I have been posting on here trying to figure out how to vent an add on furnace from my basment using the chimney that is there that goes to the attic but not thorugh the roof the way i have been looking at doing this was using a transition plate to connect the liner to class a in the attic and make a whole in the roof and run the class a out of it BUT HERE IT goES my new thought. How about running the insulated liner clear to the roof mounting the transition plate to the roof and connect the class a directly to it would this work thanks for the help