This report reviews how biomaterials and biomass have been assessed within The Green Guide to Specification, including the application of the Environmental Profiles methodology, which underlies data. The way in which biomaterials and biomass are addressed within building-level environmental assessment schemes such as BREEAM and the Code for Sustainable Homes is also explained. The report will give manufacturers and specifiers a general understanding of the significant benefits and impacts of biomaterials and biomass over their whole life cycle and help to identify opportunities for improvements to their environmental performance. It is part of a series that provides comparable information on windows, masonry and concrete, metals, floor finishes, cladding and insulation to assess the environmental impact of specific construction materials.