It’s what many car owners dread, that pinging sound as a stone flicks up off the road or bounces off the back of a truck and hits your windscreen. What starts as a small chip quickly becomes a crack making its way further and further across the windscreen.
So, while windscreens are specifically designed to provide structural support for the vehicle as well as to stand up to the stress of travelling, damage does inevitably occur.
Interestingly windscreens are actually made up of two layers of glass with an inner layer of automotive safety glass between them. This inner layer, the lamination, serves to hold together the broken outer layers in the event of an accident.
That is why windscreens crack when struck by objects, but don’t fall apart and cave in on the driver in most circumstances.
The question is whether the damage calls for a full windscreen replacement or if a repair will do.
Dewald Ranft, Chairman of the Motor Industry Workshop Association (MIWA), a proud association of the Retail Motor Industry Organisation (RMI), says a point to remember is that your windscreen is your protective shield.
Replace or repair?
"A crack or chip compromises the efficiency of a windscreen so it may not be the wisest option to go with the cheapest route which could be the wrong one if you were in an accident,” he says.
In general, however, most chips and cracks can be repaired. “Four factors are used to assess the damage – the size, type, depth, and location of the damage.
This assessment needs to be done by a qualified auto glass repair technician who can then decide whether the windscreen is repairable.”
"Most workshops should be able to repair chips of about 2.5cm diameter and cracks about 7cm long. Traditionally, any crack larger than that would not be repaired, but a full replacement needed.
However, new technologies are making it possible to repair wider chips and longer cracks."
The type of crack is also important as there are many different types of cracks, some of which can be repaired while others can’t.
"In general, chips and cracks that can be covered with a R2 coin can usually be repaired," says Ranft.
He adds that even good repairs may leave behind some discolouration, mistiness or unevenness so location of the chip or crack is an important consideration.
"If the damage is in the driver’s line of sight, a repair could distract the driver. Also, any chip or crack that is at or very near the windscreen’s edge where it meets the metal frame, weakens the windscreen and compromises passenger safety. If the technician can’t see the crack or chip in its entirety, then the repair can’t be done successfully."
Typically, an average chip or crack will take about 30 to 40 minutes to repair. A windscreen replacement can be done within a few hours. "Depending on how busy the workshop is you may need to book your car in for the day,” he explains.
Ranft says the key is dealing with a chip or crack as fast as possible so he recommends speaking to your insurer about what is covered and what excess you may need to pay.
"Cracks lengthen before you know it. Dust also settles inside chips which can cause further damage and make repairs difficult. If you don’t act quickly what could have been an inexpensive repair job may turn into an expensive replacement. It is also vital to use a repairer who knows what he/she is doing. Make sure the workshop you use is accredited and legit,” he advises.