Building in stone today by using bearing walls or in thick semi-bearing walls via a process of extraction and elaboration respectful with the environment is revealed as an interesting solution for the ‘decarbonization of the construction processes.’ This is demonstrated by our participation in the project ‘Îlot Fertile – Eole Evangile, Paris 19, Premier quartier zéro carbone de Paris’ where our Albamiel stone has been selected to carry out the stone section of part of the project due to the low CO2 emission of the product throughout its life cycle and despite its transport, as recognised by the FDES and DAP report. The project is being executed by the company Bouygues.
The ‘decarbonisation of construction processes’
How important are building materials when it comes to a home’s energy balance? Imagine a single-family house of 222 m2 located in Zaragoza, which is where the Aragonese engineer Ignacio Zabalza places it in a study published in the scientific journal Building and Environment. If the data of this hypothetical house are entered in a simulation program that complies with the current regulations of energy certification of buildings(RD 235/2013), the result is that it will generate about 1.6 tons of CO2 per year, which corresponds to the category B. Now this is only taking into account the use of the house over 50 years of life (expenses on heating, air conditioning, hot water, lighting, etc.). If you analyse the materials used in its construction, then you would have to add another 57 tons of CO2.
These additional 57 tons would represent 41% of the total emissions generated by the house over 50 years or, in other words, it would take 35 years for the emissions produced by the use of that house in Zaragoza to equal those of its construction. Paradoxically, they are not taken into account by the regulations that evaluate the energy efficiency of that house when their impact is much greater than that of other factors to which they are given much greater importance. As Zabalza explains, a great opportunity to act on the efficiency of the houses is being wasted from the very choice of materials for their construction.
Building in stone today: Bearing walls and thick semi-bearing as a possible solution
The style of construction that we propose for Low Carbon Construction is the construction in stone ashlars, and in exceptional cases, in coatings of at least 8 cm thick.
The reference in this type of construction, in addition to the historical constructions, evidently, in modern architecture, is Fernand Pouillon (1912-1986) who carried out most of his new construction projects between 1950 and 1960. A lover of stone, he defended that respect for prices and the quality of construction allowed to achieve two purposes: to give access to the luxury of living to the smallest salaries and to ensure an excellent conservation of the neighbourhoods, avoiding their degradation.
In the middle of the last century, the construction in massive stone, a denomination of the construction in solid stone in English and French, responded to other purposes: social and economic development. The importance of the reduction of carbon emissions in the construction processes had not yet been verified, but all these purposes are still valid today.
Today, Gilles Perraudin is the star architect in massive stone construction, but it is interesting to know that he started in architecture with André Ravéreau, in terms of understanding the relationship between architecture and climate or how people manage to survive in extreme conditions and how to build houses where comfort is achieved almost without energy expenditure both in construction processes and maintenance.
Perraudin worked in the new town of Cergy Pontoise with the Lyon school of architecture on buildings full of environmental concerns, but still uncovered the stone. He considered himself to be a prisoner of the dominant constructive culture, from which he reflects that ‘architects have a difficult way out and are asked less and less to be thinkers of construction to be creators of gleaming and magical shapes.’
In his words: ‘it was a fabulous and founding experience, because I discovered a material, its possibilities, its interest and its capacity at the same time; I discovered an architectural way of writing that has allowed me to find myself in the fullness of my role as an architect, which is not to invent forms that end up being thoughts.’ In addition, he invites us to start, as he does, from an ethical and social vision, since architecture is not like the rest of the arts, such as music, where we have the right to choose whether or not to listen. Architecture is imposed on us all.
With stone, Gilles Perraudin discovered a rigour in architectural writing. You can think with it the material from the beginning to the end, while most architects use products already invented and prefabricated by the industry. Without mastering either production or design, they ‘assemble’ industrial products.
Gilles Perraudin found loopholes in legislation regarding the use of massive stone for construction. The same thing happens in Spain: there is no specific law and sometimes it is complex to adapt the existing one. This is a dramatic point and indicative of a total loss of constructive culture; even though most of our heritage has been built in massive stone, everything has been forgotten! Building legislation has been invented for the use of new materials and is a clear disadvantage, despite the fact that in recent years much progress has been made mainly in our neighbouring country, France.
Why is stone low in CO2 emissions? Environmentally friendly extraction and processing process
To offer a reminder is Raquel Galarza’s statement of the company Eurovertice, which served as the headline in the Murcia Diario newspaper on 18 August: ‘If there is no commitment of companies to sustainability, there will be no future.’
In our business project, which has been ISO 14001 certified since 2005, to date:
- The different stone waste is reused, revalued and ultimately returned to its place of origin and used for the restoration of the affected natural spaces.
- Other waste, hazardous or not, is treated by authorized managers,
- We use Photovoltaic Solar Energy and we acquire Green Energy,
- We have started to change the company’s internal vehicle fleet to power supply.
- In the quarry, we cut dry, avoiding the high consumption of water resources. For other primary and secondary cutting processes made with water, we recycle the process water, with the only losses caused by evaporation or irrigation of roads and squares in the hottest season to avoid air pollution, we do not make any discharge to public channel.
- We have carried out preliminary soil studies, with the result being soil that is not contaminated.
- We regulate mostly the temperature in our facilities by means of massive stone constructions and regulation of air currents, providing us, if necessary, heating by biomass,
- We control atmospheric emissions and we have the qualification of type C industries, for low emissions,
- We have two Ecosystem Restoration Projects underway, which have been approved by the competent administration,
- We have had a CO2 emissions reduction project since 2016,
- We have intensive, flexible and remote working arrangements, to facilitate the reconciliation of family and professional life. We care for those who care.
- For years we have offered our workers space for the creation of gardens and care of animals.
- We respect the wildlife of the environments we inhabit, sharing spaces.
- We are a family business, founded in 1985, and the management positions in the company are managed equally between men and women without discrimination on the basis of gender, sexual orientation, religion or any other cause.
Results of the effort to decarbonize the production processes of our company
Our journey in terms of corporate sustainability has been reinforced by the selection of our material for the supply of one of the buildings of the First 0 carbon district in Paris. To certify this tour we embarked on a study of greenhouse gas emissions throughout its life cycle of the products demanded, (ashlars for mass construction in bearing walls of approximately 80x50x30 cm and semi-bearing of thickness 8 cm). This study was carried out in France because they demanded it from us there and because we must say that the neighbouring country has already opted for this use of massive stone under construction.