Preserving heritage and embracing sustainability
Daniel Ross, Associate Director at Harley Haddow, explains why decarbonising existing buildings is crucial for the UK’s climate goals.
As the climate crisis intensifies, we need to preserve our existing buildings wherever possible through retrofitting or decarbonisation. Knock it down and start again has too often been the damaging default within our industry. With the construction industry’s crucial role in achieving climate targets, we know we can’t build our way to Net Zero.
The UK has the oldest building stock in Europe with 5.9 million buildings built more than 100 years ago, underscoring the scale and importance of the issue. Many of these buildings represent a significant roadblock on our journey to meet important climate milestones whilst also being at risk of becoming a stranded asset.
But what does decarbonising mean?
Decarbonising refers to the reduction or removal of carbon dioxide from the environment. For the built environment, this relates to in-use energy and construction. Therefore, to decarbonise we must reduce both our energy use and our construction impacts.
To achieve true decarbonisation within our sector, we must focus on decreasing this impact.
With Net Zero an increasingly fraught and important topic, we must ask how do we decarbonise existing buildings? A common assumption is often that we should knock down existing buildings and start from scratch, which isn’t always the case. As the climate crisis intensifies, we need to preserve our existing buildings wherever possible through retrofitting or decarbonisation. Something we often see successful evidence of, specifically in Scotland, is the many churches, schools and older office buildings that have undergone these modifications to better the building and make use of its existing structure.
However, it is vital that decarbonisation methods are better utilised and continue to be enforced. As part of the Scottish government’s £20 million public sector heat decarbonisation fund, which launched last year, £11 million has been awarded to seven projects across Scotland, including Edinburgh University. This is evidence of a positive move in the right direction. In a further bid to cut carbon emissions, the Scottish government introduced a £230 million fund late last year to improve the energy efficiency of public buildings which will be available to schools, hospitals, leisure centres and other public buildings. To date, 1,000 buildings are already receiving updates, resulting in them saving thousands of pounds on energy bills.
Previously, there has been a real lack of financial support for decarbonising buildings in the UK. To see a fund for these buildings is positive and is a step the engineering industry welcomes. However, we are still at risk of falling short of our Net Zero trajectory. The industry is crying out for further funding or financial incentives targeted towards developing the skills and infrastructure we need to decarbonise existing buildings at scale.
Decarbonisation and retrofitting explained
Retrofitting is modifying an existing building to reduce energy consumption. Doing this avoids the carbon emissions that come with demolition and building from scratch, in particular the large amount emitted from cement and steel produced by construction.
Decarbonising means reducing the amount of carbon emissions across the entire building’s lifecycle, from start to finish, by reducing energy and materials used.
There are several ways to decarbonise existing building stock such as implementing fabric first, smart controls and renewable energy. However, no one size fits all and every project should be assessed on a case-by-case basis through data gathering and informed decision making.
Having a fabric first approach is also essential when it comes to reducing energy demand. Considering the materials used in the early design stage will help identify how to conserve heat. This includes identifying what materials are used for the building structure such as walls and how the roof of the building will perform when conserving heat.
Having a building fit to keep the heat in will reduce the need for energy as most of it will be stored with less chance of it escaping.
What’s holding us back?
The lack of workforce is a key challenge in the industry and our ability to achieve Net Zero. Recruitment across engineering is proving to be tough but with the introduction of this new Scottish government fund, there may be an opportunity for new jobs and training in green skills.
Obviously, not every single building can be decarbonised. Whilst there rightly should be a focus on older buildings, decarbonisation expands to wider areas such as schools and public and private sector buildings, which aren’t always decades or centuries old. Additionally, legislation continues to develop as we are advancing industry knowledge on carbon emissions reduction technology and practice.
The upcoming Net Zero Carbon Building Standard (expected in 2024) should play a pivotal role in pushing the whole life carbon agenda with regulators, which will hopefully drive retrofitting to the forefront of development.
To assist the upcoming regulations, many call for VAT relief on retrofitting to trigger the financial incentives. Under the current financial system, it is common to pay the 20% VAT on retrofit but not on a new build which is a huge financial barrier to retrofit developments and results in developers feeling pushed to knock down old buildings and start again. Whilst this is good for reducing operational energy, it has a detrimental effect on embodied carbon, as material used in the current building will go to waste, resulting in use of more carbon intensive materials to build new.
Time to speed up
With the Scottish government rethinking its target of achieving 75% reduction greenhouse gas emissions by 2023, now is not the time to slow down. We should be accelerating. Achieving Net Zero is a major driver for most of us in the industry, however, many are shying away from environmental responsibility due to lack of knowledge or hesitation to move with the times. The news of this potential target change shouldn’t be a sign to put the brakes on but a catalyst of accelerated effort towards reaching Net Zero by 2045 in Scotland.
The engineering industry must push forward and drive decarbonisation throughout various buildings across the UK and debunk this ideology that we must knock down and start again. There are tried and tested methods to better our buildings to enable us to reach approaching climate timelines, but we need to take charge to adapt and utilise them.
As businesses are obliged to publicly declare their annual carbon emissions, we see more ESG lead demands on the built environment, which hopefully aligns and aides us to travel in the right direction towards Net Zero.
Castle upgrade
Harley Haddow was involved with developing a sustainable heating strategy at Rosslyn Castle, one of Midlothian’s most important historic buildings. The entire building is now Net Zero-ready, with heating and hot water provided by six air source heat pumps, removing the need for traditional fossil fuels. The heat pumps are situated in the castle’s 16th century vaults. Harley Haddow believes that Rosslyn Castle may be the oldest building in the world to be using this sustainable, low carbon technology.
