Water within the walls poses a problem when firing the cob or brick oven. The water heats up then is converted into steam which could force to escape and may crack the oven walls. There are two solutions to avoid this: build a shelter for the oven or build the oven inside an existing structure. This structure may be built from any material; however, risk of fire outbreaks should be considered and a suitable airway for the smoke to escape from the oven should be in placed. A pizza oven placed directly under a roof without a proper chimney will most likely destroy the roofing with smoke and soot.