Heritage Retrofit

40 BCD SPECIAL REPORT ON HERITAGE RETROFIT FIRST ANNUAL EDITION YAKISUGI CHARRED TIMBER An ancient technique in new hands DIANA ROWSELL T IMBER CLADDING is a traditional feature of the historic environment, and today it is a popular finish for new developments and extensions. Although timbers such as oak and sweet chestnut might be used without any preservative, in many areas black-stained softwoods are a key element of the local vernacular due to the traditional use of coal- and pine-tar resins to preserve exterior cladding. In the southwest of Japan, however, the traditional preservative technique is wood charring, known as Yakisugi . A similar technique is used in the Swiss Alps where timber chalets last for generations, and charring is a well-known method of preserving wood in many Yakisugi cladding on a house designed by Terunobu Fujimori in Utsunomiya, Tochigi Prefecture, Japan (Photo: Dana Buntrock, Flickr) countries and cultures around the world. It is sometimes used on the ends of fence posts to slow down rotting in the ground and on timbers that are joined together with metal elements. Charring is arguably the oldest method of preserving timber known to man. Since it involves no chemicals, it also has minimal impact on the environment, making it highly sustainable. YAKISUGI AT THE WEALD & DOWNLAND LIVING MUSEUM In October 2015 Kingston University tutors Takeshi Hayatsu and Simon Jones visited the Weald & Downland Living Museum with 15 postgraduate architecture students to begin an investigation into architectural materials and building crafts. At the end of that month the students travelled to Japan to explore alternative approaches to building crafts by visiting a number of buildings designed by the contemporary Japanese architect and architectural historian Professor Terunobu Fujimori in his hometown of Nagano. This is a region surrounded by mountains and agricultural land, next to the ancient Shinto shrine complex Suwa Taisha. It is a highly charged place, because the Suwa Taisha shrine is one of Japan’s oldest. In the mountains and in the fields sacred territories are marked by four standing wooden poles which symbolise the presence of gods.