Why Britain’s Foundations Are Stuck in the Carbon Age, According to the Engineers Who Build Them

Beneath almost every tower, bridge and hospital in Britain lies a hidden reservoir of embodied carbon. Piled foundations, the deep concrete and steel elements that transfer enormous structural loads down to competent strata, are among the most material-hungry components of modern civil engineering, yet they have largely escaped the carbon scrutiny that has transformed superstructure design over the past decade. Now a study from the University of Bath, published in Environmental and Sustainability Indicators, has gone straight to the people who design and build these foundations to ask a deceptively simple question: if low-carbon piles are technically feasible, why is the industry not using them? The answer, drawn from ten senior geotechnical experts, is a story not of missing engineering knowledge but of brakes and accelerators, of commercial gravity, professional liability and risk culture pulling against evidence, collaboration and guidance that could unlock change.

The scale of the opportunity is considerable. The buildings and construction sector accounted for roughly 34 percent of global energy-related carbon dioxide emissions according to the most recent Global Status Report for Buildings and Construction, and the manufacture of cement and steel remains one of the largest sources of industrial greenhouse gases worldwide. As operational emissions fall through better insulation and renewable energy, attention has shifted to embodied carbon, the emissions locked into materials, transport, construction and demolition. Whole-building benchmarking studies suggest that foundations can represent a significant share of structural embodied carbon, particularly where poor ground conditions or heavy loads demand deep foundations. Academic work has already shown that geometric optimisation, ribbed and hollow pile systems, and alternative materials such as timber or concretes incorporating supplementary cementitious materials can cut the embodied carbon of piled foundations by more than 70 percent while still satisfying structural and geotechnical requirements.

Yet the new research reveals a stubborn gap between what is possible in the design office and what happens on site. Kareem Abushama and colleagues, working with Will Hawkins, Loizos Pelecanos and Tim Ibell, conducted semi-structured online interviews lasting 45 to 60 minutes with five geotechnical consultants and five piling contractors, all with between 11 and 30 years of experience and most holding senior technical or managerial roles. Using Braun and Clarke’s thematic analysis, the team distilled the transcripts into twenty codes and seven themes, grouped into two opposing forces they call Brakes and Accelerators. Data collection continued until thematic saturation, with no substantively new themes emerging beyond the tenth interview, lending weight to the conclusion that the concerns expressed are genuinely representative of mainstream UK practice rather than the views of a few outliers.

The most powerful brake, cited by every single participant with 47 mentions, is commercial and temporal priority. Cost, the interviewees reported, accounts for 80 to 90 percent of the weighting at tender stage, and even a 5 percent premium is difficult to justify without a tangible additional benefit. Testing that could validate an innovative design is routinely sacrificed because, as one participant put it, there is just not time before you start on site. Consultants described client expectations and fee competitiveness; contractors described programme risk and construction efficiency. The result is a decision environment in which sustainability ambitions, however sincere, are systematically subordinated to the twin imperatives of lowest initial cost and fastest delivery, unless environmental value is explicitly tied to financial certainty through mechanisms such as carbon taxation or procurement rules.

Just beneath the commercial pressure lies a deeper cultural force: risk, liability and conservatism, which attracted 40 mentions and was again cited by all ten experts. Foundation failure is catastrophic and highly visible, professional indemnity insurance is expensive, and the person who specifies an unproven solution carries the liability if it underperforms. Participants described a pervasive reluctance to be the first to try, with one consultant stating he would need five projects proving a technology before he would be comfortable specifying it, even after five years of testing a novel pile. The industry, several noted, over-designs quite a lot because it is safer and easier to justify to a client. Historical factors of safety of 2.6 to 3.0 and conservative Eurocode partial factors still push designers towards over-compliance, and poor-quality or low-resolution ground investigation data force conservative assumptions that contribute to systematic over-design. One expert explained that limited geotechnical data necessitates conservative design assumptions, which consequently contribute to systematic over-design, a feedback loop that burns carbon simply to buy certainty.

