In addition, in the case of a multi -storey building, drafts on the stairs or an open window on the top floor can affect the high -quality work of the chimney. The design of very many modern multi -storey buildings does not allow to mount chimneys at right angles (which is the most optimal option), so you have to perform inclined transitions. And if it is performed at an angle of less than 45 degrees vertically, then the probability of the formation of reverse traction is high. Problems may also arise due to the fact that you have not used fireplace for a long time. So if there was such a place, it is advisable to pre -warm the air in the chimney — burn a little paper in it.