Just bought a house that has an exterior cinder block chimney and with a clay thimble...not enough clearance around the clay thimble, so I'm replacing it. If I try to install any of the standard thimbles insul-flu, saf t, I will have to remove all combustibles and put a hole through the wall as my cinder block chimney is only 18" wide. My stove is 6"...if I use Class "A" chimney pipe through the wall and with 2" inch clearance, I will reach the cinder block chimney without putting a hole through my wall. My question is how do I connect the chimney pipe into my clay flue liner inside the cinder block chimney?
![[Hearth.com] class A pipe as a wall thimble [Hearth.com] class A pipe as a wall thimble](https://www.hearth.com/talk/data/attachments/167/167332-b746039d17a11ecfe8f646d4c49ef34b.jpg?hash=t0YDnRehHs)