The overall objective of this project when first set out in June 2003, was to investigate current practice in the construction of unventilated roofs with vapour permeable membranes and also to make recommendations for compliance with the recommendations of an amended BS 5250 Code of Practice for control of condensation in buildings. The project objectives had to be revised as the amended BS 5250 anticipated to be published in 2004, was not in fact available until January 2006. The published amended BS 5250 does not consider the situation where it is proposed to provide no ventilation to the roof void, or ventilation more limited than the equivalent continuous low level loft space ventilation opening of 3 or 7 mm depending on how well the ceiling is sealed. Where no ventilation to the roof space is proposed, it is recommended that reference be made to the conditions attached to Technical Approvals given by UKAS (or European equivalent) accredited technical approval bodies.