Abstract
This dissertation examines how public and private procurement rules influence material selection in construction and, consequently, the whole-life carbon (WLC) profile of the built environment. Through a systematic literature synthesis, the research analyses the mechanisms by which procurement frameworks shape design decisions, material specifications, and carbon outcomes across building projects. The findings demonstrate that procurement rules function as powerful determinants of what gets built, with mandatory WLC reporting, low-carbon material thresholds, and preferential scoring for bio-based materials producing measurably lower embodied and whole-life emissions. Evidence from municipal timber procurement initiatives in Finland and low-carbon concrete policies in the United States reveals reductions in embodied carbon of approximately fourteen per cent compared with conventional construction. The analysis identifies critical rule design elements, including system boundary definitions, evaluation criteria, and risk allocation mechanisms, that determine whether procurement processes reward or penalise low-carbon solutions. The dissertation concludes that procurement rules do not merely select between finished proposals but actively script which materials and carbon trajectories become financially viable, positioning procurement reform as an essential lever for construction sector decarbonisation.
Introduction
The construction industry bears substantial responsibility for global greenhouse gas emissions, contributing approximately thirty-eight per cent of energy-related carbon dioxide emissions when both operational and embodied carbon are considered (United Nations Environment Programme, 2022). As operational energy efficiency improves through enhanced building regulations and technological advancement, attention has increasingly turned to embodied carbon—the emissions associated with material extraction, manufacturing, transportation, construction, maintenance, and end-of-life treatment. This shift in focus has elevated the importance of whole-life carbon assessment as a comprehensive metric for evaluating the environmental impact of buildings.
Procurement represents the critical juncture at which project parameters are established, material selections are constrained or enabled, and carbon trajectories are effectively determined. The rules governing procurement—whether in public tenders or private development frameworks—establish evaluation criteria, acceptable materials, performance thresholds, and contractual obligations that cascade through design and construction processes. Despite this pivotal role, procurement has received comparatively limited scholarly attention as a mechanism for construction decarbonisation, with research historically concentrating on technical material innovations and operational performance standards.
This gap in understanding carries significant practical implications. Governments and major institutional clients possess substantial market power through their construction expenditure, yet frequently deploy procurement frameworks that inadvertently favour carbon-intensive solutions by prioritising upfront cost minimisation or employing narrow system boundaries in environmental assessment. Conversely, jurisdictions that have reformed procurement to incorporate whole-life carbon criteria demonstrate measurable shifts toward lower-carbon material selections and building systems.
The academic significance of this research lies in its integration of procurement theory, life cycle assessment methodology, and construction management practice to illuminate how institutional rules shape environmental outcomes. Socially, the research addresses the urgent imperative of reducing construction sector emissions to meet Paris Agreement targets and national net-zero commitments. Practically, the findings offer actionable guidance for policymakers, procurement professionals, and industry stakeholders seeking to leverage existing market mechanisms for decarbonisation.
Aim and objectives
The primary aim of this dissertation is to critically examine how procurement rules influence material selection in construction and thereby shape the whole-life carbon profile of buildings.
To achieve this aim, the following objectives have been established:
1. To analyse the mechanisms through which procurement frameworks influence material and structural system choices in building projects.
2. To evaluate the impact of different system boundaries and evaluation criteria on carbon outcomes in procurement decision-making.
3. To examine case evidence of policy and market mechanisms that have successfully redirected construction toward lower-carbon materials and systems.
4. To identify the critical elements of rule design that determine procurement effectiveness in achieving whole-life carbon reductions.
5. To synthesise findings into recommendations for procurement reform that can support construction sector decarbonisation.
Methodology
This research employs a systematic literature synthesis methodology to investigate the relationship between procurement rules and whole-life carbon outcomes in construction. Literature synthesis represents an appropriate methodological approach when the research objective involves integrating findings from diverse studies to develop comprehensive understanding of a phenomenon, particularly where primary data collection would be impractical given the scope and complexity of the subject matter (Snyder, 2019).
The synthesis draws upon peer-reviewed journal articles, government policy documents, and reports from recognised international organisations. Sources were identified through systematic searches of academic databases, including Scopus, Web of Science, and Google Scholar, using search terms combining procurement concepts (procurement, tendering, bidding, purchasing, commissioning) with carbon-related terminology (embodied carbon, whole-life carbon, life cycle carbon, GWP, carbon footprint) and construction sector descriptors (buildings, construction, materials, structures).
