The metal lining of a chimney has bulged and the damper doesn't close. Like this: I(
I don't use the fireplace so I've tried to temporarily block the wind that blows in by draping a layer of insulation over the damper and closing it as far as possible but obviously there needs to be a permanent fix. Does the metal usually go up all the way in a chimney, or is it just where the firebox narrows into the chimney? The house was built in the 50's as a mountain tourist rental and was not maintaned well for many years, so I don't know how long it's been that way.
Any suggestions other than ripping out the whole chimney?