Smashed Window Pane

What's happening?

A broken pane is two problems arriving at once: an injury hazard from the glass still standing in the rebate, and an open hole in the building. Which of them is more urgent depends on what the glass was. Annealed glass breaks into long, sharp shards that stay wedged in the frame: these are what cut people during clean-up. Toughened glass disintegrates into small blunt granules and usually leaves an empty frame. Laminated glass cracks but holds together on its interlayer, so the pane stays roughly in place. A glazier's first job is not the new glass. It is removing what is left safely, making the opening secure, and then measuring for a replacement that meets the requirements for where it sits.

What usually causes it?

• Impact: a ball, a stone from a mower, a falling branch, a ladder or a slammed door
• Attempted or actual break-in, where the pane was the way in
• Thermal stress cracking in annealed glass, where one part of the pane heats far faster than the shaded edge
• Storm debris in high wind, most often on exposed or gable-end elevations
• Frame or building movement putting the pane into bending it cannot take
• Glass with no setting blocks, bearing directly onto the frame at a corner
• Existing edge damage (a chip or nibble from an earlier knock) spreading under normal load

Is it dangerous?

Yes. Glass standing in a frame with a hole in it can drop at any point, and shards under load can move when the frame is touched. Keep children and pets out of the room, wear stout gloves and eye protection if you must be near it, and do not put your hand through the opening to clear glass from the other side. The other exposure is the building: an open pane at ground level is an access point, and in weather it lets water into floors and plaster.

Can I fix it myself?

Making the area safe is reasonable: clearing loose glass off the floor with a dustpan and stiff brush rather than a vacuum, taping across a cracked-but-intact laminated pane so it stays put, and screwing a board over the opening if you can do it from a safe standing position. Do not de-glaze the frame yourself: pulling shards out of a rebate is where most DIY glass injuries happen, and the pieces still bedded in putty or gasket are under load. Do not board up by driving fixings through the frame itself.

When should you call a glazier?

Call a glazier immediately for any broken pane in a door, at ground level, or anywhere the opening is accessible: most glaziers run an emergency call-out and the Glass and Glazing Federation keeps an emergency glazing register for exactly this. Call the same day for upper-floor breakages. Where the break involves a suspected crime, report it before the glass is cleared if the police have asked you to.

What will the glazier actually do?

• Make the area safe, de-glaze the frame and remove every shard from the rebate
• Board or temporarily glaze the opening so the property is secure and weathertight
• Measure the opening and identify the glass specification the position requires
• Determine whether the location is a critical location (a window below 800mm from floor level, or a door or door side panel below 1500mm), so safety glass is supplied where needed
• Glaze the new pane or sealed unit onto fresh setting blocks and re-bead or re-gasket it
• Check the frame and beads for damage from the impact, and confirm the sash closes and locks

Who fixes this

• Broken window repair
• Glass unit replacement

Questions people ask

Sources & References

1. GOV.UK, Protection from falling, collision and impact: Approved Document K
2. Glass and Glazing Federation: Emergency Glazing Register
3. Glass and Glazing Federation