Yakisugi

Yakisugi (Japanese: 焼杉, lit. 'burnt Japanese cedar '^[1]) is a traditional, very old Japanese method of wood preservation.^[2][3][1] It is also referred to as shō sugi ban (焼杉板), a term which uses the same kanji characters, but an alternative pronunciation. The ban character means "plank". In the West it is known as burnt timber cladding. This old technique has several similarities with the modern thermal wood modification^[4] methods used in Europe and elsewhere.

Traditional houses in Naoshima, Kagawa clad with yakisugi panels

Close-up view of charred yakisugi board

Yakisugi treated wood used in a box for sunglasses

By slightly charring the surface of the wood without combusting the whole piece, the surface becomes water-resistant through the carbonization and at the same time its hygroscopy is decreased due to chemical cell-changing process during carbonization, which results in increased durability. ^[5][6] It additionally protects the wood against insects, fungi and mold, as well as making the wood a rather fire-resistant material.^[7] However, some studies have shown that a mere charring of the surface does not improve durability or fire resistance. It also doesn't make the wood waterproof.^[8]

Western garden room with Yakisugi cladding

Examples

Contemporary architect Terunobu Fujimori works with yakisugi.^[9][10] In addition, Japanese architect Kengo Kuma uses this charred wood material in his modern creations.^[11]