Wasn't there any problem with unsticking glued boards when you've been charring the roof? I tried shou sugi ban only on softer types of wood and I had this tricky thing but maybe on oak or other hard woods it doesn't matter? Btw, really well done!;)
Did you brushed the wood before applying the oil? I ask this because in my experience with softer woods, after burning, the char surface doesn't hold, I needed a really hard varnish to keep the appearance. I just wanted a clean matte finnish but that seem impossible
