Abstract
Plaster has been used for a long time as construction materials in Japan. The element that should be solved to achieve the preservation of the building where 100 years passed after construction is not few. In the examination, it aimed at securing and the low price of safety in the thing and the building where the material was left. And, not the development of a new material but the repair was verified. It aims at the establishment of the construction method in consideration of the damage prevention of the lath and the improvement of the tool. Finally the ceiling board were able to be repaired,so I'll reports on the outcome of an experiment concerning construction by the present stage.