The Town Hall of Vandœuvres: a natural success
Stéphane Fuchs, director of ATBA, an architecture firm in Geneva, Switzerland
Interview dated June 24, 2014 in his office
Specialized in sustainable architecture, Stéphane Fuchs and his team restored the Town Hall of Vandœuvres, an 18th century building, entirely built with rammed earth. From old to new construction, the earth has proved its legacy through its durability.
Earth houses in Switzerland
Are there any earth houses in Switzerland?
The Town Hall of Vandœuvres is really unique, even though building with earth, and most of all with rammed earth, used to be common in the region, such as along Rhone valley, around Grenoble (France), and Lake Geneva.
As a matter of fact, the town hall was constructed between 1761 and 1770, and its rammed earth walls are still up! It had been renovated in 1989 though. At that time, the roughcast wall coating was redone with lime, whereas some areas were just coated with cement. In spite of that, we did not notice any damages due to the non-permeability of the cement.
What about the internal coating? Was it done with clay?
No, it was a mix of gypsum and cement. Ancient buildings are often not renovated the way it should be. Cement is commonly used, as there is a lack of knowledge of ancient materials.
Nowadays, the trouble with rammed earth walls is neither its resilience nor its quality, but instead its price! It is very expensive! Among our team, some people have mastered this technique and have built such walls. It should be considered an art rather than just mere architecture.
Do you have any clients who wish to apply clay or lime plaster in their new houses?
Yes, we have already constructed several houses on that model: a wooden structure insulated with straw, coated with clay plaster on the inside, and lime on the outside. By the way, we have just finished a little annex to a clinic in Chêne-Bougeries (Canton of Geneva). We are now trying to find cheaper alternatives.
Why are the costs so high?
Because of the time required to apply the roughcast coatings. On straw bale walls, three to five centimeters of earth or lime plaster are needed. In comparison, only one centimeter of cement would be enough. So, walls with lime plaster bear a minimal cost of CHF 200/m2 (€ 150/m2).
Relearning ancient building techniques
Can we find craftspeople skilled with earth and lime in Switzerland?
If we look, we can find some people. But many people are eager to learn and to rediscover these materials. An architecture office in Lausanne offers training on building with earth, straw and lime. Unfortunately, these techniques are not taught in professional schools.
In future, will professional courses teach these traditional techniques?
I do not think so. Rammed earth walls have become decorative and luxury elements of a house. They cost three times more than conventional walls. It is a niche market. That said, clay plaster is now available in the market. Bags of clay plaster can be bought easily and applied directly on walls.
How did you train in building with natural materials? What is your educational background?
I graduated from the Geneva Institute of Technology, Architecture and Landscape (HEPIA). Afterwards, I trained on MINERGIE®, which is about the reduction of energy consumption using renewables. I therefore studied materials, their life cycle
assessments and how to integrate them into a new construction.
Nowadays, our firm takes all of this into account. We have already built two small buildings and a few houses using natural materials – straw in particular. A façade is on the list too. We use bales of straw as standard insulation. It can also be used as load-bearing, but this technique requires more expertise. Bales here have a dual function: they support the roof, while insulating the building.
Is load-bearing straw bale authorized in Switzerland?
Of course! Peter Braun (Switzerland) is one of the specialists in Europe. Also Werner Schmidt (Canton of Grisons) has constructed several straw bale houses. Their clients are ecologically committed, since a straw bale house does not cost less than a conventional one. As I said, lime coating or clay plasters are expensive.
The mini-budget house
How much would building a 60 m2 house in Switzerland cost? Would it be possible to have a house built for less than CHF 300 000 (€ 250 000)?
That would be hard for an entire house. The more compact a house is, the more it costs. We have already built a house consisting of 120 m2 of living space. That is 150 m2 all together minus the basement. That had already cost CHF 700 000
(€ 582 000).
A 40 m2 annex, without bathroom or kitchen, costs already CHF 180 000 (€ 150 000). If you increase the surface and install a kitchen, you would easily reach CHF 300 000 (€ 250 000). So, I would estimate the cost of a 60 m2 house to about
CHF 400 000 (€ 332 000).
Which is the most expensive: the structure, the regulations or the architect?
The architect. As a fraction of the total cost, the smaller the house, the more expensive the architect’s
fees are. They can amount to 20% of the total cost of the house. That is a fifth of the price. You would be better of building it on your own, or at least supervising the construction yourself.
Is building a house without an architect allowed in Switzerland?
In Geneva, one can build up to 1000 m3 without an architect, which represents a 200 m2 house on two levels. It can be interesting. However, this option is not commonly known. Typically, the one with the means to purchase land in Geneva can afford architect’s fees.
« I have made the choice to live in a wooden community dwelling. »
Can you describe your house?
I live in a wooden community dwelling, a cooperative. It is entirely built with wood, natural insulation, mineral roughcast, wooden panels, pine for the internal structure, and larch for the external structure of the balconies.
Today’s trend: building sustainably
Is your firm known for sustainable architecture?
Yes. We have about twenty specialists in this field at our firm. For fifteen years, we have been developing wooden houses, stressing on ecological techniques, such as dry or composting toilets, and used water management. The firm has gained presence thanks to some ecological house magazines. I teach people who want to learn the “green” way to renovate a house at the World Wide Fund (WWF) as well. For the time being, we are lucky to have enough clients and – fingers crossed – do not have to solicit new ones.
Finally, how would you sum up building with earth?
In three words: « modern, rural and urban ». Earth can be used for renovations, as well as for new buildings. But rammed earth is not an insulating material. It is therefore often used for the interior and less for the façades. And as I said, the cost remains high.
Original interview in French
Translated into English by David John Kong
Interview with Stéphane Fuchs, ATBA architects, Geneva