Exploring the Use of Organic Materials in Building: Beyond Traditional Hobbit Homes and Mud Structures
Mud, straw, wood, hemp, and cork are just some of the materials on offer for sustainable building, as the construction industry moves towards more eco-friendly practices. This guide, based on an ACAN online seminar from July 2021, focuses on natural construction materials for sustainable building.
The History of Natural Materials in Construction
The use of mud-based mixes, known as cob, can be traced back to the 11th century in northern Africa. Mud has been the world's primary building material for 10 millennia and is still used by one-third of the world's population for housing. Straw bale houses have been built around the world for centuries, with evidence of their use dating back 400 years in Germany. Hemp-based structures date back to Roman times, and straw homes have been built since the Stone Age.
The Advantages of Natural Materials
Natural fibre production costs are much lower than for traditional fibre materials. For instance, a small straw bale house with two rooms may cost around £10,000 to build, while a large 3-bedroomed house can cost up to £40,000. The performance of natural fibres depends on the fibre count, their length, shape, and arrangement. In urban environments, materials should be chosen based on sound-absorbing ability, indoor air quality, and temperature regulation.
Sustainable Materials for the Future
Cross-laminated timber (CLT), engineered bamboo, recycled steel, rammed earth, and insulated concrete forms are some of the sustainable alternatives to cement, plastic, concrete, oil, and steel in construction. These materials reduce environmental impact by using renewable resources, recycled content, or lower-energy production methods.
CLT, an engineered wood product, offers comparable strength and durability to concrete and steel, is lightweight, has excellent thermal and fire performance, and can be prefabricated for quick construction. Bamboo, especially engineered bamboo, is a fast-growing and renewable material that serves as an alternative to timber and some plastics. Recycled steel maintains the strength and durability of new steel while reducing landfill waste.
For concrete and cement alternatives, mixes incorporating industrial by-products like pond ash, recycled glass sand, and textile fibers can partially replace traditional cement, reducing carbon emissions associated with concrete production. Additionally, rammed earth, a technique using compacted natural soil, is a low-impact, thermally efficient alternative to concrete walls.
Insulated concrete forms combine sustainable insulation material with concrete for better thermal performance and energy efficiency, which reduces heating and cooling demands.
Considerations for Sustainable Construction
When choosing materials for a construction project, size of the project, material availability, low-emission, healthy, and cost-efficient options should be considered. Weather conditions and climate change impact should also be considered. Locally available materials should be considered for use in construction projects.
In the UK, it can actually be easier to obtain planning permission if you decide to build with rammed earth. A life cycle analysis is a leading tool for assessing a product's environmental impact. An airtight building is important for energy efficiency and can be achieved with the right materials and design.
The Future of Sustainable Construction
Estimates suggest that natural fibre prices will remain low, likely below €1/kg. Engineered wood products have the potential to store roughly 46 million tonnes of CO-eqv. per year in the European building sector in 2030. Countries pulling ahead in terms of hemp production and the potential to develop a hemp building sector include Belgium, Netherlands, Canada, Czech Republic, Ireland, Ukraine, and Spain.
France is still leading the way with the most construction projects using hemp. Around half of the world's population still live in homes made of earth. Cork oak forests cover roughly 2.1 million hectares, a third of which is in Portugal. Cork represents 1% of Portugal's GDP with annual exports totalling over €1,346 million.
In conclusion, architects, planners, designers, local authorities, and individuals can make a difference in the materials they choose. By opting for sustainable, natural materials, we can reduce our carbon footprint, promote renewable resources, and build a greener future.
[1] "Sustainable Construction Materials." (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK552874/
[2] "Rammed Earth Construction." (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK552872/
[3] "Cross-Laminated Timber (CLT)." (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK552873/
[4] "Bamboo as a Sustainable Building Material." (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK552876/
[5] "Recycled Steel in Construction." (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK552874/
- Technology can play a significant role in the future of sustainable construction, as it allows for the engineering of materials like cross-laminated timber (CLT) and engineered bamboo, which offer comparable strength and durability to conventional materials while reducing environmental impact.
- The realm of sports isn't the only one benefiting from innovative technology; the use of cork, a renewable resource, has been essential in various construction projects, contributing to Portugal's economy and representing 1% of the country's GDP with annual exports totalling over €1,346 million.
