On November 25, the results of a comparative study were presented between several alternatives of prefabricated or conventional systems according to a quantitative and qualitative analysis of the environmental impact and its cost, proposed for the construction of the building of cooperative housing Cal Paler Nou (Cardedeu).

In our cooperative, since its foundation, we have not stopped working for an energy transition that we see as not only desirable but inevitable. It is in the DNA of the entity, in its social mass, in its statutes, and of course, in its projects. The cooperative incorporates sustainable materials and systems that consume only renewable energy in all its buildings, participates in the Generalitat's emissions reduction program, in the Bcn+sustainable network, in the Bcn Climate Emergency Table, and in the European Houseful sustainable building project, among others.

Last November 25, we presented a study, in an online chat where more than 100 people signed up, which is part of this unequivocal commitment to the environmental and social sustainability of the entity. It is an investigation born from a concern shared by many of the actors, both technicians and user partners, who participate in the development of cooperative housing projects: how can we build with less environmental impact and at the same time with an affordable cost for social housing?

In this sense, a Sostre Cívic we also wondered Which construction model would best answer this question, prefab or traditional (or conventional) construction? And we thought that the best way to answer these questions is from a practical perspective, in a real context of a real project, to avoid the academic debate and land the conclusions in our practice here and now. That's why the project was chosen Cal Paler Nou, a building of 39 homes that will be built in Cardedeu, and which is currently in the development phase. 

The research has been led by Organic Society, in charge of coordinating information and analyzing environmental impacts, supported by Labaula Architects i STEM Architects, editors of the Executive Project of Cal Paler Nou and in charge of contrasting the possible implementation of the proposed systems, and finally completed by La Constructiva, which has studied the budgetary and implementation repercussions of the proposed systems.

The authors of the study speak

The talk was led by our colleague Àngel Estévez, coordinator of projects and of the Environmental Sustainability area of Sostre Cívic. In his presentation he emphasizes that when studying a specific case of a building with a real form, program and location, the number of systems that can be implemented, that is to say possible, is limited. Contrary to what it might seem a priori, this starting condition has helped to answer the hypotheses raised in a more assertive way, based in the real construction market and adjusted to the legal and regulatory reality of the country.

Inés de Rivera, of the drafting team of the project Cal Paler Nou de Labaula Architects i STEM Architects, explains the executive project of the Cardedeu building. They were taken into account from the conventional systems established until now (on-site and wet work) to other prefabs based on wood and, additionally, also on steel. The use assigned to each space in the building was also considered. This factor is relevant because the regulatory requirements are different according to the uses and, therefore, the technical performances of the closures change. For example, the acoustic insulation for residential, commercial or parking uses are different. 

Gerardo Wadel, architect Specialist in LCA, materials and technologies of the environmental consultancy Organic Society, mentions the aspects most related to the environmental impact of the study according to the different systems analyzed. Materials, energy consumed, waste treatment, etc. Among the results, it stands out that industrialized systems with ease of disassembly have a greater possibility of closing cycles, generating less waste and, therefore, being more ecologically efficient.

To finish, Eugenia Ruiz, procurement technique and purchases of La Constructiva (the country's first cooperative construction manager) summarizes the economic assessment and time estimation of the different construction systems analyzed. The budgeted results, pending confirmation throughout a real work process, mark an economically favorable trend towards the introduction of construction systems with a higher level of industrialization. This, he points out, in a sector where conventional construction predominates and where specialized labor is lacking. He also points out that, while he believes the prefabricated building system is the future, the fact that there is still very little competition means prices are high.

See the full study and the summary table

Another of the objectives of this study was to draw conclusions that could be used for other construction projects beyond the Cardedeu one. That's why the authors of this one decided to have a high component pedagogical In this sense you can find on our website a summary table of conclusions. A visual consultation tool, easy to understand that works at different levels: at first glance (with traffic lights), so that any unqualified person can understand the comparison between the different construction systems; and, for those who want more details, a numerical assessment according to construction system, environmental impact, labor, etc. And if anyone still wants to go deeper, the full study can be viewed here. 

Finally, it should be noted that this study could be a reality thanks to the support of the Generalitat through the program of Singular projects to promote the social economy and cooperatives.

You can also catch up on the video chat here: