Humans have used fire as a transformative tool from the earliest parts of our history. The chemical reaction it initiates through heat and combustion can create anything from ceramic to steel, and the ability to change the properties of a material is one of the initial building blocks of civilization.
During the Edo period in Japan, it was discovered that certain woods, when exposed to fire under controlled circumstances by a skilled craftsperson could be made more resistant to rot, weather and warping. This process was called
焼杉板, (Shou Sugi Ban) which translates to mean, “burnt cedar board”.
The nature of this transformation is similar to what happens to a meringue in the oven. The sugars in the wood are consumed or caramelized, creating a water resistant resin. Excess moisture releases in the form of steam as the wood becomes drier and stiffer. The result is, like the toasted meringue, much more resistant to change and corruption.
Working within the inherent limitations and natural properties of a material will always create the most beautiful and lasting design. The Shou Sugi Ban process is a way to dramatically change the appearance and performance of wood while more deeply expressing it’s inherent character. The textures become deeper, contrasts in woodgrain are heightened and the particular shade of char is unique to each piece. With the application of time the color will lighten and change; from a deep, even brown to a weathered tapestry of brown, grey and black.
Traditionally, the process involved lighting a fire and slowly charring the boards a few at a time. More recently, some companies have created highly controlled systems to produce boards more quickly and consistently. Because of budget and limited space, (my neighbors might not be comfortable with a trench bonfire next door) I decided to use a simple propane torch to char the boards one at a time.
It took a while, and a fair amount of propane, but after some practice I began to feel when the wood had charred through just the right amount. I wanted to make sure to release the moisture and carmelize the sugars without burning away too much of the wood.
After letting them set and cool overnight, I lightly brushed off the blackened surface to reveal the woodgrain beneath.
As an added protection and to bring out the color I applied a generous coat of penetrating oil, which rendered an even dark brown finish across the surface.
It’s been several months since the siding was installed and as I prepare to char and finish the trim I’m still very happy with how it looks; though very curious to watch it develop with time.