Windscreen Damage and Repair Options

What can be repaired

Chips smaller than roughly a coin, not in the driver's direct line of sight, and not at the very edge of the glass, are generally repairable.

Repair involves injecting resin under vacuum, curing it and polishing the surface. It restores structural integrity and leaves a small blemish rather than an invisible finish.

Repairs take under an hour and cost a fraction of replacement. Many insurers cover them with no excess and without affecting no-claims discount, because a repair is far cheaper for them than a later replacement.

When replacement is required

Cracks of any meaningful length, damage in the driver's critical vision area, damage at the edge where the glass bonds to the body, and multiple chips in close proximity.

Edge damage matters because the windscreen is a structural component bonded into the shell. It contributes to roof strength and provides a backing for passenger airbag deployment.

Sensors and calibration

This is the change that has made windscreen replacement considerably more expensive on newer vehicles.

Cameras for lane keeping, automatic emergency braking and adaptive cruise control are mounted to the windscreen. Rain and light sensors, heating elements and heads-up display coatings add further complexity.

After replacement, camera systems require recalibration — static, dynamic or both — using manufacturer procedures and equipment.

Skipping calibration leaves safety systems operating on incorrect assumptions about where the road is. Ask specifically whether calibration is included and how it will be performed.

Glass quality

Original equipment glass matches the manufacturer's specification exactly. Equivalent-quality aftermarket glass is generally acceptable and cheaper.

Very cheap glass can produce optical distortion, poor fit and problems with sensor operation. On a vehicle with camera systems, this is a false economy.

Check what glass is being fitted before agreeing, particularly where an insurer's approved supplier is being used.

Insurance

Most comprehensive policies include glass cover, frequently with a lower excess for replacement and none for repair.

Glass claims typically do not affect no-claims discount, though they are recorded. Check your policy rather than assuming.

Using the insurer's approved network is usually a condition of the lower excess.

Practical points

Deal with chips immediately. Covering a chip with clear tape prevents dirt and moisture entering it, which improves the repair, until it can be done.

Avoid blasting the windscreen with hot air to clear ice, since thermal shock spreads chips readily.