Memory of project
The project of metamorphosis of the “Bois Le Prêtre” Tower consists in a radical transformation of the conditions of comfort and habitability of the 100 residences of the occupied building. The tower built in 1962 by the architect Raymond Lopez, develops on 50m height, 16 levels serving each one 4 or 8 residences. By addition of heated extensions, winter-gardens and balconies, the overall surface of origin of 8900 m² is carried to 12460 m². This new organization of surfaces and the precise technical improvements make it possible to adapt the rental offer while meeting by the creation of new typologies the needs for the families, to return lime pit foot the access to all the residences, to reduce passively, the consumption of energies of more than 50%, mainly by the addition of the winter-gardens.
Principle of metamorphosis.
The existing structures are preserved, the bays are opened, the prefabricated balconies of three depth meters are piled up and juxtaposed with the existing frontages, the interiors are adapted to the rental needs, the consumption of energies is reduced at least of 50%, in particular thanks to the passive energy management of the winter-gardens. The basic calculation of the rents is preserved. The surface of the winter-gardens is near 25m² for each 42m² of existing housing.
Each dwelling is augmented by large balconies and winter gardens. Moreover, all the building has benefit from extended living spaces with heated surface areas on the north and south gable-end. These additional areas respond to the resident families needs, especially linked to over-occupancy of dwellings. In consequence the project creates four new typologies of residences.
Tenants of Bois le Prêtre still live in during the renovation. A special care is guaranteed for each family, they can stay in their own residence. Otherwise they can occupied a bigger or smaller one according to their requirements. Moreover each family have the possibility to move in the building in order to discover a new point of view and position. Every dwelling received new electrical fittings, new sanitary facilities and new ventilation system. The interior layout and design can be preserved according to the occupant wishes or removed or adapted between a various choices of finishing touches and partitioning.
For each dwelling this additional winter-garden is a significant benefit for fluidity of living spaces, natural light, superficies and energy savings. The thermal performance of winter garden is more efficient than a classic heat wall isolation. The way those winter gardens work is very simple, domestic, without much sophisticated technology. It is made by four types of mobile screens. From the outside to inside there is:
- Sliding translucent or transparent shutters, no airtightness.
- Solar shading curtains on rail, associate to sliding shutters.
- Sliding bay-windows high-performance, placed in line with the old facade.
- Energy curtains made up of Mylar reflexive sheet (= same material of survival blanket), a layer of sheep wool and a decorative fabric.
The consumption of embodied-energy used for the Tower Bois le Prêtre execution is minimal if it is compared with the energy used in demolition/reconstruction project (about + 480%) or a new construction (about +230%). The metamorphosis choice is first and foremost about the quality of dwelling, area, space capacity and possibility: bigger, more luminous, easier for living. Besides it is an ecological choice with high consequences on energy management and sustainable development. It is a global economic choice because the cost of the building transformation is 40 to 75 % lower than the cost of a new construction.
Text.- Frédéric Druot Architecture.
