This something I have never done but have my eye on a couple. How do you handle smoked, charred wooden ceilings, wooden pews, etc,? Talking mainly about the cleanup part. Some folks used Mean Green on my drywall and my wooden furniture ( ). Never again will that stuff touch my wood unless I feel the person doing it knows how to mix it. i'm sorry, it was not Mean Green, it was the other green. It still removed some finish and patina.
I was in house once that had some fire damage in the attic at one time. It had been Kilzed. Must have been the wrong kind, still had a burnt oder.
If you are trying to paint something that is charred you are SOL. If you had to try cleaning it up so it would accept paint I would say you are going to be there for a while.
the only thing I could reccomend is TSP, steel wool, sand paper, a solid Zinsser primer and some patients. but seriously if the wood is burnt I would just replace it.
the reason being that on the cellular level the wood is no longer the same when it is charred. you will have to restore it to where the wood is no longer burnt which means sanding it down to where the wood wasn't burnt or replacing it (replacing would be easier).
insurance and inspectors are usually involved on these jobs. They determine what is replaced. I've done some burn outs, but not big ones. Clean the soot and shoot original kilz on it. Then paint. I'm not sure if there is really a way to get rid of the smoke smell completely.