According to Art. 62 of the Building Law, every building owner is required to have a chimney inspection carried out at least once a year. This frequency increases depending on the type of installation—smoke ducts from solid fuel stoves require cleaning up to four times a year, and flue gas ducts from gas boilers twice a year. In the case of buildings exceeding 2,000 square meters, inspections must take place twice a year, by May 31 and November 30.