Contentin Falguière, Paris – France
The following case is about a multi-story building built in the 1950s. It is located in the center of Paris, France. The building is composed of 86 dwellings distributed in 7 floors. It was already renovated in 1993, nevertheless it was necessary to upgrade it again in order to achieve less energy consumption and reach the low energy standard for renovated buildings. The renovation began in January 2013 and lasted around 18 months (counting on studies, test, work and so on) and had a cost of € 4 million approximately.
The external facade (figure 85) in regards to the street was of concrete with a sandwich thermal insulation of 2 cm thickness, while the back side
wall was concrete, but with 2 layers of insulation, one of them was a sandwich thermal insulation of 2 cm and the other one was an ETICS EPS (External Thermal Insulation Composite System of Expanded Polystyrene) of 8 cm. Moreover the basement was made of concrete without insulation. Roof was also of concrete but in this case they counted on an insulation of 5cm.
The windows were 20 years old and made of PVC with double glass. The air conditioning had two collective heating systems (figure 87) with gas boiler, as well as being fed by vertical steel canalization. Temperature was not individual and there were differences among the floors, for example when there was 20°C in the upper apartments, in the lower ones there was 25°C resulting in additional heat losses due to compensatory behaviors from the tenants. There was a natural ventilation system in kitchens, bathrooms and toilets (apparently without problems).
The production of hot water was realized by individual electric boilers, which were installed in 1993. Besides, the building did not have any renewable/recovery energy source.
Regarding lighting, the building possessed regular incandescent light bulbs in the public zones.
It is estimated that the energy consumption average was 205 kWh/m2 per year.
Now the building counts 82 apartments. The envelope of the building was modified and after refurbishment it presents: an insulation of ETICS EPS of 20 cm and λ= 0.32 W/mK was installed, both on walls street side and on walls back side. Also it was installed on some sections of the facade a new and innovative ETICS with high performance (very low thermal conductivity, λ= 0.018 W/mK, resistance to water-vapor with permeability μ=5, toxicologically safe, fire protection, soundproof, so on). It is about panels with only 5 cm of thickness and 730×730 mm, ensuring the insulation. This material is called BASF MultiTherm Aero and is an ETICS, with coating above fibrous mineral panel and contains silica air gel.
With regard to the basement and the roof, the first one was renovated with a new insulation EPS of 10 cm and λ= 0.32 W/mK below ceiling, while the second one counts on a new insulation of PUR (polyurethane) and λ= 0.24 W/mK on ceiling.
Windows were changed for other new ones, which also are of PVC with double glazing and U-Value 1.5 W/m2KAs for the air conditioning: the heating system is formed for new condensing boilers which moreover also warm up water as well as installing a heat recuperation system from waste water in order to avoid wasting it. Besides the ventilation system is controlled mechanically now.
A bio fluids system was set in order to produce energy (10 kWh/m2 a year). All public spaces are fitting with low-energy light systems and tenants.
It is important to stand out that in each dwelling, videophones were installed which show the energy consumption on their displays (daily, weekly, monthly even annually). With this, the tenants know in every moment their consumption, as well as knowing whether they are saving energy or not with their habits
According to the measures, the new energy consumption is approximately 50 kWh/m2 a year per apartment. As a result of the renovation, the building achieved a reduction of 75 % of energy consumption.
Several tests and monitoring deployment in some apartment were carried out before renovation in order to get data to facilitate the evaluation of its impact on energy performances and user comfort. Also they were made after the renovation. Tests like infrared thermography (interior and exterior), blower-door test, windows, or even acoustic test between apartments.
It is important to stand out that 2 test depressurized tests were made in order to measure the airtightness as well as one pressurized test to locate air leakage pathways with artificial smoke.
The same as doors and airtightness, windows were examined with infrared thermography and artificial smoke in order to detect colder areas and air leakage pathways.
Installation of windows and frames (figure 92): During the process, all windows were controlled by thermal camera, showing thermal bridges and poor airtightness, so that the subcontractor had to changed it.
As it has been commented previously, a new insulation was installed on the roof on it.
As for the facade, the external layer was removed, as well as installing an UV protection sheet in order to avoid that it was damaged by the sun.
18 cm Neopor polystyrene panels (R=5.8 m²K/W) are pasted on the walls with adhesives. To finish, the material is mechanically fixed with special lag screws, depending on the type of material (grey is polystyrene, and orange is mineral wool, which is set between dwellings in order to stop fire progression). The gaps between panels are filled with PU foam (Polyurethane) to avoid thermal bridges.
Following with the facade, elements of the new and surprising material, BASF MultiTherm Aero, are installed in some sections of itself. For this, the panels are pasted on the walls, and then fixed with lag screws. First, a 5 cm thick coating is applied on the panels before adding a glass fiber mesh. Final coating is composed of a 2cm thick hydraulic primer plus two coats of siloxane paint. The system is covered by a total surface of 150 m2.
Only for this purpose, 2 experts from Germany had to go to Paris for a whole day in order to explain and demonstrate how to install this material to the workers.
When this material was installed in the building, it was not authorized for commercialization in France, so it had to be approved like an experimentation material by French construction authorities.
It was also installed in the common areas an acoustic insulation on the ceiling in order to prevent noises from these areas to reach first floor dwelling as well as this insulation is useful for thermal loses because common areas will not be heated during the winter season (figure 97 & 98).
- There were tenants’ complaints due to bad existing conditions in the building before renovation.
- The most tenants did not have to leave their homes during the refurbishment.
- Huge reduction of energy consumption, around 75%.
- The video phones guarantee that tenants know in every moment their consumption and whether their habits are good or not.
- It used a new material which could reach to be very important in order to achieve buildings with very low consumption energy.