According to the Office for National Statistics, around 30% of domestic burglaries involve entry through a window. Glass is often seen as the weakest point of a property — and for good reason. Standard single or double glazed windows can be broken quickly and quietly with the right tools.

The good news is that modern glazing technology has made significant advances in security performance. Here is what you need to know — and how our window repairs and glazing service can help.

Standard float glass — the kind used in most older windows — breaks into large, sharp shards when struck. It can be broken with a single blow and provides little resistance to a determined intruder.

Even standard double glazing, while harder to break than single glazing, is not specifically designed for security. The outer pane can be broken relatively easily, and once it is gone, the inner pane offers limited additional resistance.

Laminated glass consists of two or more layers of glass bonded together with a tough plastic interlayer (usually polyvinyl butyral, or PVB). When struck, the glass may crack, but the interlayer holds the pieces together — preventing the glass from being removed and maintaining a barrier against entry.

This is the same technology used in car windscreens. It is highly effective against smash-and-grab attacks and is the recommended choice for ground-floor windows, accessible skylights, and any window adjacent to a door lock.

Laminated glass is available in various thicknesses and security ratings. For domestic use, a 6.4mm or 8.8mm laminated unit provides excellent protection.

Toughened glass is approximately four to five times stronger than standard glass of the same thickness. It is produced by heating the glass to a high temperature and then rapidly cooling it, creating internal stresses that give it its strength.

When toughened glass does break, it shatters into small, blunt fragments rather than sharp shards — reducing the risk of injury. However, once it breaks, the barrier is gone. For this reason, toughened glass is better suited to areas where impact resistance is important (such as doors and low-level glazing) rather than as a primary security measure.

For the highest level of security, laminated toughened glass combines the strength of toughened glass with the hold-together properties of laminated glass. It is used in high-security applications and is available for domestic use where maximum protection is required.

Glass is only part of the security equation. The frame, hinges, and locking mechanisms are equally important.

• Multi-point locking systems engage at several points along the frame, making it much harder to force a window open.
• Key-operated locks prevent windows from being opened from outside even if the glass is broken.
• Hinge bolts reinforce the hinge side of casement windows against being levered open.
• Window restrictors limit how far a window can be opened, useful for upstairs windows where ventilation is needed but security is also a concern.

Not all windows present the same level of risk. Focus your security upgrades on:

1. Ground-floor windows — the most accessible to intruders
2. Windows adjacent to door locks — breaking the glass allows a hand to reach the lock
3. Rear and side windows — less visible from the street, more attractive to burglars
4. Garage and outbuilding windows — often overlooked but can provide access to tools or a route into the main property

Security glass costs more than standard glass, but the premium is often modest:

• Laminated glass typically costs 20–40% more than standard float glass of the same size
• For a standard casement window, the difference might be £30–£80 per unit
• Compared to the cost of a break-in — damage, theft, insurance excess, and the stress involved — it is a very worthwhile investment

If you are concerned about the security of your windows, we are happy to carry out a free assessment and advise on the most cost-effective upgrades for your property. We cover Essex, London, Surrey, and Kent.

Call us on 07596 081381 or 0800 634 3117.

Related reading: The Benefits of Toughened Glass · Emergency Boarding Up: What to Expect · What to Do When a Window Breaks