Mat 01 - Building life cycle assessment

Clarification of ‘Embodied carbon benchmark comparison’ - KBCN1819

The embodied carbon benchmark comparison must always be based on the latest appropriate LCA stage that corresponds to the BREEAM assessment stage being pursued. The purpose of the benchmark comparison is to assess outcome-based embodied carbon performance, using data that is representative of the building at the relevant assessment stage.

Assessment stage requirements

Interim (Design Stage) BREEAM assessments

Where an interim / design stage assessment is being submitted:
- The benchmark comparison may be based on a Technical Design LCA, where this represents the latest LCA available at that stage.
- Benchmark results at this stage are indicative and intended to support design decision-making.

Final Post-Construction Stage (PCS) BREEAM assessments

Where a final post-construction stage (PCS) assessment is being submitted:
- Benchmark comparison credits can only be awarded where a Post-Construction Stage (PCS) LCA has been completed.
- A technical design LCA alone is not sufficient to support benchmark comparison credits at PCS.
- This is because the PCS LCA is the only assessment that reflects the materials and products actually installed in the completed building, and therefore the only suitable basis for outcome-based benchmarking.

If a PCS LCA is not undertaken, benchmark comparison credits cannot be awarded at final assessment, regardless of whether a technical design LCA was previously completed. This aligns with wider industry frameworks (e.g. RICS WLCA v2 and the UK Net Zero Carbon Buildings Standard), which anchor performance claims to as-built outcomes.

Early design phase LCA submission – Modified planning applications - KBCN1893

Requirement In the Mat 01 Methodology, M1.2 requires the early design phase LCA to be completed and submitted to BREEAM within 20 working days of submission of the planning application. Intent This requirement is in place to ensure that the LCA is carried out during the early design stages and can meaningfully influence material selection and key design decisions, before the planning application fixes significant aspects of the external specification. The timeframe of 20 working days post-planning submission is a concession to allow project teams to collate the LCA evidence for submission to BREEAM. Submission of the planning application In this context, this is the application that specifies and fixes the external products and materials that are considered in the LCA. By default, this is considered as the first application. However, it may also be:

A supplementary modified application, where a staged submission process is used

A replacement modified application, due to a major redesign

Where the requirement is applied to a supplementary or replacement application, the project team must provide additional evidence to demonstrate that the intent is met. Additional evidence

Confirmation of the date of the original planning application and the date of the modified application.

A description of what the modified application changes, with reference to the relevant submission documents.

Evidence that the modification significantly affects external products or materials specification, e.g. revised elevations, façade specification, external material schedules

Justification of how the early design LCA submitted in relation to the modified application was still capable of influencing relevant design decisions

Erratum – UK NC V7 – Mat 01- Table 9.2: LCA Study Periods - KBCN1830

In Table 9.2: LCA quality requirements: Item 9, the study period should be 60 years for all stages, in line with RICS. This is a typographical error in the Technical Manual and will be corrected in the next re-issue.

GN51 Guidance on LCA and embodied carbon calculations for Mat 01 in BREEAM V7 - KBCN1684

Latest version: v1.0, July 2026 Guidance Note 51 (GN51) provides supporting information for the new Mat 01 criteria in BREEAM V7. Its development is driven by the introduction of new credit allocation criteria for Mat 01. While the core principles of measuring and reporting a building's environmental performance through life cycle assessment (LCA) and benchmarking were introduced in BREEAM UK New Construction 2018, significant revisions have been made to align the criteria across BREEAM schemes and with existing LCA frameworks and methodologies. This guidance note explains the primary methodology for Mat 01, including minimum requirements and the scope of the LCA. Download Guidance Note 51 View all Guidance Notes on BREEAM Projects (licensed assessors only)

15-Jul-2026 - Updated version released (v1.0)

Independent third party – clarification on the definition - KBCN1805

For the purposes of BREEAM, sister companies or parent companies cannot be considered as third parties. To be classed as an independent third party, there must be no professional connection or relationship between the LCA consultant/energy assessor, or their company, and the verification body. The third-party verifier must be independent of the LCA or energy assessor and demonstrate impartiality (for general principles, see ISO 17029). To qualify as a third party, the verifier must belong to an organisation not involved in the project and must not provide advice to the project, as this could compromise their impartiality during verification.

