Case Studies

Original situation

Four-house residential neighborhood on the outskirts of Ossé - Châteaugiron. (Brittany)

Renovation approach

Envelope​ :

• Installation of prefabricated wood frame panels, rock wool and steel cladding ​
• Double glazed aluminum exterior joinery (integrated into the panels)
• Removal of asbestos roofing and installation of steel roofing on existing framework
• New ceiling insulation (contaminated 200 mm glass wool removed and replaced by 400 mm glass wool insulation)
• Existing slab not modified because technical and economic constraints not consistent with wall optimization
• Placomur premium garage insulation ​
• Electric roller shutters, glass entrance door, garage door replacement ​

​Energy production: Installation of photovoltaic panels on 1 roof surface per dwelling

Heating and ventilation: Installation of a prefabricated and pre-equipped energy module with a triple service heat pump (heating, hot water, ventilation)​

CHALLENGES OF THE PROJECT

• Difficulties encountered in buying back photovoltaic energy
• Important carbon impact of the CAP
• 126 000 € / housing: the economic model is not reproducible

Need for other large-scale projects to bring prices down

RENOVATION APPROACH USED

• Operation in design-build mode
• Prefabrication of walls

Rapid work (5 weeks / unit), carried out on an occupied site

Modernisation proposal

Global prefabricated Energiesprong retrofit

Efficiency improvement

The buildings went from a DPE Efficiency rating “E” (296 kWh/m².a in average) to a DPE “B” (< 100 kWh/m²a).

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