When non-renewable materials become indispensable
Just as there is a compromise for the use of non-natural materials, there is another between renewable natural materials and non-renewable natural materials, such as those whose production derives from quarry extraction activities, such as cement, lime, clay, metals, which once extracted and processed take on a different consistency and, at the end of their life, never return to their original state.
We can therefore build houses entirely in wood, one of the few renewable, recyclable and actually sustainable materials, as nature is able to recreate them, but if we have to build a solid foundation to support a multi-storey building we must draw from non-renewable resources, in combination with each other, such as cement, metals, sand and stone aggregates, with the addition of water.
At the moment, reinforced concrete is in fact the safest and most tested solution for statically supporting the building, even if, from an ecological point of view, the union of its individual components forms a product which, at the end of its use, can no longer be reused for the same functions, but for others, through mechanical recycling. The inert part will become a stone agglomerate useful for draining fills and for load distribution, while the iron, separated from the cement agglomerate, can be reused by remelting, but to fulfill purposes of another nature, since recycling causes the material to lose quality.
The limits of natural materials in real applications
Similarly, when we come across the choice of building terraces, flat roofs and flat roofs, especially if they have a low slope, we will need to waterproof the surfaces, so as to allow rainwater to drain away, avoiding infiltration into the buildings below. In these cases we will be forced to use products made with synthetic materials, considering that nature is not currently able to give us products with similar performance characteristics, materials which at the end of their life will hardly find another use and will easily end up constituting unmanageable waste to be deposited in storage areas, forever.
And here the list could be long, including many other widely used products, such as the vapor barriers of vegetable fiber coats or the breathable and waterproof membranes of roofs, currently not recyclable, as well as electric cables made of metal wire sheathed in plastic material, or certain types of vegetable materials which, to become thermo-acoustic insulating panels, must be combined with synthetic glue products or bindings of various kinds unrelated to the vegetable product, and so on.
The right balance: the true principle of ecological construction
In short, the 100% pure natural house, which has no compromises or mediations, is very difficult to create, at least for the moment, especially if pushed to heights.
Therefore, when designing and constructing a building, it is necessary to know how to dose its components well, confirming those that nature gives us, such as wood for the structures, all the plant derivatives for the thermo-acoustic insulation and for the finishes, limiting to the minimum, where possible and lawful, all the others considered indispensable and which constitute a sine qua non condition to achieve a specific purpose.
The secret therefore to building an ecological house lies in the right balance between materials coming from the ecosystem, which must be predominant compared to other materials created by human hands and not existing in nature, and natural, but non-renewable ones, to be used only where they are indispensable.
Therefore, when choosing the construction system, the most natural, pure, long-lasting one will be adopted, not treated by foreign substances that are risky for health. Likewise, the insulation system will primarily favor materials of vegetal and animal origin; in second choice a mineral product and, only where it cannot be done without, a synthetic material. This scale of values reflects the environmental character of the materials which become an ethical choice, as well as a constructive one.
