Sustainability in construction: The developments in sustainable building materials
What are sustainable building materials?
Sustainable building materials are materials used in construction that have a reduced impact on the environment. Standard building materials usually have a degree of embodied carbon emissions – the way they are sourced, manufactured, transported and used will involve CO2 being released into the atmosphere. Plus, at the end of the building’s life, the materials may not be able to be reused or recycled.
Benefits and challenges of sustainable construction
Using sustainable building materials will increase a building’s environmental credentials. Some buildings will achieve a net zero rating as a result, or their embodied carbon emissions will be so low that carbon offsetting can be used to nudge the building into net zero.
However sustainable building materials may be more costly because they are rarer to source, and the construction industry is not set up to use them at scale. Clients may be less concerned about sustainability than the contractor, or the building will have to be redesigned to incorporate sustainable building materials, increasing the expense and length of a project.
The importance of sustainable building materials
The fact is, however, that 30% of the UK’s carbon emissions come from the built environment, with 7% of that figure originating from embodied emissions. The construction industry is engaged in a net zero strategy, and needs to make more use of eco-friendly building materials if it is to help the UK hit its net zero target by 2050.
Developments in sustainable materials
In moving beyond concrete, brick, stone and other traditional building materials for more sustainable alternatives, the construction industry is in many ways going back in time. Materials like cob, bamboo and straw have been used by humanity to build houses for millennia, and they have been augmented by other innovative and green ways to build.
Natural & biodegradable building materials
Sheep’s wool is a natural insulator, so is ideal for use as an insulation material in buildings. Sheep’s wool can be used in loft spaces, walls and ceilings instead of fibreglass insulation felt.
Yes, the material from which jeans are made! Denim is another great source of insulation, and when reduced to its natural cotton state can be used in residential and commercial buildings.
Cork is light, waterproof, elastic, durable, fire retardant and reusable. Regularly harvested cork trees also store 3-5 times more carbon than those left unharvested.
A cheap farming by-product, straw makes for a highly effective insulation material. Straw is 100% recyclable and biodegradable.
Cob is a natural material composed of subsoil, water, fibrous organic material and sometimes lime. It has been used historically as a building material and could make a comeback as a sustainable solution.
Mycelium is a vegetative fungus – an unlikely type of building material. However, when dried the root-like structures have a high strength-to-weight ratio and so can be used in bricks, as a binding agent and insulator.
Perhaps the most well-known sustainable building material, bamboo’s greatest asset is its flexibility, meaning it can be applied to structure as well as decoration. Large buildings as well as small dwellings have incorporated bamboo.
Polyurethane rigid foam
This is a plant-based foam made from hemp, kelp and bamboo, which has excellent insulation and thermal resistance properties. It is resilient to moisture and heat.
Soil with the right quantities of sand, gravel, clay and silt can be compacted while damp into a formwork or frame. After curing, this ‘rammed earth’ can be used for very strong foundations, walls and floors.
Reclaimed & recycled building materials
Reclaimed wood is perhaps the ultimate in sustainable building materials. It saves on the considerable environmental cost of harvesting new wood, it’s versatile, and it’s able to be used for supporting structures, floorboards and interior features.
More steel is recycled than paper, plastic, aluminium and glass combined, because mining is one of the most environmentally damaging of activities. As a building material steel is durable and incredibly strong.
Plastic is increasingly being used in construction, and inevitably so. As we are all probably aware, plastic items can take centuries to degrade. Recycled plastic as a building material produces 95% lower emissions than concrete.
Both natural and synthetic rubber can be recycled and made into flooring surfaces, especially for sports and leisure environments.
Advanced & emerging building materials
Smart glass is a type of energy-efficient glass. It can react to solar energy and effectively controls the amount of heat and light that passes into a building, as well as having darkening properties (acting like a blind).
3D printing & prefabrication
3D printing is increasingly being used within the construction industry, both for entire builds and for creating bespoke elements offsite. It has the major benefits of speed and scalability. A 46-home housing development in Lancashire is being entirely 3D printed.
It feels like solar panels have been around for a long time. The first installation of photovoltaic panels on a residential property in the UK was in 1995, and they remain the renewable energy technology that is most cost-effective for homeowners.
Enviroboard is a type of fire-resistant board made up of magnesium, sawdust, and fibre cloth. Stronger than conventional boarding material, Enviroboard is typically used for wall lining, roof lining and underlay systems. It has a natural drying and curing process, so is carbon neutral.
Alternative concrete materials
- AshCrete – made of 97% recycled material, using fly ash instead of traditional concrete
- Hempcrete – a mixture of sand, hemp fibres and lime. Hempcrete blocks are lightweight and breathable
- Timbercrete – sawdust mixed with the less energy-intensive elements of concrete. A long-lasting and highly fire-resistant alternative
What building materials will we be using in 2050?
By 2050, the target for the UK to become net zero, the construction industry will almost certainly be using more environmentally friendly building materials than we do today. It is hard to say which will be most common by then, but the concrete alternatives could well have replaced traditional concrete, and more off-site construction will be taking place.
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