Inclusion criteria required sources to address explicitly the intersection of procurement processes and carbon outcomes in construction contexts, to be published in English, and to derive from peer-reviewed journals, government bodies, or recognised international organisations. Exclusion criteria eliminated sources focused exclusively on operational carbon without reference to embodied emissions, sources addressing procurement in non-construction contexts, and sources from non-authoritative websites or commercial publications.
The analytical framework organises findings according to four thematic categories: material prescription and preference mechanisms; evaluation criteria and system boundary effects; policy and market mechanism outcomes; and rule design determinants. Within each category, evidence is synthesised to identify patterns, contradictions, and gaps in current understanding.
Methodological limitations include the reliance upon secondary sources, which precludes direct investigation of procurement processes, and the geographical concentration of available evidence in European and North American contexts, which may limit generalisability to other regulatory environments. Nevertheless, the synthesis methodology enables comprehensive integration of disparate evidence streams to address the research objectives.
Literature review
Whole-life carbon in construction: conceptual foundations
Whole-life carbon assessment encompasses all greenhouse gas emissions associated with a building throughout its existence, from raw material extraction through manufacturing, transportation, construction, use, maintenance, and eventual demolition or reuse. The methodology derives from life cycle assessment principles codified in ISO 14040 and ISO 14044 standards, with construction-specific guidance provided by EN 15978 in Europe and similar frameworks internationally.
The standard modular structure divides building life cycle stages into product stage (modules A1–A3, covering raw material supply, transport, and manufacturing), construction process stage (modules A4–A5, covering transport to site and construction-installation), use stage (modules B1–B7, covering use, maintenance, repair, replacement, refurbishment, and operational energy and water use), and end-of-life stage (modules C1–C4, covering deconstruction, transport, waste processing, and disposal). Module D addresses benefits and loads beyond the system boundary, including reuse, recovery, and recycling potential.
Huang et al. (2024) emphasise that comprehensive whole-life carbon assessment requires consideration of both embodied and operational emissions, noting that as building energy efficiency improves, the relative significance of embodied carbon increases substantially. For highly efficient buildings, embodied carbon may constitute sixty to eighty per cent of total life cycle emissions, fundamentally altering prioritisation in design and material selection.
The establishment of national baselines and reference values has emerged as essential infrastructure for whole-life carbon regulation. Izaola, Akizu-Gardoki and Oregi (2023) developed baseline values for average Spanish residential buildings, demonstrating that standardised references enable meaningful comparison and target-setting in procurement contexts. Similar baseline development has occurred across European jurisdictions, establishing the data foundations upon which procurement criteria can operate.
Procurement as a determinant of material selection
Procurement rules establish the parameters within which design teams operate and against which proposals are evaluated. These parameters extend beyond simple cost comparison to encompass material specifications, performance requirements, environmental criteria, and contractual obligations that collectively shape what is technically and financially feasible.
Material prescriptions and green preferences represent the most direct mechanism through which procurement influences construction outcomes. Blasco et al. (2021) analysed school building procurement across Finnish municipalities, finding that tenders explicitly requiring or favouring wood as a structural material decisively shifted projects toward timber construction, overriding default concrete and steel practices that would otherwise prevail. The research demonstrates that procurement language possesses performative power—specifying materials in tender documents does not merely describe preferences but actively produces different building outcomes.
Municipal strategies that promote timber as a primary construction material have generated measurable portfolio-level effects. Talvitie et al. (2025) examined two socio-economically similar districts in Helsinki, one developed under conventional practices and one under timber-promotion policies. The timber-focused district demonstrated approximately fourteen per cent lower embodied carbon than its conventional counterpart, providing quantitative evidence that sustained procurement preference translates into aggregate carbon reductions across building stocks.
In the United States, policies mandating low-carbon concrete and materials in public works have altered mix designs, specifications, and contract structures throughout the supply chain. Assaad (2023) examined these low-carbon material initiatives, documenting how procurement requirements propagate upstream to manufacturers and downstream to construction practices. The analysis reveals that procurement rules do not operate in isolation but reshape market conditions and industry capabilities over time.
