The CSIA certified company with certified technicians told me without investigating the condition of the clay liner that it would be best to just remove the tiles due to the creosote in there. I am very wary of this recommendation and don't know how to feel about the fact that they we're not supportive of attempting to clean the chimney. But they said a line flex liner insulated would be just fine. So you think that this company will know what they are talking about. Right? Just like everyone else seems to know what they are talking about in my experience with this situation? I am honestly not so happy with anyone at this moment and they all have gotten money from me.After reading thru everything, one concern i have that nobody else brought up is the fact your clay tile is 10x14 and they want to remove it. There is tons of room in there to get a liner system with wrap down to the bottom.
Another concern is that allot of flex liner system are certified only with the clay tiles in place. Here in canada if the clay tiles are removed the liner system going back in has to be certified as a new lining system, not as a replacement liner.