Shou-sugi-ban or "the burning of Japanese cypress (sugi)," may be an age old Japanese practice, but it has become increasingly popular outside of the islands, and even seen use by Australian architects.
The process is relatively simple and involves using either an open fire or jet flame to torch the exterior of timber (around 3-5mm) so that it achieves a charred finish. See instructions on those processes below.
The process forms a carbon layer on the exterior of the boards which protects the lumber inside and is said to render the wood nearly maintenance free. It has also been suggested that it will make the boards more resistant to fire*, rot and pests, and will have an expected life span of more than 80 years.
Traditional Japanese cypress, various types of cedar and larch are the more commonly used timbers for charred cladding although decking experiments has also seen hardwood used in the process.
Charring the exteriors of your project to a black finish will of course have an impact on heat gain and therefore cooling energy costs. Some architects have incorporated rainscreens with a 20mm gap and ventilation openings to relieve heat gain and address this issue.
Here is a step by step instruction of the traditional process whereby the timber is charred using an open flame. It is performed by well-known Japanese architect Terunobu Fujimori who has used the process in a variety of applications including 'The Beetle's House' at the bottom of the page.
- Three pieces of cedar boards are bound together to form a long triangle and the fire is started within the tunnel with packed newspapers.
- Fujimori uses a tool to coax the fire up and down the boards to ensure even charring
- He waits seven minutes until the boards are evenly burned and then separates them
- Fujimori then pours water over boards to halt charring process
Photography by Adam Friedberg
.The process using a portable jet flame
Crescent House, Sydney with charred Cedar by Andrew Burns (2013)Photography by Adam Friedberg
Rooftecture HH, Shisho City Japan by Endo Shuhei (2011) (Photography: Yoshiharu Matsumura)Photography by Yoshiharu
House 2.0, Amsterdam by FARO Architecten (2009)
Photography by Hans Peter Follmi
Wabi House, California with charred Cedar by Sebastian Mariscal Architects (2008)
Photography by Daniel Hennessy
Beetle’s House, London with charred pine beams by Terunobu Fujimori (2008)
Photography by Pasi Aalto