The (in)visible traces of the landscape, From housing to matter
This research questions the (in)visible traces that the extraction of construction materials has in the landscape. An individual house built with local resources interrogates the relationship between the territory and its raw materials. Re-engaging with local materials goes beyond the simple dimension of thermal calculations and environmental. Alternative housing concepts thus establish a contemporary territorial narrative based on a sensitive use of materials and simple construction methods.
Regional
France
Mérignac, a commune in the South-West of France, located in the Gironde in the department of Gironde, in the region of Nouvelle- Aquitaine region.
It addresses urban-rural linkages
It refers to other types of transformations (soft investment)
No
No
As an individual in partnership with other persons
First name: Léo Last name: DIEHL Gender: Male Age: 24 Please attach a copy of your national ID/residence card:
By ticking this box, I certify that the information regarding my age is factually correct. : Yes Nationality: France Address (country of permanent residence for individuals or address of the organisation)<br/>Street and number: 1 rue Louis Jouvet Town: Mérignac Postal code: 33700 Country: France Direct Tel:+33 6 49 47 16 15 E-mail:pfe.2lg@gmail.com Website:https://collectifinvisible.com/collectif-invisible/
In order to find a lighter architectural production, more respectful of its environment, our project "Les traces (in)visibles du paysage : Habitat 33" opens up new fields of production and transformation of building materials. By considering the art of building as an additive force - the construction of buildings "above" the ground - and a subtractive one - the extraction of materials "below" the ground - the aim is to establish a continuity between local territories, vernacular heritage and local historical know-how.
We provide a critical view of the "networks" of building materials that reveal the (in)visible processes of contemporary construction, based on a granular analysis of a suburban housing model that is largely dominant in Europe. This allows us to sketch a portrait of the impact of standardized architecture that questions its relationship to the region in which it is implanted. For this case study, located in Gironde (France), we met the craftsmen, the extraction sites, the landscapes, the materials of the territory. The "atmosphere" at the heart of the processes of transformation of the soil resources produces a work that speaks of new spatialities and a rehabilitation of traditional ways of building.
From this narrative is born the proposal of a capable, habitable and flexible surface, anchored in the territory of the Gironde. This project seeks to find a specific architectural language dedicated to its region, to its site, through the material, the territory, the energy and the technique. At a time when the "suburbs" are expanding more and more around the cities, we must respond by developing answers to the need for living through a project dynamic, working with what is already there, while ensuring the offer of a desirable world: the desire to live.
A movie that shares our in-situ experience, close to the material and our encounters with the craftsmen:
https://www.youtube.com/watch?v=24ftrpk77R8
Tradition of the vernacular
Make the inhabitants aware of their territory
Local know-how in building
Design in harmony with the material
Resilient architectural lifecycle
With the aim of reducing carbon emissions and energy costs, as well as creating a spatiality identified with an architecture of coexistence between materials, climate and inhabitants, it seems necessary to renew the link between the built landscape and its natural environment.
Habitat 33 relies on resources that come from less than 100 km from the site. The structure consists of two 60 cm thick adobe walls connected by a post-and-beam frame and a central chimney made of very low-carbon sandstone clay bricks. The bracing of the pisé walls is achieved by assembly with the post and beam structure made of maritime pine from the Landes Gascogne forest. The two compressed and pre-stressed pisé walls are made of excavated earth from the foundations in micro piles of burnt waterproof maritime pine. The earth walls are protected from rainwater by foundations and lintels made of limestone from one of the last quarries still active in the Gironde basin. In this way, Habitat 33 perpetuates the traditional know-how of the region. Recycled materials (in particular corrugated metal sheeting) are used to cover the wooden framework, which forms a double-sloping roof. The roof collects rainwater and reduces the energy consumption of the house. The floor is paved with limestone slabs with hollow joints. This is combined with a tamped raw earth screed that avoids the destruction of the living soil. In the walls, rigid insulating panels made of recycled cork stoppers from the Bordeaux wine region are used.
In this way, the materials used for Habitat 33 create a sustainable and resilient architecture based on local know-how, local resources, a circular economy and contemporary construction solutions.
The aesthetics of the proposal is directly related to the quality of use of the built space and its adaptability over time. The aesthetics of the project is closely linked to the passive bioclimatic devices adapted to the needs and seasons of the region and necessary to produce a resilient architecture.
