The construction industry is flourishing – the ONS placed construction output in the UK at its highest level since September 2019. But this brings with it environmental challenges.
This should not be confused as a slight on the construction industry at large or the thousands of hard-working employees in the sector. The development of new buildings will always be an essential requirement for any flourishing society. The issue at hand is the whole-scale redevelopment of perfectly adequate buildings, driven by neither sustainability nor user needs.
For those new to the debate surrounding redevelopment versus retrofitting, retrofitting involves maintaining the existing structure of a building and gutting out the inside to replace energy inefficient and outdated interior elements. Meanwhile, redevelopment involves the demolition of an existing structure and construction of a completely new one on-site.
The argument made for redevelopment is often that the existing structure of a building inhibits a sustainable design, therefore, increasing carbon emissions from the site. However, this argument ignores the significant impact of demolition and construction.
Let’s take a deeper dive into the facts and science at hand.
The Built Environment – where does the carbon come from?
Of the 47% of annual global CO2 emissions for which the built environment is responsible, there are two main categories: building operations (27%) and building materials and construction (20%) – typically referred to as “embodied carbon”.
Operational carbon incorporates the total carbon emitted as a result of the building's energy usage. While embodied carbon refers to the carbon emitted as a result of the construction, maintenance, and waste management of the site. Crucially, it also incorporates the carbon released as a result of demolishing the existing site.
One of the great benefits of redevelopment is that the new site is likely to have a much lower operational carbon output. However, not only can a similar reduction be achieved via retrofitting but for the statement ‘redevelopment is a more sustainable option’ to be true, the energy saved as a result of the improved efficiency of the site must become equal to or greater than the energy emitted via embodied carbon. In essence, it takes a significant time for the benefits of redevelopment to be seen.
A similar concept that may be more familiar is payback time. If you were to replace your household filament bulb with a new LED bulb you would save money – let’s say, £5 a year – on your energy bills because the LED is a more efficient device. However, the LED had an initial cost of £10. Therefore, the payback time would be two years – it would take two years for your initial investment to be returned through the savings in your energy bills. The money you save is seldom returned instantly.
𝑃𝑎𝑦𝑏𝑎𝑐𝑘 𝑡𝑖𝑚𝑒= 𝐶𝑜𝑠𝑡 𝑜𝑓 𝑛𝑒𝑤 𝑑𝑒𝑣𝑖𝑐𝑒/𝑌𝑒𝑎𝑟𝑙𝑦 𝑠𝑎𝑣𝑖𝑛𝑔𝑠 𝑎𝑠 𝑎 𝑟𝑒𝑠𝑢𝑙𝑡 𝑜𝑓 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 = £10 (£5 per 𝑦𝑒𝑎𝑟 = 𝑡𝑤𝑜 𝑦𝑒𝑎𝑟𝑠)
The same is true for redevelopment. Yet in this example, the initial cost of the LED is the embodied carbon, and the money saved via efficiency is the difference in operation carbon.
𝑇𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛 𝑡𝑜 𝑎𝑐ℎ𝑖𝑒𝑣𝑒 𝑐𝑎𝑟𝑏𝑜𝑛 𝑛𝑒𝑢𝑡𝑟𝑎𝑙𝑖𝑡𝑦 = 𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑜𝑛𝑎𝑙 𝐶𝑎𝑟𝑏𝑜𝑛 / 𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑜𝑛𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑜𝑓 𝑜𝑙𝑑 𝑠𝑖𝑡𝑒−𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑜𝑛𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑜𝑓 𝑛𝑒𝑤 𝑠𝑖𝑡𝑒
Redevelopment is never more sustainable than retrofitting in the instance – it takes time for the sustainable impacts to take effect. However, the great contradiction hidden in the example of redevelopment is that the payback time takes several decades if not more; often beyond the lifespan of the building.
Even ignoring this fact, the embodied carbon impact of redevelopment dwarfs that of retrofitting. Fundamentally, the most effective way the built environment can reduce its egregious carbon impact is to start making better use of the space it already has. An equally important facet in achieving this end is ensuring we have adapted to the new ‘working normal’.
Flexibility is key
Covid-19 changed the way we view working patterns forever. The Monday-Friday office routine has been largely rejected for a more flexible home/office balance that accommodates the varied requirements of life, as well as the longstanding trend towards greater work-life balance.
With most office-based employees only going in a fraction of the week, the demand for permanent office space is rapidly decreasing. A study commissioned by infinitSpace among 200 office landlords revealed that 62% are struggling to secure traditional tenants, an even greater number (64%) said that they had witnessed a notable shift in the demands of existing and prospective tenants. Workspaces must adapt to meet these needs – flexible workspaces are indeed the key to achieving this.
With the dual pressures of climate change and the fundamental shift in working patterns following the global pandemic, the future of the built environment lies in flexibility and sustainability.
We must be emboldened to identify situations in which retrofitting is the more sustainable, sensible and economical solution. Moreover, the issues of the environment and the changing face of work are as much a short-term concern as a long-term one; we must champion solutions that upgrade existing sites with the latest sustainable technology and the infrastructure to allow for flexible working.
