As new cities emerge daily, the strain on global warming due to carbon emissions increases. The construction industry contributes to 37% of carbon emissions globally associated with the construction, running, or demolition of buildings, leading to environmental concerns. Following sustainable construction and practices has become inevitable and a compulsory criterion to be followed to reduce future environmental problems. The term sustainability has become a must rather than a fancy concept. More than the construction emission, the operational carbon emission has brought ecological concerns due to adaptation to climate change making it the highest carbon emitter. Though many organizations push for sustainable buildings through certifications like LEED, BREAM, etc., sustainability is majorly followed in economy and advertising. Thus, Sustainability has become an advertising strategy.
Modern-day sustainability
The UN environment program forecasts that by 2060, a net zero environment can be achieved globally through advanced technologies dealing with decarbonizing building materials and increased use of regenerative, circular biomaterials from forest and agriculture streams. Avoiding, shifting, and improving have been the key principles in promoting circular building or an economy. The use of recycled materials and repurposing building materials have been practised for centuries now. New technological advancements aid us in reducing our carbon footprint and thus contribute to a circular economy.
Carbon sequestration is one such technological advancement wherein the emitted carbon is captured and stored to reduce the greenhouse effect and mitigate climate change. This captured energy can allow the use of fossil fuels until another energy source is introduced on a large scale. This process naturally is carried out by plants through photosynthesis. About 25 per cent of global carbon emissions are captured by plant-rich landscapes such as forests, grasslands and rangelands. As a methodology, hempcrete, which is a composite of hemp fibers and a glue-like binder, absorbs carbon as much as a forest. Mineral carbonation is a developing technique where products such as cement, concrete, mortar and are made using wasted carbon dioxide.
Apart from developing new materials by taking inspiration from the natural process, new concepts involving the natural geological process are also being researched. For example, Lava forming is an Icelandic architectural concept that uses molten lava from volcanoes as a natural building material. Developed in response to the climate crisis, The process involves creating trenches for lava flow during eruptions or drilling into magma before it turns into lava. The natural eruptions are redirected to lava fields or quarries, protecting Iceland’s infrastructure. The cooled trenches can later serve as city foundations.
Vernacular architecture
Vernacular architecture involves building using traditional techniques and locally available natural building materials. It is closely tied to the local environment and culture and is often unique to a particular region. It’s built without professional guidance and outside of academic traditions. These buildings usually respond to local climatic conditions and topography. For instance, the Bhunga houses of the Kutch region have become the identity of the Kutch desert. The Bhunga houses take a circular form which is earthquake, desert storm resistant though made of mud. The mud walls and thatched roof keep the house cool in summer and warm in winter. The thatched roof is made of bamboo sticks tied together with dried grass rope forming a conical roof. Bamboo sticks are used in the walls as reinforcements while cow dung acts as a plaster to the mud walls. These Bhunga in their modern versions are testimony to sustainable architecture where from the material to construction is all done locally.
Vernacular houses are often climate-responsive and socio-economic-responsive. For example, the traditional house of Cameroon is called “Cases Obus “. They are circular clusters of adobe domes with dedicated functions and granaries in the centre. The exterior of the house is made of mud, thatch, and water only. Resembling beehives or shells, these structures go up to 9m in height. To withstand the dead and live load, a catenary-like arch is formed with a circular vent on the top. These high domes aim to collect hot air and circulate them to keep the interior at the proper temperature.
Apart from the Houses, many historic and religious buildings of the past are constructed using natural materials such as stone, mud, bamboo etc. One of the architectural marvels, the Tanjore big temple is built using interlocking granite blocks without mortar, providing high seismic resistance and showcasing the Chola dynasty’s understanding of construction and materials.
The Great Mosque of Djenné, the world’s largest mud-brick structure, is a prominent example of vernacular mud architecture. The mud used to make the bricks of the Djenne mosque is called banco, and it is made of clay, water, shea butter, powdered baobab tree, and rice husks. This building not only stands as testimony to sustainable architecture but also promotes community involvement through architecture. Vernacular architecture is a symbol of a region’s cultural identity. It can also be a sustainable way to build, as it minimizes the ecological impact of construction by using locally available resources.
