Glass Spontaneous Breakage: 2024 Guide on Causes & Fixes

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Have you ever heard a loud crash in the middle of a meeting, only to find a window or glass surface shattered out of nowhere?

As unsettling as it is, glass spontaneous breakage happens for a variety of reasons. Before you blame ghosts or poltergeists, it’s likely due to a physical stressor you didn’t even realise was there. The good news is most cases of spontaneous glass breakage are preventable with the right glass choice, glazing technique, and precautions.

This guide will walk you through the common causes of glass spontaneously breaking and what you can do to avoid walking up to a pile of shards. Read on to learn more.

Glass Breaking by Itself: Meaning

Sometimes, glass breaks spontaneously without any apparent cause. This phenomenon is known as spontaneous glass breakage. If you’ve ever had a glass table top, window, or shelf just shatter out of the blue, you’ve experienced it firsthand.

Preventing spontaneous glass breakage comes down to using high-quality, properly rated glass and expert installation. Have glass panes, windows, doors, shelves, and table tops installed by a professional glazier. They can choose glass suitable for the intended use and install it securely to avoid stress.

Regular inspections of existing glass installations allow you to spot any issues early and perform repairs or replacements to avoid breakage. With the proper precautions taken, you can enjoy the beauty of your glass structures without worrying about when they might shatter.

3 Common Causes of Glass Spontaneous Breakage and Their Prevention

Glass is meant to be durable, but sometimes, it decides to spontaneously break on its own. If this happens to you, don’t panic — it’s often not your fault or your staff’s.

So, why does glass break?

Or rather, what causes spontaneous glass breakage?

Here are the most common culprits behind sudden glass breakage:

  • Thermal stress
  • Imperfections and scratches
  • Bad glazing and installation

The following sections will discuss these in more detail and outline what you can do to prevent them from happening.

1. Thermal Stress

Extremely high heat (of more than 150 C) and rapid temperature changes (of more than 15 C) can cause the glass to break by itself. When glass heats up, it expands. When it cools down again quickly, it doesn’t have time to contract at the same pace and pulls inwards, creating stress points that lead to cracks.

Prevention Tip: Avoid exposing glass to extreme temperature fluctuations. Make sure windows and glass doors are properly sealed and insulated. Use curtains to shield glass from direct sunlight in the summer; in the winter, avoid cranking the heat up near large windows. If there’s a need to increase an office room temperature, ensure to do that gradually.

2. Imperfections and Scratches

Microscopic flaws, scratches, and chips in the glass surface act as stress concentration points. Over time, especially if exposed to temperature changes or impacts, these weak spots give way and the glass breaks.

Prevention Tip: Inspect the glass for any surface damage regularly and replace it as needed. Choose a glass that has been properly annealed, i.e., slowly cooled during manufacturing, to relieve internal stresses. Higher quality, tempered glass is also less prone to breakage from minor imperfections (more on this soon).

3. Bad Glazing and Installation

If glass isn’t installed properly with a sturdy, supportive framework and sealed to avoid moisture and airflow, it’s prone to breaking on its own. Excessive weight from the glass itself or pressure from wind and weather can also stress the glass beyond its breaking point.

Glazing being secured in place with power drill

Prevention Tip: Have glass installations checked by professional glazing inspectors to ensure it’s secure, supported, and properly sealed. For large windows or doors, choose a reinforced design to distribute the weight. Proper glazing and installation are key to preventing mysterious breakage.

Toughened vs. Tempered Glass: The Differences

Toughened glass and tempered glass are two types of safety glass, but they have some key differences in their properties and applications, as we’ll see below.

1. Toughened Glass

Toughened glass, also known as strengthened glass, goes through a process of controlled thermal or chemical treatments to strengthen it. The glass is heated and then cooled rapidly, which compresses the outer surface and puts the inner part of the glass under tension. This process makes the glass several times stronger than regular annealed glass.

Although toughened glass is more impact-resistant, it can still break under high enough impact. When a toughened glass spontaneous breakage occurs, it shatters into small granular chunks that are less likely to cause injury. Toughened glass is often used in office doors, windows, balconies, and staircases.

