Yakisugi

Yakisugi is a traditional ancient Japanese technique of preserving timber by charring it by fire, letting it cool down and then finishing it with a natural oil. Traditionally, Cryptomeria japonica (Japanese Cedar) or Jōmon Sugi as it is known in Japan, was used in the process and the resulting charred timber was used externally.

Yakisugi is still used as a way of preserving timber and paradoxically, it makes it to some extent, fire resistant too. If the construction timber of a building is thick enough, when exposed to a fire, the exposed surface will be converted to char until the thickness of the char provides enough insulation to prevent any additional charring. This layer will then protect the remaining core of the wood, leaving it structurally able to carry the load it was designed for, assuming it was appropriately designed.It is also used decoratively by architects for interiors and exteriors.

The term ‘Yakisugi’ should not to be confused with other names given to this process, that are the result of a marketing excercise only and bear no relation to this oriental ancient wood preserving technique of charring timber.