British engineers are urging the construction industry to stop demolishing buildings and start re-purposing them instead, also recycling materials as much as possible.
A new report by the National Engineering Policy Centre (NEPC), a partnership of 43 of the UK’s professional engineering organisations led by the Royal Academy of Engineering, says that is the only way to decarbonise the construction sector and reach emission reduction targets.
“The construction sector has already made real progress: the concrete and cement industry has delivered a 53% reduction in absolute CO2 emissions since 1990”, said Dervilla Mitchell, chair, Net Zero working group, NEPC and deputy chair, Arup. “But more needs to be done if we are to be on track to meet the ultimate target of achieving net zero by 2050.”
It is a huge challenge but also a great opportunity for the sector, she said: “It’s a chance to make a fundamental change in our ambitions, processes and social contribution. However, we need immediate action by government, standards bodies, the construction sector and the engineering profession if we are to make it happen.”
The report, titled Decarbonising Construction: Building a New Net Zero Industry, calls for the sector to be given more ambitious emission reduction targets – the same as the national targets of 68% by 2030 and 78% by 2035. This can only be achieved by re-using existing buildings.
Demolition and reconstruction ‘our biggest failure’
“Our biggest failure is that we build buildings, then we knock them down and throw them away,” said Rebecca Lunn, professor, Strathclyde University and one of the report’s authors. “We must stop doing this”.
Demolition should be avoided whenever possible, says the report, and it is particularly important to use existing foundations because often most of the material in an existing building is underground.
When it comes to creating new buildings, net zero should be the priority, which means re-using materials as much as possible, making the design more efficient, and using machinery powered by clean fuels.
The built environment accounts for around 40% of the UK’s carbon emissions. On a global level, construction is responsible for 11% of emissions, particularly because making steel and bricks creates large amounts of carbon dioxide. Cement alone causes 8% of global emissions.
Embodied carbon’s invisibility makes it easy to ignore
Yet people are not aware of the environmental impact of buildings and in particular of the problem of embodied carbon, the report says, because it is “invisible” and easier to ignore.
The Royal Institution of Chartered Surveyors (RICS) estimates that 35% of the lifecycle carbon from a typical office development is emitted before the building is even opened, while the figure for residential buildings is 51%.
The Architects’ Journal has long campaigned against non-essential demolition of buildings and wants the government to change the VAT rules that can make it cheaper to build from scratch than to refurbish and repurpose an existing asset.
“We are committed to reducing emissions from the construction sector, and have set up the Construct Zero programme to support the industry to achieve their climate commitments,” said a spokesperson from the UK government’s Department of Business, Energy and Industrial Strategy .