fireplace firebox close up photo


Originally contributed by • last updated 3/18/2021

Ani Kolleshi

When most people think of a fireplace, they often picture sitting in front of a big stone hearth, with the flames of a warm roaring fire crackling away inside a ~ firebox? These specialized units play an important role in most types of fireplaces, acting as safety measures to prevent damage from overheating and excessive flames. These protective barriers are must have, but what are they exactly?


The term firebox most commonly refers to the part of a fireplace (or stove) where the fuel is combusted. In other words, it’s the space inside the fireplace where the flames are located. In traditional masonry fireplaces, these specialized units are typically constructed from special heat resistant brick or sheet metal and are part of the foundation along with the ashpit and chimney. As part of a prefabricated fireplace insert, these units are usually made from metal and can be lined with decorative stone or glass. A firebox in a gas fireplace is usually part of the whole unit and typically contains a decorative (sometimes functional) fuel source, such as gas logs or glass beads, and the burners.

What Is A Firebox Used For?

On the surface, fireplaces may seem like strong formidable structures. However, without the protection of a firebox inside the fireplace, the whole structure or unit would be at risk of damage and failure. Whether you’re dealing with a traditional masonry fireplace or you’ve got a new prefabricated fireplace insert, there are a few things you should keep in mind:

  • Despite being made from strong masonry materials, traditional fireboxes are not indestructible. Extremely hot temperatures and improper usage and maintenance could lead to structural problems or worse. If you haven’t already, you may want to upgrade your traditional fireplace before your next cold night.
  • Most prefabricated fireboxes are meant for decorative purposes and could cause fires and other damage if used improperly. It’s important to follow the directions for intended use as set out by the manufacturer.
  • Fireboxes in modern gas and wood inserts are typically custom made for those units and should only be repaired and replaced with parts from the original product or a suitable replacement piece.