This report presents the results of a two-year research program to monitor and evaluate the performance of earth masonry in modern wall construction. The program made a detailed study of one new building through the complete construction process, including design, procurement, and occupation. It also took into consideration several other projects that used these materials. The earth materials studied in this project, earth bricks, mortars, and plasters, are generally held to have good environmental characteristics over a range of important criteria and, critically, are also believed to have the wide potential for use in contemporary construction. The purpose of this research was to assess the extent to which these possible benefits could be practically realised in typical construction conditions, to highlight any significant factors affecting performance and to disseminate guidance to interested parties.