Turin, the tree house turns ten: “Even the neighbors’ assembly is a celebration here”

His tree house is 10 years old and the architect Luciano Pia nothing would change about «25 verde», the first experiment in eco-sustainable bio-architecture in Turin. The condominium at via Chiabrera 25 is a class A habitable forest, so much so that it was tweeted by EU President Ursula von der Leyen as a model of a green building.

What is the outcome of your «green 25» ten years later?
«The building works, in the garden there are always 4 or 5 degrees of difference. The significant space left for trees everywhere creates a microclimate that lowers the urban heat island. In addition to the simple coat, it has great thermal inertia, controlled mechanical ventilation, thick walls and geothermal systems.”

Would it change anything?
«No particular problems have arisen, I wouldn’t change almost anything. I would leave it like this, also because the people who live there are happy.”

And it’s also beautiful, which doesn’t hurt.
«Even more important is that people are happy, the condominium meeting is a celebration among them. A sort of community has been created among those who share that space. Instead of going out of town, they invite friends for a picnic on their terrace at the weekend. It is the best result a designer could wish for.”

It’s not enough to put on your coat.
«No, it’s not enough, we must also increase thermal inertia, provide good sun protection, excellent ventilation, guarantee a certain architectural quality. Otherwise the building will no longer breathe and inside you will find an environment saturated with humidity, therefore mould, bacteria, bronchitis and pneumonia for the people who live there.”

Homes for the rich?
«When the “25 verde” homes were sold they cost around 500 euros more than the traditional ones in the context, because building was much more expensive. Not a big difference, which can be spent to have a higher quality of life and savings in use.”

How do you see the operations underway in Turin?
«I no longer live in the city, for the last 4 years I have lived in Sardinia in the winter and in the Aosta Valley in the summer. But from what I observe, I see houses that are energy efficient and not green in the true sense of the word. Making it truly “green” is not easy, architects often limit themselves to designing their building and then place a few trees in the free space.”

Why do they all look the same from an aesthetic point of view?
«It is the regulation that imposes a uniform standard, to simplify. If you do not respect it, you no longer fall within the parameters and then perhaps the building cannot be certified. So we see those “boxes” almost everywhere, it’s the required standard.”

Alternative?
«If we took back our historic buildings, with the 60 cm brick walls and vaulted ceilings, and optimized them, we would have more efficient buildings than many new ones we see around».

She goes against the grain, many say it’s impossible.
«It’s not true, with the climate we have today, in which it is more hot than cold, we need buildings with good thermal inertia. Otherwise you always need systems and technology to make them work. The goal is to design buildings that don’t need anything.”

Are you working on this?
«I’m working on the recovery of what already exists, in particular the energy-intensive building heritage of the 70s. Without thermal inertia or insulation: what can we do with it? I am working on hypotheses on buildings of this kind, the most difficult, but not in Turin.”