Sustainability continues to be a driving force in the specification of contemporary roofing systems.
According to Guaranteed Irish construction member, North West Aluminium (NWA), sustainability continues to be a driving force in the specification of contemporary roofing systems, but when it comes to being green, there is dark green … and there is light green.
NWA continue with a deeper dive into what a “sustainable roofing system” actually means. It becomes clear that it is more about the raw material than any other factor. Nevertheless, factors such as how the system performs over its lifetime and how it’s disposed of at the end of its shelf life cannot be ignored.
A Google search, for example, for “the most sustainable guttering” features the metal aluminium in the top 5 organic results.
Metal, generally, was a preferred roofing system material for centuries, with lead the original flashing detail of choice and likewise, cast iron the guttering/downpipe. But in recent decades, with awareness of the dangers of lead poisoning, lead has lost favour in the roofing industry.
So too has cast iron. While it is often manufactured from a mix of recycled scrap iron, scrap steel pressings and scrap steel casting, and while the resultant cast iron products are themselves 100% recyclable, they are often ruled out by specifiers due to their weight and price. Stainless steel and galvanised steel can also be weighty and pricey.
A plethora of other “sustainable” materials have taken the place of these heavyweight metals, including aluminium (which is 65% lighter than cast iron), steel, copper and zinc, all of which stand out for their formability, durability and aesthetics.
Copper has been installed for centuries, with zinc a more recent option for metal roofing. Both are eminently suitable for sustainable roofing systems but due to their high price point are not as versatile, tending to be restricted to high-end, design-led applications. The other metal products such as steel and lightweight but low-maintenance aluminium have a lower cost point.
Some 80% of the aluminium rainwater systems already in use in the UK have been manufactured from recycled aluminium and aluminium is 100% infinitely recyclable at the end of its life, which is typically substantially more (sometimes double or treble) the 20 years it can be warrantied for. So that’ll be dark green!
All the metal materials are mined to some extent, which in itself could generate a red, rather than green, light for sustainability. Even plastic, which is manufactured from a mixture of coal, natural gas and crude oil, among other ingredients, is not exempt.
While plastic is at a similar price point to aluminium roofing systems, this material is fragile and climate sensitive, not to mention potentially toxic - PVC plastic discharges dioxins which are hazardous to humans and the environment. So that’ll be light green!
North West Aluminium's 5 top tips for specifying sustainable roofing systems: