Many ovens are made of a special high temperature ceramic fire-brick. It's great at resisting heat, and is a decent insulator, but isn't very strong. If you b

Many ovens are made of a special high temperature ceramic fire-brick. It's great at resisting heat, and is a decent insulator, but isn't very strong. If you build an oven roof out of it, I could completely imagining some uninformed employee standing on the roof and having a foot fall through. The fix is to redesign the oven to have a stronger roof, or to paint "NO STEP, NO STEP" all over the roof of the oven.