At the heart of the house, a sandstone clay brick chimney regulates the interior heat in winter. The heat from the central clay core chimney is insulated from the glass façade by a thermal curtain to minimize heat loss. This helps to reduce heating in winter, which is very costly to occupy. The management of solar gain in winter and summer is regulated by a system of external thermal curtains and roof cantilevers.
The double orientation of the building allows natural, passive and cross ventilation. This avoids the use of mechanical ventilation systems. The inverted roof (V-shaped) collects rainwater building for domestic use. In addition to the aesthetics of the building, the landscape is also treated to reveal the subtractive forces of contemporary architecture. In the heart of the garden, the pit used to build the walls of the house is left as it is to be freely appropriated by the inhabitants.
By taking into account making, recycling, preserving and developing local, it is a matter of ensuring a more frugal "sense of living" and of interacting with atmospheric variations in a sober and committed way. Thus, Habitat 33 is a great tool that translates a telluric vision and produces an architectural aesthetic that emanates from the local territory and the experience of its inhabitants.
The aim is to stitch together the urban fabric through collaborative processes of land sharing, climate-adapted uses, and the involvement of the city's inhabitants. In this way, the residentialization of land and urban sprawl can be stopped. Housing has the capacity to generate a collective and plural appropriation of urban fields, articulating a spatial complexity that is both intimate and publicly shared. The individual house looks to the public spaces, new intermediate spaces, between the street and the house: a promising in-between. These spaces use technical options that allow a reproducibility and flexibility for the diversity of family units (single-parent families, young active people, mixed families...): 6-meter post-and-beam structural frame, which allows the multiplication of the living space in height and in width; prefabrication of architectural elements facilitates the construction process. The implementation of bio- and geo-sourced materials with local partners: the National Agency for Adult Vocational Training (AFPA), the Bordeaux School of Architecture and local associations, is essential for the local network of qualified and committed craftsmen to spread their know-how and highlight local craftsmanship.
By taking into account the specificities of a strategic urban site, a link is created between the extraction of the material and its collective appropriation. The choice of location for Habitat 33 develops the creation of a shared urban narrative in which the city transforms itself on and through itself.
The proposal is thought according to a phasing and an operating mode that respects the temporalities of the earth's materials and the natural cycles of transformation and production of biosourced materials.
Functional uses move according to the progress of the project. Initially, the objective is to conduct research around a strategic urban site in the outskirts of Bordeaux that can accommodate the proposal (orientation, land development, metropolitan or rural context nearby ...), construction channels and local bio-based materials. This first stage of study is carried out in collaboration with the inhabitants of the neighborhood, the authorities of the chosen site and the local craftsmen. The construction begins with the realization of the pit which becomes the founding act. It gives the needed material for the construction while revealing the subtractive force of the art of building. An analysis of the excavated site earth is carried out to allow the manufacture of prefabricated or cast on site construction elements. This step is carried out in collaboration with scientific institutions and AFPA craftsmen while respecting the directives of the surveyors and the inhabitants concerning the quality of the soil. Reused materials and territory matter create an intensive activation of local construction channels. This project is designed according to the climates, the material but also to needs and uses desired by the inhabitants of the Girondin district. Once the project is completed, the building will be a starting point for a potential development and densification of the basic module. Habitat 33 will have an impact on the construction know-how pooling and the creation of a building materials collaborative platform: a recycling center, a training platform, educational workshops, site visits, maintenance of the grounds, the collective landscape and shared gardens...
The Habitat 33 proposal is the result of a global reflection on the scale of the European territory. The analysis of the housing model and the origin of the materials used shows the impact of contemporary architecture and the urgency of changing our building habits. At national (France) and regional (Nouvelle-Aquitaine) level, the resources and materials available within a 150 km radius of our site have been mapped. By working together with construction actors, focusing on the production and transformation processes of local materials, we were able to meet with regional and local actors in the area. These interviews were documented in the form of deliverables, semi-structured interviews, photographs and videos. The challenge is to identify the productive capacities and potentials of the territory and its resources. This common knowledge was confronted with the uses and needs of local elected officials and inhabitants (constructive label, regional climate, lifestyles shared between urban and rural places). Thus, by taking stock of the traces left by the construction industry at national and European level, the local and regional research into know-how and traditions appears as an accumulation of alternatives and strategies that can be adapted to a variety of architectural and urban projects. The commitment of the actors who accompanied us creates a common knowledge that can be shared by all.
