ALPEDRETE – A former water cistern provides the foundation for a single-occupancy home near Madrid. In a previous life, the underground tank contracted water from an on-site well to supply the local houses. Valdivieso Arquitectos designed Casa Aljibe – literally ‘cistern house’ – to utilize the dormant architectural form, turning it into the basement level of a summer residence.
The plot has belonged to the same family since the late 1940s; the new occupants are descendants of the couple who built the original mansion on the site. The water cistern became redundant in 1955 and has existed in the same state ever since, despite being used as a storage and warehouse space when other houses were subsequently built in the area.
The firm describes the purpose of the project as ‘creating privacy while sharing an atmosphere with the rest of the family through the common garden’. The roof of the house slopes backwards to minimize the visual presence of the building.
To a stranger, the stone wall would look like a folly in the garden of a single-storey house constructed from cross-laminated timber which sits on top of a (green) steel frame. The curve of the floor-to-ceiling glass façade traces the footprint of the stone step. ‘The two structures work independently, so the typical problems associated with designing around existing buildings were avoided,’ explains lead architect Alejandro Valdivieso. The re-appropriated cistern is integrated seamlessly to include the private rooms. ‘We respected the stone of the original architecture, rebuilding it in some places, and left the old concrete beams and columns as they were to keep a testimony of what it was.’