Hi all, I'm new to the forum. I have bought a house with an internal chimney. The chimney is 13.5' tall, double bricked from the floor to approximately 7' (into the attic) then single brick the rest of the way up. Its clay lined. The single brickand tile portion thru the roof has linear cracks on two sides. My plans are to take the single brick portion down to double brick, use duraliner and transition into class A to replace the single brick. Here's the problem, the mason mortared the bricks to the tile, so there's no airspace. I'm assuming this because the o.d. clay dimension is 8" and the o.d chimney dimension is 16". So just how big of a job is this going to be removing the brick from around the clay?