I'm adding a small wood stove to a back room of my house, on the back side of an existing brick chimney (fire place faces into a different room). The only woodstove installer available has not gone through a chimney before, but thinks it will draw OK. The stove pipe will go in about 3 feet above the damper. The out of state wholesale dealer says I may need some sort of adaptor, but doesn't ship them. In state dealers won't give me info, because I didn't buy the stove from them. Question: DO I need something else, or just a stove pipe going up, then a 90 degree elbow, and into the existing chimney? Would it be better/less trouble to go straight through the ceiling and out the roof?