16 sustainable and cost-effective building materials
Posted on: 8 May, 2024
These 16 innovative and eco-friendly materials can help the construction industry address its role in the climate crisis.
The built environment is one of the single most pollutive sectors in the world, but it’s the construction industry in particular that is causing the most damage to the environment. Embodied carbon – the carbon dioxide emissions created in the construction process before a building becomes operational – accounts for 10% of all global energy-related CO2 emissions. What’s more, the production of materials like concrete is extremely energy-intensive, accounting for 8% of global CO2.
With the use of traditional building materials like concrete increasing embodied emission levels, construction businesses are now turning to new, sustainable alternatives to reduce the carbon footprint of their building projects.
Here are 16 building materials that can help make construction sustainable and protect the environment (while also saving construction costs).
1. Bamboo
Bamboo has already been used in construction for hundreds of years. An extremely flexible material, it’s very easy for construction firms to source, as this rapidly-growing plant – the fastest-growing plant in the world – can be found in multiple continents.
What makes bamboo so sustainable is how little of it needs to be wasted. An entire bamboo stem can be used in construction, and as it’s naturally biodegradable, any construction waste can be disposed.
2. Mass timber
Short for ‘massive timber’ and also referred to as ‘structural timber’, this material is the result of glueing, doweling or nailing pieces of softer wood together in order to form larger, stronger pieces. The process results in a material with the strength ratings of wood or concrete that is significantly lighter in weight.
Mass timber has generated plenty excitement for its potential implications in sustainable construction. In 2019, Mjøstårnet, a tower in Norway, was certified as the world’s tallest timber building at the time, at 18 storeys 85.4 metres in height. It has since been surpassed by Ascent, a 25-storey, 86.6-metre-tall tower in the US. Both of these buildings were created with mass timber.
3. Cob
Cob is made by crushing together subsoil, sand, straw, and sometimes lime. This natural building material has almost zero embodied carbon, and is both strong and durable, with the oldest known cob house in the UK dating back to the 15th century.
This sustainable material has been adopted and re-engineered by researchers to a new, modern mixture with the ability to absorb and trap heat, known as CobBauge. The goal is for this new mixture to become an effective alternative to concrete and a viable option for low carbon construction.
4. Recycled steel
Along with fresh, natural materials with low-embodied carbon, construction firms are also looking to recycle existing materials, with steel a prime candidate. Construction is already one of the biggest consumers of steel and it’s easy to recycle, with around 40% of all steel production involving the use of recycled material.
Recycled steel can be used to build structural components from beams, bars and columns. Steel buildings can be recycled almost entirely, with very little waste, and the resulting recycled steel can have the same strength and durability.
5. Recycled plastic
Plastic – one of the most widely used, consumed and disposed substances on the planet – has a variety of applications for construction. Its water, corrosion-resistance and thermal insulation qualities make it an ideal material for the construction of houses, and while it doesn’t have the strength of steel or even wood, it can be mixed with other materials to compensate for this.
Recycled plastic is used to build components like lumber, fencing, floor and roof tiles, bricks, concrete, and even gravel.
6. Rammed earth
The process of creating rammed earth has been used for thousands of years. It involves ramming together a mixture of aggregates (such as gravel, clay and sand) into a formwork. This formwork can then be moulded to create walls, which, once dried, become solid. These walls are extremely durable, require little maintenance and can last for hundreds of years.
This ancient technique is naturally sustainable and energy efficient, as it involves using locally sourced materials and can be easily reused and recycled. It also has high thermal mass, meaning it’s effective at absorbing and storing heat, which can help reduce energy usage and expenses.
7. Cork
Buildings and infrastructure might not be the first thing that comes to mind when you think of cork, but that could be set to change. This natural material is being touted as an option for sustainable construction, and has been used to create insulation, tiles, shingles, wall coverings, roofs and countertops.
Rather than cutting down a tree, cork can be harvested from stripping bark and, thanks to its cell structure, it actually stores carbon. As a sustainable building material, its low weight and soft structure make it easier for builders to work with and manipulate.
