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)
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.
Suitably qualified third-party verifiers – LCA training courses - KBCN1909
Purpose
Mat 01 requires the third-party verifier to demonstrate knowledge of the LCA sector, including relevant standards, EPD programmes and regulations (see Definition:
Suitably qualified third party).
Examples of relevant LCA training courses
Below are examples of training courses that BRE considers as meeting this knowledge requirement, and which can support assessors and verifiers in evidencing compliance:
This list is illustrative, not exhaustive. Completion of one of these courses is one way to evidence the knowledge requirement. It does not replace the other criteria under
Suitably qualified third party. Equally, a verifier who has not completed one of the above courses may still qualify if they can otherwise demonstrate the required knowledge.
Requesting an addition to this list
Training providers or assessors wishing to propose a course for inclusion should contact
breeam@bregroup.com and include
BREEAM Relevant LCA training course – addition request in the Subject field.
Information correct as of 10