Question: What is the maximum horizontal length for a stove pipe piece running from the wood stove through the wall ? I want to run my stovepipe past my roof overhang. Answer: It's not usually specified, but in practice depends on the height of the chimney and how many bends there are. Six feet would be a good limit to follow. Some metal chimneys have 15 and 30 degree els which allow for offsetting outside to go around your overhang.