SHOU SUGI BAN
interior cladding :: exterior cladding
reSAWN has modernized the ancient Japanese shou sugi ban process to create high performance, beautiful wood products. The designs vary greatly in aesthetics from a fully charred black to a light, subtle gray. reSAWN uses only the highest quality wood species to ensure unmatched performance in any suitable application. Species include domestic western red cedar, cypress, white oak, red oak, black walnut, and reclaimed hemlock.
reSAWN is committed to working with Architect and Designers to create projects that highlight wood’s natural beauty and sustainability. We are continually improving our charring techniques and finishes. Shou sugi ban products are available for exterior siding and interior cladding.
A SPECIFIER’S GUIDE TO SHOU SUGI BAN
WHY SPECIFY WOOD as compared to other building materials?
Before we begin to discuss the benefits of the shou sugi ban treatment, we must first examine the benefits of wood as a building material. Wood is a material that absorbs carbon from its environment – known as a carbon sink. Wood holds onto carbon throughout its life as both a tree and as a building material. The tree’s own “building material” comes from carbon when it takes in CO2, splits the molecule, and releases oxygen back into the air. Besides the advantage of being a carbon sink, wood also has a very low embodied energy. The embodied energy of a building is the energy consumed by all of the processes and materials associated with the production of that building. Wood requires minimal energy to produce and install when compared to other building materials such as steel and concrete. Another advantageous property of wood is its thermal conductivity. Wood has a low thermal conductivity because of its porous nature. Wood is a naturally insulating material – especially softwoods because of their low density. And finally, wood is the only building material whose global amount is always increasing. Using wood in the build environment decreases/avoids the use of non-renewable resources. As we say as reSAWN, the value of a natural product is without equal.
IN SUMMARY – BENEFITS OF WOOD:
- carbon sink
- low embodied energy
- low thermal conductivity (naturally insulating)
- renewable resource
BENEFITS of SHOU SUGI BAN
Charring wood is a weathering and strengthening process that has been used by many cultures throughout history. Japanese carpenters often used recovered driftwood because of its artistic and unique finish that complemented the materials weathered durability. Driftwood was in high demand and limited supply, so carpenters began looking for other ways to get an aesthetic and durable material. The Japanese “shou sugi ban” technique on Japanese Cedar proved to be the most effective way to achieve the visual and performance characteristics. With a shortage of Japanese Cedar, the process fell out of practice until contemporary architect Terunobu Fujimori began using it again. With an abundant supply of domestic softwoods, Americans began charring their own wood with a process inspired by the original Japanese carpenters.
reSAWN takes great pride in designing products on high-performance, stable domestic softwoods and contemporary modified woods. In addition, charring adds an extra layer of protection to wood’s structural durability. The shou sugi ban process carbonizes the wood’s surface and creates an outer char layer that protects against rot, insects, and moisture related decay in exterior applications.
The modernizing of shou sugi ban allows us to make products featuring many color tones that fit with virtually any project aesthetic. Wood’s grain structure and natural character marks give it its beauty. The product line offers textural and tonal variation that takes advantage of wood’s rustic appearance. reSAWN’s designs have been used in very diverse project types from Silicon Valley startups to Pennsylvania residences.
APPLICATIONS for SHOU SUGI BAN
Shou sugi ban charred woods are most often used for exterior siding and interior wall cladding. It can also be used for flooring, ceiling cladding, furniture and millwork. When selecting materials for a specific application the most important factors to consider are durability, maintenance, impact resistance and of course aesthetics.
Charred Wood Exterior Applications
For exterior applications, we recommend shou sugi ban charred Accoya and Kebony. These are two modified woods – the modification increases the durability of these woods making them an excellent choice for exterior applications. Both come with extensive warranties. Additionally, we recommend Western Red Cedar – a naturally durable softwood that create extractives (Thujaplicans and Phenolics) that ward off decay caused by insects, water infiltration, and fungi. The extractives increase with age leading to a longer lasting product life cycle–especially in exterior applications. We also offer several designs on domestic Cypress. When specifying Cypress for exterior applications, we strongly recommend using Select Grade materials for added stability.
Charred Wood Interior Wall Cladding, Ceiling Claddng and Millwork
Any of reSAWN’s shou sugi ban designs can be used for interior wall cladding or ceiling cladding. The most important factor to consider in specifying interior materials is how much impact the area will take.
When evaluating resiliency with CHARRED materials it is a trade off – the heavier the char the more weather/rot resistant as intended by burning the wood; however, charcoal is soft, especially on a soft wood. From an impact perspective, brushed designs (such as KOI, KUJAKU etc.) will be more impact resistant than MATSU as the char is only on part of the wood.
Charred Wood Flooring
reSAWN currently offers charred domestic white oak and black walnut in a variety of finishes. These are finished with hardwax oil. A hardwax oil finish respects and enhances the natural look and feel of the wood. It is easily distinguished by its elegant and sophisticated matte appearance. Charred wood finished with hardwax oil will scratch and dent, but the difference is that it may be easily spot-repaired. We offer these designs in both solid and engineered construction. For flooring, we recommend engineered wood for added stability.
HOW OFTEN DOES EXTERIOR SHOU SUGI BAN NEED TO BE RECOATED?
These materials are meant to age in place and will weather naturally over time. Exterior materials can be sprayed down with a hose and brushed with a soft bristle but are not meant to be power washed. Over time, flaking of the charred surface will occur on designs where the charcoal is left in tact, such as MATSU. Flaking of the fully charred designs such as MATSU will reveal blackened cypress with variations in color from grey to brown tones and overt time more grey tones. A reapplication of the top coat will aid in arresting the degradation of the charcoal. Some shou sugi ban products include exposed wood which has been finished with an exterior top coat. Despite this top coat, the exposed wood will naturally patina over time. Exterior materials will require reapplication of top coat as weather, sun and wind affect these surfaces. Wood siding products such as teak and soft woods such as cedar, cypress, hemlock and pine all require some form of maintenance.
Proper maintenance starts with visual inspection. A time frame of two (2) – three (3) years on the south and west exposures and three (3) – four (4) years on the north and east exposures can be used as a general guideline. However, as weathering, exposure conditions, altitude, and applications can vary, maintenance may be needed sooner and should be performed when visually necessary, regardless of time frame.
To maintain the original aesthetic of brushed designs (such as KUJAKU, HADAKA, AKA etc.), a top coat will need to be re-applied following the above guidelines. These designs have been brushed to remove some of the charring, revealing the cypress wood grain and then sealed. The exposed cypress wood grain will fade naturally to grey. This is not a defect, but a natural process of wood. Any wood siding product will grey the same and will require some form of maintenance including such materials as ipe, teak and soft woods such as cedar, cypress, hemlock.