System boundaries and evaluation criteria
The system boundary selected for carbon assessment in procurement exercises profoundly influences which options appear preferable. Patel, Feng and Ruparathna (2025) demonstrate that when procurement evaluates only upfront cost or cradle-to-gate impacts (modules A1–A3), higher-carbon options frequently appear superior and win bids. This occurs because materials with lower initial embodied carbon sometimes carry higher purchase prices, while materials with superior whole-life performance may involve greater upfront investment.
Moving to cradle-to-grave or whole-life carbon criteria fundamentally changes which solutions score best. A design that appears worse when assessed at the gate can prove superior when the full life cycle is considered, including maintenance requirements, replacement cycles, and end-of-life scenarios. This temporal dimension of assessment creates significant implications for procurement rule design—narrow boundaries systematically disadvantage options with front-loaded costs and distributed benefits.
Dynamic life cycle assessment approaches reveal additional complexity by considering the timing of emissions rather than treating all carbon releases as equivalent regardless of when they occur. Hart, D’Amico and Pomponi (2021) compared steel, concrete, and timber structures using whole-life embodied carbon methodologies, demonstrating that timber and other bio-based systems often achieve lower whole-life carbon and faster climate benefits when the temporal value of emission reductions is incorporated. Hawkins et al. (2021) similarly found that dynamic climate modelling produces different rankings than static assessment, with timber structures showing particular advantages when near-term emission reductions are valued appropriately.
These methodological considerations carry direct procurement implications. Ruta, Pittau and Masera (2024) argue that achieving zero-carbon buildings requires reversing the material pyramid—shifting from carbon-intensive structural materials toward bio-based alternatives—but note that this shift only occurs where procurement explicitly values whole-life carbon and the timing of emissions.
Policy mechanisms and market effects
Multiple policy mechanisms operate through procurement to redirect construction toward lower-carbon outcomes. Mandatory whole-life carbon reporting and limits represent the most comprehensive approach, requiring design teams to calculate and demonstrate compliance with carbon budgets across the full building life cycle. Kanafani et al. (2023) examined construction sites in Denmark, finding that comprehensive carbon accounting including construction process stages (A4–A5) captures emissions frequently overlooked in simplified assessments and creates incentives for lean logistics and low-waste construction methods.
Low-carbon material thresholds establish maximum global warming potential (GWP) values for specific material categories, most commonly concrete and steel. Jezzini and Assaad (2024) modelled the impact of such thresholds on bidding dynamics, finding that GWP limits alter strategic behaviour throughout the tender process. Bidders must either source compliant materials or invest in alternative structural systems, with competitive advantage accruing to firms that have developed low-carbon supply chains or design capabilities.
Preferential scoring for timber and biogenic materials operates through evaluation frameworks rather than absolute requirements, awarding additional points to proposals incorporating bio-based construction. This mechanism increases the share of timber and other bio-based structures without mandating specific materials, preserving design flexibility while creating systematic advantage for low-carbon options. Evidence from Hart, D’Amico and Pomponi (2021) and Ruta, Pittau and Masera (2024) supports the carbon logic underlying such preferences, demonstrating that bio-based materials typically offer substantial whole-life carbon advantages when properly specified and constructed.
The inclusion of transport and construction stages (modules A4–A5) within procurement assessment boundaries rewards lean logistics and efficient site practices. Robati, Daly and Kokogiannakis (2019) developed uncertainty analysis methods for whole-life embodied carbon in Australian contexts, finding that construction process emissions vary substantially between projects and can significantly influence total carbon outcomes. Procurement frameworks that include these stages create incentives for prefabrication, local material sourcing, and construction waste reduction.
Enablers and barriers to green procurement adoption
Research consistently identifies regulation and client requirements as the primary drivers of green procurement adoption in construction. Wong, Chan and Wadu (2016) examined enablers of effective green procurement in construction projects, finding that mandatory requirements outperform voluntary initiatives in achieving behavioural change. Their empirical study identified top management commitment, government legislation, and client requirements as the most influential factors, with voluntary sustainability aspirations proving insufficient to overcome established practices and cost pressures.
