Plastic tends to have a bad reputation, and for good reasons. The ubiquitous material is one of the leading causes of pollution worldwide, with the vast majority of the material not recycled, according to the National Resource Defense Council. It’s used in almost everything we use daily, from electric vehicles to toys to floor rugs. Single-use plastic, however, poses the biggest threat to the environment, and many initiatives are taking place to mitigate that. One of the biggest ways the problem is being tackled is through more plastic waste reuse, including as a building material. Using alternative materials in development projects is almost everywhere at the moment. Industry players, both big and small, increasingly use alternative materials like mass timber and bamboo in their projects. Choosing options outside of traditionally-used materials like steel and concrete is not only eco-friendly, it’s a way for companies to achieve green standards and ESG goals and construct something visually distinctive.
The omnipresent nature of plastics means there is an ever-growing mountain of plastic waste being generated around the world, and some countries are exploring ways to reuse it. In Europe, a circular economy for plastics has been studied extensively. Plastics Europe, an industry group for the continent’s plastics manufacturers, is aware of the harm the products can and have caused the world and are trying to mitigate it by encouraging more reuse. In a recent report, the organization found that the use of recycled plastics in buildings and construction worldwide is growing. In fact, 45 percent of post-consumer recycled plastics are used in some capacity in building and construction. The report also found that the percentage of recycled plastics being used in new products rose from 7.2 percent in 2018 to 8.5 percent in 2020. In that same time period, the amount of recycled plastic used in building and construction increased 16.5 percent. For example, plastic waste can be used to make green concrete, a more environmentally-friendly concrete that uses waste and leftover materials from various industries and requires less energy.
While it’s still an emerging concept, plastics have a lot of promise for building construction. Plastics have qualities that make them a good candidate for construction. The material is waterproof, corrosion-resistant, durable, and effective as an electric and thermal insulator. While plastic has a lot of qualities that make it ideal for construction use, it’s still not as strong as wood and steel and doesn’t have the same load-bearing capacity. It also wouldn’t work well for things like drilling and nailing due to its texture. That’s why it needs to be mixed with other materials. Mixing plastic with other materials has been considered as a way to decarbonize the concrete manufacturing process, which produces significant amounts of carbon dioxide. In one study, MIT students mixed gamma radiation-exposed plastic powder into cement paste, which ended up creating a finished product that was 15 percent stronger than standard concrete and more durable to boot.
Other research has explored using recycled plastics in the brick-making process, which also requires high energy to produce. In one experiment, stacking recycled plastic bricks like LEGO blocks was proposed, with one Colombian company manufacturing the bricks for single-family homes that could be built for just over $5,000. What’s more surprising is that recycled plastics have also been added to lumber to create something called structural plastic lumber; made from recycled milk containers and coffee cups, among other recycled plastics material, the hybrid lumber was described as “lighter than steel, longer-lasting than lumber, and strong enough to support 120-ton locomotives.”
In Germany, recycled plastic played a big part in a 13-story mixed-use building in the city of Mannheim developed in 2019 by the German developer and builder Diringer & Scheidel Group. Using a patented void former system from the company Henize Cobiax Deutschland that uses steel-reinforced plastic air bubbles in slabs, the firm could avoid using 1,778 tons of concrete and 149 tons of CO2 emissions. The project achieved a green certification from Germany’s Green Building Council for using the void formers. Back in 2020, a design studio created a structure for an annual festival celebration in Hong Kong that marked the country’s first large-scale architecture project made using recycled plastic bricks. The bricks were created using the recycled plastic material high-density polyethylene.
In another example, a California-based startup that builds 3D-printed homes partnered with the real estate company Reinhabit to build a series of tiny homes made from recycled plastic. More than 60 percent of the printing material used to build the ten homes, located in three different locations in Southern California, is recycled plastic. The company, Azure Printed Homes, is using post-industrial plastic but is looking to use post-consumer plastic for future projects. “Our supply chain should never be short in our lifetime,” said Azure co-founder Ross Maguire.
A polymeric materials scientist from Brazil who has been researching plastics for years is a big believer in the future of plastic waste used for building materials. His team has been in the process of developing a building block made of recycled plastics and other waste-stream materials like sawdust, hemp, red mud, and concrete waste. “Plastics are strong, durable, waterproof, lightweight, easy to mold, and recyclable,” said Sibele Cestari. “All key properties for construction materials.” While there are promising applications, so far, they haven’t been reproduced at any large scale. Cestari believes it will take “political will” and more awareness of the benefits of using recycled plastic instead of mining natural resources to draw more investment into the initiative.
In the US, big efforts are being made by the Department of Energy (DOE) to reduce the amount of plastic waste and increase the recycling rate. Last year, the DOE announced $13.4 million in funding for technologies that will help reduce the amount of single-use plastics by designing new plastics that are more recyclable and biodegradable. Several months after the announcement, researchers at Oregon State University made a breakthrough that could greatly expand the range of plastics that can be recycled. It’s difficult to tell yet whether using recycled plastics in real estate development would cost less than traditional materials, though some companies in the plastics industry say it is more affordable. One plastics industry association said that plastic lumber, made with a combination of recycled plastic, wood fillings, and “wood-like properties,” if used at scale, could help bring down the rising cost of homebuilding in the US.
With the staggering amount of plastic waste that continues to be generated around the world today, using it as an alternative, sustainable material for building and construction seems like a no-brainer. However, it’s still pretty early in the research and prototyping process, so it will likely be some time before we see more widespread use of plastic waste in major real estate projects in the US. There will also need to be a lot more investment into recycling waste that is typically ruled out during the recycling process, which would open up a wealth of products that could be used in creating construction materials. But as research continues and the number of projects using recycled plastic grows, as well as efforts being undertaken at the federal level to increase recycling rates, things are looking good for both supply and demand of the alternative building material.