La Balma

La Balma is a housing cooperative based on use transfer, promoted by Sostre Cívic, located in the Poblenou neighborhood on a plot won in the first competition promoted by the Barcelona City Council to develop cooperative housing. Lacol, together with Laboqueria, developed the architectural project in all its phases, from the competition to the completion of the construction. The proposal aims to focus on optimizing economic resources to achieve an affordable building with minimal environmental impact, which avoids energy poverty and understands the building as infrastructure that supports and allows free evolution from three social spheres: the neighborhood, the community, and the homes.

The building is located on a green axis full of neighborhood facilities. The cooperative wants to participate as one more facility in this axis, sharing community spaces and expressing the richness of the internal community life towards this public façade. For this reason, the main access, all the community spaces, and the vertical circulation are on the north façade, opening to the linear park.

From the initial participatory process, a program of community spaces was drawn up. These are distributed vertically throughout the building’s floors, taking on different characteristics depending on the use of each space. The idea is that the community spaces and circulation enhance human relationships, spontaneous encounters, and cooperative activities throughout the building (concept of a big house). On the ground floor, there is the communal kitchen-dining room, a bicycle space/workshop open to the neighborhood, the lobby, and two commercial premises facing Espronceda Street. On the other floors, alongside the homes, there is a program of small community spaces: multipurpose room, reading area, guest rooms, care space, and laundry. The fully accessible roof is a large terrace of more than 300 m² that the neighbors can equip with productive gardens, photovoltaic panels, shading, and recreational areas. The circulation areas always accompany the community spaces; they are open, ventilated, and sunny spaces, aiming to dignify these spaces, which are often minimized and single-purpose.

The 20 homes are designed based on a grid of 15 m² open modules. These modules allow for very diverse divisions and layouts, enabling users to decide on their own spaces. Each home starts from a base module of 50 m² fully equipped, corresponding to the small typologies (S). This basic unit can be expanded with one or two modules, becoming typologies M or L. The additional modules are private spaces but managed by the cooperative. This management allows real flexibility in the system.

To achieve a building with low environmental impact during construction, two types of structure are proposed that optimize the functions of each material, cost, construction speed, and environmental impact. In contact with the ground and street, a reinforced concrete structure is used (minimal mineral material). For the homes and community spaces, a cross-laminated timber structure is proposed, offering comfort, healthy spaces, and a very positive environmental impact on the whole building. It is a lightweight building, where reusable and dismountable materials predominate, which allows reducing the foundation and the use of mineral-origin materials.

The goal of minimizing demand is achieved through several strategies. The first is working with a changing building section, adapting to the changing reality on different floors. Maximum solar gain is sought on floors 1, 2, and 3, while floors 4 and 5 are protected from excess radiation. The second is compacting conditioned zones, making well-insulated homes with minimal energy losses. Regarding active systems, centralization of installations is chosen to facilitate maintenance, improve system efficiency, and minimize costs. The installations are conceived as improvable, leaving provisions for future systems that may improve building autonomy. From the start, infrastructure will be in place for photovoltaic panels and piping for a greywater recovery system. This reduces initial investment, leaving future investment subject to the cooperative’s possibilities. Heating and domestic hot water will be generated via a geothermal system that will allow comfort with minimal energy cost and environmental impact. This system also allows free-cooling to cool apartments during warm months without energy input, only circulating water cooled by the ground. The heating/cooling terminals are radiant clay panels. This way, geothermal energy is maximized with a system working at low temperature, allowing both heating and cooling with the same element.