For years, concrete has been a popular choice within the construction industry due to its strength and versatility, and it’s rare to find any modern buildings without it. However, new innovations within the sector mean that it should be easier than ever to wean architects and contractors off their concrete dependence.
Fortunately, there is an appetite for change, and in a rapidly evolving construction landscape, housebuilders and developers are increasingly looking to new products and materials to help meet ambitious net-zero carbon targets.
One of the most common uses of concrete is concrete backing blocks within a cavity wall. It’s a perennial system as it provides both structural sturdiness and a good level of insulation.
However, new developments in building products have removed the need for the first layer of backing blocks. It is possible to replace them with thin sheets of recycled polypropylene and still achieve the same, or better, performance as concrete. The production of these plastic sheets has a far lower carbon footprint than that of concrete. In fact, it can reduce the carbon footprint of cavity construction by up to 50%.
Moving forward, the circular economy will continue to gain importance as the industry tries to minimise its impact on the environment in as many ways as possible. As a recycled material, these panels also help to remove the amount of virgin plastic within the industry, getting us that step closer to net-zero 2050.
Another ecological bonus from using recycled plastic sheets rather than concrete blocks is their weight. The equivalent amount of polypropylene is far more lightweight and takes up less room than a hefty block of concrete. It is; therefore, much simpler to transport, as you can deliver the equivalent of 40 tonnes of concrete in the back of a single pick-up truck.
The benefits of replacing concrete with polypropylene panels do not stop at a building’s construction either. I have always said that when it comes to building a property, it’s likely that you are building a structure that will last well over a hundred years, so it needs to be done properly. When a building lasts that long, its operational emissions can easily overtake the carbon footprint from the materials’ production. Of the construction industry’s 40% share of global emissions, 28% of that is from operational emissions alone. This means it needs to be as efficient as possible.
New legislation, such as the Future Homes Standard, now means that this need for efficiency has also been enshrined in law, as any new homes need to meet a certain level of energy efficiency. This is measured using U-values, which demonstrates the rate of transmission of heat energy through the wall. The lower the U-value, the less heat escapes through the wall.
Creating a seal within a cavity wall with plastic sheets can deliver lower U-values than you would achieve with concrete blocks, resulting in superior energy efficiency and, therefore, a greener building and smaller energy bills.
Making the switch and replacing just one layer of concrete backing blocks can add up to a serious reduction in emissions when done at scale. At SureCav, over the past decade we estimate that by doing so we’ve saved the manufacture of 80,000 tonnes of concrete. In turn, this has led to reducing our haulage from 4000 lorry loads, down to just 50. In petrol emissions alone, that is a significant shrinking of our carbon footprint.
We’re proud of the work we have done over the years to help developers design out such a high quantity of concrete. However, we’re currently still a relatively small company and this could, and should, be done on a much larger scale. My vision over the next decade is to see at least 10 times the tonnage of concrete saved through the incorporation of more eco-friendly materials in cavity walls.
The use of polypropylene sheets to replace concrete is just one recent innovation in designing out climate change. As we move forward, we’re hoping to rapidly expand its use in the sector and are excited by the prospect of more building innovations to help cut the carbon out of construction.