Habitat 33 is a combination of different skills, popular aesthetics and local traditions. All the actors and fields of knowledge allowed us to learn new techniques of using and transforming materials:
- L. Mangin, manager of a sawmill in Saint-Yaguen (Landes, France), who is one of the few craftsmen able to produce timber for use in construction thanks to his 12-metre-long saw bench. Every element of woodworking (bark, sawdust, waste wood, insect treatment of burnt wood...) was used in the Habitat 33 project.
- We met F. Boizard, manager of the Frontenac quarry (Gironde, France), who was able to show us how limestone is extracted with almost no carbon impact, with no waste and infinite reusability.
- We observed the transformation of clay (Gironde, France) by the craftsman M.-F. Dubourg, who was able to show us the different states and uses of clay (clay roof tiles, raw clay bricks, pre-stressed blocks in a mixture of earth and straw, alveolar clay bricks).
- I. Bazin, responsible for the environment at Lafarge Holcim, was able to discuss with us the extraction of alluvial aggregates, the alternatives to concrete and the potential of this material in its raw state (cyclopean concrete, flooring...).
With regard to aesthetics and local architectural traditions, we contacted local elected officials and architects in the region:
- M. Bergeret and P. Rolland, architects and town planners in charge of 308+, a place dedicated to the dissemination and promotion of contemporary architectural culture in New Aquitaine.
- B. Blanc, creator of the local label dedicated to frugality and resilient urbanism in the metropolis of Bordeaux (Gironde, France).
The techniques of construction in raw earth are not limited to adobe, where the raw earth is more or less clayey, like the pisé or the cob, implemented in formworks called "banches". In Europe, the "mono-material" constructions in raw earth are not very common. The construction methods are often of a hybrid nature. In fact, a well thought-out and rational use of the material is necessary to deal with the different climatic effects and to propose sustainable constructions. The diversity of natural materials (clay, wood and stone) encourages the design of plural forms. Traditionally, different materials have been used to make components that protect against bad weather (foundations, roof overhangs, erosion lines). This innovation is illustrated by multiple construction elements (window and door lintels, reinforcing the base of building corners, waterproof flooring). The choice of materials is also facilitated by the financial aspect of creating an architecture with an economy of resources. Thus, the accuracy of the choice of materials is essential in the design, in addition to the notions of comfort, adaptability and low cost.
Habitat 33 is the answer to a clear question: how to create low-cost places that require less energy and meet contemporary domestic needs? The hybridization of materials should allow us to go further in the quality of the spaces proposed and in the potential uses that can be offered, something that has not yet been explored in the field of new construction.
In order to carry out the project, we have carried out an analysis of the genealogy of the materials used in standard architecture, which could contribute to the production of a "building origin sheet", indicating the origin of all the materials used in the project. The obligation to make this sheet publicly available would make it possible to promote the rational use of materials, the reduction of the carbon impact of the built heritage and the valorisation of local actors in the construction sector. We have also drawn up a map of the resources available in the New Aquitaine region (bio- and geo-sourced materials, reusable elements, strategic project sites, etc.). This map could be shared, developed and extended to the whole European territory. This map would facilitate the location and use of local materials, while developing the circular economy and the exchange of materials on European soil. Finally, all these educational documents (materials origin sheet, maps, European manifesto on resilient architecture) could lead to the development of a series of constructive prototypes using local materials and the creation of a contemporary regional architecture. The creation of these constructive prototypes could make it possible to train craftsmen in local materials that respect the environment, rather than training them in standard building materials that are unsuited to their environment.
The "typical" house, located in Mérignac, in a residential area in the western suburbs of Bordeaux, marks the beginning of our project. This case study of the existing context of the art of building places the stakes of this work in the context of global challenges. The sites of extraction and production of materials used in architectural fabrication question the strategies to be adopted in the face of the phenomenon of global urbanisation. Based on the pavilion model, which dominates the occupation of urbanised spaces on French territory - more than 60% in each administrative region - we have carried out a study of building materials and their origins. An overview of the network of exchanges of materials used in construction is a tool for making new spatial strategies more sober and sustainable. From this macroscale, we can develop a reflection on place and the role that bio- and geo-sourced materials must play in order to move towards more virtuous construction systems. The territorial vision is no longer an accumulation of symbols, landmarks and control points, but the expression of a circulation of living beings, of uses to be invented and of a sharing of resources.
