Like many of Europe's major cities, Barcelona is in the grip of a housing crisis. As in many places, the delivery of social housing is slow, expensive and rarely meets meaningful sustainability targets. This project, commissioned by Barcelona's municipal housing institute IMHAB and completed by Vivas Arquietctos and EXE Arquitectura in 2024, challenges all three of those conditions: 45 homes, delivered on budget at under and ahead of schedule, in a building that achieves the highest energy rating in the Spanish certification framework.

Reponsive to context

Poblenou is an area undergoing sustained transformation, from industrial area to offices and housing. The architectural form of this project is informed by the dark-colours of the industrial sheet metal factories that characterise so much of the district. The building's black envelope wraps three of the four sides, with the facade on the south—most exposed to solar irradiation—is entirely glazed. The north-facing elevation carries the access galleries, which remain sheltered from direct solar gain.

Composition

The building contains 45 social housing units distributed across eight floors. Each of the apartments measures 60 square metres and features two bedrooms and a flexible layout. The eighth floor is divided between apartments and a set of communal spaces for residents including a laundry and lounge area. The ground floor of the building also hosts complementary communal spaces, including a large open terrace with garden areas, a space for bikes to park and shaded spaces for neighbourhood use.

Construction
Construction of the building was completed almost entirely offsite. Only the ground floor, the building’s service risers and vertical trunk installations were built in situ. The remainder of the building is made up of CompactHabit’s eMii system. 104 reinforced, 3D concrete modules that were manufactured and assembled at CompactHabit’s facility in Cardona, and transported directly to the site in Barcelona where they were installed by crane in just 15 days. Each apartment is formed by two of these modules. All detailing—bathroom and kitchen installation, wiring and drainage, facades and joiner—was completed in the factory before transport.

Structure and insulation

The structural system is a concrete portico made from concrete columns and lightweight, reinforced concrete slabs. While the original design featured a steel structure, the increase in prices caused by the war on Ukraine forced a rethink, and the architects shifted to a primarily concrete solution. Two types of insulation have been used on the project to ensure an energy-efficient envelope. Between modules, sandwich panels—steel-faced PIR core panels—have been used. In all other locations, mineral wool was used. 

Sustainability

The building holds an A energy certification, the highest band in Spanish certification. This is significant in social housing, where budget constraints often push projects toward less ambitious energy performance. The building’s bioclimatic design promotes natural cross-ventilation, which is guaranteed by the building's proximity to the Spanish coast, which produces a constant north-south breeze through the building. 

Aerothermal heat pump technology is used for both heating and cooling, this system extracts ambient heat from the outside rather than generating it via combustion. This makes it dramatically more efficient than gas boilers, and produces no on-site emissions. A PV rooftop array generates electricity that feeds the building’s shared systems, including the aerothermal units. This combination of a highly efficient heat source running on self-generated energy, alongside LED lighting, results in a housing complex that runs almost entirely on renewable energy.

Budget

This is particularly notable given the project's tightly constrained budget. As a VPO development—vivienda de protección oficial, Spain's officially protected housing program—all costs are subject to regulatory caps. The base construction cost came in at €991.98/m2, a figure that makes the building's energy and construction ambitions all the more striking.