Summer Heat, Thermal Stress and Glass Façades: What You Need to Know

As temperatures rise across the UK, it’s not just buildings and streets that feel the heat. Glass façades face serious challenges too. While they’re engineered to withstand tough conditions, modern glazing systems are still vulnerable to the intense thermal stress caused by summer weather.

Here’s what every facilities manager and building owner needs to know about how the summer heat affects glass façades and why proactive façade maintenance is crucial.

1. Spontaneous Glass Breakage

One of the lesser-known risks of summer heat is spontaneous breakage, particularly in toughened glass. This can occur when:

• The glass expands unevenly due to direct sunlight on one part of the pane but not the other

• Nickel sulphide inclusions, tiny impurities in the glass, expand under heat and stress, triggering a sudden break

• Frames and fixings restrict natural expansion, building internal pressure

It might look like a sudden incident, but spontaneous breakage often has slow-burning causes made worse by high temperatures.

2. Sealant Degradation

The joints, edges and sealants that hold your glazing system together don’t perform well in extreme heat. UV exposure and high temperatures can lead to:

• Cracking or shrinking of sealant joints

• Loss of flexibility, meaning movement in the glass or structure is less tolerated

• Moisture ingress, leading to fogging, staining and long-term damage to the façade

Even premium sealants degrade faster under sustained summer heat. Over time, this impacts not only aesthetics but also energy efficiency and weather performance.

3. Structural Movement and Stress

Thermal expansion can cause subtle but significant structural shifts. As building materials expand at different rates, this can put strain on glass panels and their fixings. Symptoms include:

• Glass panels creaking or flexing

• Distorted frames or movement at connection points

• Misalignment in curtain walling or structural glazing systems

These stresses may go unnoticed until they result in visible damage or operational issues.

A Proactive Approach

Summer may be short-lived, but the damage it can leave behind is not. Regular façade inspections and preventative maintenance can identify early signs of stress before they escalate into costly repairs. At Glass Aftercare, we help clients protect their investment year-round with:

• Thermal stress checks

• Sealant integrity assessments

• Glazing system inspections and reports

Do not wait until something breaks. If your building features a glass façade, now is the time to schedule your summer maintenance.

Get in touch with our team today to arrange a professional inspection and stay one step ahead of the summer heat.