Even in relatively warm area in Japan, frost damage of roof tiles occurs. It was shown, in the previous investigations, that the roof surface temperature could be as much as 5 deg.C lower than the outdoor temperature, depending on environmental conditions such as nocturnal radiation and outdoor wind speed. In the field of material science and technology, the mechanism of the frost damage has been investigated. Our research deals with the frost damage from a thermal environmental point of view. In this paper, an accelerated aging test for roof tiles and a numerical analysis of the test are carried out. The experimental results show there is a significant difference in temperature depending on the location even in the same tile. The profiles of temperature and water content inside the tile are estimated by numerical calculation. The influence of several parameters such as water resistance of the surface finishing is also examined.