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Why Repair Cracks In Fireplaces

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  • 13-04-2022
Why Repair Cracks In Fireplaces

Have you asked: why you should repair a crack in a fireplace?   This article looks at what it means when a crack appears and why it should be seen to by an expert.

Why Is It Important to Fix a Fireplace Crack Fast?

Well-constructed chimneys typically utilise two or more efficient fire-resistant layers, for example, double-walled steel, steel with some stone wool insulation and double bricklayers. However, once cracks start forming in your appliance, there is a significant threat of flames penetrating through each of the layers, eventually reaching the combustible materials that surround your firebox.

If you discover that your fissure is much more prominent, there could be wood burning embers under the surface that may blow through the gaps and into your wall. The house fire risks are grave, and that is why it is paramount to fix a wood-burning fireplace crack as soon as you discover it, regardless of how small.

Once they grow more expansive, too many risky hazards could affect your other interior appliances in the space and household. 

Beginners Guide To Fireplace Restoration

How do I Repair a Fireplace Crack?

There are numerous ways to repair a small crack in your fireplace or chimney; however, you must remember that once cracks have gotten too wide, they are irreparable and require replacing. 

These are the steps you must follow to repair a small crack:

Firstly, if you discover a cracked brick in your fireplace masonry, you must patch it up immediately.

Suppose the bricks are crumbling; you must replace them with new firebrick inside the mortar joint.

If you find that your mortar joints are crumbling in the firebox, you must replace the old loose mortar after chiselling it out.

Such processes are called tuckpointing, and it is a process many follow to repair mortar joints in most brick structures.

The primary difference between the two is refractory mortar is designed to withstand extreme heating and temperatures.

Professionals must replace any panel that develops wide cracks or gradually crumble, especially from a prefabricated metal.

However, if you are skilled at DIY tasks, this also may be a job for you.

Begin by removing the old panel after unscrewing its screws and installing the brand-new panel. You'll find that it should fit perfectly against any adjoining panels.

When you have the rear panel replaced and professionally installed, you must first remove the panels on its side.

You do not require refractory mortar as it will often be a precise fit against one another.

You must employ or hire a qualified masonry fireplace contractor or chimney sweep to inspect the integrity of your fireclay mortar and firebrick. Leave it up to the professionals if you need any replacements or a second opinion.

What is a Fireplace Refractory?

Many houses across the UK often have prefabricated fireplaces. Such fireplaces are manufactured in a factory and utilise fireplace panels on the sides and bottom of the firebox. The panels are usually durable enough to withstand incredibly high heat from the fire; they provide immense strength for your fireplace. 

When refractory brick panels are compromised with gaps and cracks, they pose a considerable risk whenever you utilise your new fireplace. 

Tiny hairpiece cracks are nothing to worry about, but as soon as minor cracks start to get even a little bit wider, they can put your entire household at risk. The flames and smoke could gradually begin to penetrate the walls, igniting the combustible materials inside your firebox and creating massive fires that you require emergency services to put. 

Dangers of Cracked Refractory

You are likely aware that your brick fireplace panels can retract and expand whenever they heat up or cool down, as it is a relatively standard process.

Another common aspect you may discover is tiny hairline gaps inside of your fireplaces panels; these are normal and shouldn't concern you, as you'll find that your fireplace can have them and still operate safely and efficiently.

Why Repair A Crack In A Fireplace?

However, if these cracks widen over time, they can develop into other issues that are more problematic.

Suppose you've discovered a wide gap opened within your fireplace, below the chimney where the damper is often cemented in. If you find that your fireplace and chimney are experiencing substantial movement due to this gap, you mustn't strive to use your fireplace as it is unsafe.

However, not using the fireplace often doesn't allow you to assess whether there aren't any more glue gas or serious fire hazards in the home. Fireplace maintenance is crucial to ensure you and your household are safe.

Dangers of Cracked Refractory

Once you have noticed that your chimney and fireplace are unsafe for use, you must then turn your attention to various other appliances in your home or property.

You must determine if your furnace, boiler, wood stove or water heater utilise other flues from the same chimney.

If your chimney flues have multiple users, it will become unsafe to use your other appliances.

It may also be worth it to remove any flooring close to your fireplace, installing new masonry to support it from underneath. However, it's best to contact an experienced professional to assess the repair options before you tear away your fireplace hearth, floors and carpets.

Many in the industry would not recommend you do so unless they know the damage is done, the materials, and the type of fireplace within your home or building.

We do not recommend that you lay any materials such as marble, concrete or after-market heart on top of your existing floors. There can be a variety of potential fire hazards that can come from sparks falling through gaps and cracks of the fireplace or chimney onto heat transmissions and combustibles.

If you find an enlarged cracked refractory, you must contact restoration professionals so that they may complete an inspection report.

They will also repair the holes or cracks and replace your entire chimney flues so that they do not do any further damage to your household appliances.

These are often combined with pyrolysis, and you could risk igniting your hearth floors and surrounding exterior structure. 

Many chimney safety institutes worldwide warn that you must replace a cracked fireplace refractory, especially if the cracks are approximately 1/16 of an inch width.

If you discover that the surface of your fireplace refractory is abraded to 1/4 of an inch wide, you must seek to replace it immediately.

 chimney safety

You must understand that most safety institutes would highly recommend a skilled replacement with original manufacture panels over repairs.

Crack repairs of such significance and hazards are not entirely dependable and could result in putting your firebox at a greater risk.


Do you have a period fireplace which needs repair or restoration? If you live in the Hastings and East Sussex area, our expert antique fireplace restoration services can help.