Abstract
The deterioration of paint-coated steel sheets which are used as roofing materials for heavy snowfall area in Japan, has been investigated with special attention to their morphological changes in the microscopic surface. Some samples of them were taken from the roofs of dwelling houses to make a microscopic observation and measure the surface roughness of the sheets. The result shows that the surface roughness of paint layer gradually increases in depth till about five years. Afterwards, from that time till about fifteen years there is little change of the surface roughness, however, after that, more rapid change occurres on surface due to rust that causes the sheets swell their thickness. It also reveals that there is a big difference in the surface roughness of the sheet on steep sloping roofs between the even roofs. Not only slight damage but also abrasions have been noticed on the film in proportion to the direction of the roof slope. This paper obviously proves to have something to do with snow and ice on the roof.
