Within the south-west, she said areas where there are much larger land ownerships, like was Oran Park, offer more opportunities to make sustainable  as  larger scale land parcels can accommodate an integration of social and economic facilities as well as housing, with necessary transport.

Paul Robilliard, a director at JBA urban development consultants, says the north-west and south-west corridors offer promise and adds that the driver of opportunities revolve around not only transport but also utility related infrastructure such as water and sewerage.

In terms of the north-west, he says opportunities centre along the rail corridor. A good example is areas such as Riverstone East which surround the planned Cudgegong Road station, whereby he says the new station will enable delivery of a mix of housing including some dense housing within proximity of the station. Further west, areas around Richmond Road such as Marsden Park and West Schofields offer available land which is not too far from transport and is benefiting from road upgrades – employment opportunities created by a new business park will help.

Heading south-west, Robilliard said Leppington offers a less developed area which is serviced by a train station and upgrades to roads such as Bringelly Road. Longer term, options also exist along Bringelly Road and heading toward the new airport as the new airport drives opportunities in areas such as Bringelly, Rossmore and Kemp Creek.

Further south, Robilliard said the priority growth area of Menangle Park and down as far as Wilton offered opportunities, albeit with distance to employment serving as a barrier to these areas over the short term.

In terms of infill, Robilliard says again, opportunities are being driven by transport. The Greater Parramatta corridor would be a big area thanks to the Parramatta Light Rail, the West Metro and the WestConnex road expansion, he says. The Sydenham to Bankstown corridor was also important thanks to urban renewal efforts there as was the north-west rail corridor to Rouse Hill, where Robilliard said the new rail link will be a ‘game changer’.

More infill and high-density residential development is also starting to happen in Western Sydney places such as Blacktown, Penrith and Liverpool, Robilliard says – the latter of which he says offers opportunities for conversion of industrial areas.

Robilliard says limitations upon outward expansion are dictating a greater focus upon density rather than sprawl.

“I think rather than urban sprawl which we have seen historically in those Western Sydney growth areas, the Greater Sydney Commission is looking at opportunities which are more transit oriented and getting more diversity of housing with a greater range of apartments and townhouses and trying to bring more jobs out in those growth areas,” Robilliard said.

“As those greenfield areas develop, they are going to look quite different to what we are used to seeing in fringe areas of Western Sydney. More centres, more density. There is demand and we are seeing a lot of developer interest in areas like Leppington and up around that Cudgegong Road Metro Station. A lot of developers are proposing apartment developments out there that you wouldn’t have contemplated even five or six years ago. The market has shifted and the housing preferences have shifted.

Sydney has significant challenges in housing its growing population.

With sensible strategies, the city can go a long way toward meeting this challenge.