Using low carbon solutions in building materials

From plastic-bottle kerbstones to waste-based building blocks, countless companies are now turning to greener building materials to create sustainable buildings.

The UK construction sector is facing a major challenge. How does the sector tackle a growing housing shortage and expand infrastructure services while also achieving emissions reductions in line with the government targets of a 50% reduction from the built environment by 2025? Meeting this challenge will require – amongst other things – a rapid decrease in the use of carbon-intensive building materials in the next few years, and an increase in low-carbon alternatives. Building materials account for roughly 19% of the UK’s total greenhouse gas emissions. Of these, the majority come from steel and cement.

Luckily lots of research is happening and a growing range of alternative building material is now available. Alternatives to traditional cement and concrete include blended cements and concretes, concretes that store CO₂, cements made from alternative materials, and using entirely different materials, such as wood, hempcrete, straw bales and mycelium.

Jack Cawthra, Senior Quantity Surveyor at Gleave advises: “One of the key barriers holding these materials back is the lack of demand. Clients, architects, engineers and contractors are often cautious about using novel building materials, perceiving them as too risky, more costly and more difficult to use. They are wary of changes in a product that has to ensure safety over decades and have a strong preference for a product that is easy to use in most applications without additional training. Finally, they are subject to financial, insurance and legal constraints that shape how innovative they can be.”

Cost and time

The Construction industry is looking at ways to adopt new technologies but they typically faced with a trade-off against cost or time that makes them difficult to adopt. As part of any construction project, a quantity surveyor will draw up detailed lists of materials to be used during building, which is then sent to Building Control for approval and helps to give an idea of costs for the build. It as at this point that they can ensure sustainable materials are used and have input into the development of the project.

Quantity surveyors also have a list of so called “ten commandments” that they can adhere to which help promote sustainability. These are a set of ideals which help improve sustainability but it does require effort and thought, and for everyone to be aligned with the same goal of sustainability on the project.

Sustainable Materials

Using the example of a well-known cement alternative, Cemfree: This product provides all the strength of normal concrete, but the curing times are a lot longer, which will reduce construction cycle time on high-rise buildings. Resulting in an extra day’s curing on a 40-storey building, which is eight weeks added on the programme schedule. Clients will find this a little unpalatable. Invariably contractors may struggle to off-set the increased programme time because projects are awarded based on the lowest cost and fastest programme.

Timber is another readily available material with low embodied carbon impact that is now being widely shunned amid the post-Grenfell caution.

Conclusion

With contractors ramping up their carbon commitments amid bleak climate warnings, you might think now is the right time for the industry to embrace sustainable alternative materials. But this will also require a re-evaluation of how projects are procured.