2. Tempered Glass

Tempered glass undergoes a slightly different treatment using controlled thermal or chemical processes. The glass is heated and then cooled rapidly with air jets, which puts the inner and outer parts of the glass under compression. This compressive stress creates surface tension that strengthens the glass — see our guide on how to identify tempered glass for more details.

Tempered glass can withstand significantly higher impacts and temperatures than toughened glass before breaking. When tempered glass spontaneous breakage occurs, it fractures into small, relatively harmless fragments. Due to its increased durability and safety, tempered glass is commonly used for side windows and rear windows in vehicles, computer and TV screens, and architectural glass doors and tables.

4 Signs That Your Glass May Spontaneously Break

There are a few signs you should look out for to ensure your office building glass structures don’t spontaneously break for no apparent reason. By identifying these signs early on, you can avoid costly glass replacement or injuries.

  1. Cracks or scratches in the glass surface: Even small cracks or scratches in the glass surface can eventually lead to spontaneous breakage. As the glass expands and contracts with temperature changes, these flaws become weak points where breakage can start or spread. It’s best to contact commercial glass replacement experts if your glass structures have visible cracks, chips or scratches.
  2. Cloudy or stained areas: Cloudy, stained or etched areas on glass are also warning signs that the glass integrity may be compromised. These marks indicate that chemicals or minerals have started to break down or penetrate the glass, weakening its structure. Glass in this condition is more prone to shattering without warning and should be replaced.
  3. A “popping” sound: If you hear a “popping” sound coming from your glass, that is a sure sign that breakage is imminent or has already begun. The popping sound is the result of fractures quickly spreading through the glass. Even if you don’t see any visible cracks yet, the glass is significantly weakened and should be replaced as soon as possible to avoid injury or greater damage.
  4. Condensation or fogging on the inside of windows: Excess condensation or fogging on the inside of glass can be a warning sign in some cases. When warm, moist air contacts cold glass surfaces, condensation forms. However, if there is air or gas trapped inside the glass unit itself, it may also fog or cloud the glass from the inside. This indicates the glass seal has failed, compromising its strength and insulation. The trapped air can expand and contract, leading to spontaneous breakage. Consider hiring leak resolution professionals to fix this issue.

By catching these warning signs early, you may avoid the hassle and cost of emergency glass replacement or repairs. It’s a good idea to inspect glass areas, especially those exposed to more extreme temperatures (up to 150 C), for any visible changes on a regular basis. Prevention and early detection are key to reducing risks associated with spontaneous glass breakage.

5 Extra Tips To Prevent and Minimise Risk of Breakage

Once the glass has spontaneously broken, there’s no going back — the best approach is prevention.

Here are 5 additional tips to minimise the risks of glass spontaneous breakage in your building.

  • Choose tempered or laminated glass.
  • Install appropriate framing.
  • Maintain proper humidity.
  • Regularly inspect glass.
  • Protect glass from impacts.

1. Choose tempered or laminated glass.

For office windows and doors, use tempered or laminated glass, which is much stronger than regular annealed glass. Tempered glass is heat-treated to withstand significantly more pressure and impact, while laminated glass has a protective interlayer that holds the glass together even if it breaks. These options reduce the chance of spontaneous breakage and protect from injuries if breakage occurs.

2. Install appropriate framing.

The framing system used to install the glass also affects its durability. For large panes of glass, choose a framing system specifically designed to support the weight. While aluminium framing may bend or flex over time, putting extra stress on the glass, steel or wood framing provides more long-term support. The glazing compound used to seal and secure the glass in the frame should also be appropriate for the glass type to allow for expansion and contraction.

3. Maintain proper humidity.

Extreme temperature changes and humidity fluctuations can create stress in glass and increase the risks of spontaneous breakage. For indoor glass, use a humidifier or dehumidifier to keep relative humidity at 40–50% during summer and 30–40% during winter. For outdoor glass, plant trees or install awnings to shade the glass from intense sun exposure when possible.

4. Regularly inspect glass.

Schedule routine inspections of all glass in the building to check for any signs of damage or stress cracks. Have a professional evaluate any cracks or flaws in the glass immediately. It’s best to replace glass at the first indication of damage to avoid potential injury from breakage. An ounce of prevention is worth a pound of cure.

