Choosing the Right Nakamoto Forestry Yakisugi “Shou Sugi Ban” Products

Simple Guidance on Choosing the Right Nakamoto Forestry Product for You

Choosing a yakisugi (or shou sugi ban) product can be daunting or easy. Use this brief guide to cover the standard range of topics and decisions we go over during consultations with new customers.

If it is too much to read or you’re not sure what to spec even after review, then simply order select grade shiplap with the surface and color finish you’re after, and tell us whether exterior or interior.

Remember, there are no bad choices. Everything we offer is highest-grade millwork, best sustainability achievable, and fabulously beautiful. 

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Shou Sugi Ban Product Factors to Consider

  • Residential, commercial or institutional?
  • Exterior or interior?
  • Is your project a custom build or a development?
  • Widths, thicknesses, and profile layouts

Is your Project Residential? Commercial? Exterior? Interior?

We mill all of our wood products to accommodate both residential or commercial, exterior or interior. It is the different finishes and installation that will vary by application. Exterior finishes are elastic, leathery, and contain a fungicide. Interior finishes are hard shell and non-toxic.

[Exterior fastening needs to be over a screen wall assembly with headed face nails (or screws), interior wood is simply glued and tacked up. All this stuff is standard carpentry 101 so the installers or GC should not be alarmed by the exotic material; it installs just like any other wood.]

Exterior Yakisugi

Photo by Alan Tansey

Feel free to use any product we offer on residential exterior applications, just make sure it is an exterior-grade finish. It really is a free aesthetic exercise with the full range of options. Subjective beauty is often the main decision driver with people’s homes since cladding is such an important visual design component.

We often consult on commercial exteriors. Commercial is rarely a match for Suyaki® since exterior Suyaki is too delicate for high-traffic locations. If the public can’t touch the exterior Suyaki then it is fine to spec for that location. 

Some commercial projects might be a better match for an alkyd oil finish instead of linseed oil finish. This is because commercial exteriors are aesthetically more basic, and so generally warrant a more solid color with less fading. You can also more easily remove graffiti from the alkyd.

Interior Yakisugi

Interior simply needs to be an interior-grade finish. This means a hard-shell that doesn’t easily damage. Also if it contains a fungicide then the surface should be dry to prevent the chemical coming off when touched. Suyaki with interior polyurethane finish is completely fine for high-traffic locations. It is one of our best-sellers for both residential and commercial. Hospitality interiors are often especially flamboyant, so interior Suyaki and Pika-Pika are commonly specified.

Is Your Project a Custom Home or a Development?

For custom homes we see it all-whatever the design and budget dictate. Development projects are generally either single family spec homes, residential multi-family, or mixed use. These all fall into a set pattern of lowest price point, least exotic appearance, and ease of handling. 95% of the time these parameters translate into Gendai® select grade shiplap with a factory oil finish color matching the branding.

Gendai is the lowest price point per square foot, the most user-friendly option, and the fastest installation time. You wouldn’t want to put something on a spec home build that might turn off most of your potential buyers, or leave any money on the table.

Yakisugi Durability Considerations on Exteriors

Photo by Read McKendree

All of our shou sugi ban siding products will have superior durability in exterior applications over other products that are random resaw pattern, more affordable species, tongue & groove profile, KD, or made from engineered materials. The species and millwork are the key factors, with heat treatment as an extra durability kick. Oil finishes will keep the color longer if re-oiled periodically, but this is a color subject not a durability subject. The more soot left on the wood the longer it will last (i.e. Suyaki), but this really is a multi-generational discussion that most people don’t need to worry about. Everything we offer will outlast the current owner, even if not re-oiled. So I recommend you simply choose what you like the most and don’t hand-wring over durability.

Widths, Thicknesses, Profiles & Layouts (Form Follows Function)


Width is a form-follows-function exercise and the sweet spot for yakisugi is 6”-8”range. This is due to sustainably harvested log availability, dimensional stability, durability, and cost. In our world, due to yield and straightness narrow widths such as 3”-4” are much better when ripped from wider boards with the edges stained (keep the rips book-matched for best appearance). Burning narrow boards is problematic for a few reasons. Wider boards than 8” will move and check too much under high heat to make for a consistent product.


