Shou-sugi-ban or Yakisugi, the art of charred cedar

Shou-sugi-ban or Yakisugi, the art of charred cedar

In a recent conference at Polytechnic University of Puerto Rico, Parsons’ Assistant Professor Alice Min Soo Chun explained through images various techniques for using natural or living materials in a smart way, exposing amazing techniques for local use and integrative design.
One of the most captivating techniques, is the use of what the ancient japanese culture calls Shou-sugi-ban, term for charred or carbonized wood or better yet, the Art of Charred Cedar as a found page pronounces. The technique described by the same page, reads as follows:

“Shou Sugi Ban 焼杉板 (or Yakisugi) is an ancient Japanese exterior siding technique that preserves wood by charring it. Traditionally, Sugi (cryptomeria japonica L.f., also called Japanese cedar) was used. The process involves charring the wood, cooling it, cleaning it, and finishing it with a natural oil. It is an environmentally friendly way to preserve the timber and (paradoxically) make it fire resistant. Chemical preservatives, paints, and retardants are thus unnecessary.”-

This is just…fascinating. And besides being fire-proof, this process allows properties to last longer, as it becomes also insect, rodent proof, and weather resistant. It is said to last more than 80 years with little or no maintenance.
In the world of sustainable design, the use of natural sources is one of the best practices proven for centuries, no doubt this technique has lasted centuries and can still look as sexy and appealing as you see in the images. The process is sublime and at the same time  a bit dangerous, but with the necessary caution, this can be perfectly achieved and the results are stunning.

On this next video you will witness the traditional process for preserving wood or charing, although it is adapted to new technologies for easier and safe handling, the results are very similar. Although traditionally the charcoal created by the burnt wood is left on surface to provide more protection and texture, this video demonstrate the scrapping technique for finishing the wood planks with an oiled finish. The oil used in this video is allegedly tung oil.

History and facts:
According to various sources, Shou-sugi-ban’s origin is unknown but it has been utilized by constructors and artisans since the 1700’s. One important factor for this technique is that is “best achieved on open cell species that have a moisture content of 12 to 17 per cent”, states author Tom Kilian for Travis Creek Wood Products. Moisture is mainly important in this process as originally.

Cedar wood obtained from discarded or drifted coastlines, moistened and sun burned sufficiently, represent the best selection for sou-sugi-ban process, for being open celled wood. Kilian then remarks the following important detail:

“(…) to achieve fire resistance, only the outermost cellulose must be burned off, leaving the blackened lignin of the wood behind. This is the same reason charred firewood is difficult to reignite once it has been exposed to a flame. Close celled wood has little cellulose ad does not result in a suitable patina.”

Traditionally, the blackened lignin, the natural surface created by cellulose on fire, is sometimes brushed off by some manufacturers, so the “alligator skin” is not harmed or that would stain users. If the surface is brushed some would leave it as is, some would oil it with linseed oil or tung oil in other cases.

In the end, the results are astonishing releasing wood from being painted black just for aesthetic looks. Under personal consideration, aesthetic should not be compromised by means and methods, but the function might need more relevance and connection to the end of our aesthetic taste. This process provides better function to this natural material other than what paint might add to its surface. Solar reflectance being compromised? Possibly, greater if used on areas with lack of shading, but it used wisely, this technique que provide the most beautiful and sustainable design.

References and credits:

Featured image by: japanese_craft_construction, flickr user, (creative commons.)

• “Shou Sugi Ban.” Web log post. Shou Sugi Ban. N.p., n.d. Web. 28 Nov. 2014.
• Kiliam, Tom. “Shou-Sugi-Ban.” Shou-Sugi-Ban (2014): 42-44. 30 Apr. 2014. Web. 28 Nov. 2014

Keep updated with more about Wood treatments and surfaces and for more images about shou-sugi-ban preservation, follow this Pinterest Board!:

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Mabelle Plasencia

Founder and Editor at INmatteria©
• Architect | LEED AP BD+C, with an intense passion for materiality, innovation, technology and science. • Arquitecta | LEED AP BD+C apasionada por la materialidad, innovación, tecnología y ciencia.