Constructability adds a further layer of friction. Contractors questioned the practicality of complex optimised geometries when standard augers and casings come in 150-millimetre increments, and described quality-control risks when misaligned precast components require extra machinery and labour to correct. Durability loomed equally large: participants expressed deep nervousness about the long-term performance of more exotic concrete mixes over a 120-year design life, and explained why timber piles, despite their carbon-sequestering appeal, are unsuited to Britain’s wet, dry, temperate climate and fluctuating water tables, unlike the preserved piles of Venice or Amsterdam. Market structure compounds the problem, with consultants reluctant to specify a solution that only one contractor can provide because clients want to go to competitive tender, effectively penalising single-source innovations however promising their performance.

Against these brakes, the interviews identified clear accelerators. The most frequently cited, with 37 mentions and unanimous agreement, is the requirement for empirical proof: full-scale testing, documented case studies and official guidance from bodies such as CIRIA, BRE, ICE and the codes themselves. Participants stressed that authoritative guidance is needed to unlock a lot of interest and to convince insurers and warranty providers, who are often the real gatekeepers of innovation. Collaboration and dissemination, cited by all participants with 35 mentions, formed a second accelerator, with practitioners urging researchers to get out on site and watch people building piles to ensure solutions are practical, and recommending trade magazines such as Ground Engineering over long journal papers because they are what the industry actually reads. Practical, accessible design tools, with several participants noting that anything to do with Excel is great, ranked alongside early contractor engagement as prerequisites for translating academic optimisation into routine specification.

The study’s authors argue that the challenge is not a deficit of technical capability but a deficit of trusted knowledge pathways that translate research into design practice. Their proposed roadmap is a coordinated, system-level response: independently funded full-scale testing programmes, potentially through facilities such as Constructionarium, to validate alternative pile geometries and materials under conditions representative of a 120-year design life; transparent design tools that let engineers evaluate embodied carbon alongside capacity, serviceability and cost within standard workflows; and an open-access database of pile load tests and long-term performance data to allow progressive reductions in conservatism without sacrificing reliability or professional indemnity. Policy levers, including embodied carbon caps in public procurement and infrastructure tenders aligned with frameworks such as PAS 2080, would shift decision-making from lowest initial cost towards whole-life value. Responsibilities are distributed across the ecosystem: researchers must generate reproducible evidence on failure modes and boundary conditions, consultants must integrate carbon as a routine design parameter, contractors must validate constructability early and share performance data, and clients, especially in the public sector, must create demand through carbon reporting requirements and value-based procurement.

What makes the findings compelling is their timing. Regulatory frameworks and emerging planning requirements for whole-life carbon disclosure are progressively reshaping the sector, and substructures, historically exempt from detailed carbon scrutiny, are beginning to face explicit embodied carbon reporting and, in some cases, performance thresholds. As those requirements intensify, the long-standing reliance on conservative do-minimum foundations is likely to become commercially and strategically disadvantageous, and the ability to propose optimised low-carbon pile solutions may shift from discretionary innovation to competitive necessity. The Bath team’s verdict is ultimately optimistic: the brakes are entrenched but identifiable, the accelerators are actionable, and with codified innovation, accessible tools, shared data and clear client demand, the industry could move from a lowest-cost paradigm to a whole-life value paradigm, unlocking the substantial carbon-saving potential already demonstrated in the laboratory and the design office, and finally bringing the hidden half of the built environment into the net-zero equation.

Subject of Research: Barriers and enablers to decarbonising deep pile foundations in UK geotechnical practice

Article Title: Barriers and enablers to the decarbonisation of deep foundations in the UK: Insights from geotechnical industry experts

Article References: Abushama, K., Hawkins, W., Pelecanos, L., & Ibell, T. (2026). Barriers and enablers to the decarbonisation of deep foundations in the UK: Insights from geotechnical industry experts. Environmental and Sustainability Indicators, 32, Article 101521. https://doi.org/10.1016/j.indic.2026.101521

Image Credits: AI Generated

DOI: 10.1016/j.indic.2026.101521

Keywords: embodied carbon, pile foundations, geotechnical engineering, decarbonisation, UK construction, net zero, thematic analysis, risk aversion, sustainable construction, ground investigation, piling contractors, whole-life carbon