An upright piano with exposed strings rests on a carpet of sawdust. For the first time in six days, at the old textile colony of Cal Rosal, in Berguedà, silence has fallen. The artist Bru Ferri prepares to play and sing. But first, he highlights the work of the tired yet moved audience in front of him. In less than a week, among many other things, the stage where he will perform has been built. And not in just any way, but with natural, traditional construction, making each piece by hand. Wood, earth, lime, stone, and plant fibers serve to recover traditional techniques such as the Catalan vault, wood joinery, stuccos, and earth construction. "Without spaces, there is no culture," asserts Ferri.

Houses built or renovated with wood, earth, straw, or a wide variety of biological materials are proliferating in the Girona regions thanks to a unique ecosystem in Catalonia that brings together dissemination and training entities, architects, surveyors, and all kinds of sustainable construction professionals. It is a very well-connected network that helps, among many other things, to train self-builders, share experiences, resolve doubts, obtain labor, and find natural materials with a zero (or negative) carbon footprint.