with wood sub-floor, covered w/vinyl, can i lay hary board over vinyl?
I'm guessing hary board = hardy board. Tile should NEVER be installed over vinyl or luan. Vinyl/luan plywood will compress over time in high traffic areas and cause the tile to fail. Even with hard board/durock/plywood over the vinyl or luan. I think the only way I would give it a go ahead is if concrete was poured on it and ditra was used. Some people will give you the go ahead but I have seen this done and fail many times.
I did a small article on my website about this very subject. http://forum.creativecoveringsolutio...topic.php?t=12