Executive summary
Embodied carbon is the greenhouse gas impact of materials and construction across a project's life, from manufacture to end of life. It forms part of whole-life carbon alongside operational impacts. Developers, designers and contractors should check the planning requirements, client brief and assessment method before comparing options. Early estimates help challenge quantities and design choices; later assessments should use specified and installed evidence. A focused materials review can identify choices and gaps, but its agreed scope is narrower than a full whole-life carbon assessment. [1, 2]
Start here
Confirm the required assessment method, then test retention, reuse and quantity reduction before choosing substitute materials.
In plain terms
A project's carbon account has stages called modules: A covers work before use, B covers use, and C covers end of life. Module D reports potential effects beyond that boundary separately. Embodied carbon concerns materials and construction; operational energy and water are separate. [1, 2]
Where the emissions sit
| Modules | Plain-English meaning |
|---|---|
| A0-A5 | Upfront: pre-construction, products and construction. Under RICS, A0 is normally zero for buildings but can matter for infrastructure. [1] |
| B1-B5 | Product effects in use, maintenance, repair, replacement and refurbishment. [1, 2] |
| B6-B7 | Operational energy and water, separate from embodied carbon. [1, 2] |
| C1-C4 | Deconstruction, transport, processing and disposal. [1, 2] |
| D, separately | Potential benefits and loads beyond the boundary; not a guaranteed future saving. [1, 2] |
Check the applicable method
The Royal Institution of Chartered Surveyors (RICS) whole-life carbon assessment standard, second edition, Version 3, is effective from 1 July 2024. RICS members undertaking assessments must follow its requirements and identify departures. [1]
London Plan policy SI 2(F) requires assessments for referable development. Use the Greater London Authority (GLA) guidance and template, including its specific departures from the RICS method; do not assume the latest RICS edition alone satisfies a London submission. [2]
The UK Net Zero Carbon Buildings Standard is voluntary. Version 1 appeared in March 2026 and verification opened in July. [3]
Biogenic carbon is carbon absorbed by plants and stored in materials such as timber. RICS reports this stored carbon separately from upfront carbon. Module D also stays separate. [1]
Recommended actions
A practical way to start, with suggested owners and timing:
Define the assessment
Record the project, method, modules, units and study period (the years assessed). Confirm the planning or contractual purpose.
Client and assessor, before commissioning
Challenge demand and quantities
Record retention, reuse and quantity-reduction options before considering material substitutions.
Design lead, before fixing the solution
Build the evidence register
Link quantities to Environmental Product Declarations (EPDs), source dates, coverage and assumptions; flag generic estimates.
Commercial and procurement teams, at specification
Check equivalent performance
Record quantity conversions, service lives, losses, scenarios and exclusions. A declared unit is an amount of product; a functional unit also describes the service it provides. [4]
Assessor and design lead, before selection
Update the assessment and check changes
Replace assumptions with specified or installed evidence. Explain changes from the previous assessment and approve the final comparison.
Project manager, each gateway and completion
Example in practice
Illustrative example: two wall options must provide the same fire, thermal and structural performance over the agreed study period. A lower product-stage figure can be outweighed by extra quantity, replacement or operational impacts. Record these assumptions before making a choice. [4]
Common mistakes
- Starting with substitutions: test retention and quantity reduction first.
- Matching units only: also check function, service life, modules and scenarios.
- Deducting Module D from the lifecycle total: report it separately and explain uncertainty.
How Reinventives can help
Our embodied carbon review can produce a materials-evidence register and an options summary for an agreed part of a project. We organise quantities, check data coverage and highlight assumptions and gaps. Full asset assessments, engineering decisions, EPD production and independent verification require the appropriate specialist scope and appointment.
Sources and review dates
- 1.RICS, Whole life carbon assessment, second edition, Version 3, 2024; standard and official guidance.
- 2.GLA, Whole Life-Cycle Carbon Assessments guidance, March 2022; sections 1-2 and Box 1.
- 3.UK Net Zero Carbon Buildings Standard, Version 1 and verification information, 2026.
- 4.BRE, PN514 to EN 15804+A2, revision 3.1, 30 November 2023; section 5.3.
Sources accessed and correct as of 9 September 2026.
Next scheduled review 9 December 2026.
Review on RICS, GLA or Buildings Standard changes, and before a new planning submission or assessment brief.
This briefing is general information, not legal, procurement, engineering or assurance advice. Check requirements for the specific organisation, project and contract.