Across all aspects of building design, architects constantly face the challenge of balancing the creative with the practical. Their work needs to combine aesthetic appeal and some level of context with the local built environment. It may also need to make a statement, create a landmark or articulate the prestige of its purpose. Meanwhile, practical considerations not only include cost and length of programme, but also buildability, ease of maintenance and length of service life.

As buildings become more complex, sustainability considerations take higher priority and legacy costs and management increasingly influence design choices. It’s the role of the construction supply chain to develop new products that fuel creativity, practicality and sustainability for architects. By re-thinking traditional materials to pioneer practical alternatives with a comparable aesthetic, the supply chain can open up new design possibilities for architects to transform roofs into jaw-dropping features.

Copper vs synthetic

Copper has been a versatile and prestigious building material for centuries. Eye-catching, hard-wearing and recyclable, it ticks lots of boxes for both aesthetics and practicality. But amongst its many advantages, there are some significant issues with specifying copper as a construction material in any sizeable quantity. Indeed, when it comes to designing a roof, the pitfalls of specifying copper can sometimes outweigh the benefits.

The first – and often biggest – issue is cost. Copper is a material that will offer excellent longevity, but it can substantially increase the build costs of a project. Using a synthetic alternative costs 50 to 60% less per square metre, which, for a larger roof area, equates to a saving of thousands of pounds.

The high monetary value of copper also creates risk for the building owner following completion. Like lead, copper is often stripped from buildings to be re-sold. For example, at Leigh Road Baptist Church in Leigh-on-Sea, thieves stole the copper used to refurbish the spire just before the scaffolding was removed. It was a devastating blow to the congregation, who had raised £20,000 to pay for the project. To protect the church from further incidents of theft, the spire and cupola were then refurbished using Soprema’s Flagon Copper Art. The synthetic waterproofing membrane has provided high performance and the appearance of copper at a lower cost and risk.

Collateral damage

The potential for copper theft not only has an immediate financial impact; it can also have longer-term consequences too. When copper is stripped off by thieves, the building may suffer additional damage and, with the copper gone, water ingress can cause more costly issues with the substrate and the internal areas.

Alongside the cost of replacing the copper is the impact on insurance premiums. Following one incident of copper theft, a premium is likely to rise. If the theft recurs, it may become uninsurable. By comparison, a synthetic membrane is more difficult to remove and, as it has no value as a scrap material, it is not attractive to thieves.

Comparing performance

For many architects, copper’s natural ageing over time is one of its attractions, but for the building owner, the patina that develops and changes the appearance of copper features is not always considered a benefit. If the client prefers a copper appearance that will retain its freshly-built aesthetic for decades, a synthetic membrane, impregnated with copper particles for a genuine copper appearance, provides a durable and high-performance alternative.

A synthetic membrane is also more temperature-stable than traditional copper. The natural expansion and contraction of copper can result in distortion to the roof or copper feature in hot or cold weather conditions. During the summer months, copper’s natural property as a conductor can also increase the building’s solar gain, which may affect indoor temperatures and cooling load requirements.

Buildability and design potential

While copper is a soft and malleable metal, it cannot provide the flexibility of a synthetic roofing membrane, which will flex to any shape, including complex curves. The membrane can also be cut to accommodate the contours of any building design.

What this means for architects is limitless design possibilities for using ‘copper’ as an exterior feature of the building, while providing a high-performance and durable waterproof surface with an extended service life. Flagon Copper Art is suitable for either fully-adhered or mechanically-fixed installations, and can be installed as a standing seam roof with joints hot-air welded onto the membrane following installation. For example, the cupola at the Baptist Church in Leigh-on-Sea was installed as eight triangular pieces of membrane with standing seam joints installed to complete a perfectly symmetrical feature.

Looking to the future, referencing the past

Whether the design ambition is a complex structure, copper-clad vertical surfaces, a wave-form roof or a conceptual building that plays with form and materials, a synthetic alternative can be used to offer all the aesthetic advantages of copper, combined with the versatility of a flexible, durable waterproof membrane.

There will always be a place for traditional construction materials but, just as architects are pushing the boundaries of traditional building form and function with innovative design, the construction supply chain must innovate to provide versatile new materials.