A sustainable construction ethic isn’t a luxury any more, we really need to rethink our building practices and aims to make sure they’re as environmentally friendly as possible. It’s a need, not a want.
The National Institute of Building Sciences tells us, in its Whole Building Design Guide, that US buildings use up 39 per cent of America’s energy and 68 per cent of its electricity. Buildings also give out 38 per cent of the country’s carbon dioxide, a shocking 49 per cent of its sulphur dioxide and a quarter of the nitrogen oxide. Most of these emissions are from non-renewable fossil fuels.
One of the main ways we can reduce the heating, lighting and cooling demands of our buildings is to use construction and design methods that respond to the environment and climate. We need high-performance cladding on roofs and walls, we need to think about how to use our space differently, so that our structures use less energy, and maybe even generate it.
A building material that’s set to rise in popularity is zinc. Zinc is the earth’s 23rd most abundant element. It’s rust and corrosion-resistant, weatherproof, ultra violet light proof and even earthquake proof. This means it can offer decades of service with virtually no degradation.
Its durability is down to the layer of zinc hydroxyl-carbonate that the metal forms upon exposure to the air. This layer prevents any more water or air getting to it, and if the layer is removed, it just grows back. This is why a zinc wall or roof often lasts for a century.
Zinc also uses very little energy to make, and the fact that it’s virtually maintenance-free and 100 per cent recyclable makes it an attractive option. Zinc never ends up in landfill as it just gets used again.
The metal was once in demand by builders and architects in Europe, as they knew it could withstand the hard winters there. It found favour in America in the late 18th century, and buildings like the Washington Monument were built with zinc roofs.
Then came the 1960s, when everything from razors to roofs became disposable. Builders wanted asphalt shingles because they were cheap – it didn’t matter that they had a life expectancy of 30 years. This throw-away attitude is a thing of the past now, as we want durability and sustainability.
We’re seeing zinc appearing on government and commercial buildings in the US now, and it’s also finding a place on people’s homes. Many progressive architects are encouraging clients to use metal cladding made of zinc, whether it’s for a new build or a restoration.
There are cheaper metals than zinc – aluminium and copper, for example, but even so, zinc wins out in the long run.
Most other metals need a topcoat that can be scratched off, and they tend to last only a third as long as zinc.
Copper has significant run-off, which can contaminate soil and discolour its surroundings. Zinc’s run-off doesn’t do this – there is more zinc in any given soil sample than there is from the run-off from a zinc roof.
So, think zinc!