Duncan Rudall, chief executive of the National Federation of Demolition Contractors
When thinking of sustainability in construction, retrofitting is often the topic that is first to mind. The argument is simple: keeping rather than replacing buildings reduces carbon emissions and minimises waste. But, while well-intentioned, retrofitting isn’t always the most practical or long-term-sustainable solution. In some cases, demolition is the best option for delivering energy-efficient, high-quality buildings fit for modern use.
“Conversations around the sustainability of buildings must evolve beyond the ‘retrofit at all costs’ mindset”
An excellent example of this was the controversial plan to demolish the Marks & Spencer store on the western side of Oxford Street. In 2023, communities secretary Michael Gove rejected the plan, citing heritage and sustainability concerns. His decision was quashed in the High Court in March last year and the project was finally approved in December by his successor, Angela Rayner.
The debate about whether to demolish or retrofit the store highlighted the critical issue of sustainability decisions when looking to preserve a building at all costs, taking into account the energy efficiency of the space and what could be done to improve it.
While retrofitting is the current go-to solution when thinking about how to revive old buildings, it is not a one-size-fits-all approach. Many ageing structures suffer from design flaws, making them unsuitable for modern needs.
A study by the UK Green Building Council (UKGBC) found that in some cases, retrofitting an inefficient building could be more resource-intensive than demolishing and rebuilding with low-carbon materials. The World Green Building Council also reported that by 2030, all buildings would have to achieve net zero carbon emissions to meet climate targets, something that would be far easier to adhere to by demolishing and building new spaces rather than retrofitting inefficient structures.
Tipping point
The argument surrounding demolition leading to more embodied carbon is only one part of the equation. Operational carbon emissions, generated throughout a building’s lifespan, may be far more significant to the environment and personal health in the long run. A UK developer, interviewed by the UKGBC, identified that there could come a tipping point where sacrificing embodied carbon to demolish and rebuild something new could be operationally more efficient.
If an old building continues to consume excessive energy due to inefficient systems such as heating and cooling, poor insulation and an outdated layout in a large space, its overall carbon footprint – even as a retrofitted space – could be far less sustainable than a newly built, energy-efficient replacement.
The M&S redevelopment is a prime example of this principle, with the space set to be used for a new store and modern arcade that will revitalise Oxford Street, as well as energy-efficient offices. Ultimately, it’s clear that demolishing the building will not only see energy-efficient developments built in its place, but also more modern upgrades for urban development on Oxford Street.
The conversations surrounding the sustainability of buildings must evolve beyond the current one-size-fits-all, ‘retrofit at all costs’ mindset. Although preserving structures may be the most efficient option in some cases, it is crucial to remember that sometimes demolition can be the more responsible choice, depending on the state and structure of the building. The focus should be on its overall environmental, social and economic performance across its lifespan.
The M&S case serves as a reminder that each building and structure needs to be assessed on an individual basis to determine the best option for efficiency, development and consumer needs.
In the race towards net zero, we need to identify demolition as a legitimate option, weighed up against retrofitting, which is sometimes necessary to achieve sustainable and forward-thinking projects.