The Balearic Social Housing Institute has become internationally recognised in the development of sustainable housing. Its projects share a simple means of construction without relying on elaborate technical services and by referring to building traditions adapted to the local subtropical climate. The two-storey multifamily house in the municipality of Puigpunyent – roughly ten kilometres northwest of Palma de Mallorca – follows these principles. Similar to the projects preceding it, predominantly materials sourced in the region were used, such as limestone and brick. For the striking cyclopean facade – a kind of hybrid masonry combining lime cement and rubble – the team comprised of two architectural offices, Joan Fortuny from Palma de Mallorca and Alventosa Morell from Barcelona, also used stones and earth excavated on site and locally available demolition material. As a result and in comparison to conventional buildings the carbon emitted during construction, calculated at 230 kg CO2/m2, was halved. A single skin brick masonry wall on the inside serves loadbearing purposes and supports the exterior skin.
The building features a symmetrical floor plan with six subsidised apartments that are accessed by two entrances: Four 2-room apartments on the ground floor and two 3-room apartments including roof terraces on the upper floor. The centre of all six units is the open-plan living and kitchen area. In the interior, surfaces with unfinished appeal define the character of the rooms: masonry painted white, loam render, lime floors, and visibly exposed timber beam ceilings.
The housing project was designed to optimally utilise sun radiation in winter and lower cooling demands in summer. The solid exterior walls play a significant role in this regard as natural heat storage. A further central element is the attic space. It remains unused while serving the function of a climate buffer. The large scale glazing allows capturing solar energy in winter. In summer the roof windows are opened and provide a means for venting the warm indoor air outward. Based on this passive system, the building demonstrates a low annual heating energy demand of 7 kWh/m2a.
