The Importance Of The Firebox

Houston Fireplace Fireboxes

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Both masonry and prefabricated fireplaces contain what is known as a “firebox,” which is the visible area of your fireplace where your fire is lit and burns openly. If you want a specialty firebox built, you can reach out to ASAP Chimney Services.

Masonry fireplaces, which are made of bricks, blocks, or stone and mortar, have fireboxes that are built on-site and made of firebrick, which is often yellowish in appearance. Meanwhile, prefab fireplaces—which have become much more common and popular over the past 25 years or so—have lightweight metal fireboxes along with metal chimneys. These metal fireboxes are made of cast refractory panels. Both types of fireboxes can present their own problems. Because masonry fireboxes are built to the specifications of the original mason, their quality varies greatly, and the firebrick therein tends to deteriorate over time because of the direct exposure to extreme heat. Prefab fireplaces, meanwhile, must abide by installation instructions to confirm proper clearances are met. It is critical that their fireboxes be professionally inspected for inevitable signs of wear and tear. Because of the amount of water we get here in SE Texas and the infrequency with which we use our prefab fireplaces, it’s common to see improperly maintained fireboxes rusting out.

Masonry Fireplace Firebox Issues

If you see loose firebricks or holes in the mortar or brick in your firebox, don’t put off calling about having your firebox repaired or rebuilt. A firebox in disrepair means that your fire may not stay contained and could wind up posing a huge danger. Your firebox receives the brunt of your fire’s heat and understandably begins to show wear over time. The firebrick joints will eventually begin to deteriorate from the expansion [or contraction] cycles caused by the extreme heat of a fire as well as the changing seasons. Chimney leaks are also notorious for causing damage to the firebox, as rain mixing with soot creates an acid like substance that detiorates mortar joints. History shows that original fireboxs were built without special high-temperature refractory panels and this leads to quicker wear and tear.

Prefabricated Fireplace Firebox Issues

It’s important to have a Professional check out your fireplace so you can be assured that all parts [including the firebox of course] are compatible, installed correctly, and still in good working order.

In our industry, it is well known that factory-built fireplaces cannot withstand the amount of use that their masonry counterparts can. According to the Chimney Safety Institute of America (CSIA), the majority of prefabricated units are improperly installed. Prefab firebox clearances are difficult for homeowners to check themselves….and we can help out here.

Safety is critical and in SE Texas, we find that many prefab fireboxes rust out quickly due to the large rain amounts we receive. Add the infrequency of fireplace use, a perfect storm [no pun intended] is created for deferred maintenance issues on Fireboxes.


To learn more about the chimney sweeping process, view the video below.


If you want a more energy efficient home and us to assess your Chimney issues in general, ASAP Chimney Services can install a top-sealing damper on your chimney. Schedule an appointment by calling 346-27-SWEEP or using our appointment request form!

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