Shen, Zhang and Zhang (2017) reached similar conclusions in their analysis of green procurement determinants in Chinese real estate development. Regulation emerged as the dominant driver, with market factors and organisational capabilities playing supporting roles. The research highlights that construction industry actors respond primarily to binding requirements rather than aspirational guidance, suggesting that voluntary procurement reforms will achieve limited impact without regulatory reinforcement.
Clear standards, data availability, and established baselines enable practical implementation of whole-life carbon criteria in procurement. Without standardised methodologies and reference values, procurement officials lack the technical basis for specifying requirements or evaluating compliance. The development of national databases, default emission factors, and benchmark values has therefore proved essential preconditions for procurement reform across jurisdictions (Huang et al., 2024; Izaola, Akizu-Gardoki and Oregi, 2023).
Contract forms and risk allocation mechanisms shape how aggressively bidders pursue low-carbon solutions. When contractual responsibility for meeting carbon targets rests with contractors, incentives align for ambitious material innovation. Conversely, when carbon outcomes are treated as aspirational rather than contractual obligations, competitive pressure drives bidders toward proven solutions regardless of carbon implications. Assaad (2023) and Jezzini and Assaad (2024) document how risk allocation in low-carbon procurement affects bidding strategies and ultimately construction outcomes.
Discussion
The synthesised evidence demonstrates that procurement rules function not merely as selection mechanisms among completed proposals but as active determinants of what becomes thinkable and financially viable in construction projects. This finding carries profound implications for construction sector decarbonisation, positioning procurement reform alongside technical innovation and regulatory mandate as essential policy levers.
Procurement as performative practice
The research evidence reveals procurement’s performative quality—the capacity of procurement rules to produce the outcomes they purportedly merely select. When Finnish municipalities specify timber preferences in school building tenders, they do not simply choose among pre-existing proposals but reshape the design possibilities that teams develop. The fourteen per cent embodied carbon reduction observed in Helsinki’s timber-focused district represents not the selection of inherently superior options but the production of options that would not have existed under conventional procurement frameworks.
This performative dimension suggests that procurement reform offers multiplicative rather than additive benefits. Each tender incorporating whole-life carbon criteria not only produces a lower-carbon building but also develops design team capabilities, establishes supply chain relationships, and demonstrates technical feasibility—effects that propagate to subsequent projects regardless of procurement requirements. The distinction between procurement as selection and procurement as production fundamentally reframes the policy opportunity.
System boundary effects and unintended consequences
The evidence regarding system boundary effects raises significant concerns about current procurement practice. Where procurement assesses only upfront cost or cradle-to-gate carbon, structurally perverse outcomes become probable—options that appear preferable under narrow assessment prove inferior across the full life cycle. This finding suggests that well-intentioned environmental criteria may produce counterproductive outcomes when poorly designed.
The temporal dimension adds further complexity. Static assessment treats carbon released during material manufacture as equivalent to carbon released during eventual demolition, ignoring the atmospheric physics that make near-term reductions more valuable than distant ones. Dynamic life cycle assessment approaches address this limitation but require additional methodological sophistication in procurement frameworks. The research suggests that procurement rules should not only expand system boundaries but also incorporate temporal weighting where feasible.
The regulation-voluntary action interface
The consistent finding that regulation and mandatory requirements outperform voluntary initiatives challenges assumptions underlying many current green procurement programmes. Voluntary commitments, sustainability policies, and aspirational targets appear insufficient to overcome established practices and cost pressures in competitive tendering environments. This evidence supports regulatory approaches to procurement reform, including mandatory whole-life carbon limits, required use of environmental product declarations, and binding contractual obligations for carbon performance.
However, the relationship between regulation and voluntary action is not simply substitutional. Voluntary programmes may serve valuable functions in developing technical capacity, testing methodological approaches, and building political support for eventual mandatory requirements. The evidence suggests that effective decarbonisation strategies should employ voluntary initiatives strategically while pursuing regulatory reforms as the primary mechanism for achieving scale.
Data infrastructure and institutional capacity
The emphasis across multiple sources on standards, baselines, and data availability highlights procurement reform’s dependence on supporting infrastructure. Procurement officials cannot specify whole-life carbon requirements without standardised assessment methodologies, cannot set meaningful limits without baseline reference values, and cannot evaluate compliance without accessible emission factor databases. Jurisdictions that have successfully implemented whole-life carbon procurement have typically invested substantially in data infrastructure before or concurrent with regulatory reform.
