The world’s most popular cities have a serious affordability problem. People of normal means have no hope of ever buying a home in places like Sydney and Melbourne. According to the Australian Bureau of Statistics, the average house price in Australia is now $656,800. New South Wales’ average is $865,000, and Victoria is next at $690,000.

Investor activity in Sydney and Melbourne is driving price growth, according to Ben Phillips, an associate professor of economics and public policy at the Australian National University. Investors currently enjoy low interest rates and incentives such as negative gearing and tax discounts on capital gains. At the same time, wage growth remains flat, at only 13 per cent over the last five years.

Solutions to the affordability crisis seem scarce, but an evolution of current housing calls to mind the shared economy, in which people don’t necessarily need to own everything that they use on a regular basis. According to designer and “creative superstar” Ronny Matzat of DSGN KARTELL, who will be speaking on the subject at Green + Building Exhibition 2017, housing that follows the shared economy model offers an opportunity to introduce more affordable housing options into expensive cities.

“It’s the next step of what we need to do,” Matzat said. “We need to make people understand that it’s fun to have your own house, and you can still have it, you have your privacy. But there’s a certain component to it which has to be shared in order to make it affordable and in order to make it feasible for our economy, as well.”

If two neighbours, for example, each built energy-efficient homes, they could join forces and share internet service, water tanks, and a micro-grid. That would greatly decrease costs for new homes, compared to each home having each component.

The sharing economy model provides economic benefits, but with a social layer, as well, Matzat said. “You know your neighbors and the kids know each other, and you’re sharing food, you’re sharing resources, and you’re doing this in an honest way that would improve the entire economy, the entire circle of things.”

In addition, Matzat’s model includes space for home-based business. “That’s what I’m trying to promote. The talk will focus a lot on this, showing as an example a cluster home area where houses work together as this is a mixed zone for working and living.”

The concept sounds a bit like co-housing, but takes the concept further. Co-housing generally consists of a plot of land under shared ownership with individual housing units that are individually owned. Utilities and services can be shared or individually owned, and co-housing tends to favor less urban locations. “That’s usually more the hippie communities,” Matzat said. “We have those kinds of models somewhere in Australia, but they’re usually in the hinterland somewhere in the mountains.” Communal or shared spaces may be included in this type of housing, but often the communal spaces are an addition to each dwelling.

In contrast to co-housing, Matzat’s shared economy model is focused on the urban setting. “We need to bring those models to the cities and prove that they can work in an urban environment. So once we do this, I think that could change the building market for the better.”

The form that Matzat advocates fits naturally into an urban setting, and evokes the standard urban block of historic European cities, with commercial space at street level and residential space above. Matzat envisions entire blocks of this form of housing, at 150 by 50 metres.

“The lowest level will act as a community space. You’ll put your home office in there so the neighbors can connect and you can have a shop front or whatever you want to do there. Then the two upper levels are a little bit more private,” he said.

The design is flexible and shipped flat-pack style. Residents decide what amenities they need and can afford, then plug them into place. “Literally it’s open plan and you click in the wall so as to move the wall the way you want and the way you can afford it,” Matzat said. A space can be open and cheap for a single person or young couple, then easily be changed to add space for roommates or children. The only fixed space is the bathroom, and a kitchen is not necessarily included.

That approach would require a communal kitchen, which would be a radical departure from the typical urban flat. Including a kitchen in each dwelling, Matzat said, would help people ease into the concept, “but you know if you have your own kitchen you will not be forced to go out there and set up. I think it’s a good start to ease people into it maybe but it’s not radical enough to actually make the proper change.”