LOCATION: Saint Jean Bonnefonds, France
Architects: Patrick Bonner and Elena Roig
DATE: 2017

Construction systems and project philosophy:

The plot where the project is to be developed is situated in a green zone. Right from the outset, therefore, a dwelling was conceived of, which on completion, would only be as self-sufficient as possible in energy as far as daily functioning is concerned, but would also employ the least aggressive construction processes and materials, so reducing the impact on the environment and keeping energy costs to the minimum while in construction.

Bearing that in mind, we began by making various sketches of the possible layout of the dwelling, taking the east-south-west location of the plot on a hill and its excellent views of the Pilat Natural Park into consideration. Once the layout had been decided upon, a bio-geologist was called to study the effect of the surrounding flows and energies in the different living spaces proposed (underground water flows, energy flows for the different areas of the plot for the future dwelling, etc.) The dwelling is being planned to make the most of the daylight in the east-south living spaces, and for the west-north night-time spaces to be protected by deciduous trees to the west. There are no crossover access points to the bedrooms and the doors and windows are designed to provide good air circulation. There are also extra windows outside the bedrooms to provide cross ventilation for the entire house and natural light. The layout and situation of the dwelling on the plot met with the enthusiastic approval of the geo-biologist.

The dwelling, which has been designed almost entirely as a single storey building, seeks to take advantage of the sloping land. In the area where this proved problematic, it was decided to build a basement that is only accessible from inside the house to be used as a storage room.
The construction system foreseen is based on a wooden skeleton lined by hempcrete (a mix of hemp fibres with lime as the conglomerate). Although reinforced concrete is to be used in the foundations, the internal and external finishes will be of lime mortar which will provide a homogenous look to the materials and create harmony throughout the house, based only on hemp, lime and wood. This system allows us to use a single material for the outer walls and to take advantage of the hygroscopic properties of lime to achieve natural exterior/interior transpiration throughout the dwelling. The appropriate thickness of the hempcrete compound has been studied to exceed the minimum demands of thermal insulation. This system, by allowing the entire building to breathe naturally, prevents the condensation that is so customary in sandwich-type walls. The internal framing is constructed using local timber, for both the internal and external carpentry. The roofing is built using the same wood/hempcrete system and based on green roofing solutions, with the exception of the garage area that consists of a sloping roof with sufficient inclination for positioning solar and photovoltaic panels on the surface.

With regard to installations, the impact of electrical wiring and plumbing in the various rooms has been taken into account, as well as the soundproofing of any noise coming from the disposal facilities. Rainwater storage has been accounted for and the geotechnical study undertaken on the land has been used to analyse the possible sanitation systems depending on their particular characteristics.

Finally, the dwelling is designed to comply with the minimum demands for the disabled, with a specifically designed access to the inside of the building from the garage and a bathroom to meet their particular needs.