f there is one word that has characterised the construction sector over the past decade, it’s ‘sustainable’. Unfortunately, as with many terms that are over-used and misrepresented, it’s a word that has lost much of its meaning during that time, becoming a generic label that is often used as a catch-all alternative to ‘environmentally-friendly’.
The problem is that a truly sustainable project needs to go much further than using environmentally responsible building materials; a sustainable project needs to ensure that eco-specification and the reduced carbon footprint of a scheme can be sustained over the long term.
How long should a building last?
While the lifespan of a building is usually an influence in its design and specification, a greater influence is often its ‘working life’ taken to mean the period for which the building will be used for its intended purpose, with reasonable maintenance but without major repair. As a result, the anticipated working life of many buildings is around 20 years: in a world with limited resources and a construction industry that claims to put sustainability at its heart, that’s simply not long enough!
Part of the problem is that legislation surrounding the topic of sustainability is primarily focused on a building’s services installation and thermal performance, rather than its long-term viability. So, while specifiers must consider Part L as a mandatory element of building design, there is no such mandatory requirement to ensure that the fabric of the building will still be fit for purpose 10, 20 or 50 years down the line.
Instead, the lifespan element of a building’s sustainability is viewed as more of a commercial consideration. Consequently, the longevity and long-term performance of construction materials are weighed against their purchase cost to determine the specification strategy instead of being prioritised as a key element of the building’s sustainability credentials.
Roofing contractors can – and do – influence this commercial specification approach, however. While there may be pressure on the contractor to stay within spec and within budget, demonstrating the long-term benefits of a system that is designed to offer a prolonged service life, greater adaptability if future changes are required and reduced maintenance can help the contractor to upsell to a higher specification at little or no extra cost, in addition to improving the sustainability of the building.
Effective overlay
For refurbishment projects, the first indicator of whether a roofing system contributes to the building’s sustainability is whether or not a strip out of the existing substrate will be required.
Overlaying an existing sound structure and coverings not only reduces the length of the programme but also prevents strip out waste from being sent to landfill, limits impact on the building and occupants and contributes to sustainability when carried out to a high standard with due consideration for achieving optimum service life by using materials that are compatible with the existing substrate and each other. For example, if the requirement is for upgraded insulation and new waterproofing, it’s essential that the waterproofing membrane is compatible with the new insulation and the selected attachment system components are compatible.
The roof build-up should always be specified in line with the manufacturer’s recommendations and best practice guidelines and each component should be able to demonstrate an extended service life as a component of the overall roof system. An EPDM membrane, for example, will last up to 50 years – much longer than the designed working life of many buildings extending the building’s lifespan. The extended waterproofing service life can only be achieved if the complete system comprising membrane, accessories and substrate used all offer long-term performance.
Sustainable service life
The environmental impact and embedded carbon of any construction material are important specification considerations but service life is also critical. Too often, too much emphasis is placed on meeting criteria set out by Building Regulations and initiatives without sufficient regard for genuinely reducing average carbon footprint and waste by specifying buildings that last longer. Surely it’s now time we started building longevity into mandatory sustainability requirements as well as forward-thinking cost strategies?
