Once maligned for their perceived architectural monotony and crowded living conditions during the late-19th and early-20th centuries, Berlin’s tenement houses or Mietskasernen – characterised by multiple apartments stacked on top of each other – are now some of the most sought-after properties in the city.

In recent years, the need for more living spaces has meant the creation of coveted penthouses on the top floor of these buildings, many of which are readily snapped up by young professionals. Such was the case with this home, bought by a couple (one a scientist, the other an illustrator) who had recently moved to the German capital from Amsterdam.

The pair were quick to realise the potential of this rooftop three-bed located in Kreuzberg and bought it as a shell before turning to interior designer Kasia Kronberger, the founder of Berlin-based Studio Bosko, to bring it to life.

Her brief was open-ended and yet exacting. ‘They wanted as little white as possible and no pastels,’says Kasia, who was presented with two zellige tiles – mustard for the kitchen and a bottle-green colour for the bathroom –as a jumping-off point.

Her clients’ desire for a punchy palette stemmed from two key factors: he has a form of colour blindness that only allows him to distinguish bold shades, while she, an illustrator, thrives on saturated hues.

The owners had assumed their chosen yellow tile would simply form a splashback, but Kasia was keen to push the colour narrative further. So, instead, the shade was used to define the functionality of the space. As well as lining the wall above the main run of cabinetry, the tiles were used to clad the island, and complemented with honey-toned oak.

The kitchen design helped inform the other hues in the apartment and Kasia landed on a bright palette of green, yellow and red that’s playfully youthful, but a world away from a kindergarten art project.

The tomato-hued ‘Carimate’ chairs by Vico Magistretti set the tone and composition for the dining area, while green is used as a unifying device to connect the dining and living spaces, thanks to the custom cabinetry that runs across the entire length of the 10-metre-long main wall.

‘The clients needed enough space for their many books and memorabilia, so it had to have a strong construction but also to feel light,’ says Kasia. The bookcases were designed to be divided by a large painting of the legendary musician Frank Zappa, but she was keen not to press for uniformity on each side, and let the architecture dictate the room’s scheme instead.

‘I appreciate balance,’ she says, ‘but I try to avoid symmetry, because it feels too formal.’ In this spirit, the sloping ceiling is underlined by a ribbon of black paint. The bathroom is enveloped in glossy green zellige tiles, with white ones on the slanted walls to attract more light. Other rooms are just as saturated, from a maroon bedroom to a luminous citronella-yellow study.

‘The owners gave me a lot of space for creativity,’ says Kasia. ‘We say our projects are only as good as the clients permit us to make them. In this case, they allowed me to experiment and push my own boundaries.’ bosko.studio