This is a problem that I have been avoiding for about 7 years. I bought this house (built in 1970's) knowing the original clay liner was cracked. I currently have a fireplace insert inside the opening. I was able to aquire enought 7" diameter stainless steel pieces to drop a rigid liner down my clay chimney. NOW here is the problem. When I pulled out the insert to look up into the chimeny, it is a straight shot up but the dampner opening is about 6X27 with the piece sticking up in the center where the original dampner was. (it's gone now,just an opening) The clay liner stops about 3 feet above the dampner area, which is well out of reach. My original plan was to drop my new liner down to the bottom of the clay liner with a plate installed to fill most of the void around the liner and then seal the top with a second plate using high heat silicone. NOW I'm seeing on the web that this may not be up to fire codes even thought that's what the original owners were doing. I understand that there is a problem with creasote building up and have no problem keeping up with cleaning this area and the chimney each year. Can anyone help? I'll look at any ideas. I'm doing it myself because I had one guy give me a quote of $2000 and I don't have that in my budget. I would like to use the fireplace but not at the cost of safety.