Once a rabbit warren of small rooms, narrow corridors and an isolated kitchen, this 1950s apartment near Madrid’s El Retiro Park is now spacious, light-filled and splashed with colour thanks to architect Javier Jiménez Iniesta of local design practice Studio Animal (which also has an office in Barcelona). Addressing the overly compartmentalized lay-out by doing away with it completely, Jiménez Iniesta clustered Casa Nube living, dining and reading areas into one all-white, three-metre-high communal space that is open to the kitchen. This move not only created a free-flowing floor plan that better supports the mother and son who live here, it also lets sunlight pour in from two sides and allows for natural temperature regulation through cross-ventilation. The designer then sequestered the bathrooms and bedrooms behind a truly spectacular intervention: a sculptural curved wall that signifies the transition from public to private.

“The cloud,” as Jiménez Iniesta refers to it, is a self-supporting wall (constructed from drywall with a metal substructure that is anchored to the floor and ceiling) in a compelling semicircular geometry, with two arches opening to reveal passages to the bedrooms (one for the homeowner and one for her son) through two symmetrical yet separate bathrooms. “The house is born from the idea of passing through, of the vaporous, the soft, the voluminous,” says Jiménez Iniesta of the unique arrangement. “Passing through that cloud had to be an experience.

The curvatures continue inside, dictating the usage of each bathroom by forming individual nooks for the toilet, sink, shower (in the son’s space) and bathtub (in the mother’s). In both, every surface is finished with 2.5-by-2.5-centimetre glass mosaic tiles, compounding the architectural interest through colour saturation — all-pink chosen by her, all-tangerine chosen by him. Serving as intermediate spaces, the bathrooms create a sense of ritual for the inhabitants as they move from the privacy of their bedrooms to the main shared living area.