Sustainable Renovation Consultant

Viviane Hamon has been working in the sustainable building industry for more than 20 years, particularly in renovation, as a consultant. We met with her to better understand the existing landscape of bio-based insulation, the actors involved in renovations, the challenges of creating a new material and the potential implementation of our product. Her background in psychology and ethnology allowed us to better understand the considerations at play during a construction site: while we thought that architects were responsible for the choice of insulation, it turns out that the insulation specialist is indispensable. However, we must note that a focus on the French situation is undeniable in this discussion.

Bio-sourced Insulation

First of all, we learn from Viviane that there is a market for bio-sourced insulation. Wood fibers, various wools (hemp, cotton...), cellulose wadding (from recycled newspapers) or even rice straws allow an environmentally friendly insulation from natural materials, with minimum lambda values between 0.035 and 0.040 mK/W (double of our expected value !). Usually applied in the interior insulation, we learn that the application in the exterior, allowed by rigid panels, begins to exist. These insulations have the advantage of being carbon sinks over time. As our aerogel is made from cellulose, we can say that this will probably be the case for our aerogel too!

Actors of the Ecosystem

In the construction site ecosystem, many actors are brought to work together. The architect, the various specialists, as well as the customer himself, must compose from technical, economic, aesthetic and logistic constraints (all the more in renovation!).

Technical, because each type of insulation has its advantages and disadvantages. Expanded polystyrene, inexpensive but resistant to humidity, is harmful to the environment because it is produced from oil (fossil energy, by definition non-renewable) and is difficult to recycle. Moreover, security speaking, it is highly flammable, unlike rock wool!

The installation techniques, the thickness necessary to obtain the thermal resistance (R) are all parameters to be taken into account. Thus, insulating from the outside (reducing thermal bridges and dew point problems, but potentially more difficult to install) or from the inside is never a trivial choice! Especially since the installation of the insulation must not encroach on the realisation of the other parts of the construction site, like a well-interlocked puzzle.

Economic, because despite the resulting decrease in energy consumption (the more efficient the insulation, the greater the energy savings), it is only seen as a legal minimum to be met, and not an investment.

Logistics, as Viviane points out, because the supply chains play a central role. The wider the product is distributed, the more it will be used by building experts, who rely on a few products that they know well, and where to find them! To do ecological renovation, it is necessary to address craftsmen whose expertise is!

The customer, whose house is renovated, is at the crossroads of these parameters. Overflown with a lot of information, sometimes indigestible, often contradictory, and having to achieve a clever balance, it is a challenging and mentally draining experience! We will speak more about this during our interview with Olivier H

Challenges to be Met

As mentioned above, the building trades require expertise built up over the years, with products that are mastered and deemed trustworthy. Thus, a first challenge to the implementation of a new product, and more globally, of new more ecological practices will be to convince the majority of this trade to use new solutions, respectful of the environment, representing a departure from the comfort zone.

At the legal level, in France but also in Europe, we are gradually shifting from an energy saving logic to a decarbonation logic, and therefore, what is the carbon footprint of our product. Since 2020, in the French regulations applied to new buildings, it is required to make the carbon balance! Unfortunately, this leaves aside other parameters such as resource depletion, use of toxic products that pollute the air and water, difficulty in recycling material, etc. A shift from a carbon-focused towards a global view of the impact of the insulation materials is necessary, to protect to the best of our ability, and promote the most sustainable solution.

Application of the HESTIA Solution

An important point to determine is also the application of the cellulose aerogel! Interior or exterior technical insulation, which implementation makes the most of this product? How to avoid the exposure of the insulation to humidity and dew point (phenomenon due to the contact of the "heated" insulation with a thermal bridge or a cold portion of the wall), how to apply it, will it resist mechanical constraints?

Viviane provides us with resources to dig into these points, in particular "L'isolation thermique écologique"1, the ADEME2 or her own writings, to enable us to answer these questions, in the Implementation page.