How does Shou sugi ban improve timber? 

The process of Japanese burnt timber cladding starts with careful selection of the right timber species. Not all timbers suit the charring process, some like Western Red Cedar and Californian Redwood produce a beautiful timber finish when charred then brushed, but the char produced by these timbers is far too soft to be used as a traditional full char finish. The Char may only last a year  or two.

 

Grading the timber is for imperfections is important and you must grade for straightness, grain density, and only heartwood is suitable.

 

The heat conditioning through Shou sugi ban is intense, up to 1060 degrees  C to achieve the preferred level of char. The Japanese charred timber process give the timber a longer life and hardens the surface. This strengthens the timber's cell structure through burning off cellulose which improves stability. Then the wood is misted at just the right moment to finish the hardening and start the cooling process.