The people of Canada love renovating their homes. According to a study, Canadians spend more on home renovations than on new construction. The average homeowner in Canada spent over 8,000 dollars on home renovation in 2021. These renovations include fixing double-glazed glass cracks and various other renovations.  Double-glazed glass, a staple in modern buildings, consists of two glass panes separated by an air or gas-filled space to enhance thermal and sound insulation. Predominantly used in windows and doors, this type of glass plays a crucial role in energy efficiency and comfort in homes and commercial spaces. Understanding why double-glazed glass can crack is essential for proper maintenance and longevity. Whether you’re a homeowner, a builder, or simply curious about construction materials, knowing these reasons can help you prevent damage and ensure the durability of your installations. In this article, the top three reasons why double-glazed glass cracks are discussed, including insights into thermal stress, impact and pressure changes and improper installation.

Window Glass Choices in Canada

There are many choices for window glass, and each comes with its distinct advantages. However, a double-glazed window is a standard requirement for residential and commercial units in Canada. This is because the weather conditions in Canada, especially in winter, are severe. A double-glazed window can help conserve the heat inside the house and keep the room warm and cozy.

What is a Double Glazed Window?

A double-glazed window is made by setting up two layers of glass closely together, leaving a gap in between for vacuum. This vacuum acts as a barrier to prevent heat from getting out.

Often, this gap is filled with gas or chemical materials if the window is to be installed in places with high heat circulation, like a factory. The layer in between helps create a barrier to trap heat inside, prevent leaks, and maintain a consistent temperature, ultimately lowering your energy costs.

Another factor that makes double-glazed window glass the ideal choice is its ability to withstand pressure, both from the inside and outside, simultaneously. The glass can balance the pressure on either side and maintain its shape for a long time.

However, when the external pressure is too high, the glass may lose its shape and tilt inwards, cracking and requiring you to schedule an emergency glass service.

Why Double-Glazed Glass Cracks

Temperature Variation Thermal Stress Can Cause Double-Glazed Glass Cracks

Before you face such trouble, it’s important to understand what may factor in cracking your double-glazed window. We have listed some reasons below:

Double-Glazed Glass Cracks Due To Scratches on the Glass Surface

Large parts of window glass are cut down to fit specific shapes and sizes for commercial use. This can cause the glass to get surface scratches, making it weak. The usual wear and tear worsens this scratch over time and may cause the glass to crack.

Temperature Variation / Thermal Stress Can Cause Double-Glazed Glass Cracks

Window glass frequently encounters temperature changes both on the inside and outside. This constant change in temperature and the heat of the chemical inside the gap can make the glass crack. This usually happens when the temperature drastically shifts from hot during the day to cold at night. Thermal stress occurs when different parts of a glass pane expand or contract at different rates due to temperature variations. This differential can lead to significant stress within the glass, potentially causing it to crack. Double-glazed glass, despite its insulating properties, is not immune to these effects, especially in environments with extreme temperature fluctuations.

Seasonal Changes:

During winter, the inner pane tends to be warmer due to indoor heating, while the outer pane remains cold. Conversely, in summer, the outer pane might get extremely hot from the sun, with the inner pane staying cooler. These seasonal variations contribute to ongoing stress cycles, compounding the risks over time.

Sun Exposure: 

Parts of the window exposed to direct sunlight can heat up much faster and expand more than shaded parts of the same window. This creates stress points where the hot and cooler sections meet, increasing the likelihood of cracks developing, particularly if the thermal tolerance threshold of the glass is surpassed.


Impact and Pressure Changes on Double-Glazed Glass Cracks

Double-glazed glass is designed to withstand normal environmental pressures, but unexpected impacts or sudden changes in pressure can cause it to crack or even shatter. Here’s how these factors play a crucial role in the integrity of double-glazed units:

  1. Physical Impacts: Everyday accidents, such as a ball striking a window or debris being blown against the glass during a storm, can cause immediate cracks or weaken the pane over time. The impact doesn’t have to be severe; repeated minor strikes at the same spot can also degrade the glass’s strength.
  2. Barometric Pressure Changes: Rapid changes in atmospheric pressure, often associated with weather events like storms, can create a pressure imbalance between the air inside the double glazing and the external environment. This imbalance puts stress on the glass, which can lead to cracking, especially if the edges of the glass are not sealed properly.
  3. Installation Near Doors: Double-glazed windows installed near doors can experience frequent pressure changes due to the opening and closing of the door, creating air pressure waves that stress the glass. Over time, this repeated stress can lead to the development of cracks.


Improper Manufacturing or Installation

The human factor is another reason for these glasses to crack. Even using the most advanced technologies, errors often occur with the manufacturing or installing the unit. Double glazing needs precise engineering to make and install it the first time.

A worker installing and checking a window glass

Improper Installation can lead to premature failure and double-glazed glass cracks

Improper installation is a significant factor that can lead to the premature failure of double-glazed glass. Errors during the fitting process can introduce stress points that eventually become the origin of cracks or complete breakages. Here are some key aspects where improper installation plays a role:

  1. Poor Frame Alignment: If the window frames are not correctly aligned or are warped, they can put uneven pressure on the glass panes. Over time, this uneven stress can cause the glass to crack, especially at the corners where the mechanical stress is concentrated.
  2. Incorrect Sealing: Sealing not only keeps moisture and air out but also ensures that the internal and external pressures are balanced. Poor sealing can allow moisture to enter, which may lead to condensation and additional stress on the glass, especially with temperature changes.
  3. Mismatched Glass and Frame Sizes: Using a glass pane that doesn’t precisely fit the frame can lead to points of excessive tension once the glass is secured. These tension points are often the first to develop cracks under any additional stress from environmental or human factors.

By ensuring that installation is handled by qualified professionals and regularly checking for signs of stress or seal failure, many of these issues can be mitigated. This careful attention to detail not only prolongs the life of the windows but also enhances their performance and safety.


Double-Glazed Glass Cracks Conclusion

Understanding the reasons behind the cracking of double-glazed glass can greatly assist in maintaining and prolonging the life of these installations. Thermal stress, impact and pressure changes, and improper installation are all preventable with proper knowledge and care. By taking preventive measures such as appropriate installation, regular maintenance, and using protective elements like curtains or shades, you can ensure that your double-glazed windows remain functional and intact for years to come.

For top-quality precision for residential glass repair and glass replacement, consider our expertise at Crystal Glass.

We’re one of the leading glass shops in Edmonton, serving our clients for over 70 years now for their residential and commercial glass repair and mobile auto glass repair in Calgary and Edmonton.

Get in touch with a professional at Crystal Glass to discuss your doubl-glazed glass cracks today!