Retrofit for savvy developers
Article by Naomi Kelsall
Architects' Role in Retrofitting: Bringing Technical Expertise and Creative Solutions to Sustainability Challenges
Mustard Coworking Space
80% of the buildings we will occupy in 2050 are already in existence. That’s why efficient retrofitting is vital in the transition to a net-zero built environment. Kelsall Architects' approach to sustainability and financial viability involves understanding fabric performance to optimise development potential. By giving priority to improvements that provide the most significant energy savings and focusing on long-term benefits such as increased building value and reduced operating expenses, retrofitting can ultimately become a wise investment.
80% of the buildings we will occupy in 2050 are already in existence
Efficient retrofitting of existing buildings is becoming increasingly attractive to developers as material costs continue to rise, and awareness and understanding of embodied energy in building materials grows. However, although the increase in retrofit and conversions is positive from an embodied carbon perspective, it creates technical design challenges to avoid damaging the existing building fabric. Achieving a balance between low energy design, technical detail and financial viability requires architects to deliver creative solutions.
Sustainable retrofit of existing buildings can feel a little like building Whack a Mole, that’s why a more holistic approach must be taken.
Part L of the building regulations is tightening for both new build and refurbishment, but it is insufficient to address the individual elements of an existing building in isolation, as it can unintentionally cause problems elsewhere. For example, internally insulating and increasing air tightness without due regard to thermal bridges and movement of moisture can cause surface and interstitial condensation. This is especially true in historic building retrofits where a delicate microclimate often exists, dependent on air movement and breathable materials. The Sustainable Traditional Buildings Alliance, STBA guidance wheel demonstrates how one element of a building retrofit can impact another. Sustainable retrofit of existing buildings can feel a little like building Whack a Mole, that’s why a more holistic approach must be taken.
STBA guidance wheel
‘The refurbishment of Little Underbank in Stockport involved a balance of thermal improvement and conservation restrictions.’
While the Passivhaus Enerphit Standard is the well known gold standard for whole building retrofit, we understand that achieving this level may not always be financially viable (yet). At Kelsall Architects, we take a practical approach to sustainability and prioritise long-term energy efficiency beyond building regulations. Our guiding framework is the AECB CarbonLite retrofit Standard, which allows us to maximise energy efficiency while balancing economic feasibility. We hope that in the future, the viability of ‘deep retrofit’ will be increasingly common with the role-out of realistic incentives and funding packages. In the meantime, we can ensure that the buildings we work on are ‘retrofit ready’ and take a phased approach that plans for future measures that avoid abortive work and waste, when finance allows.
‘We need to massively reduce operational energy in our buildings, but it is essential that we think retrofit first, new build second…There are substantial embodied carbon savings made in re-purposing existing buildings, compared with the ultra-high embodied energy costs of demolition and rebuild’.
Source: Passivhaus trust
The AECB CarbonLite retrofit standard focuses on addressing heat and moisture issues in buildings to avoid unintended consequences that can arise from repair, insulation, draught proofing, and ventilation. The standard balances costs against performance on each project, with energy targets set as "CO2 prioritised" or "Cost prioritised". This allows designers and developers to pitch the performance of the building on a sliding scale of energy usage and capital cost.
To ensure the viability of retrofit projects, it is essential to understand the easy wins, options, and pitfalls associated with retrofitting. Investing in expertise early in the design process can prevent coordination issues, Planning issues, and on-site issues, ultimately saving time and cost. Kelsall Architects recommends initial surveys and opening up works to understand existing fabric performance, insulation, and cavity widths ensuring that our designs accommodate the nuances of the existing building before committing to a planning application or entering into a contract for construction. This upfront cost can potentially save weeks (and significant £££) in lost time should these risks not be headed off early.
Investing in expertise early in the design process can prevent coordination issues, Planning issues, and on-site issues, ultimately saving time and cost.
The AECB encourages the sharing of performance data of completed buildings in order to better understand and improve upon the performance gap (which is a topic for an article in itself…). Given the rapid changes in standards and technology towards decarbonisation, it is imperative that we learn lessons and share knowledge as we go.
Mustard Coworking Space
Architects are essential to achieving the goal of net-zero retrofit, and as professionals, we must constantly develop our skills and knowledge to advance our field responsibly. While retrofitting inherently promotes sustainability through minimising embodied energy, we also seek to celebrate the unique spaces, details and history of existing buildings, creating extraordinary architecture that honours the legacy of the site. At Kelsall Architects we are passionate about promoting the art of retrofit and maximising the potential of every development.
If you want to talk to us about how you could future-proof your next development please do get in touch, we’ll be happy to help!
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