We recently launched our Shou Sugi Ban Barn Door, inspired by the centuries-old Japanese practice of burning cypress planks to make them more durable. While this type of treated wood is usually used for exterior siding, we decided to use it for our classic barn doors because of its beautiful color and texture. In this blog we’re going through some FAQs about this type of preserved wood.
What is Shou Sugi Ban?
Shou Sugi Ban is the commonly used name in North America for a traditional Japanese wood product. It consists of Japanese cypress planks that are subjected to a hot, fast burn with an open flame. Traditionally three planks are stacked against each other to make a triangular chimney. The fire starts at the base of the chimney before traveling up to the top, which results in an even burn. The planks are then quenched with water to stop the burning, and quickly affixed to the exterior of structures. It has a distinctive, black alligator-skin pattern. There are also brushed variants that remove the loose char, which reveals a raised texture and color contrast between the hard grain and soft grain.
This practice has been in use for at least four hundred years. Burning the cypress wood in this way results in dramatically improved rot and insect resistance. It also results in fire resistance. Traditional Shou Sugi Ban siding lasts for an average of eighty years with no maintenance.
The term “Shou Sugi Ban” is actually a mistranslation of the original Japanese word for this product, yakisugi. The new term became popular in North America, but it is not used in Japan.
Why does Shou Sugi Ban work?
If burning wood to make it rot, insect, and fire resistant sounds strange to you, you’re not alone. How does damaging the wood make it stronger? At the structural level, softwoods like cedar contain carbohydrates (sugars) and lignin, the rigid substance that fills out wood cell walls. Essentially, with Shou Sugi Ban, the carbohydrate portions of the wood are burned away, leaving the more rigid material lignin behind. Without the carbohydrates, fungi and wood-eating insects don’t have anything to eat.
Burning away the carbohydrates means that if the wood is exposed to fire again, there’s less fuel for the fire to consume. It also raises the temperature threshold at which the treated wood will burn. Of course, our Shou Sugi Ban door is an interior door, and we brushed away the loose char, which is partly what adds all this protection. So we have used the technique for how it looks more so than protecting the wood from insects and water damage. Since it's an interior door, insect and rot resistance are not things you'd need to be concerned with anyway.
Does Shou Sugi Ban work on pine or other species?
The short answer is no. Cedar and cypress are related trees that have unique properties that help them respond favorably to a hot, fast surface burn. Accoya, a chemically treated form of pine, also burns well. In Europe, Siberian larch is occasionally used for Shou Sugi Ban. Other species will turn into a splinter-y mess and won’t give you the beautiful texture you’re looking for. Trust us, we tried several other options ourselves—creating some spectacular duds--before settling on using cedar exclusively.
Shou sugi ban vs Yakisugi: what word is correct?
As we mentioned above, the term “Shou Sugi Ban” is the name used in North America for this product. It’s actually a mistranslation of the original Japanese term for this product, “yakisugi”. So why don’t we use the word Yakisugi? The fact is that while we are inspired by the traditional process, we deviate from it in our method (we use a blowtorch rather than an open flame) and in our materials (we use North American variants of cedar instead of Japanese cypress).
We also deviate in our prescribed purpose: we burn and brush the wood because it's beautiful, not for the increased protection from insects and weather damage. As such, it did not feel accurate for us to use the name that refers to the traditional product. But you should know that in Japan, the word Yakisugi is the correct word. If you say "Shou Sugi Ban" in Japan, no one will know what you're talking about!
So there are some of the most common Shou Sugi Ban questions, answered. If you want to know more about this process, let us know in the comments!
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