Richard Besant, Sales Director for Powdertech (Corby) Ltd, discusses the benefits of working with aluminium. Powdertech, the architectural metal finishing company, was established in 1988 and is a leading industry supplier. Richard's Co-Director Giles Ashmead is ex-chair of the Aluminium Finishing Association (AFA) and also an ALFED (Aluminium Federation) council member.
"Using aluminium in a construction project is one of the most responsible and cost-effective decisions you can make, and one which provides enormous flexibility in terms of application and appearance.
The 'Greenest' Building Product
Aluminium is the most abundant metal in the earth's crust, found as bauxite or alum in most common rocks . It is easily recycled and loses none of its properties in the process since refining does not alter its atomic structure. A 'bank' of aluminium is being built up for use in current and future buildings and typically a new building will use 45% recycled aluminium. With no loss of strength or integrity, just over 97% percent of aluminium from a building is recyclable. It has been calculated that the recycling process uses over 90% less energy than that used to extract new aluminium from its sources.
Of the aluminium produced since it was first extracted for commercial use in 1880, it is estimated that 75% is still in use today. This is a remarkable statistic and of huge importance when considering sustainability in building. Wood may be regarded as an environmentally sound building material but it cannot better the sustainability figures for aluminium; one million tonnes of wood waste is sent to landfill each year.
Aside from recyclability there are other factors enhancing the credibility of aluminium as the "greenest building product". Aluminium roofs reflect 95% of solar energy striking the surface. It can therefore be used in "green buildings" to contribute to cooling efficiencies or for energy conservation where heat is reflected back towards the interior. In terms of waste, the small amount of aluminium that is disposed of will not pollute the air, water or soil.
Space, weight and time
Around 20% of the world's aluminium is used in construction, a purpose for which it is admirably suited given its light weight combined with its strength. The use of aluminium in the construction industry can be summed up in three words - 'space, weight and time'. With aluminium, an architect can expand the space of a building, reduce the weight of any structure and speed up the construction process. Using different alloys, aluminium structures can weigh between 40% and 80% less than steel whilst providing equivalent strength. City skyscrapers could not be built without it - the Empire State Building was the first major building to use this material. The lighter structures mean that transport and erection on site are easier and quicker.
Aluminium is used widely across the construction industry in components such as curtain wall and window systems, rolling blinds, doors, wall panels, exterior cladding, roofing and solar shading. It is also used for design elements, such as balustrade, cappings, soffit and feature panels and interior support structures such as stairs, handrail and column casing.
Appearing in many different guises
Aluminium is unparalleled in its versatility of appearance through anodising and powder coating. Powder coating protects the metal from the environment and prevents corrosion. It does not detract from the 'green' credentials of the metal as the coatings are free of solvents and VOCS and there is no hazardous waste. Furthermore powder coating can be removed with no detrimental effect so recyclability is not affected. The different finishes add design value in differentiating the surface and suiting it to purpose, as well as offering protection to the underlying metal.
At Powdertech (Corby) Ltd we offer a range of finishes for aluminium. These include architectural polyester powders, PWF (Powdertech Wood Finish), Plascoat (a thermoplastic coating) and Powdertech Anomatch (a range of finishes that closely resemble architectural anodising.) Each finish has its own particular features and benefits. Over 2000 colours are available and most colours have 3 gloss levels; matt, satin and full gloss. Many are also available in textured finishes. Most manufacturers have special house colours and finishes such as levels of texture, metallic, hammer finishes and feel which can be made up to specification.
Thermoplastic powders have a built in advantage in the level of grip the surface offers, and the ‘warm to touch’ feel. There are powders with ‘anti-graffiti properties’ through incorporation of a polymer making the resulting surface especially resistant to paint. There are also ‘self-cleaning’ powders with a hydrophobic surface that sheds rain water, taking dirt and grime with it. More recently, some designers have returned to the more organic and natural look of stone, terracotta and copper, and powders have been developed to suit this trend. In this category, Powdertech Wood Finish (PWF) gives the appearance of wood to a metal structure.
Looking to the future, we are finding that new enhanced architectural powder coatings for aluminium are being developed continuously, expanding the versatility of this abundant, sustainable metal yet further within the building industry."