This report (BD2414) summarises the main findings of the project Impacts of Improvements to Part L and Robust Construction Details (RCD) on Part C. The work consisted of a fieldwork element, undertaken by Leeds Metropolitan University and a modelling element carried out by University College London. The fieldwork consisted of the analysis of design material and site surveys from 16 housing developments constructed to Part L 2002 and adopting the Robust Construction Detail route to compliance. The modelling element of the project sought to identify the extent to which the 'as built' details give rise to a significantly increased condensation risk as compared to the relevant 'standard' robust construction details, as defined in the guidance. This report draws together the important conclusions from the project which has previously been presented in several very detailed interim reports and also for the first time presents the results of a workshop where these results were discussed to obtain industry feedback. The overall conclusions, future work and dissemination plans are also presented.