Why has the glass cracked on my woodburning stove?

Cracked Stove Glass

What Causes Cracked or Broken Stove Glass

There are a number of reasons why the glass in your woodburning stove may have cracked or broken. However, almost all of these can be broken down into two categories:

– Impact
– Usage


Impact damage is a result of something coming into contact with your stove glass at force. Remember stove glass is ceramic, and cannot be toughened like normal glass – it is by nature fragile and will not withstand force.

– Overloading the firebox with logs for fuel, you could have knocked the stove glass into a log protruding from the box. This can result in the glass cracking.
– Glass hit from the outside by a heavy object can also cause cracks.
– Spilling cold liquids on hot glass.
– Over-tightening screws and bolts holding the glass in place. The glass expands slightly once the stove is up to temperature, if the glass is fastened too tightly it can crack.

It is possible for the glass to have a hairline crack after impact, which will be difficult to see with the naked eye. Once your stove is up to temperature the glass could weaken further, and a more visible crack could appear.


Woodburners and multi-fuel stoves are extremely sturdy due to the materials they are manufactured with, but they still need to be operated as they were designed to be used. Your first port of call here should be your manufactures manual.

– Sulphuric acid is corrosive. Burning fuels with high sulphur content, such as petcoke (petroleum coke) can cause damage to your stove and cause the glass to crack
– Overfiring can happen when the stove is too hot, which in turn can crack the glass on the door of the stove.
– Burning household coal in the enclosed space of a woodburner stove can result in volatile mini-explosions

How To Prevent Your Stove Glass From Breaking

There are a few steps you can take to preserve the life of the glass in your stove. Most of these tips are about the way you operate your stove and for full details on optimal stove usage you should see your manufactures manual.

– Do not burn fuel with a high sulphur content.
– Do not burn wet, unseasoned, or processed wood.
– Regularly clean and dry your stove before usage.
– Avoid slumber burning (after low burning always burn on maximum heat for 30 minutes).
– Always maintain airwash flow (do not fully close the secondary air).
– When replacing stove glass hand tighten the screws only, do not use tools. The glass needs space to expand.
– Replace the gasket at the same time as replacing the stove glass.

If in any doubt, read your manufacturers manual which will advise you how to run your stove efficiently, and to help when replacing stove glass.

Replacement Stove Glass

Should you find yourself with broken glass in your woodburner or multi-fuel stove, the good news is that you don’t have to replace the entire stove. We provide Shot Roblax replacement stove glass that is cut to size. Simply measure your glass, or if you know the make and model you can search for the appropriate piece.