Cover systems reduce the hazard to human health from contaminated land and provide a medium for plant growth but their design has sometimes been ad hoc, resulting in designs that may be unnecessarily thick, or inadequate. This publication and the accompanying CD ROM help you assess the need for cover systems to reduce exposure to contamination, and to design the thickness of such systems. The design method is intended for simple cover systems on brownfield sites where exposure to contamination must be reduced. The guidance is not appropriate for sites where contamination is so significant that exposure must be completely prevented. The CD ROM includes three elements: -Powerpoint Presentation: sets the scene and introduces the study that has led to the proposed new method for cover thickness design -Report: details the findings of an in-depth study of current design approaches, literature review and on-site research. It proposes a simple method for designing cover thickness and a more rigorous spreadsheet-based method and worked example -Spreadsheet: enables combinations of cover thickness and ground contamination for a wide range of contaminants to be incorporated easily into the design This suite of information and guidance has been prepared by RSK ENSR Ltd on behalf of the Association of Geotechnical and Geo-environmental Specialists in partnership with BRE.