Natural materials today
Stone, mud, hempcrete, bamboo, and wood are the most commonly used natural building materials. Mud construction has been widely used and adapted to the current needs. Compressed stabilized earth blocks (CSEBs) are sustainable building materials made from local soil, sand, water, and a small amount of cement or lime. They are an alternative to burnt clay bricks and cement concrete blocks. These bricks are mostly made using the local soil. The strength of the blocks depends on the quality of the soil, the type and amount of stabilizer, the quality of workmanship, and the curing process.
Nalanda University is one such campus which is constructed using a CSED block made of the local soil from the site, hence using passive design principles. Apart from the blocks, The university uses integrated Indigenous strategies in architecture, design, construction and services that include biogas, cavity wall concepts, solar, geothermal and passive approaches.
Uchimura Kanzō Memorial Stone Church is a standalone structure depicting a linear journey. Designed by Kendrick Bangs Kellogg, this church was constructed using local stone, concrete, and glass. The visible stone foundation supports the east-west oriented slanted concrete rings which gradually grow in radius from the chapel hall. Like a row of dominoes in mid-fall the spaced arches are filled with continuous obscured glass skylights that diffuse constant natural light throughout the day. The primary hall uses natural light to illuminate the stone foundation walls, with a large glass backdrop exposing the green landscape beyond.
The lotus-inspired Sports Hall for Panyaden International School is a net zero building constructed out of prefabricated bamboo trusses spanning over 17m with steel reinforcement connections. The hall covers an area of 782 Sq.m, housing futsal, basketball, volleyball, badminton courts and a hydraulic stage. On either side of the structure, balconies provide space for parents and visitors to observe sporting events or shows. The roof is layered ensuring openings to ventilate the hall naturally. Bamboo ensures a cool and pleasant climate all year round through natural ventilation and insulation. The bamboo is treated with borax salt to avoid toxic chemicals and is estimated to have a life span of 50 years. More than a sustainable building, this sports hall is an exhibit of bamboo craftsmanship.
Today’s modern materials, especially concrete and glass are changing the skyline to a monotonous façade leading to the loss of identity and culture. The sustainable concept is achieved using technological advancements rather than building materials and design principles. The technological intervention and modified building materials increase the sustainability quotient but fail in operational carbon emission. The circular economy achieved by using solar energy is a contradicting criterion. An average solar panel which consists of silicon and other chemically treated materials lasts up to 35 years. 35 years later, these solar energy converters end up in dump yards or as electronic waste and probably create environmental concerns. Hence, what a sustainable approach is today might become an environmental concern in the next few decades. Though using natural materials comes with both advantages and disadvantages, the span of sustainability also matters when starting a construction project.
Reference:
- United Nations Environment Programme (2023). Building Materials And The Climate: Constructing A New Future. [online] UNEP – UN Environment Programme. Available at: https://www.unep.org/resources/report/building-materials-and-climate-constructing-new-future.
- designboom, danny hudson I. (2017). a look inside kendrick kellogg’s hoshino stone church in japan. [online] designboom | architecture & design magazine. Available at: https://www.designboom.com/architecture/kendrick-kellogg-hoshino-stone-church-04-16-2017/.
- architectureindevelopment.org. (n.d.). A–D — Mousgoum dwellings. [online] Available at: https://architectureindevelopment.org/project/68.
- United States Geological Survey (2017). What Is Carbon sequestration? [online] Usgs.gov. Available at: https://www.usgs.gov/faqs/what-carbon-sequestration.
- Brandon, E.M. (2022). Lavaforming: One architect’s wild idea to construct buildings from molten lava. [online] Fast Company. Available at: https://www.fastcompany.com/90752124/lavaforming-one-architects-wild-idea-to-construct-buildings-from-molten-lava.
- Bamboo Earth Architecture – Chiangmai Life Construction. (n.d.). Design & Construction of the Bamboo Sports Hall. [online] Available at: https://www.bamboo-earth-architecture-construction.com/portfolio-item/design-construction-bamboo-sports-hall/.
