Yakisugi (Shou Sugi Ban) Frequently Asked Questions

What is your minimum order?

400 square feet for the first line item.


What advice can you give me to help DIY yakisugi (shou sugi ban) for my project?

There is a holistic series of millwork steps to get good heat treatment and dimensional stability that are different from American millwork–it is not just burning lumber until it looks right or copying techniques from videos online.  The information available in English is incomplete and few people actually know the correct process (though lots of people think they do).  We have been milling yakisugi (shou sugi ban) for several decades and use logs from our own forests–so in any case there is little chance you will be able to DIY it for less cost than we sell retail for the same grade of wood.  However, if you’re dead set on doing it yourself here are the rules: use cypress only, face the outside of the log to the outside of the resawn moulder blank, do shiplap or square edge (not T&G), use planks about 1/2″ thick, dry the wood completely, use the traditional triangular flue method (weed burners do not work well at all) and burn it way beyond your comfort level to where you think you’ve ruined the plank, then if desired use a soft wire brush to knock down the soot.


Is yakisugi suitable for all climates?

We get asked a lot but actually very cold and very dry climates are super easy for wood compared to humid or marine climates.  Yakisugi is time-tested in Japan (a long, skinny country with climate ranging semi-tropical to Siberian, and almost all coastal marine) and will probably outlast any other softwood in any climate.


Is there potential radiation contamination in Nakamoto Forestry’s yakisugi due to being from Japan?

Absolutely zero for a number of reasons.


Is Nakamoto Forestry’s yakisugi more expensive and does it have a larger carbon footprint due to being imported?

We are actually able to offer a lower price point since our logs are sourced internally and our kilns and entire manufacturing process are to economies of scale above and beyond any “shou sugi ban” manufacturer in North America.  In terms of shipping cost and carbon footprint, 99% of the trip is by efficient ocean freight with only a total trucking time of two hours.


Is yakisugi installed horizontally or vertically?

Both–also diagonally.


Some of the samples are cupped but will the wood be cupped when received?

Due to the traditional resaw pattern optimized for wood longevity and dimensional stability, as well as the nature of how wood dries, there will generally be cupping of approximately 1/16″ in most boards. We spec two face nails every 16″OC to minimize cupping.  Note samples cup much more than final product due to short lengths.


Can yakisugi be used for interior paneling?

Absolutely.  There are also more stain, topcoat, and fire retardant options for interior applications.


Do you offer a yakisugi product for flooring or furniture?

The Japanese heat treatment process is never used for flooring or furniture since cypress is too soft for flooring, and yakisugi planks are too thin for most furniture applications.  Yakisugi is for wall and ceiling cladding only.  Burning flooring or furniture or counters is a fun design thing we’ve seen but it is not Japanese yakisugi (shou sugi ban) heat treatment.


What are the standard dimensions?

In Japan standard thickness is 3/8” (10mm), but we stock 9/16” (15mm) since that is as thick we can heat treat with good yield.  Trying to heat treat a plank thickness over 9/16″ (example 3/4″) by the Japanese process doesn’t work since interior moisture content will stay around 12% while the surface goes down to 0%–which results in crooking, warping, twisting, or checking.  Siding and panelling needs to be straight and flat, and this is heat treatment not a cosmetic surface finish.  Please see the standard profile cross section here.


Why don’t you sell T&G?

T&G will wick water and rot on an exterior unless covered by a roof.  Exterior wood cladding cannot be blind nailed since it will always move over time and the fasteners must be accessible to tighten the wall plane back to flat.  Plus you can’t burn a thin T&G profile deeply enough to heat treat.  We only stock profiles that can be used for interior and exterior, and we specialize in products that have best possible longevity.


Can Nakamoto Forestry supply custom profiles, dimensions, or clears?

We have premium select clears in our Portland stock.  Our focus is to supply at a low price point and ship quickly, therefore we do not mill custom profiles or lengths.


Can North American carpenters and painters install and finish yakisugi without specific experience?

Yes, yakisugi is just regular wood with a unique surface treatment.


Why do you recommend prefinishing with an oil stain?  Doesn’t yakisugi have improved longevity without oiling?

The wood is heat treated and therefore has improved longevity, but most people want the color to remain consistent over time.  Without an oil stain the wood will change color just like any other wood.  Some people embrace the traditional “sabi” patina aesthetic, and look forward to the organic, colorful weathering.  With yakisugi, owners have the choice of doing maintenance or not.  Re-oiling can be done as a periodic maintenance, or the patina can be enjoyed as it develops over the decades.  Also most owners want the soot to be bonded into the surface with an oil stain so that it doesn’t come off when touched.  Another reason we use oil stain prefinishes is that most designers or owners want a specific color or look, and since all exterior grade oil stains have a pigment load as the primary UV inhibitor, the designer or owner can decide what color they want their siding to be.  Note that Gendai is the only product we will sell without an oil stain.  Suyaki is too soft to ship and install without prefinish, and Pika-Pika will get sooty fingerprint blemishes all over it without a prefinish.


