Domestic Refurbishment / 2012 / 05 - Materials /

MAT 01 - Environmental Impact of Materials

Information correct as of 20thApril 2024. Please see for the latest compliance information.

All life cycle stages EPDs - KBCN0822

A third party, independently verified EN 15804 EPD that includes life cycle stages A, B and C may be considered a tier 1 EPD in the MAT 01 issue.

Assessing basement external walls - KBCN0241

Only the external walls above ground level are required to be assessed under 'external walls'. The external walls below ground (i.e. within a basement area) perform a specialist function, these are not comparable with other external walls in a building. These are included in the 'basement retaining walls'.
20/08/2021 Scope clarified in accordance with the New Rules of Measurement (NRM) by the Royal Institute of Chartered Surveyors (RICS).

BRE Environmental Profile certificates - KBCN0777

BRE Environmental Profile certificates are compliant EPDs and can be used as evidence for the purposes of Mat 01.

Green Guide ratings for domestic buildings of more than four storeys high - KBCN1106

For domestic projects of greater than 4 storeys it is advised to use the domestic ratings for the first four storeys and commercial ratings for the higher storeys. If the designed structure of the first four storeys are more similar to commercial than domestic due to the load of a higher structure, you may use the commercial ratings for the whole building. This approach ensures the most appropriate ratings are used based on the characteristics of the building. 

Green-roofs - KBCN0263

When assessing green roofs,  only the structural elements of the roof construction need to be considered i.e. the waterproof layer and above can be excluded. Where Green Guide is being used to assess the issue, it is likely that the online Green Guide Calculator will need to be used to provide a rating for the roof construction. HQM - For the purpose of HQM, green roofs fall under 3.3 Specialist roof systems therefore should be included in the IMPACT model.

Location of the Refurbishment Green Guide Calculator? - KBCN0288

The Refurbishment Green Guide Calculator is within the generic Green Guide Calculator on the BRE Website. When adding a new specification please select 'Refurbishment - Domestic' as the name of the scheme. This will allow you to specify 'reused' elements which can have a green guide rating up to A+(6)  

Material not listed in the Green Guide calculator - KBCN0377

Please refer to Guidance Note GN17 'Bespoke Green Guide Specification Guidance' available from the BREEAM Extranet under 'Green Guide to Specification - Assessor information'

U-values - KBCN0191

U-Values should be based on the data shown in section 3 of the SAP assessment, or in the case of RdSAP should be provided from your Domestic Energy Assessor.  
Information correct as of 20thApril 2024. Please see for the latest compliance information.