Insulating fire brick – best solutions

There is no better way to build your own oven or furnace rather than do it with the use of insulating fire bricks. What should you know about this type of fire bricks? Which one to choose? What do you need to pay attention to before making a decision? Read the text below and find out!

Photo by Viviane Okubo on Unsplash

What’s the meaning of a fire brick? 

The insulating fire brick (IFB) is a soft brick made of refractory ceramic material. In other words, this is a type of brick that is made with the use of fire clay. This kind of brick has got a great resistance against high temperatures that are used in lining furnaces, kilns, fireboxes, and fireplaces. Fire bricks are manufactured similarly to ordinary masonry bricks, however, they are fired in significantly higher temperatures until the moment when partial vitrification has occurred.

It’s worth mentioning that insulating fire bricks are also known as chamotte, fire-clay, and fireplace bricks. IFP, fire brick or refractory brick are also acceptable name variations. Those bricks are made from clays containing a high level of alumina and silica. They also include trace amounts of manganese and iron. Coming back to the issue of alumina content, it can range from 18% even up to 90%. The higher the percentage of alumina, the denser the bricks and the greater resistance to high temperatures.

Fire bricks bring unsurpassed performance in a large variety of markets. If you’re looking for the best fire bricks, you should be guided by the temperatures needed for each particular application. Do you need insulating fire bricks for a brick pizza oven, fire-pit, barbecue, or for smokers? Think about it. The refractory material should not be softening and melting at too high temperatures. 

What makes insulating firebricks stand out from the others?

As you already know, fire bricks are resistant to high temperatures (they are refractory to 1200oC), but not only. They are also resistant to abrasion due to the fact that they are more dense than typical masonry bricks. What also distinguishes insulating fire bricks is having a lower thermal conductivity – they absorb heat but, at the same time, they don’t transfer it to surrounding materials.

What’s more, they can boast of high thermal mass, which is a plus because they can easily retain heat that radiates back after the source of the heat. This is the case with, for example, masonry stoves or ovens. An additional advantage of insulating fire bricks is that they can be used in commercial and domestic applications. It’s worth adding that they help people reduce their operating costs by saving energy.

insulating firebrick
Image by Takeshi Hirano from Pixabay

Insulating fire bricks – which one should you choose?

When you face the challenge of choosing the most appropriate insulating fire bricks, you should search for the ones made from high-purity refractory clays. Quality matters! The best solutions for finding the most suitable fire bricks are listed below.

Decide on the perfect colour

Decorative fire bricks in white colour are recommended for both indoor and outdoor using. White fire bricks have smooth surfaces and will work perfectly for wood-fired ovens, especially bread and pizza ovens. They can also be used in barbecues. However, buying black firebricks is a reasonable idea.

It’s worth knowing that there are a variety of different colours in which firebricks can come in. Thanks to the diversity of colours it becomes possible to fit firebricks into the current room design or architecture. Take a moment to think deeply about the colour that best harmonises with the surroundings, and thus you can make your brick or fireplace truly one of a kind.

Consider the ideal size

As you might guess, fire bricks come in different sizes. Some of them measure ‎9 x 4.5 x 2.5 inches. Rectangular ones are usually 9 x 4 x 3. Actually, when it comes to sizes, we can divide fire bricks into two categories – split and full. The first one includes bricks which are typically thinner. Such bricks are often placed on the sides.

The latter are definitely thicker. They are designed to be placed at the back and base of the fireplace – so in places with the biggest exposure to fire. With this knowledge, it will become much easier for you to choose the exact size that you need. 

Think about patterns

There are lots of different patterns which can easily be implemented when installing firebrick. Some are more traditional, others are more complicated, available on request. A professional mason with outstanding craftsmanship can help you with that. Patterns are worthy of consideration, as they can give your fireplace or oven depth and complexity. 

Photo by Anthony Ortiz on Unsplash

Choose thermal shock stability

The refectory is to a large extent affected by the kiln operating conditions. There is a risk of causing damage to the furnace in a situation when the temperature changes sharply. The same applies to the case when the masonry is not heated evenly in various parts. Because of such unevenness, there is a danger that stress will be generated inside your brick, which as a result will cause the refractory to peel and crack. You can prevent this by having refractory with certain thermal shock stability.

Seek for good corrosion resistance

Refractory materials such as fire bricks must have a strong resistance to erosion damage. Why? The answer is simple – bricks available on the market are pretty often subject to chemical action by liquid solutions, chemical action in gaseous media, furnace dust, or solid substances when they are in use, all leading to damages caused by erosion. Having certain abrasion resistance is also required, as well as air permeability, electrical conductivity, and hardness (under certain special conditions).

insulating fire bricks
Image by Jeon Sang-O from Pixabay


The best insulating fire brick solutions are the ones that perfectly suit your needs. Such bricks come in different colours and sizes. Choosing a certain colour is a matter of taste. However, there is one issue that cannot be ignored – the issue of safety. Not without reason there’s a saying “safety first”. No matter what, you should always look for fire bricks with thermal shock stability and great corrosion resistance. You will not regret it!


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