Answer: there are masonry conduits and metallic conduits, of different formats (with or without angle) and of different shapes.
They can be built with masonry conduits or metallic conduits. For masonry conduits, the possible materials are terracotta (which has been very successful in recent years), ceramic or pozzolan (very ecological but also more expensive). The three are very suitable for this use, and their performance is quite similar. Stainless steel metal conduits are also accepted in single or double wall. The chimney flue must take the shortest possible path to the roof, but sometimes technical constraints complicate the task, so an angle is allowed if it is less than 20 ° (less than 45 ° for a flue less than 5 m ). The chimney flue can have a square, rectangular or circular shape as desired. You too, send us your brico question