What if we could change the way we use plastic? What if instead of the current economic model of use and waste, we could use and recycle plastic on a large scale? You might be surprised to find out that plastic has the potential to be a sustainable and reliable construction material.

The problem with plastic

When you think of plastic, you probably picture single-use plastics polluting our oceans and bodies. It’s true, plastic waste is a monumental problem. Each year, the world produces 400 million tons of plastic waste. Much of it ends up in our oceans. This is such a problem, that as you probably know, there is a patch of mainly plastic debris two times the size of Texas floating in the Pacific Ocean– and it isn’t going to go away on its own. 

Plastic degrades at an extremely slow rate. A piece of plastic can take 1000 years to break down. And, while it breaks down, it divides into smaller pieces. These pieces eventually turn into tiny fragments known as microplastics. Microplastics not only harm marine life, they can be harmful to human health too. While a lot of the impacts of microplastics on health are still unknown, they could cause a whole host of problems, including metabolic and neurological problems and cancer. This is terrifying given that the average person consumes a credit card size worth of microplastics every week. 

So what can the construction industry do about it? 

For all the bad they do, plastics are also waterproof, durable, lightweight, moldable, cheap, convenient, and recyclable. All of these factors could make them ideal for certain types of building materials. This includes piping, roofing, insulation, and plastic beams. If the construction industry can start making these materials out of recycled plastics, they could keep plastics out of oceans and landfills, and create a circular system that would prevent new plastics from being created. 

Contrary to popular belief, most plastic is recyclable

Sadly, only 5% of the world’s plastic is recycled each year. This is mainly because some plastics are extremely difficult to recycle. These are plastics that either cannot be melted down, or whose polymeric chains break down more readily than others (this can change their mechanical properties and make them not usable). However, there are still ways the industry might recycle these kinds of plastics. Plastics with polymeric chains that quickly break down can be fixed by mixing in additives or more virgin plastic. Plastics that cannot be melted down can be shredded and used as filler in things like asphalt and concrete.

Construction materials made out of plastic

There are actually entire houses made out of recycled plastic like this one, which is made out of recycled water bottles. However, plastic houses aren’t being made on a large scale yet. More common recycled plastic building materials include:

Tile

You can now purchase tiles made out of recycled plastic including these beautiful tiles made out of discarded fishing nets. 

Lumber

Recycled plastic lumber can now be purchased easily at stores like Home Depot. Plastic lumber is ideal for some projects as it is waterproof, will not rot, is pest resistant, and is very durable. 

Fences

Like recycled plastic lumber, recycled plastic fencing is ideal because it can withstand the elements, is cost effective, and low maintenance. Plastic fencing is popular and can be purchased in many places including here

Roofing

Roofing tiles are also now being made out of recycled plastic. Again, recycled plastic is ideal for roofing as it can withstand the elements, and is long lasting and durable. 

Filler

Plastics that cannot be recycled by being melted down can be shredded and used as filler in things like asphalt and concrete. 

Block and bricks

Some companies are developing recycled plastic blocks. These blocks could one day be used to make cheap, long lasting housing and other structures. These plastic blocks have already been used in installations including this pavilion in Hong Kong made almost entirely out of recycled plastic bricks. 

There are downsides to using plastic construction materials 

One big concern with using recycled plastic materials is that plastic isn’t always fire safe. Most notably, the Grenfell fire in the UK, which tragically killed 72 people in 2017, was caused by combustible plastic materials. When using plastic in construction, it is paramount that only non-combustible, fire resistant plastics be used.

Another concern is that recycling plastic, while good for ridding our oceans and landfills of waste, can create toxic fumes. As plastic is heated up to be melted down, it releases fumes that can be harmful to human health and can contribute to greenhouse gasses. However, the common practice of burning plastic waste, as well as creating new plastics can also cause these effects. 

Recycled plastic construction materials have potential to be a real solution to our waste problem

Recycled plastics are already being utilized in the construction industry with materials like tiles and beams. However, in the future, homes could be made almost entirely out of recycled plastic bricks. If the construction industry can find a way to recycle plastic safely and effectively without creating more carbon emissions and too much virgin plastic, we could see a sizable reduction in ocean bound plastic. Still, the industry has a long way to go to make plastic sustainable. Investment in other building materials like carbon sequestering mycelium, is vital. 

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