Application of photocatalyst into the building materials and components is rather newly developed technology. One of the advantageous features by applying this photocatalyst would be the capability of self-cleaning or self-desoiling on the surface of materials. This paper introduces the results of the outdoor exposure test for the various exterior finishing materials treated with photocatalyst. As relatively limited amount of data are available at present stage, the following conclusion could be made; the self-cleaning effect was recognized in the outdoor exposure test. The degree of effect was dependent upon each commercial product at present stage; however, with the photocatalyst applied products showed the significant higher self-cleaning effect compared with the ordinary products.
