Suyaki
The original Yakisugi / Original Shou Sugi Ban
Suyaki is the most traditional and easily recognisable of our Yakisugi. It is also often referred to as “alligator skin” or “silk wood” outside of Japan. The charred soot is water-repellent and also partially protecting from UV. Therefore, Suyaki has the best wood and colour longevity as well as maximum fire resistance. We apply oil prefinishes to have the soot layer fixated. This prevents soot from coming off when touched, but also reduces blemishes and makes installation easier. In Japan there are numerous houses with Suyaki products applied for 80+ years with little to no maintenance.
1. Available Suyaki coatings and colours
2. Available profiles and widths
Shiplap profile
145 mm (135 mm reveal) – #S14
Square Edge profile
145 mm – #S04
Square Edge profile
195 mm – #S09
Suyaki original Shou Sugi Ban Specifications
SUYAKI: “Pure Char” original Shou Sugi Ban: heavily charred with magnificent charcoal black colour – no brushing
Exterior application: Delicate surface with maximum longevity
Interior application: Eye-catching surface with distinct texture
Species
Cryptomeria japonica, an endemic Japanese Cypress species (commonly known as "Japanese cedar") is extremely fragrant, weather and insect resistant, soft, with a low density, and high dimensional stability. It is the national tree of Japan, it is called "Sugi" in Japanese and stands for the “sugi” in Yakisugi and “Shou Sugi Ban”.
Heartwood
Unlimited combination of heartwood and sapwood, pith allowed.
Colour
Black with silver opalescence on the unfinished, or oiled, burned surface depending on light and angle. Polyurethane-bonded surface for interior applications will lose the iridescence and become an even black colour.
Checks
Checks allowed to ca. 2 mm as long as plank stability, weather-resistance and cosmetics are not adversely affected.
Moisture Content
Air and sundried, then burnt to 11~14% moisture content. Moisture content may fluctuate according to conditions during transport or warehousing. Please acclimate on site for approx. two weeks prior to installation.
Fire Resistance
Yakisugi shows higher resistance to fire compared to untreated timber, due to its charred layer. Additionally, exterior and interior fire-retardant treatment is available for code compliance. Currently surface treatment with B1 class performance (according to EN 13501-1).
Dimensional Stability
Culling of warped, crowned, crooked, or cupped boards is carried out during milling, air drying, sun drying, moulding, charring, packing, and finishing operations. Since growth rings are always aligned towards the outside of the plank profile, minor cupping is common and acceptable. Cupping is not noticeable after installation, and samples will cup more than shipped product.
Texture
Small to large crevasse pattern variable according to grain pattern, production environment, board density, moisture content, etc. The original Shou Sugi Ban soot layer is approximately 2 mm thick. The charred surface has an easily damaged shell unless prefinished.
Knots
Unlimited sound, tight knots permitted.
Hardness
320 –510
Grain
Outside of log faces outside of plank profile to ensure weather resistance, always with flat grain centre and angled grain to edges. Planks are graded for consistent grain density and pattern, with irregular grain patterns or boards deselected.
Finish
There are two oil prefinish formulation options for original Shou Sugi Ban Suyaki:
- For exteriors a penetrating natural oil finish with flexible hardening oil component will bond loose soot into the surface enough to ship and install. After drying minimal soot will wipe off when touched, though surface remains soft. This prefinished surface has maximum wood longevity but is not recommended for high-traffic areas.
- For interiors a high-traffic surface-hardening finish will bond loose soot into the surface and stabilize the soot layer for a more robust, washable finish. Colour is a consistent satin black.
- Unfinished charred Suyaki is soft and sooty when touched, and damages easily. Due to surface abrasion during transportation, and unfinished Suyaki simply being such a foreign product in the West, we do not ship without prefinish.