5. Protect glass from impacts.

Warn all staff and visitors to be cautious around glass windows, doors, and partitions. Place barriers like plants, sculptures or furniture in front of large panes of glass when possible. This helps prevent impacts from trolleys, carts or other equipment that could shatter or weaken the glass over time.

Taking proactive steps to strengthen glass, provide proper support, regulate temperature changes and prevent impacts can significantly reduce the possibility of spontaneous breakage in a building. An investment in preventative measures now helps avoid costly glass repairs or replacements down the road.

3 Options for Glass Replacement After Breakage

Once you encounter a glass spontaneous breakage, you’ll need to consider your options for replacement. Your choice of replacement will differ based on the kind of glass damage/breakage, and here are the 3 top options:

  • Full Glass replacement
  • Glass repair or patch
  • Partial Glass replacement

1. Full Glass Replacement

If the breakage has damaged or weakened a large portion of the glass, full replacement by high-level glass replacement experts may be necessary. This involves removing the existing glass pane and installing an entirely new one. While the most expensive option, it provides the benefit of a clean start with glass specifically chosen for your needs. It also allows for upgrading to a more energy-efficient or soundproof glass type if desired.

Tall Glass Building Missing Full Glass Panel

2. Glass Refurbishment / Repair / Patch

For small cracks or holes in the glass, a glass refurbishment or repair by commercial glazing refurbishment professionals may suffice. This often involves injecting a special UV-cured resin into the damaged area or applying a glass patch over the break. The resin or patch then bonds strongly to the glass surface. This provides an inexpensive fix, but the result may still show visible signs of damage and won’t last as long as a full replacement. It can, however, buy you some time if replacement isn’t immediately possible.

3. Partial Glass Replacement

If only a portion of the glass has broken, but the remaining glass is still intact and securely installed, a partial replacement by commercial glass replacement experts may be an option. The damaged glass section is removed and replaced with a glass patch to match your existing window. This provides a balance of cost and longevity but requires finding a matching glass type and can be difficult to blend in seamlessly.

Here are 3 tips to aid partial window replacement:

  • Ask your glazier or glass company for recommendations based on the specifics of your breakage and needs. They can help determine which choice will provide the most long-term value.
  • For large commercial windows, full replacement may be the only option to restore security and prevent further breakage.
  • If opting for a patch or partial replacement, choose a glass pro like GLRE, with experience matching and installing replacement glass. Our skill and expertise will be key to a result that blends in well.

The cause of your glass’s spontaneous breakage will also influence which option is optimal. In any case, addressing the issue promptly is important for safety, security and preventing expensive damage. With the right solution, you can restore your office windows and have peace of mind. Contact us now to discuss your project needs.

Frequently Asked Questions

Does the warranty cover spontaneous glass breakage?

Not usually. Manufacturing defects that cause the glass to break shortly after installation may be covered under warranty. However, if the glass has been in place for some time without issue before breaking spontaneously, it typically wouldn’t be covered. The exact cause of breakage in these cases can be difficult to determine definitively.

Can glass shatter from heat?

Yes, rapid or uneven heating of glass can cause enough stress to lead to breakage. For example, if one area of glass is exposed to direct sunlight while another area remains shaded, the temperature difference can be enough to cause spontaneous breakage. The same risk applies to rapid heating from fireplaces, space heaters, or HVAC vents blowing hot air directly onto glass.

Can glass break from cold?

Cold temperatures can also cause the glass to break spontaneously. When glass cools too quickly, it can develop internal stresses that lead to breakage even after the glass has returned to room temperature. For this reason, glass that has recently been exposed to extremely cold temperatures, such as during shipping or installation in winter weather, may be more prone to spontaneous breakage.


While there are several reasons behind glass spontaneous breakage, there are equally different precautions to prevent these occurrences. Keep these tips in mind, choose a reputable glass supplier and installer, and your office building should enjoy clear, uninterrupted views for years to come. As the leading glazing refurbishment and replacement service provider in the UK, we’re always available to repair broken glasses in your office buildings or install new ones — contact us now to discuss your project needs.

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