Casas de Trás is a social housing project built as part of a municipal rehabilitation programme in Porto (Portugal). The programme was set up to resettle low-income families in the city centre. It is an important initiative for the local area and represents a paradigm shift in this type of programme: small units located within the urban fabric instead of large housing blocks in suburban areas. Like other European cities with long-established historic centres, neglect has made way for rehabilitation in Porto in recent decades to attract mass tourism. As a result, many of the buildings have been converted into small-sized housing units suitable for short stays.

This project is based on a different premise: building spacious houses suitable for long-term habitation for families. It consists of rehabilitating two buildings on two different streets (Rua de Trás and Rua dos Caldeireiros), which communicate with one another inside the plot.

On the ground floor, three commercial units with independent entrances were created. A new entrance on Rua de Trás leads to nine apartments linked by a courtyard, staircases and balconies providing access. A staircase occupies the ‘void’ above the entrance, operating as a kind of vertical street.

The courtyard/staircases/balconies form the core of the project. The nature and dimensions of these common areas encourage socialising and interaction on several levels and expand the domestic space beyond the interior of the apartments.

Inside, the space is laid out in such a way as to accommodate domestic habitation and future appropriation. In the small building on Rua de Trás, three studios intended for couples or individuals were created. In the larger building, apartments for families were designed, with living rooms facing the courtyard and bedrooms facing the street.

Given the depth of the existing building, two interior courtyards were built to allow natural light to reach the apartments. The width of the connecting corridors, which run around these small courtyards, make them appealing places for socialising and appropriation for a variety of uses.

The Casas de Trás combine careful restoration of the existing building and insertion of contemporary elements. The materials used are simple and several low-cost solutions have been adopted, including reused granite slabs in the courtyard and reinforcement rods in the balconies.

Overall, the building mirrors the city itself as a space of cohabitation and social interaction.