Low Carbon Renovation, Zehrfuss Tower, St Denis

“ A winter overcoat ”
A building that wraps itself up when it gets cold and takes off a layer when it gets hot. This is the principle underlying
the renovation of the tower block built in 1970 by Bernard Zehrfuss. In 2009, this project won the Low Carbon Renovation competition organized by EDF.

Program	Renovation of a building constructed by Bernard Zehrfuss
Site	Saint-Denis ,France
Floor Area	5 170sqm / 55 650sqft
Cost of construction	€ 8 800 000 / $ 9 900 000
Timetable	2009 (not completed)
Project owners	Siemens, EDF
Certification	HQE, BBC, Low Carbone

Built in 1970 by the architect Bernard Zehrfuss, the eponymous tower block is elegant and innovative, but notoriously poorly insulated. The project aimed to remedy this drawback while conserving the originality of the façade. With windows that can now be opened, the building breathes in summer without the use of air-conditioning. Thanks to its structural concrete shaft and to the thermal points on the façade, the heat is chased outside the building. In winter, inflatable blinds made from EFTE, a highly insulating material that is transparent, are lowered along cables and cover the exterior façade, providing a warm overcoat for the building.

Low Carbon Renovation, Zehrfuss Tower, St Denis

©Fond Zehrfuss

©Fond Zehrfuss