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What is the most sustainable formwork?
As the construction industry strives to be more environmentally friendly, an increasing amount of importance is being placed on the sustainability of the materials that are used. In terms of formwork, the main choices are plywood (timber), plastic-faced formwork, or metal. Each of these materials have their own advantages and disadvantages. Yet when it comes to sustainability, which is the best option?
How Sustainable is traditional Plywood/Timber Formwork?
Timber is often considered a green material as it sequesters carbon and is also renewable. Whilst timber is a greener choice for some applications, this needs to be balanced against the considerable environmental impact of deforestation to harvest the material and the waste created from plywood formwork.
In terms of advantages, plywood formwork stores harmful carbon within the material itself, protecting the environment. It can also be harvested and produced locally, so that the material does not have to travel so far to the site – which saves emissions from transportation vehicles. In addition, it is lightweight and easy to handle, meaning less heavy plant is required on site to transport and place it.
On the other hand, increasing demand for timber products is driving deforestation and illegal and unsustainable logging, as well as creating an ecological imbalance. According to the World Wildlife Foundation, trade in forest products has increased significantly in the last 50 years, with illegal logging representing 40–50% of all logging in some of the most valuable and threatened forests on Earth. As forests store large amounts of carbon, destroying these areas contributes to global warming by releasing carbon into the atmosphere – in fact, 15% of global greenhouse gas emissions are caused by deforestation. Biodiversity loss is a further consequence of deforestation, as approximately 80% of the Earth’s wildlife live in forested areas.
The energy requirements to produce timber products are also higher than they may appear for a natural material. To process raw timber into a useable product, a large amount of energy is used to dry and refine it into various forms. In the case of formwork, this involves further processing, such as creating plywood sheets. Timber formwork also has a limited lifespan, being suitable for only 30-50 uses before the material is too worn and must be replaced. Unfortunately, because of the glue used within the plywood, it is unable to be recycled and needs to be treated as hazardous waste.
How sustainable is plastic-faced formwork?
Plastic-faced formwork includes a smooth polypropylene face that is attached to a steel frame. It is one of the most commonly used types of formwork, next to plywood. It offers better longevity, but is still a petroleum-derived plastic.
In terms of advantages, plastic facing is both durable and sustainable. Not only do the panels last longer than plywood, but they can also be easily repaired without affecting the performance should they get scratched or perforated – unlike plywood, which has a finite lifespan.
For example, our alkus® all-plastic facing can be used up to 1,500 times – a considerable increase in comparison to plywood and up to six times more than many other plastic panels. Not having to continually re-order and replace formwork by being able to re-use or repair existing stock saves time and money, as well as raw materials. This increased longevity is a significant contributor to sustainability efforts.
A common concern is whether plastic formwork can be installed as easily as wooden formwork, which provides a high degree of flexibility. However, plastic formwork is just as adaptable. Just like plywood, plastic-faced formwork can be nailed and screwed together, and then repaired if needed for the next application. Cleaning the panels for re-use is simple – they can withstand high-pressure washing of up to 1000 bar (14,000psi), and because they are impervious to moisture, they will not warp or rot whilst in storage.
That said, there is a drive to reduce the amount of plastic we use, as plastics take a long time to biodegrade, can create microplastics which harm wildlife, and are derived from unsustainable sources such as crude oil and natural gas. In addition, there is also a low recycling rate of plastic in some countries, and plastic pollution and litter can be a further problem.
However, the polypropylene that is used in plastic-faced formwork, such as our alkus® all-plastic facing, is easy to repair and recycle without releasing any toxic chemicals during the recycling process. Polypropylene also consumes the least amount of energy during production, therefore producing the lowest carbon dioxide emissions when compared to other plastics. Our alkus® panels are also fully polypropylene with a smooth polypropylene face and polypropylene foam core, unlike other products which are simply plywood sheets with a plastic facing.
How sustainable is metal formwork?
Metal formwork is another option, often made from aluminium. While this means that the metal must first be mined, refined, and then transported to site, it offers excellent longevity compared to plywood. It is extremely robust, and the lightweight nature of aluminium makes it easy to handle on site, so fewer emissions are generated from plant and machinery.
Supporting sustainability
The keys to sustainable formwork are reducing our reliance on short-lived products and re-using existing formwork over longer periods – both of which can be achieved with plastic facing such as our alkus® solid plastic panels or metal formwork. However, regional differences in availability can mean that in some cases, plywood formwork is the more sustainable option. At MEVA, we offer a range of sustainable formwork options to support our customers with their unique requirements.
