In Taverny, a rehabilitation that rhymes with decarbonization

How to improve the environmental impact of rehabilitation projects? Many project owners are looking for solutions to limit greenhouse gas emissions linked to their energy renovation projects. This is particularly true for social housing stakeholders, as demonstrated by the rehabilitation of a 112-unit residence that CDC Habitat carried out in Taverny (95).

For Thierry Brocheriou, program director of the lessor for Île-de-France: "Our aim is to increasingly integrate the carbon impact of the work in our construction sites, at least for large-scale projects carried out in design-build. Similarly, we are increasingly attentive to reducing CO2 emissions during operation, thanks to the efforts made on the envelope and on energy systems."

An insulator that stores carbon

In Taverny, this positioning led CDC Habitat to ask the winning group, made up of the company GCC and the firm AOCA – Agence Olivier Cabanes Architecte – to carry out all of the external thermal insulation (ITE) with the StoTherm Wood system, which uses wood fibre insulation.

This bio-sourced material has an incomparable environmental record. Since wood fiber stores CO2, the StoTherm Wood solution is 32 times less emissive than under-plaster systems (ETICS) using polystyrene or rock wool (based on generic FDES). On a classic ITE site, Sto estimates the gain at 155 tonnes for the renovation of 100 homes: for Taverny, this means the emission of nearly 174 tonnes of CO2 was avoided.

The ITE has also kept its promises in terms of energy savings. The 112 homes in the Les Primevères residence now benefit from a C label on the DPE, instead of an E label. Finally, the renovation of the envelope has made it possible to reduce CO2 emissions during operation, from 15 to 7 kg CO2 / m2 / year – a saving of 68 tonnes of CO2 per year for the residence.

A variety of possible finishes

In addition to its environmental qualities, StoTherm Wood allows for a multitude of textures and shades in finishing. Before renovation, the Les Primevères residence had solid bricks visible on some facades, also visible on neighboring buildings: Sto proposed the use of Stolit Effect moldable coating in a deep red, and with a sweeping effect, to obtain a materiality close to terracotta. Reserved for the sills and some gables, this finish made it possible to "find a style that reinterprets the original facades, and dialogues with the surrounding buildings," emphasizes the project architect, Olivier Cabanes.

In the current parts, the finishing coating used is StoLotusan®, a high-end product that integrates Lotus-Effect® technology. Equipped with a self-cleaning function, the solution allows you to keep beautiful facades for longer: dirt beads up under the effect of rain, leaving the surface dry and clean.

Easy implementation

Another strong point of the solution is that StoTherm Wood has a laboratory assessment (APL) which avoids the use of rock wool overlapping strips for continuous fire protection, as required by regulations for other wood fibre ITE systems.

The main point of vigilance concerns the protection of the insulation against the risks of bad weather. In Taverny, a service provider was commissioned to store the panels and deliver them as the work progressed. "This adapted logistics solution made it possible to overcome the risks linked to humidity while ensuring availability of the material throughout the construction site," points out Nicolas Martins, Sto business manager in Île-de-France.

A test site on reuse

CDC Habitat's environmental ambition was not limited to the use of wood fiber for ITE. The Taverny construction site was an opportunity to test innovative reuse devices.

Several materials or equipment removed at the start of the work were able, after refurbishment and, where appropriate, after renovation, to be reused in the residence: this is the case for the railings of the terraces and balconies, the floor tiles in the common areas, as well as the bathtubs for which a re-enamelling workshop was created on site.

Technical specifications

• Type of building: Collective housing
• Location: 7 rue des Pervenches, 95150 Taverny
• Surface of facade treated: 6.000 m2
• Client: CDC Habitat
• Project manager : AOCA - Olivier Cabanes Architect Agency
• Applicator company: GCC
• Delivery date : February 2024
• Solutions used: StoTherm Wood 2, StoLotusan® K1,5 finish in the main sections, and Stolit Effect in the sills and gables