Can yakisugi be treated with flame retardant?

Yes, please inquire on your project’s specific requirements.


How is yakisugi installed?

Yakisugi is just solid wood lapped siding and is installed the same as untreated wood siding.  See our Installation Guidelines.


What fasteners are recommended?

For exterior we recommend headed, ring-shank stainless nails at least 2” long.  Since unavailable elsewhere in a high grade, we custom order and stock black factory painted stainless nails.  Most customers buying dark-colored siding from us also buy nails.  Other nail colors such as brite, brown, white, or gray are available through your regular fastener supplier.  We have yet to see a screw option that installs efficiently and looks good, and siding nails are standard for installing our product on exteriors same as most wood.  For interior applications finish nails and construction adhesive work well.


What corner or window/door detail do you recommend?

There are several options same as any siding/paneling, and it really is a designer decision.  We stock extruded aluminum profiles for outside corners (specs on our Accessories page), you can use our square-edge profiles, stain thicker un-heat-treated trim-stock to match, miter, square cut with shadow gap, etc.


Does the charred finish shed from weather exposure and will it be sooty?

Yakisugi (shou sugi ban) will shed soot over time on an exterior but the erosion is simply so gradual that you will never notice.  Most yakisugi is installed prefinished, which bonds any loose soot to the surface with the oil stain.  Wipe the wall down after install with a sopping wet rag to clean any soot residue from the install, or simply let a good rain or two wash it off.  Our Gendai can be installed without a prefinish so it will be sooty for several months.  Otherwise surface soot is never an issue due to oil stain prefinish.

Note that since cypress has tannin content, on an exterior application there is always a chance the tannins could bleed out from rain.  This can temporarily stain a lighter color underpinning below the wall.  There is a chance tannins could leach out during the first several months, but after a year or more the stains will wash off resolving any staining (see pics below). This clause acts as a disclaimer, and actually we have not had a complaint yet about tannin bleed.

What is your minimum order?
400 square feet for the first line item.

What advice can you give me to help DIY yakisugi (shou sugi ban) for my project?
There is a holistic series of millwork steps to get good heat treatment and dimensional stability that are different from American millwork–it is not just burning lumber until it looks right or copying techniques from videos online.  The information available in English is incomplete and few people actually know the correct process (though lots of people think they do).  We have been milling yakisugi (shou sugi ban) for several decades and use logs from our own forests–so in any case there is little chance you will be able to DIY it for less cost than we sell retail for the same grade of wood.  However, if you’re dead set on doing it yourself here are the rules: use cypress only, face the outside of the log to the outside of the resawn moulder blank, do shiplap or square edge (not T&G), use planks about 1/2″ thick, dry the wood completely, use the traditional triangular flue method (weed burners do not work well at all) and burn it way beyond your comfort level to where you think you’ve ruined the plank, then if desired use a soft wire brush to knock down the soot.

Is yakisugi suitable for all climates?
We get asked a lot but actually very cold and very dry climates are super easy for wood compared to humid or marine climates.  Yakisugi is time-tested in Japan (a long, skinny country with climate ranging semi-tropical to Siberian, and almost all coastal marine) and will probably outlast any other softwood in any climate.

Is there potential radiation contamination in Nakamoto Forestry’s yakisugi due to being from Japan?
Absolutely zero for a number of reasons.

Is Nakamoto Forestry’s yakisugi more expensive and does it have a larger carbon footprint due to being imported?
We are actually able to offer a lower price point since our logs are sourced internally and our kilns and entire manufacturing process are to economies of scale above and beyond any “shou sugi ban” manufacturer in North America.  In terms of shipping cost and carbon footprint, 99% of the trip is by efficient ocean freight with only a total trucking time of two hours.

Is yakisugi installed horizontally or vertically?
Both–also diagonally.

Some of the samples are cupped but will the wood be cupped when received?
Due to the traditional resaw pattern optimized for wood longevity and dimensional stability, as well as the nature of how wood dries, there will generally be cupping of approximately 1/16″ in most boards. We spec two face nails every 16″OC to minimize cupping.  Note samples cup much more than final product due to short lengths.

Can yakisugi be used for interior paneling?
Absolutely.  There are also more stain, topcoat, and fire retardant options for interior applications.

Do you offer a yakisugi product for flooring or furniture?
The Japanese heat treatment process is never used for flooring or furniture since cypress is too soft for flooring, and yakisugi planks are too thin for most furniture applications.  Yakisugi is for wall and ceiling cladding only.  Burning flooring or furniture or counters is a fun design thing we’ve seen but it is not Japanese yakisugi (shou sugi ban) heat treatment.

What are the standard dimensions?
In Japan standard thickness is 3/8” (10mm), but we stock 9/16” (15mm) since that is as thick we can heat treat with good yield.  Trying to heat treat a plank thickness over 9/16″ (example 3/4″) by the Japanese process doesn’t work since interior moisture content will stay around 12% while the surface goes down to 0%–which results in crooking, warping, twisting, or checking.  Siding and panelling needs to be straight and flat, and this is heat treatment not a cosmetic surface finish.  Please see the standard profile cross section here.

