Windscreen damage always needs to be dealt with as soon as possible because it can impair your view of the road and can lead to bigger windscreen problems. Repairing the windscreen will be cheaper and quicker than a full replacement, so how do you know which option you should go for?
Whether a chip can be repaired depends on its size. As a general rule, a chip can be repaired if it is smaller than an Australian two-dollar coin, particularly if it is not on the driver's side and impairing vision. However, you should ensure that this repair takes place as soon as possible — chips can easily become larger and will eventually necessitate a full replacement.
Whether a long crack can be repaired also depends upon its size and position. If it is on the driver's side, a crack can probably be repaired if it is less than thirty millimetres long. If it is elsewhere on the windscreen, a crack can be up to seventy-five millimetres before the windscreen will need replacing. Again, cracks will only become worse over time; if they are not dealt with quickly, they will impair vision and could lead to the windscreen shattering.
If a crack extends to the edge of the windscreen, this will weaken the entire glass to an extent that it probably cannot be repaired. It does not matter in this case how long the crack is — the damage to the windscreen is so great that it is no longer safe to use on the road.
Chips in the glass that have cracks extending out from them in the shape of a star are far more weakening to the glass than others. These chips can only be repaired if they are smaller than sixteen millimetres in diameter. The area of the glass that has been weakened is far greater than with a single chip, and so is the risk that the glass will break further.
Any damage that impedes the driver's vision is dangerous and needs immediate treatment. Such damage is likely to require the replacement of the entire windscreen rather than the type of repair that will only work on small cracks.
Damage to your windscreen should never be ignored, and your windscreen service will be able to advise you whether the glass can be repaired or will need to be replaced.