Red roof-tile, formerly most popular building element that Okinawa's traditional wooden houses have had, has been definitely decreasing in use as those wooden houses diminished in number, while the ferro-concrete houses are gaining a decisive popularity in Okinawa.
The Okinawa Development Finance Corporation, a nation-funded loan corporation, has set up a policy to finance the red roof-tile houses to be built in Okinawa, in order to make the red roof-tile serve as an element of the extensive urban landscape beauty.
The authors made a study on the effect of the policy including a rain water permeability test in the light of sustainable prevalance for the future.
The results reveal that the red roof-tile is being accepted as a tool for the attractive urban landscape, thougth it has some difficulties to tide over.