In the latest of our in-depth interviews, Andrew Gaved discusses the integration of engineering with the social value of sustainability.
As Director of Sustainability and ESG at McBains, Tassos Kougionis focuses on integrating sustainability into both traditional and innovative construction engineering practices. At McBains Tassos had the unique opportunity to establish a new unit from the ground up. Throughout his career, Tassos has worked on UK policy development, advancing, technical buildings and construction standards, best practices, risk and cost in construction, research and implementation all while promoting a vision of a better-built environment.
Since joining McBains in 2021, he has been part of a multidisciplinary team that includes architects, engineers, project managers, urban planners, and cost consultants, all under one roof.
“It’s a privilege to collaborate with such skilled construction experts,” Tassos notes. “This environment allows us to bring together individual expertise and collective excellence to develop new buildings, enhance existing structures, and ensure successful project outcomes.”
Tassos’s academic background supports his holistic approach – it includes civil and structural engineering, environmental engineering and fluid mechanics, energy and sustainability in buildings design, and biomedical engineering, along with over 14 years of UK construction experience.
His team at McBains addresses sustainability considerations across all project stages, with a particular focus on early planning (typically at RIBA stages zero to two). This approach, he notes, marks a significant improvement over past practices, where sustainability disciplines were often viewed separately from engineering and applied retrospectively or abstractly to projects.
Combining disciplines
Tassos explains that sustainability in construction was initially seen as a checklist to meet standards like BREEAM, which created both opportunities and challenges. Involving professionals from various fields, such as humanities, politics, and others, often led to confusion, with engineers feeling their expertise was being questioned by non-engineers. Despite this, sustainability gains from diverse perspectives, which can sometimes blur roles but also encourage creativity and innovation.
“Understanding the role of each discipline and the knowledge required to fulfil these roles is crucial,” Tassos says. “Just as in medicine, where different specialists collaborate, the construction industry can integrate diverse skills to achieve balanced growth and sustainability. However, it’s essential that each role is backed by the appropriate knowledge and expertise to ensure effective outcomes.”
Working with the client
Tassos believes the industry now widely understands the importance of sustainability, ESG, and net zero, but these terms can have different interpretations. Fundamentally, they aim to change standard practices to reduce environmental and societal impacts, he says, and the focus should shift from offering services ‘for the sake of it’ to genuinely adding value.
“As clients aim to lower carbon footprints, a pragmatic and results-driven approach is essential,” Tassos notes. “Everyone wants to commercialise ESG, net zero, and sustainability. The key is achieving measurable impact and integrating these elements into our practices, translating them into best practice.”
While certification sets standards and promotes transparency, Tassos stresses that it’s not just about ticking boxes: “The real value lies in asking the right questions and tailoring our approach to deliver both sustainability and economic benefits,” he explains, “At McBains, this means providing intelligent solutions that improve environmental outcomes and enhance cost efficiency. By minimising material usage, reducing maintenance, and cutting energy consumption, bespoke strategies deliver tangible benefits.”
Recent policy changes have complicated the adoption of sustainable practices too – uncertainty around targets like the 2016 zero carbon homes policy (which never materialised) and delays in implementing new robust standards (notably questions around Future Homes & Buildings) have created confusion, he notes: “Inconsistent messaging from the previous government, especially regarding retrofitting and embodied carbon, has made it hard for the industry to keep up. Clients need a clear value proposition. Strong policies and lifecycle assessments help us identify solutions that meet sustainability goals and provide long-term value, making sustainable practices essential investments, not just perceived added costs. This is also critical for innovation. We have many advanced analytical tools we can use, coming from all science disciplines”.
The importance of data
Monitoring building performance is crucial, but comprehensive, mandatory monitoring is lacking, Tassos contends: “Currently, most buildings only require an energy performance certificate, which provides a snapshot rather than a full picture of performance over time. And while smart meters have been used for the past five or six years, their data often lacks the detail needed for meaningful insights.”
He also stresses the importance of understanding the impact of actions on energy and carbon. “We need to assess whether a building’s energy demand is appropriate and how effective our interventions are. Tools for mapping and discussing energy use in terms of policy are still developing, but clients are increasingly keen to improve their environmental impact. We support them in decarbonisation efforts, such as through Salix funding.”
He underscores the value of long-term monitoring for informed decision-making. “Accurate data tracking helps clients make decisions that comply with regulations and achieve lasting improvements in energy efficiency and carbon reduction’’.
Mind the gap
While all-electric solutions reduce combustion and pollution, Tassos warns that their long-term impacts are often overlooked. “Embracing new technologies isn’t enough – we must consider their entire lifecycle,” he explains. “For example, solar PV panels last about 25 years, but inverters need replacing every 10 to 15 years. Similarly, lithium-ion batteries for home storage last 10 to 15 years, depending on use and conditions.”
