I’m curious as to whether anyone within the 4specs community know about this type of finish: “We have cedar siding, both inside and out, that we are staining black. The client’s just asked about charred finishes - something we proposed to them many months ago but they were not excited until they recently saw a sample from another project. So now I’m researching this finish, it is apparently a traditional Japanese method known as “shou-sugi-ban” or “yakisugi.” The idea is to burn the surface of the wood, then rinse/brush off the loose char, then maybe seal with oil (or maybe not).”
Hi Peggy.
I’ve seen samples from Delta - http://deltamillworks.com/. There are a number of options in terms of finish and even wood species but I have never specified the process. I presume other millwork houses have different names for the various finishes. Delta uses ‘alligator’, ‘tiger’ and other ways to describe the end product. Keep in mind that their ‘alligator’ finish looks like it will weather and will probably rub off if placed in a location where people can get to it. I don’t know how permanent the finish is or if there is any way to maintain it once it is installed.
Delta Millworks’ photo reminds me of the black charred surface of the well-preserved interior wood sliding doors in the ruins of Herculaneum, which was engulfed in fine ash and pyroclastic flow by the eruption of Vesuvius in 79 AD. Those doors have lasted 1,933 years. If properly protected, it can be a long-lasting finish…
I guess mimicry, as in similarity in appearance, is one of the human traits. Similar solutions to a problem occur at the same time between cultures at the antipodes Japan and the Swiss Alps for instance. While traveling in Switzerland a few years ago, I asked one of the locals how they achieved the finish (between medium to light brown) on their wood chalets. I was convinced that a stain was used. The answer was the same as Peggys client request the wood was charred.
Unfortunately I wasnt able to get the information as to further treatment after the wood is burned.
Peggy I know this doesnt answer your question, but I thought bringing up the connection between the two cultures was interesting.
I wonder if you have to treat the wood before charring it. I know that’s how you get wood to be fire-retardent, charring it after treatment since the char then protects the wood from further damage.
Bob, are you saying that we have to embed the wood in volcanic ash for 20 centuries before we can use the wood? I wonder how to specify THAT.
My guess is that any treatment after charring will affect the look. Some of the samples do look like they’ve been smoothed, with most of the char removed. The ‘alligator’ finish seems to be more of an ‘as-charred’ appearance.
It would be fun to see how different pre-char finishes and wood species react to the charring. Who’s up for a bonfire?
Its an intriguing topic, isn’t it? Here is a video I found that demonstrates a fairly simple approach, including applying a finish: http://www.youtube.com/watch?v=8CLvXUcOM-U
Gerard - yes, the cultural connection is interesting. Switzerland and Japan - who knew?
No, I wasn’t suggesting volcanic embedment, especially for millennia, as a viable treatment. Among other things, the availability, location and scheduling of such treatment would be problematic for both specifiers and estimators.
Though in the example cited it wasn’t a specified (or even desired) finish, the treatment itself took very little time–maybe only minutes or seconds. However, protection from human contact (and perhaps exposure to other destructive organisms, light, and the atmosphere) were likely key factors in preserving the wood’s appearance and integrity.
You would certainly want to specify a water-based varnish or at least recommend that fabricators allow the wood to cool sufficiently before applying a flamable finish coat.
Presumably you would get more contrast in the finished product if you only lightly charred the surface before abrading. Probably no abrasion for the as-charred finish. The duration of charring would seem to affect how deep the char would get, at least until the point when the char would be sufficiently thick to finally protect the core of the wood.
I guess this wouldn’t be a good option for retrofitting onto an existing wood framed building with cedar shingles.
The youtube video shows that doing this by hand with a torch and brush is labor-intensive, time consuming, and likely expensive, and probably not suited for in-situ application. Delta Millwork likely has semi-automated equipment to produce the finish. It may even be one of few shops set up to do that. Unusual finishes may best be specified through well-worded sample submittal requirements; I’d be especially chary about means and methods…
oddly enough, there was a letter to the editor in the SF Chronicle today about this topic. The writer is an adjunct assistant professor of medicine, Division of Occupational and Environmental Medicine, UCSF, and her letter says:
“The article described the recent use of a traditional Japanese wood treatment called shou-sugi-ban and recommended it for interior decor. Shou-sugi-ban uses controlled burning to change the color, texture and chemical makeup of wood. When you burn wood, you create carcinogens, including polycyclie aromatic hydrocarbons. Some of the carcinogens are released in the smoke, but some with remain in the charred wood if you put out the fire before the wood burns to ash. There is no sealant available that has been proven to seal in polycyclic aromatic hydrocarbons. There is no safe level of exposure to these carcinogens, and it is not safe to cover your walls with charred wood.”
Yes, but it smells good, you know, like hot tar being placed on your street or that smell when you walk into a tire store.
As to the sealers, most of those probably aren’t good to be inhaling either. Probably true of most of the products we design into our buildings like nylon carpet fiber, fiberglass insulation and ceiling products, mineral fibers, stain resistant coatings on fabrics, etc. It’s great how some of the better advancements have been in the paint and adhesives industries with reduction in VOCs.
I’m still waiting for someone to come up with the idea that we shouldn’t allow any wood-based products in buildings because all wood has naturally occuring formaldehyde.
Exactly. Get rid of the humans and our buildings will be much more pristine, especially hospitals. Hospitals are not good places for humans. Humans belong outside as much as possible with the rest of the formaldehyde-forming organisms.
Doing away with the human element on the planet would solve most, if not all, of the problems in the world. It is messy, destructive, careless, and dangerous at best.