What’s the Difference Between Common Brick & Firebrick?

Bricks have been a construction powerhouse for centuries. They offer strength, durability, and aesthetic appeal. But not all bricks are created equal. To brick it down (pun intended), different types of bricks are composed of different materials, created differently, and designed for different functions.

There are numerous types of brick, but the two categories we’re examining here are general common brick (sometimes referred to as red brick) and firebrick. While both serve distinct purposes in construction, understanding their differences and properties is essential for gaining understanding – and if needed, making informed decisions about – their uses.

Composition

Common bricks are made primarily from clay, sand, and other natural materials. After molding, they’re kiln-fired to harden to their strong finished state. These bricks do possess moderate heat resistance, especially compared to many other construction materials, but aren’t designed for extreme heat.

On the other hand, firebricks are specifically engineered to withstand high temperatures and thermal shocks. They’re composed of refractory materials including silica, alumina, and other minerals. With these ingredients combined, you have a brick that can maintain its structural integrity even when subjected to intense heat, making it ideal for applications that require insulating or containing high temperatures.

Properties

The composition of these bricks leads naturally to understanding their properties. Imagine this: you’re building a wall, and it needs to be able to withstand some serious weight. Where do you turn? Common bricks will be your go-to because of their compressive strength. Versatile, affordable, and strong, they’re excellent for general construction purposes.

When it comes to high-heat applications… firebricks take the cake.

When it comes to high-heat applications, though, firebricks take the cake. Because common brick has more limited resistance to heat, it may crack or spall when subjected to sudden, extreme temperature changes or when exposed to elevated temps for prolonged periods. Firebrick, however, is designed for low thermal conductivity – in layman’s terms, that means it doesn’t let heat escape very easily. This means firebricks are great insulators, holding on to heat without lots of transfer to the surrounding environment. If you have a kiln, an outdoor barbeque, or an indoor fireplace, this means heat will be kept where you want it instead of lost. In addition to holding heat, firebricks also have exceptional heat resistance and can handle more extreme thermal shocks.

Common bricks are more porous than firebrick. This means that, while they may be considered relatively heavy, they are less dense (and therefore not as heavy) and less smooth than firebrick. Also, firebrick tends to be naturally white in color, though it’s often tinted in the manufacturing process to obtain different colors in the finished products. Black, grays, and variations of red tend to be popular to blend them into the overall aesthetic of a given project.

Applications

Common bricks are the jack-of-all-trades in the construction world. Whether a facade or load-bearing wall, a patio, fence, or chimney, they’ll bring their strengths into the game. But when fire is directly involved, bring on the firebrick! Fireplaces, wood-burning stoves, and industrial furnaces make use of firebrick for its ability to deal with high temperatures without breaking a sweat (or a brick), to keep heat where it belongs, and to help diminish some of the hazards involved with fire.

A well-constructed [fireplace] system capitalizes on the strengths of both types of brick. 

Typically, your fireplace system will include both common and firebrick. The reason? A well-constructed system capitalizes on the strengths of both types of brick. 

Typically, your chimney is constructed of cement block or common brick, with terracotta tiles used in the exhaust flue. This is where common brick’s strength, moderate heat resistance, and relatively lower density and cost are put to good use. 

The firebox, or area where you build your fires, is typically lined with firebrick. Firebrick’s superiority in handling temperature changes and extreme temperatures, coupled with its low thermal conductivity, makes it the right fit for these applications. In addition to these important heat-related properties, the smoother, less porous surfaces of firebrick help contain ashes, facilitating easier cleaning and maintenance – an added bonus!

Chimney Safety

A well constructed, properly installed fireplace system is important because it leads to increased safety, efficiency, and longevity of the system – and therefore the entire home. This is why it’s critical that you rely on a trustworthy, seasoned professional for your fireplace needs. Your chimney professional should have proven experience demonstrated through credible professional certification. A good place to begin is by checking to see that they’re certified by the Chimney Safety Institute of American (CSIA). 

Whether you’re starting from scratch with a new construction, doing masonry repairs, or giving your fireplace a new look, we at English Sweep are ready to answer your questions and help you find optimal solutions for all your chimney needs.

Enjoy Your Fireplace to the Fullest – Work With Us

With your chimney in place, it’s time to enjoy! But be sure not to ignore annual chimney inspections and routine sweepings, which help ensure long-term functionality, safety, and protection of your investment in your home. During them, your pro will examine your chimney system from top to bottom, clearing obstructions, and examining the masonry and other components of your chimney to help you stay on top of maintenance needs.

Ready to schedule? Call 636-225-3340 or reach out online now.