Environmentally Friendly Building Materials
With green building initiatives growing rapidly across the globe, there’s never been more interest in finding better alternative construction materials. Whether it’s looking back in time to the naturally available resources that our ancestors used to construct their buildings or harnessing the latest technology to make unconventional building materials more durable and sustainable, it’s certainly a dynamic field. Here are a few of those methods showing the most promise, and making us rethink the built environment.
One of the oldest building materials used by humans, adobe is essentially earth and water mixed together and dried to form bricks or compressed into larger molds. The soil used needs to be between 15 to 30% clay, so this is an attractive option for buildings to be constructed on naturally clay-rich soils. Chopped straw or other small fibers are often added to make the structure stronger and better insulated. While this method works best in naturally arid climates, it is possible to strengthen the structure against bad weather by incorporating a small amount of cement into the mix, finding a clever compromise between modern and ancient technologies. Even if the building itself is not constructed from adobe, it remains a popular sustainable alternative for floors. Colored with a layer of clay and polished with natural oils, adobe floors are extremely resilient and very beautiful.
Cob building is fast growing in popularity, and it’s not difficult to see why. Numerous examples of cob buildings are still in use in the UK, many well over 500 years old. Local materials can be used, no complicated machinery is required, it is extremely versatile and can easily be mixed in with other building techniques, it insulates the building extremely well and lends itself to individualized and flowing, organic sculptural designs. The catch? It’s slow to build and labor intensive – but if you want to create a home that’s truly your own and will last for centuries if you need it to, there are few cheaper and more sustainable options.
Building roads on mud, sand and clay
Of course, designing our homes and buildings to be more sustainable is one thing, but consideration also needs to be given as to how we travel between them. And in areas where soft soils, expansive clays or sand is found, shipping in expensive aggregates to create a stable enough base layer for roads is the required norm. But with an innovative cellular confinement system known as geocells, it’s actually possible to put the locally available materials to use instead.
Not only does this technique use 50% less aggregate, it’s also a lot more cost-effective and uses less fuel, while also making roads more durable. In the case of road reconstruction, this solution can also be used for the repurposing or recycling of reclaimed asphalt pavements.
As a rapidly renewable and versatile resource, hemp has been getting a lot of attention lately, and its usefulness in construction is no exception. Made from the woody inner fibers of the plant mixed with lime, HempCrete offers many of the benefits of concrete without the large environmental footprint. Hemp absorbs CO2 as it grows, which is then locked away within the structure of the building. And because the blocks are extremely lightweight, they’re both safer to work with and require less fuel to transport.
Although still being researched and developed, Ferrock could certainly be a game changer in the construction industry. Actually, stronger than concrete, this cutting-edge material actually absorbs CO2 during the drying process, meaning that any building made from would be carbon neutral. Better yet, the key ingredient is steel dust, which is usually discarded as a waste product by the steel industry. The name is a shortening of ferrous (or iron-rich) rock. And unlike many of the older building methods we’ve covered here, because it looks similar to concrete and is more structurally sound, it might be easier for the construction industry to accept it as a viable alternative.
Another older building technique that’s seeing a comeback is the use of straw bales, and they’re one of those materials you might not believe a structure is made from unless you’d been there to see it done. Once sealed and painted, straw bales houses look remarkably “normal” – and they provide excellent insulation. They are also extremely cheap, easy to build with, and made from a rapidly renewable carbon-negative resource.