Passive houses in Ytong Energie in Carquefou in the largest eco-district in France

More than 600 housing units have already been built there. In order to generalize the Passivhaus label, which guarantees the building good air quality and thermal comfort in both summer and winter, the operation was entrusted to the developer Loire-Atlantique Développement - SELA, who joined the office. TY eco² studies, specializing in training and support in sustainable and passive construction.

Within this ambitious environment-friendly and energy-efficient program, during the first phase of the work, around thirty plots were acquired for the construction of individual houses. Among them, four were made in Ytong Energie 25 cellular concrete, a solution with excellent thermal and airtight performance to achieve passive levels.

With an area of ​​100 to 110 m² on the ground and built on 2 levels, the four houses required around 150 m² of cellular concrete each. Owners and builder, on the advice of the developer and TY eco², opted for the Ytong Energie 25 blocks.

YTONG ENERGIE 25: Highly insulating walls compatible with passive construction

Martial Chevalier, manager of TY eco², underlines the particularity of the eco-district of La Fleuriaye:“This large-scale set of passive-labeled buildings includes a subdivision free from builders. This daring choice has multiplied the number of speakers, techniques and architectures, and has contributed to creating all the richness of the district. Houses with wooden frames, shuttering concrete or cellular concrete ... The owners of each site had to find the skills of a project manager or an architect authorized by us. We therefore support the owners from start to finish to scrupulously meet the specifications that we had written with the developer for this eco-district. Beyond the prerequisite of RT 2012 on French territory, we have sought passive performance with very low consumption and heating needs. "

Thermal performance and sealing

With excellent thermal inertia and offering a very good phase shift, which protects against heat in summer and retains it in winter, cellular concrete is a material of first choice in the design of passive and bioclimatic habitats. It forms a very insulating thermal envelope. Thus, the Ytong Energie 25 blocks offer an R value = 2,78 m2 K / W for maximum comfort and minimum energy expenditure.

For Martial Chevalier of TY eco² : “Ytong Energie 25 blocks have the advantage of being very insulating in the material, which makes them extremely valuable for the work of managing thermal bridges. "

Ytong Energie walls are perfectly airtight: solid and massive. Their glued implementation with a thin joint thus avoids energy losses. A wide range of accessories completes this constructive system: plates, U shells and lintels, roller shutter boxes and adhesives allow thermal bridges to be treated and to strengthen the waterproofing and insulation of the wall from the outside.

Clément Sikorski, owner of one of the cellular concrete passive houses in Fleuriaye, testifies to the advantages of this constructive solution: “Our house is passive certified since the waterproofing tests carried out with TY eco² have been successfully passed. We have lived there for over a year. We have no heating, apart from a pellet stove which allows us to adjust the temperature when we come back from Christmas holidays and it is really cold, for example. It is an emergency heater, which creates a pleasant atmosphere in winter but it is not used on a daily basis. In one hour, we gain 3 degrees. The advantage of a house like ours is its great inertia: the house always remains in the same temperature range. We rarely go below 19 ° and in the event of a heat wave we do not exceed 24-25 ° C. "

A clean and healthy material

Composed of natural mineral substances, aerated concrete is durable, ecological and clean. Made from natural raw materials, aerated concrete is durable, environmentally friendly and has a low carbon footprint. Incombustible, non-flammable, this material has a better performance than A +. Perspiration, combined with very good insulation, removes cold spots and prevents the development of mold.

Ytong walls with added insulation: an excellent alternative for passive construction

In addition to its thermal resistance and insulation qualities, Ytong aerated concrete walls are a virtuous construction method and very easy to implement. They present an interesting alternative to timber frame houses for passive housing projects. Mrs Stefan, whose house is under construction, says: “We did not want a wooden house, because we came from a neighborhood where houses with wooden cladding aged very badly. My brother, who works in the building industry, praised me the properties of aerated concrete in terms of insulation and we followed the advice of the builder. »Benefiting from a good load-bearing capacity, aerated concrete blocks are ergonomic and light (18 kg against 22 for a classic concrete block). In addition, they are easier to work, saw and install.

Martial Chevalier, seduced by cellular concrete for twenty years, develops: “To the touch, the material is very pleasant. Its insulating nature allows a structural mechanical work of the work coupled with the insulation, all with interesting components. The blocks offer freedoms from an architectural point of view since they are used instead of other systems. The construction technique of cellular concrete is more similar to the know-how of current masons than that of the wooden frame. "

Ronan M., works supervisor of Cmiste Comeca, who was responsible for the construction of two of the houses, adds: “Thermally, the product is excellent, it goes far beyond brick and concrete block. These passive houses have very demanding standards compared to those which applied to constructions ten years ago, cellular concrete adapts very well to them. "

Raoul Féjean, sales engineer at Xella, who followed the La Fleuriaye project, explains: “Today, to build passive houses, projects must have a U wall <0,15W / m²K. To achieve these performances, the cellular concrete used as an ITI solution like at Fleuriaye offers a very attractive price-quality ratio. With Ytong Energie 25 blocks and 160 insulation behind, the cost per m² is between 130 and 150 euros. For a passive wall in this market, it is a very economical price. "

Finally, the lightness of the material is also a major asset for the health of the teams responsible for implementation.

To know :

The PassivHaus label includes 4 main criteria. It is a question of carrying out constructions which respect the following parameters:

• A heating requirement of less than 15 kWh of useful energy per m² of energy reference area and per year.
• Total primary energy consumption (all uses, household appliances included) of less than 120 kWh per m² of energy reference surface per year.
• An air permeability of the envelope measured under 50 Pascals of pressure difference less than or equal to 0,6 per hour.
• A frequency of internal overheating (> 25 ° C) less than 10% of the hours of the year. Ytong cellular concrete walls contribute to obtaining the PassivHaus label thanks to its performance in terms of thermal resistance, treatment of thermal bridges, airtightness and thermal comfort.

La Fleuriaye project

Construction sheet for individual houses in aerated concrete

• Place: Carquefou (44)
• Developer: Loire-Atlantique Développement SELA
• Manufacturer - design office: Comeca - Ty éco²
• Area: 100-160 m² / house
• Construction system: Xella cellular concrete with ITI
• Wall insulation: 14 cm mineral wool
• Roof insulation: mineral wool 40 cm
• Floor insulation: UP 23 + polyurethane insulation 10 cm
• Enclosure insulation: U ≤ 0,15W / m²K
• Joinery / glazing: Mixed pvc / alu or wood / alu with triple
• glazing Uw installation ≤ 0,85W / m²K
• PHPP heating requirements: ≤ 15KWh / m².an
• Total primary energy requirements PHPP: ≤ 120kWh / m².year
• Air tightness test n50: ≤ 0,6 h-1
• Ventilation: double flow CMV, efficiency ≥ 0,75%
• P≤ 0,45W / M³ / h
• Heating: heating vents
• Auxiliary heating: pellet stove (option)
• ECS: Thermodynamic tank
• Cost: excluding solar panels between 1.800 and 2.200 euros / m² (with solar panels: between 2.200 and 2.600)