Creation of an eco-district with high energy performance housing in Lunéville

On April 15, the first inhabitants of the Liberation eco-district, in Lunéville (Meurthe-et-Moselle), moved into their accommodation. Between avenue de la Liberation and allée des Lilas, on just over one hectare, a former nursery has given way to a new construction program of 31 high-quality housing units led by the Office Public de the Habitat (OPH) of Lunéville in Baccarat.

Positive energy

This new social housing space combining sustainable urban planning and energy performance combines individual and collective housing while promoting a strong social mix. It has twenty individual houses and a building housing eleven apartments.

“Energy performance is our hobbyhorse, underlines Adrien Kremer, operations manager at the OPH. When we launched the design-build competition, our specifications imposed an energy consumption 20% lower than the requirements of the regulations in force RT 2012. As an option, we envisaged a target RT2012 -50%. We had the opportunity to respond to the E + C- call for projects for positive energy buildings with a low carbon footprint meeting the future RE 2020 environmental regulations. The collective building is labeled with an E3C1 level. "

To ensure the control of rental charges, the social landlord also aims for the sustainability of performance. This involves the use of sustainable, recyclable and reusable materials. Adrien Kremer rejects any sophisticated gadget and favors simple solutions that have proven their worth, such as thermal insulation from the outside (EIT) for a long-lasting and efficient building envelope.

high insulation

The ITE is the solution adopted to ensure high insulation in the collective building by the winning team of the competitive dialogue, led by Eiffage Construction Lorraine. To house the eleven housing units, the architects of the Bagard & Luron agency and the Huguet design office designed a R + 2 building made up of two wings framing the vertical circulations.

"As this central part is not heated, the two north and south wings are treated as separate buildings, each with their own envelope", describes Jérôme Guillaumond, the architect of the agency in charge of the operation.

The two parallelepipeds built in concrete blocks, simple and compact, with no setbacks other than the balcony slabs, are wrapped in an ETI under plaster. The facades are animated by a play of contrasts between white buildings and dark gray gables.

E + C label

This simple design of the building and its envelope is proving to be very effective, as confirmed by the thermal study carried out by the Huguet design office. Indeed the Bbio coefficient (conventional bioclimatic need), which measures the thermal performance of the building independently of the energy systems used, is very favorable here. It is 45,3 for the north wing and 38,6 for the south wing, i.e. 46,1% and 54% respectively less than the maximum Bbio set by the 2012 RT (84) for all new buildings.

Another requirement of the RT 2012 thermal regulations, conventional primary energy consumption is limited to 76,1 kWh / m2.year for the north wing and 77,9 kWh / m2.year for the south wing. However, it reached respectively only 23,7 kWh / m2.year (i.e. - 68,9%) and 27,2 (i.e. - 65,1%) for the two parts of the building equipped with gas boilers.

To complete these excellent results, around 3 square meters of solar panels on the roof of the building provide enough electricity to provide the building with a positive energy balance: it produces more energy than it consumes. The objective of the E + C- label is thus achieved with an E1CXNUMX level.

Quality products well implemented

The application of the ITE on the facades of the building was entrusted to the company Enduiest. For about thirty years, this family business has been carrying out renovation and ITE projects in Lorraine and Champagne. Recruited two and a half years ago to develop the activity in new buildings, the project manager Sébastien Piernot followed the site of the Liberation district of Lunéville from costing to reception. The prescribed ETI for this operation is the StoTherm Vario 1.

“We are very vigilant about the choice of products used and the Sto range offers a complete solution making it possible to respond qualitatively to this type of operation. But a quality product must also be well implemented. For this the Sto website is a great help, it allows you to consult the various detail books, application guides, etc ... However, when there is a technical question we seek the opinion of the technical advisor Sto, for this operation we had recourse to him twice, this last was very reactive and brought us the solutions. "

Hydraulic ITE system

The 15 mm thick Sto-Panel PS 200 SE expanded polystyrene panels are first glued to the 650 m2 of concrete block facade using Sto-Mortier Colle B. Then the thin underlayment StoLevell Uni is applied. reinforced with a standard Sto-Fiberglass mesh. This undercoat is obtained by mixing a powder based on hydraulic binder with water.

“The StoTherm Vario 1 is an ITE system that we know well since the Enduiest company uses it on 80% of its exterior thermal insulation projects. Accustomed to mixing powdered products, our fellow coaters appreciate the hydraulic undercoat delivered in bags ”, explains Sébastien Piernot.

In order to protect the lower parts of the building from impact, the company has installed a complementary glass fiber reinforced mesh, Sto-Fiber de Verre Blindaget, over the entire height of the ground floor. This reinforcement is mounted in the StoLevell Uni plaster before a second pass reinforced with the standard Sto-Fiberglass mesh.

Contrasting colors

The finish is finally provided by a ready-to-use floated organic plaster based on Stolit K 1.5 acrylic resin. White on three quarters of the facade, the plaster is tinted with a deep gray on three walls. In order to avoid the absorption of heat which could reduce the durability of the system by causing cracks or deformations, this dark plaster features X-black technology developed by Sto.

All that remains today is to complete the development of the park to promote meetings between residents and showcase the new buildings.