Although thatch is the traditional roofing material of many Japanese structures, it is most often seen today on homes in Japan’s remote rural villages. Well-preserved hamlets such as Shirakawa-go have become popular destinations for tourists seeking a unique lodging experience. One of the greatest concentrations of thatched-roof dwellings in Japan is found in the Kyoto district of Tamba.
For thousands of years, the homes of Tamba were roofed with kaya (a term for miscanthus, bulrush, and pampas grass), or wara (straw harvested from rice or other grains), both materials readily available in and around farms. Not only was it free; after serving for years to protect the home, it could be returned to the fields as compost.
While thatch was also widely used as roofing material in Europe and England, the Japanese thatched roof has many characteristics that make it unique. Most notably, the rush reed – preferred over straw for its greater longevity and insulating properties – is bound to bamboo crosspieces to erect a steeply-pitched, sometimes slightly curved roof. This sharply-angled roof was essential in a land of frequent rains and heavy snowfall.
As mentioned, the commonly used kaya lasted much longer than straw, due to its higher oil content, but it offered another important advantage to the Japanese dwelling; the hollow stems of the rush provided excellent insulation in the hot season. This consideration cannot be over-emphasized. For instance, the homes of Tamba are oriented with their gables facing into the prevailing valley breezes, for optimal ventilation, a further measure to keep them cool throughout the hottest summer months.
The Japanese thatched-roof farmhouse is a testimony to the sustainable culture of rural Japan. For anyone interested in this subject a day-trip to Kyoto Tamba, where the craft of thatching lives on, is highly recommended.