Why embodied carbon is now the priority for developers
As operational energy performance improves — driven by tighter Part L requirements, heat pump adoption, and grid decarbonisation — embodied carbon is accounting for an increasing share of a building's whole life carbon footprint. For new developments targeting net zero carbon, getting embodied carbon right is no longer optional.
The RICS Whole Life Carbon Assessment 2nd edition, published in 2023, provides the methodology framework for embodied carbon assessment in the UK. Its adoption across institutional development programmes has accelerated significantly in 2024 and 2025, driven by planning requirements, funder expectations, and NZCBS alignment.
Where the hotspots actually sit
Across development programmes we have assessed, the pattern of embodied carbon hotspots is consistent — and often surprises design teams who have focused solely on structural frame carbon:
Structural frame and foundations — as expected, reinforced concrete frames and piled foundations carry significant embodied carbon. However, the margin between concrete and steel frame options is often smaller than assumed when full lifecycle analysis is applied.
Façade and cladding — curtain walling, cladding systems, and glazing consistently represent 15-25% of total A1-A5 embodied carbon. Specification decisions here have disproportionate impact.
MEP systems — mechanical and electrical plant is frequently underweighted in early-stage assessments. Chillers, AHUs, and electrical distribution carry material embodied carbon that is often not captured until detailed design stage — too late to influence specification.
Fit-out — for Cat A and Cat A+ commercial office developments, tenant fit-out (lifecycle stage B5) can exceed the structural frame in embodied carbon terms over a 60-year assessment period. This is rarely discussed in planning submissions.
Design decisions that move the needle
Based on assessments across office, industrial, and mixed-use schemes, the interventions with the highest embodied carbon impact per pound of additional cost are:
Concrete specification — moving from CEM I to blended cements (CEM II/III/IV) in structural concrete delivers 20-40% reductions in concrete embodied carbon with minimal cost premium. This is the single highest-impact low-cost intervention available on concrete frame buildings.
Façade glazing ratio — reducing glazing ratio from 60% to 40% on office façades reduces both embodied carbon (less aluminium and glass) and operational energy (reduced solar gain and heat loss). The challenge is architectural — but the carbon and energy case is compelling.
Reuse of existing structure — where feasible, retaining and adapting existing structural elements delivers embodied carbon savings that no new-build specification can match. The RICS WLCA framework now requires explicit consideration of retrofit versus demolition and rebuild.
Timber in non-structural applications — mass timber structural systems receive significant attention, but the more broadly applicable opportunity is timber in non-structural applications — internal partitions, raised floors, and ceiling systems — where like-for-like substitution for steel and concrete delivers consistent reductions.
What good assessment practice looks like
The most common failure mode in WLCA assessments is late engagement — assessments commissioned at RIBA Stage 4 when specification is largely fixed. The RICS guidance is clear that assessment should begin at Stage 1 and be updated at each RIBA stage gate.
Practical minimum requirements for a credible WLCA:
- Whole life carbon assessment covering A1-A5, B1-B7, and C1-C4 stages
- Explicit treatment of the retrofit versus demolition decision where applicable
- Sensitivity analysis on key specification variables
- Alignment with NZCBS embodied carbon limits where certification is sought
NZC Consultants provides RICS Whole Life Carbon Assessments for new developments and refurbishments. Get in touch to discuss your project.