This finding suggests that technical assistance and capacity building represent essential complements to procurement policy reform, particularly in jurisdictions with less developed life cycle assessment ecosystems. International knowledge transfer and harmonisation of methodological approaches may accelerate implementation by enabling jurisdictions to leverage infrastructure developed elsewhere.
Implications for achieving research objectives
Regarding the first objective—analysing mechanisms through which procurement frameworks influence material choices—the evidence identifies material prescription, preference scoring, and contractual requirements as primary mechanisms, each operating through distinct pathways to produce different outcome patterns.
The second objective—evaluating system boundary impacts—is addressed through evidence demonstrating that narrow boundaries systematically disadvantage options with superior whole-life performance, with significant implications for procurement design.
The third objective—examining case evidence of successful policy mechanisms—is satisfied through analysis of Finnish timber procurement, US low-carbon concrete initiatives, and Danish construction carbon accounting, each demonstrating measurable carbon reductions through procurement reform.
The fourth objective—identifying critical rule design elements—is addressed through evidence highlighting system boundaries, evaluation criteria, data availability, and risk allocation as determinant factors in procurement effectiveness.
The fifth objective—synthesising recommendations—is enabled by the integrated evidence base, though specific recommendations require interpretation appropriate to jurisdictional contexts.
Conclusions
This dissertation has examined how procurement rules shape material selection in construction and thereby determine whole-life carbon outcomes in the built environment. Through systematic literature synthesis, the research has demonstrated that procurement functions as a powerful lever for construction sector decarbonisation, with properly designed rules producing measurable reductions in embodied and whole-life emissions.
The research objectives have been achieved through analysis demonstrating that material prescriptions, preference scoring, and whole-life carbon limits operate as distinct but complementary mechanisms for redirecting construction toward lower-carbon materials and systems. Evidence from Finnish timber procurement and American low-carbon concrete initiatives quantifies the carbon reductions achievable through procurement reform, with Helsinki’s timber-focused district demonstrating approximately fourteen per cent lower embodied carbon than conventional comparators.
System boundary definition emerges as a critical determinant of procurement effectiveness. Rules assessing only upfront cost or cradle-to-gate carbon systematically disadvantage options with superior whole-life performance, potentially producing outcomes worse than would occur without environmental criteria. Expansion to cradle-to-grave boundaries and incorporation of temporal emission weighting address these limitations and align procurement incentives with genuine decarbonisation objectives.
The consistent finding that mandatory requirements outperform voluntary initiatives suggests that procurement reform requires regulatory support to achieve scale. Voluntary programmes may serve developmental functions but cannot overcome competitive pressures that drive bidders toward established, typically carbon-intensive, solutions. Effective decarbonisation strategies should therefore pursue mandatory whole-life carbon limits, required environmental product declarations, and binding contractual obligations alongside technical assistance and capacity building.
The significance of this research extends beyond academic contribution to practical policy application. Governments and major institutional clients possess substantial market power through construction expenditure, and procurement reform offers a mechanism for leveraging this power toward decarbonisation without requiring new technologies or substantial public investment. The evidence synthesised here provides the analytical foundation for such reform while identifying design elements critical to effectiveness.
Future research should address several limitations and gaps identified through this synthesis. Longitudinal studies tracking procurement reform impacts over extended periods would illuminate whether observed effects persist and accumulate. Comparative research across jurisdictions with different regulatory and market contexts would enhance understanding of contextual factors affecting procurement effectiveness. Investigation of supply chain responses to procurement reform would reveal how material producers adapt to changing demand signals. Finally, research into optimal system boundary and temporal weighting approaches for procurement contexts would support methodological refinement in policy implementation.
The built environment constitutes a substantial component of global carbon emissions, and its decarbonisation represents an essential element of climate change mitigation. Procurement rules actively script which materials, systems, and carbon trajectories become viable in construction. Where rules mandate whole-life carbon assessment, establish appropriate limits, and reward bio-based and low-carbon options, the result is measurably lower emissions in the building stock. The evidence presented here supports procurement reform as a necessary and effective component of construction sector decarbonisation strategy.
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