LCA Concept Design stage submission before the assessment is registered - KBCN1437

In certain circumstances, it may be necessary for the design team to submit the Concept Design stage LCA before the BREEAM assessment has been registered. In such cases, please submit the LCA tool and associated files along with details of your situation as follows:

Licensed BREEAM assessors should do so using the webform: https://tools.breeam.com/projects/queryadd.jsp
Other interested parties can submit their case to breeam@bregroup.com

Life Cycle Assessment – Similar buildings approach (GN20 – Section 4) - KBCN1834

Where multiple buildings are included within the scope of a single BREEAM assessment following the Similar Buildings approach, in accordance with Section 4 of GN20, unless identical, each building must be assessed and reported separately within the LCA. Where all buildings are demonstrably identical in design and specification (and differ only in scale), a representative LCA approach may be used (see KBCN1890). Shared elements (e.g. substructure, external works, or building services serving multiple buildings) may be apportioned between buildings using a reasonable and transparent method (e.g. by gross internal area or other appropriate project-specific metric), in line with recognised industry approaches. For the purposes of BREEAM benchmarking under Mat 01: • The results submitted to the platform must represent a single building, not a combined site-wide result. • Where multiple buildings are included within an assessment, the worst-performing building (in kgCO₂e/m²) must be used for benchmarking in line with the Similar Buildings methodology (section 4.2 of GN20). Full evidence must be provided to demonstrate: • That all buildings within scope of the assessment have been included, with individual LCAs completed for each building, and • How results have been separated and, where relevant, how shared elements have been allocated.

Rationale: In line with Section 4.2 of GN20, BREEAM issues must be assessed for each individual building, with credits awarded based on the worst‑performing building for each assessment issue. The Similar Buildings approach therefore remains an individual‑building assessment methodology and does not constitute a site‑wide assessment, even where multiple buildings are included.

09.07.2026 Reference to KBCN1890 added

Life Cycle Assessment – Similar buildings with identical design (GN20 Section 4) – Representative LCA approach - KBCN1890

Where multiple buildings are substantially identical in design, construction and specification, and any differences are limited to scale, a representative LCA approach may be used instead of completing a full LCA for every building. Where buildings are not substantially identical, see KBCN1834. For the purposes of BREEAM benchmarking under Mat01:

A representative LCA and a single options appraisal may be applied across all buildings, provided that all specifications (including scoped elements) are consistent and carbon reduction measures are specification-driven rather than scale-dependent.
Robust justification and supporting evidence must be provided to confirm representativeness. The representative model should normally be the largest, most carbon-intensive, or otherwise demonstrably representative building within the development.
Results must be expressed in normalised form (e.g. kgCO₂e/m²) and demonstrated to be applicable across all units, with any variation in outcomes shown to be not materially significant (e.g. within ±10%).
Shared elements (e.g. substructure, external works, or building services serving multiple buildings) may be apportioned between buildings using a reasonable and transparent method (e.g. by gross internal area or other appropriate project-specific metric), in line with recognised industry approaches.

Demonstrating representativeness does not require full LCAs for additional units; proportionate methods such as parametric scaling of quantities or elemental intensity comparisons may be used to evidence that variation in normalised results is not materially significant. Where there is uncertainty regarding representativeness, a secondary check model for an additional unit is recommended to verify consistency of results.

Rationale: The representative LCA approach provides a proportionate means of assessing developments containing multiple highly similar buildings while maintaining confidence that reported results are representative of individual building performance. It is intended as a limited exception to the standard requirement for building-specific assessment.

New Construction / UK / V7 / 06 - Materials /