8. Recycled glass
Glass is yet another substance than can be reused and recycled in construction. Recycling it is involves far less energy consumption than producing new glass. It also reduces the need for virgin materials, and loses none of its strength of quality in the recycling process.
9. Straw bale
Bales of straw are another sustainable material with potential energy saving benefits. It’s already being used for insulation – it has three times the R-value (a measurement for heat resistance) of traditional insulation – and can be tied together with bamboo or wood to create walls.
From a sustainability perspective, bales of straw are 100% biodegradable, and have very low embodied energy. Straw has already been used in the construction of houses, theatres and university buildings, and these structures could stand for over a century if they’re properly maintained.
10. Earth blocks
Often referred to as compressed earth blocks (CEB), this sustainable material is similar to cob in its composition. It’s a mixture of dry subsoil, aggregate, sand and clay. These natural resources are compressed together through high pressure and dampening to form a block shape, which can function as a brick.
Earth blocks have a naturally low carbon footprint owing to their composition, making them a viable and sustainable option for building houses. They’re also fire resistant, and as they’re composed of water, they can easily be produced at a construction site.
However, one potential weakness of earth blocks is their low tensile strength – the maximum amount of stress they’re able to bear. They’re also known to lose strength and stability when in contact with water for long periods of time.
11. Sheep’s wool
Unlike some of the other sustainable materials listed, sheep’s wool has a very specific application as an effective insulator. Sheep’s wool has evolved in order to keep sheep warm in extremely cold weather conditions, and construction confirms can benefit from its ability to absorb and release moisture, regulate humidity, stabilise temperatures and ultimately purify the air.
Amid concerns around rising energy costs and demands for improved air quality, sheep’s wool is an insulation alternative is something construction firms should take note of.
12. Clay brick
Clay is another green material that can be easily sourced and has been used in building projects for hundreds of years. For the modern construction industry, the most promising application of this versatile material is in the creation of clay bricks that are hard-wearing, recyclable, low maintenance and have strong thermal insulation qualities.
What’s more, along with having low embodied energy, clay bricks also align with the lean methodology, in that they enable the reduction of waste and can be easily sourced locally to a building site.
13. Recycled rubber
While used tyres most often end up in landfills, rubber has a variety of applications for construction, from landscaping, asphalt and flooring to potentially a sustainable replacement for traditional concrete. This new concrete-like material, dubbed ‘rubbercrete’, is made by replacing the fine aggregate in traditional concrete with crumb rubber from used tires.
Learn more: 12 sustainable alternatives to traditional concrete
14. Newspaperwood
Despite the fact that newspaper circulation is declining, in the UK they’re still read by 1 in 4 adults every 15 days. The majority of newspapers are recyclable and compostable, and they can even be used by construction firms to create a substitute for wood.
Newspaperwood, as the name suggests, is a wood-like material made from coating sheets of newspaper together with glue into logs. It can even be varnished so it resembles wood, although many prefer newspaperwood’s distinct appearance. Just like traditional wood, it’s versatile, durable and can be made waterproof.
15. Plant-based polyurethane rigid foam
One of the most exciting eco-friendly building materials on this list, polyurethane is a rigid foam made out of foamed polymers that, while prevalent in the construction industry, are problematic in terms of sustainability. This indispensable material, crucial to effective insulation of buildings, is largely made from petrochemicals and difficult to dispose of.
Plant-based foams or ‘biofoams’ have emerged as a new alternative with a lower carbon footprint than traditional foam. They’re made from a variety of natural fibres, including bamboo and hemp plants.
16. Ferrock
Ferrock is a green building material often used as a substitute for cement. Created from a mixture of waste steel dust silica, it’s both stronger than concrete and extremely sustainable, being that the process of producing it causes no damage to the environment.
What has people most excited about ferrock is that it is CO2 negative – in other words, instead of emitting CO2 when drying, it actually absorbs and binds to it.
Sustainability isn’t a passing trend – it’s here to stay and is constantly evolving. If you want to inspire and action change in your career, UCEM’s MSc Innovation in Sustainable Built Environments will give you the skills you need, both now and in the future.
Find out more: MSc Innovation in Sustainable Built Environments – University College of Estate Management
