In the next few days and after only four weeks of work, an eight-story building that will have 45 industrialized homes will have been erected in the Barcelona district of Sant Martí (at number 180 Marroc Street). The block, the tallest of its kind in Spain, is an enormous meccano of 104 prefabricated three-dimensional modules that allow for more than substantial time savings in the entire work. It will require one year instead of the two that would have been required with conventional methods.

The development, which began construction in January, is carried out by the Institut Municipal d’Habitatge i Rehabilitació de Barcelona (Imhab) and involves an investment of 5.25 million euros. The forecast is that it can be delivered to the residents, who will obtain them under a surface right regime for 75 years, in the first quarter of 2024. A public facility will be installed on the ground floor.

Each home has two modules. One with a fitted kitchen and living room and the other with two bedrooms, sink and distributor. Facilities, doors, windows, switches… are installed. The useful area is 58 square meters, initially designed for three people.

A large 350-ton crane moves these enormous pieces into place at a rate of six a day. They are assembled together using screws and plates that are welded. The complex sits on foundations, which were built in four months. The process requires great precision so that everything fits correctly. The roof, which will have a community terrace and photovoltaic panels, and the stair and elevator cores are also modular. At the end of the process, the connections of the supplies and elements of the facades and roofs will be finished.

The building is designed by Vivas Arquitectos and Exe Arquitectura. The work is carried out by a joint venture composed of Constructora del Cardoner and Constructora d’Aro. The latter, through its subsidiary CompactHabit, is responsible for the production of the modules in its Cardona factory, a system that is still uncommon for large residential buildings. The manufacturing of these three-dimensional pieces started at the same time as the foundation of the site, so the time savings occurred from minute zero. The placement of these large blocks – each one weighs 32 tons – was planned to take place over a month. The final finishing work requires two or three more months.

“This system is very interesting because the construction time is cut in half compared to conventional construction, but also because it allows working in the factory without the need to set up scaffolding or tower cranes, which provides more security,” details the head of work, Francesc Cots. “Also,” he adds, “there can be better control of the quality and quantity of material used, reducing CO2 emissions and inconvenience to neighbors.” The overall costs are similar to those of other buildings and their quality and useful life, too.

The time factor is key. “The battle to get more public housing is also about deadlines, we have to shorten them both in the process of executing the work and in the processing,” explains Joan Ramon Riera, Housing Commissioner. The City Council currently has seven developments underway that are carried out with different industrialized methods, which will contain a total of 328 homes.