Like any other part of a car, windscreens can suffer damage that hampers their safety and performance. If you drive with a damaged windscreen, you need to be aware of the safety risks and the fact that you could be in breach of the law.

Here, we look at common issues that can arise from a damaged windscreen, including how to stop cracks from spreading and whether your car will pass its MOT. Use the links below to navigate the guide.

Quick Links

  1. Is a cracked windscreen a major problem?
  2. Is it illegal to drive with a cracked windscreen?
  3. Will my car fail its MOT if the windscreen is cracked?
  4. How can I prevent damage to my car’s windscreen?
  5. How can I repair my windscreen or stop a crack from spreading?

Is a cracked windscreen a major problem?

Windscreens are vital to the safety of your car, acting as a barrier from the weather while ensuring good visibility. If your windscreen is cracked or chipped, this could impair your vision and cause dangerous dazzle from the sun and the headlights of oncoming cars.

Not only that, but windscreens are an important part of a car’s structure, and help to maintain the rigidity of the roof – which is important in the event of a roll-over accident. Also, if there’s a chip or crack in the glass, this could have an impact on the protective UV coating, leaving you and your passengers exposed to the sun’s harmful rays.

Is it illegal to drive with a cracked windscreen?

Driving with a damaged windscreen could constitute a motoring offence, particularly if the police think that the crack is affecting your view of the road and causing you to drive dangerously.

If a crack on the windscreen appears within your eye-line, you could receive a fixed penalty notice of a fine plus three points on your licence. That’s because The Highway Code states that drivers should always have a full view of the road ahead, and that the front-facing glass should be kept in a reasonable condition.

Naturally, if you’re involved in a collision while driving with a damaged windscreen, you could face more serious charges if it’s believed that a crack played a part in causing the accident.

Will my car fail its MOT if the windscreen is cracked?

A damaged windscreen could lead to your car failing its MOT, but only in two specific circumstances – we’ve listed them below:

windscreen dyagram

  • If there is damage to the windscreen which extends over 40mm, your car will automatically fail its MOT, regardless of where the crack is on the glass. The windscreen will have to be repaired or replaced before it can be re-tested.
  • If there is a 10mm chip or crack in ‘Zone A’ of the windscreen. This is a 290mm-wide area that falls directly in the driver’s eye-line. If it’s in ‘Zone B’ the car may not fail the test, but the assessor will note down the crack as an advisory warning on the certificate.

Your car could fail its MOT test if there’s damage to the windscreen, side windows or rear window, so we’d recommend having any cracks or chips repaired ahead of the test for peace of mind.

How can I prevent damage to my car’s windscreen?

While windscreens are constructed from laminated safety glass that’s stronger than ordinary non-treated glass, they can still be damaged by flying objects and collisions. To stand the best chance of avoiding cracks and stone chips, we’ve listed some practical tips for preventing windscreen damage.

Keep your distance from the car in front

Most windscreen stone chips occur as a result of debris being thrown up into the air by other cars, so you should always maintain a sensible distance from the car in front. Even if stone chips don’t damage the windscreen, they could still make a mess of your paintwork and bonnet.

High traffic density on highway

Replace windscreen wipers once a year

A build-up of dirt and debris on the windscreen makes it more likely that a chip or crack will form, so always make sure your wipers are in good condition and replace them every year to limit the amount of harmful road deposits on the glass.

Inspect your windscreen regularly

It’s always better to catch a chip or crack in its earliest stages, as this will make repairing the problem much simpler. So keep an eye on your windscreen and check it inside and out regularly to make sure there are no signs of damage that could get worse if left untreated.

Don’t use hot water to de-ice the windscreen

Cleans frozen windshield

Pouring hot water on the windscreen to de-ice it may seem like a convenient solution, but it could prove a pricey mistake. Sudden temperature changes can crack glass, so only ever use de-icer and a scraper to remove ice and frost from your car.

Drive carefully on untreated surfaces and poor roads

Stone chips are more likely to happen when you’re on gravelly surfaces like during roadworks or on a badly maintained road – so make sure you drive carefully to prevent stones hitting the windscreen.

How can I repair my windscreen or stop a crack from spreading?

If you spot a chip or crack in your windscreen, however small it may be, it’s never a good idea to ignore it as it’s almost certain to get worse over time. A small chip could become a large crack with one severe speed bump or a very cold night, so it’s vital that you repair small imperfections in the glass before they can become more serious problems.

Catch a chip or small crack early enough, and it may be possible to repair it simply by sealing the area with an epoxy resin or acrylic adhesive. These specialist products restore the rigidity of the glass and create a moisture-tight seal to stop it spreading and causing more damage.

damaged windshield

There are now several car glass specialists in the UK offering this type of repair, and depending on the level of insurance you have on your car, you may be able to claim back the cost of repairing the glass from your policy provider. If the glass is cracked beyond repair, you might need a new windscreen.

Prestone car maintenance products are tested in extreme conditions, so they’re guaranteed to look after your car no matter how gruelling your daily commute. Click here to find out more.