For a building's facade to be successful, everything from the structural engineering to the intricate detailing needs to be closely scrutinised. Choosing the correct cladding is a tricky process that involves taking the durability and versatility of certain materials into account. These days, architects and designers are also required to use sustainable, environmentally friendly materials as stringent regulations limit the use of hazardous chemicals. To cater for these demands, designers are turning to coil-coated products to create high-quality environmentally sound facades.
Coil-coated metals are made through a highly efficient production process where coiled metals - primarily steel and aluminium - are unwound on an automated production line and the strip metal passed through various processing stages. Following cleaning and pretreatment of the strip, primer and topcoats are applied and cured before it is recoiled. The correct selection of pretreatment, primer and topcoat systems provides a high-quality and durable surface finish to the metal.
For Terry Goodwin, sustainability director at the European Coil Coating Association (ECCA), these sophisticated processes are the result of years of experimentation and innovation. "The industry has been operating in Europe for over 50 years and during that time the process has been refined and improved," he says. "Architects now have a range of colours at their disposal, from metallic finishes and solid colours to suit their demands."
Vibrant colours and weathered rustic finishes are available, while the prepainted metal can be formed into fluid shapes, allowing architects and designers to achieve unique, expressive designs.
Whereas, previously, designers had to worry about climate conditions and city pollution damaging the exterior of these buildings, novel alloy coatings and anti-corrosion primers mean that these colourful facades can remain in pristine condition for over 40 years.
"Because the coating is done on a continuous processing line, there's a really good consistency in terms of product quality and product uniformity," Goodwin says. "The application of the primer coat and the top coat means that the products are now anti-corrosive and highly durable."
Environmental legislation has been a driving force for the industry, particularly in Europe, as REACH and other organisations have prohibited the use of hazardous chemicals. One of these is chromate, a chemical previously used as an anti-corrosion chemical, which has been banned on account of its potentially carcinogenic effects. This has led to the creation of much safer alternatives.
"People in the industry have developed no-rinse technology," Goodwin explains, "which is where you use a roller to apply a small amount of liquid to the strip. That effectively forms your conversion layer without having large amounts of liquid flying around. So you don't need to rinse anything off. It's a very controlled methodology for applying the chromate-free pretreatment to the metallic substrate."
This has coincided with a move to cut down solvent emissions, as curing ovens used to dry the paint have become more energy efficient. Solvents are captured and used as fuel in a self-sustaining method that destroys over 99% of the emissions once the process is complete.
As a non-profit association dedicated to spreading the benefits of coil-coated metals, the ECCA is awarding a premium label to high-quality products made with sustainable, eco-friendly methods.
"It's not just about guaranteeing the performance of the product, but also the ingredients and way the product is made," Goodwin says, "and that's a concept that is gaining traction in the market right now."