Peaks and troughs accommodate planting on the roof of this concrete extension to a south London house by Bureau de Change Architects, which has a blue and white interior.
Bureau de Change Architects, which was co-founded by Katerina Dionysopoulou and Billy Mavropoulos, extended house in Clapham to create a lounge and kitchen with sliding glass doors that open to the garden.

The architects named the project Slab House after the appearance of the thick concrete roof. Inside, the exposed concrete ceiling of the living area features pronounced beams that form sunken roof planters above.
"We wanted to create a volume whose form would be meaningful both inside and out," said Mavropoulos.
"Inside, the motion of the roof slab breaks up the minimal surfaces of the living area," he continued. "Outside, it creates appealing views through hollows and humps, which bring nature and concrete into immediate proximity."
A skylight stretches the full width of the room where the living area adjoins the kitchen, which is set back within the footprint of the original house.
This strip provides the kitchen, which would otherwise be overcast by its position, with natural light as well as offers views into the space from the roof.

Inside, Dionysopoulou and Mavropoulos wanted to create different atmospheres for the kitchen and the living room.
A change from white to blue marks the transition from the lounge to the kitchen. All surfaces of the kitchen...