What are fire bricks?

Find out all about fire bricks and the role they play in your wood-burning stove.

You might have seen the term fire bricks mentioned in relation to wood-burning stoves. If you are unsure what is being referred to, you should have a better understanding by the time you have finished reading this article.

What are fire bricks?

Fire bricks are internal parts of your woodburner that protect the inside of the stove body. For the vast majority of appliances, there are three fire bricks. They are often referred to as stove liners instead.

One fire brick — sometimes called the fire back — sits at the back of the firebox. There is then one fire brick to the left and one to the right. They are usually made from metal or vermiculite.

Fire bricks are also used in other types of fire, including kilns, furnaces and pizza ovens.

What is the purpose of fire bricks?

Fire bricks have two main purposes in wood-burning stoves and multi-fuel stoves. These are to protect the stove and to increase its efficiency. Let's explore how it achieves both of those things.

How fire bricks protect logburners

The first reason fire bricks are used in wood-burning stoves and multi-fuel stoves is to protect the inside of the stove body from the most intense heat produced by your woodburner.

Stoves are built to withstand very high temperatures. But over time, even the sturdiest cast iron or steel will start to feel the effects of being subjected to those conditions. It is the job of the fire bricks to act as bodyguards for the stove body, putting themselves in the way of flames that would otherwise risk causing lasting damage to your appliance.

As such, fire bricks are considered to be consumable parts of a woodburner. In common with other stove spares, they are relatively cheap stove parts that are supposed to sustain wear and tear. Indeed, that is their primary purpose. For that reason, they are generally excluded from warranties. But far better to discover a hole in a fire brick than in the stove body itself.

How fire bricks make logburners more efficient

The second key purpose of fire bricks is to increase efficiency. They help to make the firebox more compact by filling in space around the edge of the inside of the stove and providing a vital layer of insulation. 

Fire bricks are also made from materials that conduct or reflect heat. This keeps the temperature inside the firebox high to help the stove achieve a more efficient burn.

How long do fire bricks last?

How long fire bricks last depends on how a stove is used. You can ensure your fire bricks last for as long as possible by:

• Operating your stove in accordance with your manual
• Only burning the types of fuels suggested by the manufacturer
• Not overfiring your stove and only operating it at a suitable temperature
• Using a stove pipe thermometer to ensure your stove is at the correct temperature

When do you need to replace fire bricks?

When fire bricks become damaged or worn, you will need to replace them to ensure your stove continues to be protected effectively. Repairing damaged stove bodywork is a bigger and more expensive job, so it is worthwhile investing in new stove bricks.

Spare fire bricks are readily available, although they do vary dramatically in size, style and material, so make sure you get the right part for your appliance.

Browse fire bricks.

How to tell when you need to replace fire bricks

A quick visual check will tell you whether you need to replace fire bricks in your logburner. If you see significant cracks or holes in a fire brick, you will know it is no longer doing its job correctly. That means it is time to replace it.

Cracks in fire bricks are inevitable. They are caused by the constant expanding and contracting caused by the high temperatures inside your stove. Small and hairline cracks are not a cause for concern. You need only replace a fire brick when a crack goes deep through the fire brick or, in the case of vermiculite fire bricks, the material has begun to crumble.

You can incorporate a visual check of your fire bricks into your regular wood-burning stove cleaning routine to monitor the situation.

How to replace fire bricks

Your stove manual will tell you exactly how to replace the fire bricks on your woodburner. Generally speaking, the fire bricks slot into place quite easily. There are different ways of putting the fire bricks in place, depending on the models.

Some fire bricks rest against each other, while others may need to be positioned to fit snugly on a shelf or against a piece of metalwork.

Can you use any fire bricks on your stove?

No, you'll usually need to replace fire bricks like-for-like with ones that are meant for your stove. Since fire bricks are designed to be the correct size and shape to protect your stove, the dimensions vary considerably between different stoves. Even models by the same stove manufacturers can often have very different fire bricks.

Find the right fire bricks for your stove.