Pizza Oven Floor Cracked: Split Tiles, Lifted Bricks, Crumbling Stone

What it
usually means.

The floor of a pizza oven is refractory stone or firebrick laid over insulation, or in a deck oven a thick stone slab resting over the burner or elements. It lives through huge swings of heat, and hairline cracks are common and usually harmless: stone expands and contracts every firing. What matters is whether the crack stays closed and flat. Floors split wide from thermal shock, when something cold meets hot stone: water splashed on to cool it, wet or frozen wood dropped on, snow melt dripping through a door, a pie tray pulled from a cold room. A new oven fired too hot too soon, before curing drove out the water in its mortar and tiles, is the classic cause of broken floors in the first season. Steel tools do their part: a metal peel driven into a raised tile edge, an ash rake dragged hard, heavy logs dropped from height. In a deck oven, a stone cleaned with a wet cloth while hot or dropped during reinstallation cracks the same way. A floor with lifted or loose pieces is swapped before it chips into food.