The more environmental issues grow, the more we must focus on sustainability, especially if we are architects. Building materials become extremely important to reduce environmental impact, enhance energy efficiency, and create healthier living spaces. They also help conserve natural resources and build resilient and long-lasting structures. With this article, we wanted to provide a quick guide to some key sustainable building materials and their benefits.
1. Bamboo
Bamboo is a fast-growing plant that can be harvested without killing it. This feature makes it a renewable resource and a highly sustainable option for construction. This material is mainly associated with South Asia and South America, especially in constructing houses and bridges.
Benefits:
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Renewability: Grows much faster than traditional timber.
- Strength: Strong and durable, often compared to steel in terms of tensile strength.
- Versatility: Can be used for flooring, walls, and structural elements.
Example Use:
The Green School in Bali, Indonesia, uses bamboo extensively, showing its potential in sustainable architecture.
2. Recycled Steel
Recycled steel is made from scrap metal, reducing the need for new steel production. According to the Worldsteel Association, “steel is the world’s most recycled material and 100% recyclable,” and in 2021, 680 million tonnes of steel had been recycled. As it can be recycled infinitely without loss of property, it is one of the most sustainable building materials.
Benefits:
- Durability: Long-lasting and robust.
- Environmental Impact: Significantly reduces carbon emissions compared to new steel production.
- Recyclability: Can be recycled multiple times without loss of quality.
Example Use:
The Bank of America Tower in New York City incorporates recycled steel, emphasising sustainability in urban skyscrapers.
3. Hempcrete
Hempcrete is a bio-composite material made from hemp fibres and lime. It is an excellent insulator and can be used to insulate the interior and exterior of existing buildings and fill wooden frames in new constructions.
Benefits:
- Insulation: Provides natural insulation, reducing heating and cooling costs.
- Eco-Friendly: Carbon-negative material, meaning it absorbs more CO2 than it emits during production.
- Health: Non-toxic and mold-resistant, contributing to healthier indoor air quality.
Example Use:
The IsoHemp House in Belgium demonstrates the practical application of hempcrete in residential construction.
4. Cross-Laminated Timber (CLT)
Cross-laminated timber (CLT) is an engineered wood product made by stacking layers of solid-sawn lumber perpendicular to each other and bonding them with structural adhesives. This technique provides strength, stability, and rigidity. CLT is suitable for various structural applications, such as walls, floors, and roofs. The panels are prefabricated and can be assembled quickly on-site, which reduces construction time and labour costs. So, CLT is one of the sustainable building materials. It utilises renewable resources and stores carbon, which means that it contributes to a lower environmental impact than traditional construction materials.
Benefits:
- Sustainability: Made from sustainably harvested timber, CLT is a renewable material.
- Strength: Strong and stable, suitable for large-scale construction projects.
- Carbon Storage: Wood stores carbon dioxide, helping to offset carbon emissions.
Example Use:
The Stadthaus in London is a nine-story residential building which was constructed using CLT.
5. Rammed Earth
Rammed earth is a technique to construct foundations, walls and floors. It involves compacting a mixture of damp soil, sand, gravel, and sometimes stabilisers like cement or lime into layers within a formwork to create building components. This ancient method has been used for thousands of years. The natural aesthetic and minimal environmental impact make rammed earth attractive for eco-friendly building projects.
Benefits:
- Thermal Mass: Provides excellent thermal mass, helping to regulate indoor temperatures.
- Durability: Extremely durable and long-lasting.
- Low Environmental Impact: Using natural and locally sourced materials reduces transportation emissions.
Example Use:
The Great Wall of China is one of the most historical examples of the usage of rammed earth.
6. Straw Bale
Straw-bale construction is a building method that uses bales of straw, typically wheat, rice, rye, or oat straw. Bales of straws can be used as structural elements, insulation, or both. The technique can involve stacking bales within a frame or using them as load-bearing walls. It can be covered with plaster. This method is accepted as eco-friendly, using a renewable and biodegradable agricultural byproduct. It is also cost-effective, contributing to buildings’ sustainability and energy efficiency.
Benefits:
- Insulation: Provides superior thermal insulation.
- Renewability: Made from agricultural waste, which is renewable and biodegradable.
- Cost-Effective: Often cheaper than traditional building materials.
Example Use:
Fri & Fro (Free and Happy) ecoVillage in Egebjerg, Denmark, is an example of straw-bale construction.
7. Cork
Cork is a natural, renewable material harvested from the bark of cork oak trees (Quercus suber). The harvesting process does not harm the tree, and the process itself allows it to regenerate its bark. The material is highly valued for its unique properties, such as being lightweight, buoyant, elastic, and impermeable to liquids and gases. These characteristics make cork suitable for various applications, including wine stoppers, flooring, insulation, soundproofing, and even fashion and design. Its sustainability and versatility make it an eco-friendly choice for many industries.
Benefits:
- Renewability: Cork trees can be harvested without being cut down, and the bark regenerates.
- Insulation: Excellent thermal and acoustic insulation properties.
- Durability: Resistant to moisture, fire, and pests.
Example Use:
Cork House in the UK uses cork as a primary building material, demonstrating its versatility and sustainability.
Conclusion
Incorporating sustainable materials into construction practices is not just a trend but a necessity for a healthier and more sustainable future. Bamboo, recycled steel, hempcrete, cross-laminated timber, rammed earth, straw bale, and cork are just a few examples of how the industry is evolving to meet environmental challenges. By choosing these materials, we can reduce our carbon footprint, conserve natural resources, and create more sustainable living environments.
Join us at our upcoming Sustainability Conference to gain more insights into sustainable architecture and explore the latest innovations. This event brings together experts from various fields to discuss cutting-edge developments in sustainable architecture. Learn more about the conference here.
By embracing these materials and participating in events like our conference, you can contribute to a greener, more sustainable future in architecture.
References & Further Reading
Bamboo and sustainable construction. (2023). In Environmental footprints and eco-design of products and processes. https://doi.org/10.1007/978-981-99-0232-3
Minke, G., Friedemann, M. (2005). Building with Straw: Design and Technology of a Sustainable Architecture. Birkhauser Verlag AG.
Peacock, A. (2023). Top 10 tallest mass-timber buildings around the world. Dezeen Timber Revolution Series. https://www.dezeen.com/2023/03/29/worlds-tallest-buildings-mass-timber-revolution/
RIBA, (2019). RIBA South Award Winners. https://www.architecture.com/awards-and-competitions-landing-page/awards/riba-regional-awards/riba-south-award-winners/2019/cork-house
Stanwix, W., Sparrow, A. (2014). The Hempcrete Book: Designing and building with hemp-lime. Green Books.
Straw Bale ecoVillage homes. (n.d.). http://naturalhomes.org/timeline/freeandhappyecovillage.htm
Worldsteel Association, (2023). Steel – the permanent material in the circular economy. Retrieved on 21 May 2024 from https://worldsteel.org/publications/bookshop/steel-permanent-circular-economy/?do_download_id=2801be14-8237-4d8c-b52b-d122bc3bfa32