A full-scale ventilated roof component was tested under real climatic conditions. Key constructional parameters, such as the air gap height and application or not of a layer of a radiant barrier, were examined during the tests and the performance of the component was assessed by direct comparison to a simultaneously operating conventionally constructed roof. The experimental results of the summer period are presented in this paper. The direct comparison with the conventional roof indicates significantly improved performance of the ventilated component. (C) 2005 Elsevier B.V. All rights reserved.