44 dwellings 'Passiv Haus' in Orvault, Nantes, France
The competition program imposed a high environnmental quality and the Passiv Haus certification. A passive dwelling is a nearly self-efficient unit for its heating needs with solar gains, the energy released by the occupants and household appliances and good insulation.
Completed in december 2015
The site has a specific topography with a «balcony» position on the Valley, giving an open view on the landscape.
This particularity of the plot is fully used to set the volumes in the East-West axis, creating «through» housing North-South and taking advantage of a homogeneous light all the day.
The North facades of the buildings are used to provide access to the dwellings with access balconies, and the South facades are almost fully glazed to enjoy the view.
The collective dwellings are located along the road, divided in three buildings. Their maximum height doesn’t exceed two storeys, creating view sequences and keeping the perspective on the valley for the passer-by.
The three semi-subterranean houses are built in the Park, far from the road, enjoying the view of the landscape.
Requirements induced by the PassivHaus are numerous: cost control, design detail, collaborative work with all the project actors, etc ... These objectives can sometimes interfere with urban requirements (the urbanist wishing a pronounced fragmentation of volume).
As mentioned above, the South-North orientation position the site itself as a balcony opening on a green view. And this situation is also interesting for a PassivHaus proposal. Passivhaus is a German label, recognized in France (for the passive house), whose requirements are:
- Reduced heating needs <15kWh / m²
- Limiting global consumption <120kWhEP / m²
- Very high airtightness The project focuses a bioclimatic approach:
- A concrete and timber frame structure gives inertia to the building
- A double insulation from the outside and inside is provided with treatment of thermal bridges
- Looking for a compact design
- Double flow ventilation recovering internal heat
- The access balconies and south balconies are made of wood and metal structure detached from the primary structure
