As unlikely as it sounds, Brazilian architect Fernanda Marques has installed a swimming pool in the courtyard of a duplex apartment in São Paulo’s upscale residential neighbourhood of Villa Nova Conceição. The pool may be just one element of her design for the 477 sq m ground and lower ground floor flat in a 1990s block; but it’s a crucial one.

The 10m-long pool takes up 25 sq m of the outside area and is accessed via the stairway in the exterior garden or from the gym on the upper floor. All that water is kept at bay by an 8cm-thick sandwich of glass panels bonded by a high technology structural membrane.

The pool overlooks the living room, which houses some of the owners’ mostly Brazilian art collection. Pieces by Ernesto Neto, Edgard de Souza, Manoel Rio Branco, Zerbini and Tunga are complemented by Marques’ choice of furniture, much of by Brazil’s late, great modernist heroes. The dining table and chairs are by Joaquim Tenreiro; a pair of Jangada armchairs by Jean Gillon – who was originally from Romania – stand near the artworks on the ground floor; and there’s an armchair in the master bedroom by Zanine de Caldas, who had worked with Oscar Niemeyer. Meanwhile the wooden bench on the terrace is by Hugo França, who is still living. Marques’ aim was to keep the interiors relatively simple, to leave room for the collection to be added to.

Despite the artworks, it is the aquamarine water that draws the eye. Marques, whose mostly female team is headquartered in São Paulo, has a track record in magicking luxuriant interiors for residences in her home country, Miami and increasingly Lisbon. She says of the pool: ‘It was intended to be more than a leisure experience, but a poetic presence inside an art collector’s home.’