New glass shattering

[LittleEsme]

We renovated an old house 3 -4 years ago. At the beginning of the year one of the glass panels in our downstairs double glazing shattered (stayed in tact) but shattered with no known (to us) explanation - no impact, nothing fell on it. Glazers replaced it under warranty and said it was either temperature change (unlikely - we’re hardly in the tropics of South Wales) or the building settling.

Fast forward to today, we have an en-suite with a shower and an enormous tempered shower glass panel. For some unknown reason, it shattered and fell in thousands of pieces to the floor. The sound it made was terrifying - I honestly thought DH had gone through the glass but he was in our room, nowhere near it.

The bathroom store we bought it from will check on Monday what the warranty is and we are in the big, careful clean up now. Nightmare. Glass is everywhere quite literally.

We’ll hopefully sort this through warranty and/or insurance but my concern is why this actually happened.

This original house is 200 yrs old but we ripped out everything and created new walls and ceilings. Why would top quality safety glass behave like this? Could it be coincidence?!

any ideas?

How freaky, I'd be calling a priest! 😂

I was so intrigued by this that I asked Copilot, which came up with this:

Tempered glass is designed to be strong and safe—it breaks into small, blunt pieces rather than dangerous shards. But it’s not invincible. Here are the most common culprits:

1. Nickel Sulphide Inclusions (NSI)

• Tiny impurities in the glass from manufacturing.
• These can expand over time and cause internal stress.
• The glass might hold up for years before suddenly failing.
• This is a known issue in tempered glass and often the cause of spontaneous breakage.

1. Edge Damage During Installation

• Even a microscopic chip or scratch on the edge can weaken the panel.
• Over time, with temperature changes or vibrations, that flaw can propagate and cause failure.
• Especially relevant if the panel was tightly fitted or handled roughly during install.

1. Thermal Stress

• While South Wales isn’t tropical, even modest temperature swings (e.g. hot shower steam vs cold air) can create stress.
• If one part of the glass heats up faster than another, it can cause uneven expansion.

1. Building Movement

• Your house may be newly renovated, but it’s still 200 years old.
• Settling, shifting, or even subtle vibrations from nearby traffic or construction can stress fittings.
• If the glass was installed rigidly without room to flex, movement could trigger a break.

1. Poor Mounting or Pressure Points

• If the glass was mounted with uneven pressure or tight brackets, stress can build up.
• Silicone seals or rubber gaskets are meant to cushion it—if those failed or were missing, that’s a risk.

🧪 Is It Just a Coincidence? It could be. But two spontaneous glass failures in the same house within a year—after years of no issues—suggests a pattern. Here’s what might link them:

• Post-renovation settling: Even years later, new walls and floors can shift slightly.
• Humidity and temperature cycles: Especially in bathrooms, these can be more extreme than we think.
• Installation practices: If the same contractor or supplier handled both, it’s worth reviewing their methods.

🛠️ What You Can Do Now

• Ask the supplier about NSI testing: Some manufacturers test for nickel sulphide, but not all.
• Check installation records: Were proper gaskets and seals used? Was the glass edge protected?
• Review insurance and warranty: Some policies cover spontaneous breakage, especially if it’s safety glass.
• Consider laminated glass next time: It’s less prone to spontaneous shattering and stays in place even when cracked.

Are you on clay or something, could dry weather have caused more movement if the ground shrinks?

That must have been very scary. Some years ago, we had double glazed windows replaced and one of them, in my daughter’s bedroom shattered shortly after installation. Fortunately, it didn’t shatter into the room and the company replaced it, but it took a while for them to accept that a piece of glass had simply shattered during the night.

There must be some fault inherent in the glass surely, for that to happen. I hope you can resolve it without difficulty.

😂 Something spiritual quickly crossed my mind I have to admit.

What a great reply you’ve given me - so much so I’ve cut and pasted it to DH. Thanks loads.

We are actually on rock - so nothing like clay. DH pointed out that despite paying top-notch labour prices, the workmanship of lots of our build leaves us questioning the quality of their skill, so it could be installation. Thanks again - you’ve given me loads to think about.

Thank you. I’m just relieved that DH wasn’t in the shower when it happened. It’s his en-suite so only used by him.

The clean up has been a nightmare - we even borrowed our neighbour’s industrial building hoover to finish up. It’s taken us hours!

A but nervous of having another glass screen in there now though, got to admit.

We had this happen with the glass in our sliding patio doors. The sound was unbelievably loud. I thought something must have hit it as it was so sudden and loud and the glass looked shattered from a specific point. Luckily it didn’t go everywhere and the window people put a plastic covering to hold it all in place until the new glass order came in. The man that came to fix it says it can just happen because of a weak point in the glass so who knows!?! I agree that the sound was really shocking.

Yes - a weak point. It could be as simple an explanation as that.

The sound was nothing I’ve ever heard before - terrifying. I’m worried about replacing it tbh.