Finding a crack in a new oven is unsettling, but small hairline cracks are a normal part of owning a refractory oven. In most cases, you can carry on cooking.
Why ovens crack
Refractory materials expand as they heat up and contract as they cool. An oven goes through a wide swing in temperature every time it's used, from the air temperature outside to 350–400 °C inside. That repeated movement naturally creates fine hairline cracks over time.
Cracks that are normal
- Small hairline cracks. These are a normal characteristic of refractory ovens and don't affect how the oven cooks.
- Cracks between the dome and the floor. On a Ferno Vera these sections are deliberately not glued together, so they can expand and move naturally.
Neither of these needs a repair, and neither affects the oven's functionality or performance.
What causes excessive cracking
Larger or unusual cracks usually have a cause. The most common are:
- Incorrect curing: rushing or skipping the 5-day cure.
- Overheating: going above the oven's safe limit. A Ferno Vera is safe up to 500 °C.
- Thermal shock: lighting a sudden big fire or adding too much wood at once.
- Rapid cooling: using water or forced air.
- Water: rain or standing water getting into the oven.
- Poor installation: an unsuitable surface, or not enough insulation underneath.
How to prevent cracks
- Follow the curing schedule exactly.
- Start every fire small and build it up gradually.
- Use only dry, untreated hardwood, and add it a little at a time. See our guide to the best wood to burn.
- Let the oven cool naturally to the outside temperature.
- Keep it covered when it's not in use, and protect it from standing water.
- Install it on a suitable non-combustible, properly insulated surface.
- Inspect the oven regularly for wear or damage.
What if you're worried about a crack?
If a crack looks larger than a fine hairline, is growing, or you're simply not sure, don't guess. Stop using the oven and take a clear photo. Ferno Vera customers can WhatsApp it to us on 072 554 0632, and we'll have a look.
Read the Owner's Manual and the Disclaimer & Warranty Conditions for the full care instructions and warranty terms.
Questions, answered
Are cracks in a pizza oven normal?
Yes. Small hairline cracks are normal in refractory ovens, and they don't affect how the oven performs.
Why is there a gap or crack between the dome and the floor?
On a Ferno Vera the dome and floor are deliberately not glued together, so they can expand and move naturally. Cracks between these sections are normal.
Do I need to repair hairline cracks?
No. Small hairline cracks don't affect the oven's functionality or performance.
How can I stop my pizza oven from cracking badly?
Cure it properly, build every fire gradually, let it cool naturally, protect it from water, and install it on a suitable insulated surface.
Can I use water to cool the oven down?
Never. Water or forced air can damage the oven. Always let it cool naturally.