Shou Sugi Ban Siding Maintenance

Wash, Tighten, Re-oil.

The main challenge for the North American shou sugi ban market is that it hasn’t been around for very long. Not only have most people never seen charred wood siding in person, in most cases they’ve never even heard of it. One of the basic premises of shou sugi ban is the need for little or no maintenance. However, it will last longer and look better if you do some basic maintenance. There are three types of regular maintenance used for shou sugi ban siding: washing the walls to keep them clean, tightening the nails to keep the siding plane flat, and re-oiling to keep the color looking fresh.

Shou Sugi Ban Maintenance in Japan

In Japan, once the siding is on the structure it won’t get touched again. Unless the building is torn down first, the wood will still be on the walls fo a century. What started out as what we call Suyaki or Gendai will become worn by the weather over the years. This eventually washes off the soot layer entirely and exposes the wood below. The exposed wood will then turn silver, reddish brown, or cycle between silver and brown over the decades. The natural, unique cycle of patina will depend on several factors. Which direction the walls are oriented, how much sun exposure they have, how much moisture hits them, and whether or not an oil coating has been applied to further protect the surface.

See more historic Japanese yakisugi (shou sugi ban) in our gallery

The Japanese building culture allows this weathering, differing significantly from North America. In Japan, they demolish and rebuild buildings with new materials every generation or two. In North America, we are much more likely to maintain and renovate buildings, sometimes extending their lifespan indefinitely. The average residence lifespan in Japan is 33 years, while in North America it’s around 70. That’s why our historical gallery is important to look through! To help understand how traditional yakisugi will age over a long period of time, especially without regular maintenance.

Shou Sugi Ban Maintenance in North America

Here in North America we have regular painting maintenance as part of our building culture. We also typically value the beauty in things that look fresh and new. Since it’s expected that buildings last longer here, we should therefore give shou sugi ban siding more care and attention than is standard in Japan. This will maintain its appearance over time. This starts with correctly identifying what is happening to different areas of the wood and going through the proper procedures.

We’ve assembled a few quick tips on what to look out for in the first five years of your shou sugi ban’s life based on Bill’s personal home as a case study. He has a shou sugi ban privacy fence self-built using Suyaki and Pika-Pika when Nakamoto Forestry North America was still young back in 2017–and he hasn’t done any maintenance until now. Check out the video below if you want to see firsthand what Bill’s tips and results are, otherwise read on! 

What you’ll need: 

  • Hammer
  • Loose siding nails (recommended)
  • Straightedge
  • Hose with pistol grip or similar nozzle 
  • Rags
  • Soft or medium bristle hand brush
  • Soap or TSP
  • Bucket
  • Touch-up oil (optional)
  • Paintbrush for oil (optional)

Shou Sugi Ban Maintenance Steps

  1. Survey the siding for blemishes such as scratches or gouges, places where the oil is fading more quickly than others, or dirt and pollen buildup. Also check for areas where the wood has moved from weather exposure.
  2. Tap loose boards back into place using a hammer. You can use a straightedge to gauge where boards may have shifted. Always use headed face nails for yakisugi siding. Wood will always move and headed nails are easy to periodically retighten to keep it looking great. 
  3. Wash your siding by spraying it down with a regular hose and pistol grip or similar nozzle, NEVER a power washer. For areas where dirt or pollen buildup is severe, use soapy water and a damp rag to gently wash the surface.
  4. Scrub areas to be re-oiled using a rag or soft to medium bristle scrub brush with soapy water or a light TSP solution. Allow it to dry fully before applying any oil. 
  5. Either touch up or re-coat areas that need freshening up using a hand brush, and keep a rag handy to catch drips. We provide touch-up oil with every order we ship, so please keep it on hand for any touchup during the first several years of your shou sugi ban’s lifetime. You can also re-oil the entire wall or structure to like-new appearance, though you will need a lot more than one quart!
  6. Let it dry and enjoy! Your shou sugi ban shouldn’t need maintenance for another few years. Keep an eye out for spots you may want to address on your next round of maintenance. Or simply do nothing and let it age and patina, appreciating its beauty as they have done in Japan for centuries. It’s maintenance-optional and this is up to you!

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