Hello - can you help me from the beginning, please? I have had a stove in my lower level family room for years - it's an insert and we use the fireplace chimney for venting...I just added a patio room, and have a small cast iron stove - I just have to figure out how to put in a chimney pipe - It's a small stove about 12 x 24 and takes a 6" pipe with the "exit" on top of the stove. Easiest would be to go straight up, but I could go up about 3 feet, and then through the wall - the roof is completed, but the "wall" has not been finished...Should I use double, single, insulated? How high? Thanks for any help.