Architecture for Humanity recently announced Mobius Architects as the winner of its  competition to design prefabricated homes with a 20×20 foot plan, roughly the size of two parking spaces.

Their design is intended to be built on the roofs of social housing tower blocks, which are often unused and capable of holding extra weight. The rooftop location means no additional land is needed, and development costs are minimized as the building foundations and utilities already exist on site.

Prefabricated housing suffers from a bad image, but it is highly sustainable and has the potential to play a significant role in accommodating our growing cities.

Check out this article on New Scientist for more from the winning team and runners up.