Due to high temperature heat treatment the sweet spot for thickness is ⅜”-⅝”. Any thicker and the boards will move dramatically during heat treatment, or will burn inconsistently. You can’t get a high yield of straight, long boards with ¾”, 6/4”, or 8/4” material. This is the reason so much faux sugi ban is on the market. [Also timber applications are not the Japanese heat treatment and will by nature be inconsistent in texture and tone-so timbers need a solid pigment oil finish to get consistent texture and color, not via burning.]

Profile and Layout

This subject is another example of how regular wood standards sometimes don’t work for yakisugi. Tongue and groove and nickel-gap (also called channel-lap or lap-n-gap) are commonly specified for siding, but both are problematic for us. More water tension and less air flow causes t&g to dry out very slowly, so we do not recommended using it on exteriors since it has a propensity to move and rot. Also the thin planks necessary for high-temp heat treatment are too thin for exterior t&g. Both t&g and nickel-gap profiles are problematic to apply oils to since they require physical contact to get into the nooks and crannies-not a good idea with a sooty product and an oil recirculating pump filter.

Shiplap with a bevelled edge and square edge are therefore the standard profiles for real yakisugi. Please see these diagrams for examples of different wall layout options using standard yakisugi profiles. It’s important to understand that the vapor barrier and flashing prevents water entry, not the siding itself. Listen to me now and think about it later: don’t spec tonue & groove on exterior walls, it is not good.

On Yakisugi Finishes and Fading (IMPORTANT!)

Photo by Nakamoto Forestry

All exterior options we offer have good color durability, but there is no way to avoid weathering and color change with stain-grade wood (stain-grade means high grade and paint-grade means low grade in the lumber world). Change is part of the Japanese aesthetic and you should embrace it if you want to use yakisugi. If fading or patina or blemishes are not your cup of tea, then better to save your budget for elsewhere on the project and go with painted wood siding.

There is nothing wrong with painted wood. Also off-species or lower grades with chemical or thermal modification and solid-color finishes marketed as faux or lightly burned yakisugi are a hybrid option. The Japanese heat-treatment produces a case-hardened surface and basically makes oil finishes redundant in terms of durability. The wood is the secret sauce, not the finish. But the market wants oil finishes in order to achieve a specific color, have the color last longer, and to glue in the soot.

Oil-Based vs. Water-Based Finishes

Choose either an oil-based or water-based finish. Appearance and weathering are a little different between the two, and if you’re not sure then simply go with oil-based for exterior, water-based for interior. We present linseed or tung oil finishes as standard options on exteriors simply because we think they are more beautiful and weather with a more traditional patina.

A basic premise with exterior finishes is that you can either have natural beauty or color longevity, but not both. The reason is that more pigment gives more UV protection, but it also blocks the wood’s beauty (called depth of grain). More and more pigment, and eventually you have a paint not a stain. That is why paints have superior color longevity to oils. You can also bring the cost down by hiding lower grade wood by using more pigment in a solid stain. We use semi-transparent to semi-solid pigment loads as the sweet spot.

Yakisugi Wood Grade

Premium clear grade wood is almost knot-free and is about a 200% upcharge over more common select grade that has lots of knots. Due to cost most projects end up being select grade. However, even considering the cost lots of our customers love the knotty texture and choose select grade for the character. 

There are two patterns I see in terms of why customers choose premium clear grade wood over select grade:

  1. It is a minimalist or modern design and they want as little busy-ness as possible
  2. They simply want the highest grade material available whatever the cost

In case you’re wondering, durability will actually be better with the select grade since it has more heartwood and therefore more mineral content. Sapwood is softer and will abrade more quickly in an abrasive climate. But we’re talking a lifetime before any meaningful difference shows, so let’s be realistic and call this a moot point.

Yakisugi Availability

Contractors have to manage a constantly fluctuating array of subcontractor and vendor schedules and pricing. Even if a certain item is listed with a vendor or spec, in the end it has to be available. The owners need completion and the contractor needs to get paid. Lead time is a major factor in the building materials market.

The Multiple-Decider Dynamic

Photo by Ema Peter

Suyaki or Pika-Pika are often the preferred choice by the owner or designer that initially finds us. But there are usually multiple decision-makers (spouses, partners), and Gendai is often the compromise choice.

Whether you need siding for a large commercial development or shiplap on an interior accent wall, we probably have a match for your build. Hopefully you’re more prepared to make a decision on which siding option is best for your upcoming project after reading through this guide. If not, our team is always happy to help.

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