The damper can be made of cast iron or steel, it can also be retractable like a regular lock and at the same time have several positions for fixing, which is used to adjust the thrust if necessary, or it can be rotary when it is opened with a handle on a special axis. It is best to install the damper at a height of 20 cm from the edge of the furnace hole, so that the smoke apron remains the one that is needed in volume, which prevents smoke from entering the room. Also, we need to install a visor on the top of the pipe, its design will prevent external precipitation from entering the pipe hole. By the way, now a saw blade is often used in repairs, they usually buy it before repair.
If a chimney is necessary, then after its installation and after the frame is installed, it is worth making sure that all the necessary electrical cables are laid, which will make it possible to provide power to the electric heating panel of the fireplace (it is most often used in multi-apartment high-rise buildings, for arranging fireplace) or lighting.
After that, you can make plasterboard sheathing. Using a sheet of magnesite, you can make the inside of the skin, and then insulate it using a heat-resistant foil material – faerok, which has good heat reflection.