The choice of materials and the first problems
Luckily for me it was a client sensitive to the values of (green) building, i.e. healthy building which involves the use of natural materials, not processed by excessive anthropic manipulation. It was the classic client that all architects sensitive to environmental problems would like, because, as an ecologist, he spoke the same language as me.
The project was not complex and involved the insulation of the casing around the housing unit located on the first floor of a building with two floors above ground, intervening with passive criteria on the walls, floor and attic of the accessible attic, partly outside and partly inside. The result would have led to the creation of a more performing casing, exceeding the famous two energy classes required by the standard.
The choice of materials and solutions was simple: all the insulators came from the plant world and the customer accepted them without any objection. But here the first problem arose: the price list that had to be considered was that of the DEI publishing house, which reported a large number of materials external to the world of green construction and very few insulating materials of a vegetal and animal nature, mostly also defined by completely incongruous prices on site.
Then a second problem arose: the sudden increase in prices and the objective difficulty in finding materials, especially thermo-acoustic insulation. While the first was resolved, the second instead constituted a serious problem for a particular supply, despite the order having been widely anticipated.
The search for an alternative solution
The biggest problem concerned the insulation of the extrados of the attic floor, which had a workable height, with which a walkable surface had to be obtained, on which a substantial layer of insulation with a material of plant origin had been provided. For construction simplicity and an economic advantage, the original solution involved the use of a granular material, which would have assumed its own stability simply by pouring it onto the floor of the attic and mechanically pressing the composite layer, without the use of water or any binder.
Unfortunately, that precious granulated insulating material was no longer available at the time of the request and led to the construction site being stopped, with the consequent shift of the timetable to an unknown time. Driven by the urgent need to find a quick solution, I remember that I spent several days in phone calls and contacts with insulation suppliers and distributors in search of an alternative material, avoiding modifying the project as much as possible, with the risk of increasing costs. Everything seemed to be working against us, no manufacturer or building retailer had green building materials, and those few that remained had been the subject of monstrous speculative economic attacks.
Cork: a technical and ecological solution
But in the fog of uncertainty and fear of not finding a valid solution, an ancient material came to my aid, which I knew well, which I had adopted little in the past, but which I nevertheless believed to be very valid in the context of interventions of this nature: cork, in the granular format and in the consistency lightened by toasting. A natural material, with technical characteristics that improved compared to the original project solution and which, with the addition of a minimal quantity of a stabilizing product, gave solidity to the insulation system, allowing the studied static solution to be maintained. The product was available immediately and, moreover, at a cost similar to that envisaged in the project, and therefore without an obvious increase in price.
I can only thank the supplying company Tecnosugheri srl for this treatment today. Among the many insulating materials of plant origin, toasted granular cork is one of the few that maintains its total naturalness, being usable without added substances, such as glues and various additives. As a cavity filler, it maintains its natural state. By aggregating the natural granules with a simultaneous action of pressing and heat, compact panels are created, thanks to the total escape of suberin, the natural glue element of cork.
The granules obtained from the waste from the manufacturing of the toasted panel can then be amalgamated with the addition of a stabilizing vitrifying product, which gives them solidity and stability, also to create large thicknesses. By doing so, however, its naturalness is partially compromised, even if its use constitutes a compromise that is common to many other plant-based insulators.
In fact, there are very few insulating materials that we can define as one hundred percent pure. Many of them are aggregated with synthetic glues, even if minimally, to give them solidity and compactness. But, as I often say, green building also accepts mediating compromises, when foreign compounds, perhaps even of a petrochemical nature, are added to the pure material in order to determine particular technical characteristics.
