The single wall method refers to the installation of a single wall stovepipe. This is a stovepipe that only has one layer, one metal shell to channel smoke. A single wall is more simple and cheaper than a double wall, but it has a very restricted use. It can only be installed if you are directly channeling smoke from the stove pipe into a chimney that is located in a nearby wall.
The double wall stovepipe usually has a stainless steel inner wall and heat-resistant coated outer wall. There is an airspace between the two walls that helps stop heat from escaping too easily and causing fire damage problems. The double wall can also help protect pot belly stoves sufficiently to be used over longer distances or channeled into a chimney section in the ceiling. Some states may require that only double wall pipes be used no matter the arrangement.
The stove pipe will always need to travel at least some distance, because the pot belly stove needs to sit away from the walls. Too close to a wall and the heat can present a fire danger. Requirements for the distance can vary, but the amount for a typical masonry wall is 24 inches. This may be lowered to 18 inches with the addition of insulation boards and noncombustible protection layers.
Floors also need to be protected, including the floor area where you put your stove and any floor you run your pipe over. Regulations usually require a concrete slab covered with brick or tile, or approved stove boards, master or cement underlayments that are then covered with tile. This section must extend 18 inches in all directions from the stove and meet the wall surface protection behind the stove.