These Apartments Are Designed To Sit On Rooftops

For cities like Paris that are running out of space, there’s an easier solution than new construction: Drop an extra apartment on buildings’ roofs.

A typical apartment building in the middle of Paris probably hasn’t changed much since 1890. But as the city grows–and it gets even harder to find a place to live–housing is finally growing more quickly as well. In 2015, the first new high-rise to be built in decades went up in central Paris. And now one architect wants to add housing in another, faster and cheaper way–by sticking new, sustainable apartments on top of older buildings.


Architect Stéphane Malka calls it “urban enheightenment”: making use of unused vertical space to keep the city center densely populated. “Building on top of the roofs is not only an ecological and economical solution, it’s working against the urban sprawl that kills the social link,” he writes. The first project, still in process, is designed to fit three new homes onto an older building on the banks of the Quai de Valmy.

In Malka’s design, a modular home is made in a factory off-site, then delivered, complete, to be attached to a rooftop. “You don’t pollute with the noise and the dirt that you’d have if you were doing something with concrete,” he says. We’ve developed a system that is very easy to install prefabricated, but yet it can be very adjustable.”

The house kit is so well-insulated and energy-efficient that it can produce more power than it consumes. It’s also cheap to make–and because it avoids the process of acquiring land to build, the home can cost 40% less than the equivalent elsewhere. And in exchange for the right to build, developers make improvements on common areas inside the older building as well.

“It was not possible before,” says Malka, but new updates in housing laws make this type of addition feasible. “In the few cases where it was possible, the different owners in the building had to agree to have it. Now they just have to be the majority.”

The new law allows extensions up to certain limits that vary by neighborhood. Malka calculates that it opens up the potential for new housing on around 12,000 buildings in the city.

About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.