It’s a counterintuitive but ingenious idea: heating wood to render it fireproof. If you’ve ever tried to rekindle a campfire using burnt logs, you get the idea. The combustion also neutralizes the cellulose in the wood — the carbohydrates that termites, fungus and bacteria love — making it undesirable to pests and resistant to rot. The resulting charcoal layer repels water and prevents sun damage as well. By some estimates, boards that have undergone this process can last 80 years or more, but Japan’s Buddhist Horyuji Temple in Nara prefecture, whose five-story pagoda is one of the world’s oldest extant wooden structures, has been around for much longer. Initially built in A.D. 607, the pagoda caught fire and was rebuilt in 711 using shou sugi ban.
It works on other wood, but I read it works best on softer open grain woods.
