Don't mess with chips and cracks

That little crack in your windscreen may not be big enough to bother you, but keep in mind that chips and cracks can weaken a windscreen.

On modern vehicles, windscreens play a key role in the overall structural strength of a car – up to 47 per cent. A damaged windscreen reduces its ability to protect the vehicle's occupants in a collision or rollover accident. It can also cause headaches when the time comes to sell your vehicle and the windscreen fails a roadworthy test.

If your windscreen does have some damage, and you're not sure whether it is roadworthy, take your vehicle to a VACC repairer to have it inspected.

Repairing a chipped or cracked windscreen

If you do have a chip or crack in your windscreen, it's best to repair when it first happens, or it could start to spread. Chips and cracks left for too long can collect dirt and moisture, which makes them more difficult to repair and more noticeable.

Chipped or cracked windscreens can often be repaired, however, there is an Australian standard for windscreens specifying the size, type and location of damage that can be repaired safely. For example, if the damage exceeds the size specified in the Australian standard, or the damage affects more than the outer layer of the windscreen, it can't be repaired.

To repair a windscreen, a vacuum method is used to draw out air from the damaged area, which is then injected with an acrylic resin. Once set, the resin has a similar strength and transparency to the glass. The larger the size and the greater the number of windscreen repairs you have, the more potential there is for light distortion, impaired vision and driver distractions. Sometimes it's best to simply have the windscreen replaced. If you decide on replacement, make sure you see a specialist to ensure the windscreen meets the highest safety standards.

Windscreens in later model cars are bonded in place with a urethane adhesive, which provides structural strength. The correct procedures must be followed when replacing a windscreen fitted in this way, or problems will occur and vehicle strength will be jeopardised.

Remember that a badly damaged windscreen can render your car unroadworthy, particularly if the damage affects the primary vision area and interferes with the driver's vision of the road.