A STUDY FOR A HIGH QUALITY PRESERVATION SYSTEM OF KOKERA ROOFING USED IN TRADITIONAL WOODEN ARCHITECTURE PART 1 : THE ANALYSIS OF THE LIFE CYCLE PROPERTIES OF KOKERA ROOFING

摘要

One type of traditional wooden architecture uses Kokera roofing in Japan. These Kokera are made from natural stands of Japanese cedar, and other evergreen trees. These trees are traditionally over 100 years old before they are used. Although recently, natural stands of Japanese cedar forests and also the numbers of 100 year old Japanese cedars has been decreasing rapidly. We researched all existing National Government buildings in Japan using information collected from the Agency for Cultural Affairs. The results of our research show Kokera roofed buildings. Many the National Government buildings use Kokera roofing. Material demand and the Kokera roof life cycle relationship needs to be reconsidered. The cost of materials needs to be reduced otherwise we fear that the future of Kokera roofing may not continue.