Reinforced concrete roof slabs can be an ideal alternative to traditional roofs considering the better cyclone resistance that can be offered due to the self weight. However, the concrete slabs do not perform satisfactorily in warm humid tropical climatic conditions and tend to act as heated bodies for the occupants in free running spaces. As a solution, a robust roof slab insulation system is proposed and its thermal performance was determined experimentally using small and large-scale models. With comfort models developed for the people acclimatized to tropical climatic conditions, it is shown that insulated roof slabs could provide acceptable indoor conditions while providing many valuable benefits such as cyclone resistance, regaining of land lost for the house and the possibility of creation of roof top gardens. (C) 2007 Elsevier B.V. All rights reserved.