FAQs

Find out about windscreen chips on this page and click the links on the left for information about chip repair and the MOT.

 

 

1. What is a windscreen chip?
It's damage to the glass usually caused by an impact from a stone or other debris hitting the windscreen while the vehicle is being driven.

Impact damage usually consists of an area of damage surrounding the impact point.

 

 

2. Are there different types of impact damage?
Impact damage can take several forms:

• 'Bulls eye' - a circular indentation
• 'Star break' - small cracks radiating out in all directions
• Other combinations of the above with names such as, 'cloverleaf', 'beeswing', 'half moon'

 

 

3. Are certain types of vehicle more susceptible to damage than others?
As windscreens increase in size so does their chance of sustaining damage since there is a larger surface area for objects to hit.

Windscreens that are of a complex shape also have areas which are more "stressed" than others and any further stressing of the glass, e.g. a stone strike, can result in a chip or crack.

 

Rake angle and the position of the strike on the glass can also be a factor. A strike near the edge of the glass will usually result in the screen continuing to crack right to the edge which cannot then be repaired.

 

 

4. What else influences damage?
Road conditions:
- number of cars on the road, road type (motorway, 'B' road, etc.), quality of road surface

Driving behaviour:
- speed, number of miles driven

Missile characteristics:
- type and properties of the missile causing the impact damage to the screen

The weather:
- e.g. heavy rain washing debris onto the road or highway gritters operating because of frosty conditions.

 

 

5. What makes a chip develop into a crack?
Shock, vibration, extremes of temperature (such as turning the air-conditioning on full on a scorching hot day), driving time or factors such as frost, dirt and moisture getting inside a chip can all contribute.

 

Glass has no inherent strength and therefore no ability to resist outside factors. Once a chip or crack appears, external stressors, such as heat, vibration or movement are likely to cause it to expand.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6. Windscreen wipers can be damaged by chips
A chip in a windscreen may cause damage to the rubber of the vehicle's windscreen wiper blades if left unrepaired.