The programme begins with an overview of the category's three sections: Environmental Impact of Materials (Mat 1), Responsible Sourcing of Materials – Basic Building Elements (Mat 2) and Responsible Sourcing of Materials – Finishing Elements (Mat 3).

Richard Garland, managing director of Sandwood Construction and NBS's John Gelder, run through the three sections, starting with an explanation of the BRE's Green Guide. The guide's rating system and the way it translates into Code credits is then explained.

The practicalities of working out the Mat 2 and 3 elements sections are then discussed, including demonstrations of the necessary calculator tools.