What advancements in paint mean for the future of sustainable construction. By Dr Aidan Bell

When it comes to combating environmental issues within construction and engineering, paint is often overlooked as something that can contribute as an option of sustainability. Across a variety of commercial and residential industries in fact, paint is typically not associated with sustainability in any manner. Principally this is because it is not a naturally occurring product, now growing concerns about the chemicals used in paint impacting negatively on the environment and our health are driving a shift in paint technology and the availability of sustainable paint within the industry. This has the ability to help change the construction industry as forward thinking early adopters begin to implement its use into projects globally, from the Norwegian parliament building and the International School of Berne, to Brighton Jubilee library.

Modern paint ingredients
Over the last few decades, it’s fair to say the construction industry has not paid much attention to the factors that qualify paint as a sustainable product. There are three parts in consideration here, ingredients, breathability and production.

Ingredients of paint can be further broken down into colour (in pigment), a binder and a carrier (disperses the binder). All of these are made with toxic chemicals in the majority of modern paint, such as cadmium, lead, and chromium in pigments; solvents, petrochemicals, formaldehyde, ammonia and other volatile organic compounds (VOCs) in binders and carriers. Further environmentally harmful and toxic chemicals are also found in modern paints such as stabilisers, thickeners, and driers.

VOCs are organic gas compounds that are given off by paints. They evaporate easily in the atmosphere, contain solvents and are known to be a major contributor to global climate change. Many VOCs are highly toxic and linked with health problems including respiratory disease, asthma, eczema, nausea, eye irritation, liver and kidney damage.

Thankfully, the government already regulates how much VOC is in paints forcing conventional paint companies to significantly reduce their gas compound content. However, when a company says their product is environmentally friendly because they are low-VOC, this simply means they meet regulations and despite being low, paints continue to emit VOCs many years after their application, something that is hard to regulate on large construction projects. Another common misrepresentation is paint labelled water-based, as it’s often diluted with water but still made from acrylic resins.

In addition to the harmful chemicals, modern paints contain plastic, which when applied creates a plastic barrier trapping air which can lead to a variety of problems, including mould. Sustainable paints negate this problem by being ‘breathable’ as a result of using only natural ingredients.

If a company claims to be sustainable, the ingredients list will be able to provide evidence displayed on the paint pots or available upon request. However, as paints are so often misleading in their naming structure, it is difficult for construction companies to take responsibility for the sustainability implications of using damaging products in projects.

Lime and clay based paints
Lime and clay based paints have been available for some time now and are a popular alternative to other harmful paint choices. As the name suggests, these paints are made from natural lime or clay which offers several consumer health and environmental benefits over plastic based counterparts. The porous nature of the paint means surfaces can breathe, plus lime based paints can act as an absorbent surface for carbon dioxide, which gives the added benefit of purifying the surrounding air preventing damp and condensation. This breathable property combined with the naturally high alkaline pH of lime prevents the growth of microorganisms, bacteria and fungi.

Sustainable paints on the market
In large construction or smaller consumer based projects, there are several factors to consider when looking for sustainable paints. It’s important not to forget that the way in which paint is produced has an environmental impact so consider the company’s carbon footprint as well as the product to establish a truly sustainable product.

A few popular sustainable paint products already exist within the market, including paints from Edward Bulmer and Auro. Edward Bulmer is currently setting the level, pioneering natural paint manufacturing methods. The company is transparent with all of its ingredients, comprising of plant, animal and mineral sources, and proudly boasts a carbon neutral production.

Auro’s sustainability effort goes one step further with its production process completed within a carbon-neutral factory, which uses harvested rainwater and is powered on solar energy. Auro paints never use plastic or oil, instead they favour natural ingredients such as coconut fat, rapeseed oil, linseed oil and sunflower oil, with a full transparency on ingredients listed on their product.

What is the future of sustainable paint?
Graphene
The first paint using graphene was launched in the UK last year by Graphenstone, claiming it to be the most eco-friendly paint in the world. The current Graphenstone range is 98 per cent lime-based, available in a 1000 colours for both indoor and exterior use.

As far as materials go, graphene is something impressive. It was discovered in 2004, is sourced from pure carbon and is the strongest material known to science. The addition of graphene in paints and coatings improves tensile strength, hardness, durability, makes the covering highly inert and reduces the weight of materials. As well as improving structural properties, graphene fibres added to the paint form a transparent mesh that makes the paint finish extremely long-lasting. This also increases the coverage of the paint, meaning one litre will cover two 8m2 coats, providing considerable savings in large construction projects. Both factors reduce the necessary labour and paint, contributing to offsetting the carbon footprint on the project as a whole.

Furthermore, graphene has superconductivity; in fact, it is 1000 times more conductive than copper meaning the paint improves the thermal regulation of buildings. For example, instead of heat being radiated through the walls when it is used on the interior, graphene paint will capture heat and conduct through the paint across the whole surface of the walls. This heat conduction property acts as an insulation measure, ultimately saving energy on heating.

The advantages of Graphenstone paint are already being seen around the world in various construction projects from the Hotel Vela, in Barcelona to the Sixth People’s Hospital in Jinan, China and in restoration projects like The Cellar and Winebar project in Spain.

Solar paint
Although still in the early stages of research, the team from the Royal Melbourne Institute of Technology (RMIT) have developed an extraordinary paint which can absorb moisture from the air and turn it into hydrogen fuel for clean energy, that could be commercially available in approximately five years.

‘Solar paint’ combines titanium oxide, which is the white pigment already common in wall paint, with a new synthetic compound called molybdenum-sulphide. This compound acts much like silica gel to absorb moisture and prevent damage.

This material has the added properties of a semiconductor, which means in combination the paint has the ability to absorb solar energy and moisture from the atmosphere, catalyses the splitting of water atoms into hydrogen and oxygen and collect hydrogen for use in fuel cells.

Of course, the potential for this technology is incredible. It could turn any brick wall exposed to water vapour into fuel producing real estate. Furthermore, this isn’t limited to damp climates; the solar paint will also be effective in a hot and dry climate near oceans, where vapour coming from the nearby sea water can be absorbed as it evaporates in the heat.

The application of this sustainable paint technology could work hand-in-hand with solar, covering areas that previously would receive enough sunlight to justify solar panels. Realistically any surface that can be painted, such as a garage, fence or shed could contribute toward the building power generation.

When will we see this adopted?
As the world becomes wiser to the environmental implications of the use of unsustainable materials in construction and engineering, these ecologically viable options will not only become more popular, they will become a mandatory requirement. As legislation changes to reflect the increasing importance of environmental measures in construction, early adopters of sustainable alternatives will find themselves at an industry advantage.

Dr Aidan Bell is one of the founders of sustainable construction company, EnviroBuild, a manufacturer of green building supplies and construction materials for the domestic and commercial markets in the UK and Europe. EnviroBuild actively supports the Rainforest Trust and Ocean Cleanup, donating ten per cent of its profits to sustainable causes.
For more information, please see www.envirobuild.com