This requires planning for replacement logistics and costs, including access for repairs and ongoing maintenance, Tassos adds: “Environmental factors, like corrosion from sea air or wildlife damage, must also be considered. Ignoring these practical aspects can undermine the sustainability of these technologies,”.
A strategic approach involves more than just adopting technologies. “We need to choose the right technologies for each context or consider alternatives, such as leasing equipment or offering ‘sustainability as a service’,” Tassos says. This ensures solutions are flexible, scalable, and aligned with long-term goals.”
Integrating various disciplines is crucial for effective implementation. “Combining engineering with social sciences and economics helps design systems that are technologically sound and socially and economically viable. This means considering the entire value chain, from material supply to end-of-life disposal,” he explains.
Supply chain dependencies are also a critical factor. “Sustainable solutions like heat pumps or electric vehicles may create new global supply chain dependencies. For instance, if we need 600,000 new heat pumps annually, we must ensure a reliable supply of components,” Tassos notes, adding that what is needed is a more holistic, strategic approach to sustainability: “It’s not just about adopting new technologies; it’s about ensuring they offer long-term environmental, economic, and social benefits. We must ensure that our actions are eco-friendly, economically viable, and sustainable in the long term.”
The importance of the supply chain
Tassos reflects on the previous Conservative government’s changes to the national retrofit strategy, which de-emphasised improving building fabric despite heating’s significant role in high energy use: “Improving building fabric was deemed too costly, requiring major investment in scaffolding and planning,” he notes, “Instead, the focus shifted to installing heat pumps. However, without first enhancing building energy efficiency, particularly for those in fuel poverty, high energy bills persist. This issue is worsened by higher electricity prices due to green taxes, while cheaper gas remains a significant carbon emitter. This pricing imbalance may deter the adoption of electric heating solutions.”
The issue extends beyond technology choice to the supply chains supporting these technologies. The Covid-19 pandemic exposed vulnerabilities in supply chains, affecting material availability and skilled labour. “Heat pump manufacturers are innovating with new technologies, but ensuring a reliable supply of materials and skilled labour remains a challenge. The market needs the capacity for installation targets and infrastructure for ongoing maintenance,” Tassos explains.
A flexible and adaptive approach is crucial, therefore, he says: “As a sustainability director, I remain technology agnostic. We must assess each situation individually – considering the client’s specific needs and constraints, available resources, and the technology’s longevity. Even the best technology can fall short if it cannot be properly maintained or does not fit the site’s requirements. Frameworks like PAS 2035 and PAS 2038 promote best practices in energy conservation, ensuring interventions are effective, sustainable, and economically viable.”
Tassos stresses that the approach should go beyond just the technology: “It’s about creating robust, adaptable systems that deliver long-term benefits. This approach supports a sustainable and fair transition that meets both environmental and economic objectives.”
Seizing the retrofit potential
Tassos has been actively working with local authorities, social housing providers, and private stakeholders to integrate sustainability into their projects. These clients deal with a complex mix of regulations, policies, and incentives, such as local plans and National Regulations, he notes: “Our role is to guide these clients through these requirements and support them with both understanding and where possible improving them. We help them develop strategies, submit funding applications, conduct complex assessments, and ensure their projects align with both local needs and broader sustainability goals. Local authorities, in particular, aim to exceed central government’s minimum standards to better serve their communities.”
While national policies provide a baseline, local authorities do have the ability to tailor their approaches to meet specific local challenges, he adds: “Planning inspectors are crucial in examining local plans and upholding them if they are well-justified and align with sustainable growth goals. This collaboration ensures that local insights are considered, promoting positive growth and minimising environmental impact.”
Retrofit remains a critical focus: “Our unit supports a wide range of projects, recognising that both new and existing buildings are vital for a sustainable future. Retrofit, energy-efficient upgrades, and sustainable refurbishments are essential, as they address the majority of the built environment. New buildings must integrate with existing structures, tackling challenges like appearance and infrastructure. Retrofitting is not just about improving efficiency; it’s about creating actions that support a sustainable ecosystem.”
Tassos compares new buildings to seedlings that can be nurtured from the start, while existing structures are like mature forests requiring careful management: “With new buildings, we plan with the future in mind. For existing buildings, we need to revitalise and sustain what’s already there. Both new and existing buildings are essential for a sustainable future. The concept of ‘new’ is about applying our best current knowledge, which evolves into ‘old’ as we progress.”
This approach addresses immediate needs while supporting the broader goal of a resilient and sustainable built environment, he concludes: “We should remember that what is innovative today will be standard tomorrow, which highlight the need for continuous improvement.”
- Tassos Kougionis is on the Advisory Board for our new elementalLONDON show, which launches officially on 9th September. More details here.
