Develop an insulating stucco for building exterior walls that can be sprayed directly onto all types of materials.
Residential and commercial buildings account for 44% of France’s total energy consumption. One of the key measures to fight climate change outlined in the nation’s Energy Transition for Sustainable Growth Act is improving the thermal performance of existing buildings. One way of achieving this is by adding interior or exterior insulation. The PAREX.IT project developed a new type of insulation for building exterior walls.
France’s Energy Transition for Sustainable Growth Act has established some ambitious goals. These include slashing 1990 greenhouse gas emissions levels fourfold by 2050 and improving the energy efficiency of 500,000 housing units per year starting in 2017. To achieve these goals by the target dates, the widespread adoption of rehabilitation solutions for existing buildings is a top priority. Interior insulation, which does not alter exterior appearance, is the solution of choice for buildings of architectural or historic interest; however, the technique does have some substantial disadvantages: The building cannot be occupied during the work, the insulation reduces the interior surface area, and plumbing and wiring must often be modified. Current exterior insulation solutions consist mainly of insulating panels. These solutions are effective, but difficult to implement. The number of panels must be carefully calculated, installation is complex in terms of logistics and handling, and shutters and gutters must be moved.
The PAREX.IT project developed an insulating stucco for building exterior walls. The product can be sprayed onto building facades in a single layer with equipment and methods commonly used by building contractors. The product was developed to be easy to apply and, for new construction projects, could contribute to obtaining low-energy building certification.
The major innovation of the PAREX.IT project—built on work completed by the project partners during previous projects—consisted of integrating a silica aerogel with unrivalled insulating properties into an industrially-manufactured stucco.
Parex was extremely satisfied with the opportunity to work with the other project partners. The project allowed the company to:
- Develop a product with very high insulating power (0.028W/m.K) by integrating silica aerogel, a fragile material, into a formulation in which all of the ingredients must be carefully blended to make a product offering the desired insulation rating, adherence, fire-resistance, and hygrothermal and mechanical performance
- Test the product’s compatibility with the spray equipment commonly used by building contractors; this aspect was especially complex as the product must not be altered as it passes through the spray nozzle
- Test the product in real-world conditions; testing was initially completed on a model validated by project partner CSTB and subsequently at the INCA lab in le Bourget du Lac
- Confirm the high thermal efficiency of a continuous building envelope; a few centimeters of the stucco applied as an additional insulating layer on a new Monomur brick building meets low-energy building certification requirements
- Implement modelling tools at Parex to generate thermal efficiency forecasting data
- Establish a new approach to innovation at Parex; this was made possible through very constructive relationships with the publicly-funded research labs involved in the project, which are ongoing in the form of new research partnerships with particularly ambitious objectives
One obstacle to developing sales of PAREX.IT is the complexity of the product’s supply chain. One of the major advantages of silica aerogel is how lightweight it is. However, this also creates some challenges. First, the product must be shipped from Enersens, the PCAS subsidiary created to develop and volume-manufacture the different forms of aerogel required, to Parex, where it is then blended to create the PAREX.IT stucco, which is then packaged and delivered in a ready-to-use form. The blend is fragile and the packaging must be resistant to crushing, which raises storage issues. The project partners are working on solutions to these problems.
The project partners must now also reduce the current cost of the aerogel, which remains a barrier to market penetration. The partners are engaged in EU Horizon 2020 project Homeskin, which aims to overcome these challenges by incorporating the aerogel into a fiber matrix that will serve as the basic material for new interior and exterior insulation panels. Parex is also involved in the IBIS project, funded by France’s national research agency. This project is building on the results of the PAREX.IT project. Finally, Parex is a partner in the creation of a new industrial chair on bio-based materials and is a partner on the DIVA project, certified by Tenerrdis, on the use of agricultural byproducts to produce bio-based materials.
French Single Interministerial Fund, Isère General Council, Ain General Council, Greater Grenoble, Intermunicipal Authority, Porte de l’Isère Intermunicipal Authority