Hi all I need help fireplace. I am told it is a old heatalator style fireplace liner. Hopefully from the pictures you ca see what sad shape it is in. Previous owner had installed a Lopi insert that I removed because of a lot of heat coming out from behind the wood mantel From the pictures I hope you can see that that hole is right where the the firebox and the terracotta flue meet .The stove was installed with a ss insulated liner .I hope to fix this myself .P.S. the fire box liner is in bad shape and some of the cement is lose. Can I remove the liner and use chamber tech to repair the firebox and will the same method work for the hole behind the mantel. thank you