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Environmental Impact of Materials

Mat 1: Environmental Impact of Materials

Credits Available: 15 (mandatory elements)

It is a mandatory requirement for three of the five main building areas (listed below) to achieve a rating of between A+ to D within the 2008 version of The Green Guide when using the Code Mat1 Calculator Tool.

  • Roof
  • Windows
  • Upper and Ground Floors (including separating floors )
  • External Walls
  • Internal Walls (including separating walls)

All levels are mandatory.

Evidence Required

At design stage and post construction a completed Code Mat1 Calculator Tool (spreadsheet based tool) must be presented with the relevant Green Guide element numbers plus references stating the design specification documentation used to complete the tool. Alternatively written confirmation by the developer that the building envelope has been constructed as per the Code Mat1 tool and references provided.

Green Guide ratings are allocated credits according to the table below:

Green Guide ratings with associated credits

Table taken from the Code for Sustainable Homes, Mat1, Page 95.

If a main building area (e.g. the roof) comprises a number of different specifications for its construction, which each have different Green Book ratings, the overall rating is awarded based on the weighted green guide rating for each specification. The Code Mat1 Calculator tool allows four different specification types per element.

Note: if a specification does not match with those in the Green Guide the Assessor can request a bespoke rating or use the online facility.

More information about The Green Guide to Specification can be viewed here or from BRE Global. Green Guide ratings are also available for a number of building materials or products, which have gained certified environmental profiles. A list of materials and products with certified environmental profiles are displayed on the Greenbooklive website.

The final credit allocation is based on the Code Assessor's assessment using the CSH Mat 1 Calculator Tool (pdf, username:public, password:public) from the BREEAM Extranet within the public section under documents, materials section.

Definitions amended November 2010

Building Envelope:

This is defined as the overall superstructure of the building which may include multiple dwellings. Where multiple dwellings occur the Green Guide can be applied to the building overall not each individual unit.

Green Guide Element Number:

A unique reference number from BRE Global is given to a Green Guide rating for any building element type specification. Both standard Green Guide ratings and Online Green Guide Calculator ratings will have an element number.

Online Green Guide Calculator Tool

This tool has been created to speed up the calculation process and is available to BREEAM and Code Assessors to generate Green Guide ratings. The calculator is based on the database from the Online Green Guide and components can be selected and combined to generate an instant rating.

The Green Guide to Specification

This is a reference website and tool offering guidance for specifiers, designers and clients which looks at elemental specifications and their environmental impact. Ratings are based on Life Cycle Assessment using the Environmental Profile Methodology.

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