Why don’t you sell T&G?
T&G will wick water and rot on an exterior unless covered by a roof.  Exterior wood cladding cannot be blind nailed since it will always move over time and the fasteners must be accessible to tighten the wall plane back to flat.  Plus you can’t burn a thin T&G profile deeply enough to heat treat.  We only stock profiles that can be used for interior and exterior, and we specialize in products that have best possible longevity.

Can Nakamoto Forestry supply custom profiles, dimensions, or clears?
We have premium select clears in our Portland stock.  Our focus is to supply at a low price point and ship quickly, therefore we do not mill custom profiles or lengths.

Can North American carpenters and painters install and finish yakisugi without specific experience?
Yes, yakisugi is just regular wood with a unique surface treatment.

Why do you recommend prefinishing with an oil stain?  Doesn’t yakisugi have improved longevity without oiling?
The wood is heat treated and therefore has improved longevity, but most people want the color to remain consistent over time.  Without an oil stain the wood will change color just like any other wood.  Some people embrace the traditional “sabi” patina aesthetic, and look forward to the organic, colorful weathering.  With yakisugi, owners have the choice of doing maintenance or not.  Re-oiling can be done as a periodic maintenance, or the patina can be enjoyed as it develops over the decades.  Also most owners want the soot to be bonded into the surface with an oil stain so that it doesn’t come off when touched.  Another reason we use oil stain prefinishes is that most designers or owners want a specific color or look, and since all exterior grade oil stains have a pigment load as the primary UV inhibitor, the designer or owner can decide what color they want their siding to be.  Note that Gendai is the only product we will sell without an oil stain.  Suyaki is too soft to ship and install without prefinish, and Pika-Pika will get sooty fingerprint blemishes all over it without a prefinish.

Can yakisugi be treated with flame retardant?
Yes, please inquire on your project’s specific requirements.

How is yakisugi installed?
Yakisugi is just solid wood lapped siding and is installed the same as untreated wood siding.  See our Installation Guidelines.

What fasteners are recommended?
For exterior we recommend headed, ring-shank stainless nails at least 2” long.  Since unavailable elsewhere in a high grade, we custom order and stock black factory painted stainless nails.  Most customers buying dark-colored siding from us also buy nails.  Other nail colors such as brite, brown, white, or gray are available through your regular fastener supplier.  We have yet to see a screw option that installs efficiently and looks good, and siding nails are standard for installing our product on exteriors same as most wood.  For interior applications finish nails and construction adhesive work well.

What corner or window/door detail do you recommend?
There are several options same as any siding/paneling, and it really is a designer decision.  We stock extruded aluminum profiles for outside corners (specs on our Accessories page), you can use our square-edge profiles, stain thicker un-heat-treated trim-stock to match, miter, square cut with shadow gap, etc.

Does the charred finish shed from weather exposure and will it be sooty?
Yakisugi (shou sugi ban) will shed soot over time on an exterior but the erosion is simply so gradual that you will never notice.  Most yakisugi is installed prefinished, which bonds any loose soot to the surface with the oil stain.  Wipe the wall down after install with a sopping wet rag to clean any soot residue from the install, or simply let a good rain or two wash it off.  Our Gendai can be installed without a prefinish so it will be sooty for several months.  Otherwise surface soot is never an issue due to oil stain prefinish.

Note that since cypress has tannin content, on an exterior application there is always a chance the tannins could bleed out from rain.  This can temporarily stain a lighter color underpinning below the wall.  There is a chance tannins could leach out during the first several months, but after a year or more the stains will wash off resolving any staining (see pics below). This clause acts as a disclaimer, and actually we have not had a complaint yet about tannin bleed.

What else should I know about yakisugi (shou sugi ban) but don’t know to ask?

Please keep in mind that yakisugi (shou sugi ban) is a unique and organic wood product.  You can learn more about what it is and how it’s made here.  While our grading and millwork produces the most consistent yakisugi (shou sugi ban) product available in the world, it is still somewhat foreign, sooty, and will weather over time.  Make sure you are completely comfortable with the product before specifying it for your project.  In the end what really matters is that you use a beautiful, sustainably harvested, and natural wood siding–not chemically treated wood or cement board–for your project.

What else should I know about shou sugi ban but don’t know to ask?

Please keep in mind that yakisugi (shou sugi ban) is a unique and organic wood product.  You can learn more about what it is and how it’s made here.  While our grading and millwork produces the most consistent yakisugi (shou sugi ban) product available in the world, it is still somewhat foreign, sooty, and will weather over time.  Make sure you are completely comfortable with the product before specifying it for your project.  In the end what really matters is that you use a beautiful, sustainably harvested, and natural wood siding–not chemically treated wood or cement board–for your project.

cypress logs for Yakisugi mill - Nakamoto Forestry
cypress logs for Yakisugi mill - Nakamoto Forestry
cypress logs for Yakisugi mill - Nakamoto Forestry