More contractors should join the ‘Construction Declares’ initiative on carbon reduction, says Hero Bennett
The covid crisis has shifted attention from the biggest risks we face: climate change and biodiversity loss. But the issue hasn’t gone away. Globally we have less than 10 years to halve CO2 emissions. Business as usual is no longer an option.
As an industry the mood is changing, with the Construction Declares movement on the climate and biodiversity emergency launching in 2019 and being supported by architects, building services and structural engineers. Signatories agree to advocate faster change, share knowledge and evaluate all new projects against the aim to contribute positively to mitigate climate and biodiversity breakdown.
After a delay, contractors are now stepping forward to acknowledge the crisis, with BAM, Morgan Sindall, Sir Robert McAlpine, Skanska and Willmott Dixon among the founding members of UK Contractors Declare. But 36 signatories compares poorly with over 1,000 architects.
Personal experience suggests contractors are less knowledgeable about the risks posed by climate change, which include systemic risks to their operations and supply chains. Yet the contractor’s role is significant. The quality of construction on site can be a key component of reducing the ‘energy performance gap’ seen between the designed energy and actual building operational energy consumption.
For example, the quality control process employed on a Passivhaus construction site virtually eliminates unexpected heat loss. Experienced Passivhaus constructors have acknowledged how much they have learned through their Passivhaus projects and that the required processes can reduce a project’s overall risks and associated costs.
Contractors can also significantly influence a building’s embodied carbon, sometimes convincing a client to switch from a low-carbon to a high-carbon product once on board, where cost and construction familiarity is more of a priority than environmental impact. Concrete usually has the most significant embodied carbon impact in a building, though encouragingly, more contractors are becoming comfortable with using low carbon forms of concrete through cement replacements. Contractors can use their close ties with their supply chains to influence behaviour, requiring data on embodied carbon and selecting greener or locally sourced products.
Contractors Declare is a positive movement that I hope will grow and benefit the industry as a whole. We have less than 10 years to make a sizeable dent in the CO2 emissions our industry is responsible for and every one of us has a role to play.
Hero Bennett is principal sustainability consultant at Max Fordham and a member of the CIOB sustainability special interest group