Repairing A Chipped Windscreen

Posted on November 29th, 2013 by GEM Motoring Assist

A chipped windscreen can be an expensive hassle. Rob Marshall explains what you need to know.

Like many components within the modern motor car, windscreens have become considerably more complex over the past thirty years. In the early days of motoring, occupants sustained serious injuries from a screen breaking into large, sharp pieces.


Toughened windscreens were common in the 1950s and this type of glass is still used for side and rear windows on most models. ‘Laminated’ windscreens became widespread by the mid-1970s and so modern windscreens consist of a plastic sheet, sandwiched between two glass panes.

Although a broken windscreen will no longer shower the interior with glass, the thinner panes make it more vulnerable to damage. If you have a chipped windscreen, you must to repair it immediately, which will not only prevent the damage from spreading, but also dirt will be prevented from entering the affected area.



Now that most cars have their windscreens glued, with an extremely strong bonding adhesive, the glass becomes integral to the vehicle’s structure. Natural bodywork flexing can even cause a glazing defect to enlarge, which might result in the need to replace the whole screen. In the winter, water can enter the crack, freeze and expand, potentially extending the damaged area.


Obvious vandal damage, to this extent, cannot be repaired. A replacement windscreen is necessary.

Many windscreen repair businesses can repair a windscreen scratch or chip and the glazing can even be replaced at your home. Some insurance policies will cover the cost of windscreen repair or replacement, without affecting your no-claims bonus.

Windscreen cracks, such as a ‘Star Break’, ‘Bull’s Eye’ or ‘Clover Leaf’ can be more difficult to repair, and may require a new windscreen, depending on the location and size of the damage.

 Cracked windscreen

The Area of Damage. Both the location of the damage and its size will influence whether a repair can be affected or not. In the pictured areas, a chip or crack cannot exceed the following diameters:
ZONE A: 10mm
ZONE B: 15mm
ZONE C: 25mm
ZONE D: 40mm

cracked screen

The Severity of Damage. Chipped windscreen damage can vary in severity. Here, several small chips are located close to a more serious Star Break.

cracked windscreen

  Small areas of impact damage can turn into large cracks, which cannot be repaired on passenger cars.

 Windscreens, which have UV-reflecting layers or heating elements embedded within the laminated layers, may not be repairable by a specialist. You should check with your insurance company whether glass repair or replacement is included in your policy. Replacing these types of screen can cost as much as £500.


Windscreen repair kit

 An effective windscreen repair can be made with DIY kits, which are sold through many motor factor outlets, although most repairs are best left to professional companies.

 Repairing either a chipped windscreen, or a cracked one, involves injecting the affected area with a specialised resin, to not only seal the glass from external moisture but also to strengthen the crack and prevent it from spreading. Windscreen repair kits are available from most motor factor retailers but, if you do decide to try one, follow the instructions carefully.

While a DIY repair should restore the glass’s strength, it can be impossible for even a professional repairer to restore the glass’s optical clarity fully and so con-sider that a windscreen replacement might be your only option.