06 - Materials

Life Cycle Assessment for multiple buildings within a single assessment (GN20 – Section 6) - KBCN1835

Where a BREEAM assessment includes multiple buildings on the same site with a single, over-arching function, in accordance with Section 6 of GN20 (e.g. a principal building with one or more ancillary or supporting buildings), and where these are not classified as ‘similar buildings’, each building must be assessed and reported separately within the LCA. A single aggregated result for the whole site is not sufficient on its own, even where a single coordinated LCA model is used. 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, benchmarking (in kgCO₂e/m²) must be based on the principal building. Where no clear principal building exists, the largest building should be used. Full evidence must be provided to demonstrate: • That all buildings within scope are included, with individual LCAs completed for each building, and • How results have been separated and, where relevant, how shared elements have been allocated.

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Rationale: Industry standards such as RICS guidance and the UK Net Zero Carbon Buildings Standard define assessment boundaries at the building (asset) level, while allowing aggregation at project level only where individual building results are also reported. Requiring building-level results ensures consistency with industry practice, maintains comparability with BREEAM benchmarks, and avoids distortion where multiple buildings are combined into a single result.

Note: This approach applies until further platform functionality is available to support multi-building submissions directly.

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Life Cycle Assessment where similar buildings approach is being followed (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. 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.

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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.

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Meeting the minimum standard requirement – compliance when chain of custody is broken - KBCN1816

Where there is a broken chain in the last link between the purchase and delivery of certified timber from the supplier and the forwarding distribution of the timber to the site under assessment, such as where the timber has been delivered to a subcontractor or fabricator’s premises instead of direct to site (e.g. as part of a bulk order or where limited storage is available on site), compliance can still be achieved if a documented risk assessment confirms that there is low risk of mixing or substitution of certified and non-certified timber. Ways to demonstrate compliance: A. Verification that the subcontractor or fabricator only purchases and uses certified timber. There must be robust mechanisms in place to verify that all timber materials purchased and delivered originate from sustainably managed sources. This includes maintaining documented timber procurement policies and procedures that mandate certified timber orders and delivery checks. Comprehensive supplier details should be readily accessible for review upon request to demonstrate that all timber is certified. B. Where non-certified timber is handled/stored or sourced, that there are robust control measures in place to prevent any substitution or mixing of certified and non-certified timber at every stage of the process. Documentation demonstrating compliance should be maintained and made available upon request. Examples of appropriate control measures are listed below:

Control	Evidence required
Purchasing records	All purchase orders, requisition notes, and contracts must explicitly specify the product details and confirm that materials are to originate from legal and sustainable sources.
Segregated storage of timber	Site layout map, stock control processes and records to confirm that certified timber is stored away from non-certified timber.
Segregated delivery of timber to site	- All timber must be thoroughly inspected and verified before shipment to confirm that it is correctly marked/labelled as FSC/PEFC-certified. - Delivery notes must be accurately maintained. - A second-party verification process to check tickets and stock, must be carried out upon site delivery to confirm certified status of timber.
Documentation	Comprehensive documentation must enable independent assessors to trace any timber back to its sustainable source. This includes maintaining purchase records, goods-inward notices, stock records, and sales documentation such as orders and invoices.

The above is guidance and should not replace any local or national requirements for the sourcing of legally traded and harvested timber.

1 June 2026 - Updated to apply to UK New Construction and RFO Schemes

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