CHAPTER ONE INTRODUCTION 1.1 BACKGROUND OF THE STUDY Ceiling materials are overhead interior surfaces that can cover the upper limits of the room. They are not generally considered as structural element but finished surfaces concealing the underside of room structure or the floor of store above. In Nigeria, the use of zinc made roofs without ceilings are very common, thus there is intense heat transfer to the internal environment, which may cause thermal discomfort to the inhabitants (Etuk et al., 2007). One way to reduce the thermal discomfort is by the use of radiant barrier (i.e. ceilingboard) which reduce the heat flux. However, the knowledge of thermal properties of different materials is very important in the choice of the types of materials to be used as a radiant barrier since the heat flow through any building depends on the thermal properties of the materials use in the building (Etuk et al., 2007). The study of the thermal properties of materials will help us to know whether materials are suitable to use as Ceiling materials in our houses, school and industries. Heat propagated in the interior spaces in buildings through roofs and walls and partly through Ceiling panels by the process of conduction and radiation (George et al., 2010). This is because the common materials used as roofing sheets are materials like zinc and aluminum which have high thermal conductivities (Michael et al,2012). To reduce the intensity of this heat, there is need to use materials of tolerable thermal responses as ceiling materials in buildings.