Windscreen Glass, Which Type Is Best?

Windscreens have a lot of responsibilities. Not only do they protect occupants from the weather, bugs, leaves and life’s flying debris; they help with noise reduction, heat control, and protection from UV rays. Your windscreen aids the function of your airbag, and does its best to protect you and the structural integrity of your entire vehicle in the event of an accident. Today they also house sensors, cameras and other micro-technologies for features such as automatic wipers, and ADAS safety functions.

When we think of vehicle features, generally the fancy mod cons come to mind. Rarely do we consider our windscreen. The windscreen is an unsung hero and one of the most important features of any vehicle. But they’re all the same right? Just a big sheet of sturdy glass? You might be surprised to learn there are two different types of windscreen glass, and one might be safer, stronger and more or less costly than the other.

What are the different types of windscreen glass

Laminated and tempered. Both are considered safety glass; but which is best? Let’s explore the details, pros and cons of each.

Laminated

Laminated glass is constructed of two sheets of glass on either side of a transparent polyvinyl (PVP) layer. PVP is a form of plastic. The two sheets of glass are fused together using extreme heat and high pressure until they become one.

Pros: The use of vinyl between the sheets of glass helps to prevent the glass from shattering. Although laminated glass can break, it prevents shards of glass from flying off in a collision and injuring occupants. This type of glass also protects unrestrained passengers or drivers from being catapulted out of the vehicle in an accident – acting like a barrier to the dangers of the outside world.

Laminated glass can be fixed if the damage is minor. Generally small chips or cracks can be repaired, restoring the strength and integrity of the windscreen. As chips and cracks are common, this saves on hefty replacement costs whilst helping the environment. Not only this, It is also the easiest to install and is the most common glass used for motor vehicle windscreens.

Cons: It is slightly higher in price than tempered glass

Tempered

Tempered, also known as toughened glass, is about 4 times stronger than standard glass. It is made via a rapid heating and cooling process in a tempering furnace, reaching top temperatures of approximately 620°C.

This type of glass is mainly used in side and rear vehicle windows but is also used for windscreens.

Pros: The tempering process ensures that should the glass break, it will shatter into small pebble-sized pieces (rather than shards) to diminish the risk of injury. The shattered glass is blunt, not sharp, greatly lessening the chance of cuts and abrasions.

It is typically less expensive than laminated glass.

Cons: Damage to tempered glass such as a small chip or crack cannot be repaired. Should it become damaged, it will need to be replaced in its entirety. Frequent replacements of tempered glass means it could become costly.

Windscreen manufacturing laws

The laws governing windscreen legislation are stringent and many. There are pages and pages of rules and regulations outlining everything from materials to be used to impact tests. If any company is found to be in breach of any of theses laws, they will be immediately removed from the list of accredited manufacturers and in some cases, legal proceedings can be commenced. According to government legislation,

‘The function… is to specify the performance requirements of material used for external or internal glazing in motor vehicles…ensure adequate visibility under normal operating conditions…minimise obscuration when shattered, and… minimise the likelihood of serious injury if a person comes in contact with the broken glazing material.’

It also states that all glazing materials should be of such a standard that they will reduce atmospheric and temperature damage, are not combustible in normal conditions, and are ‘sufficiently transparent…not to cause any noticeable distortions of objects as seen through the windscreen… ’  

Tests for fragmentation, resistance to the environment, temperature fluctuation, radiation and mechanical strength are just a small range of the tests performed on windscreen and window glass in Australia.

Different types of damage

There are many different types of windscreen damage but there are four things you must consider in determining whether your windscreen needs to be replaced or repaired. The type of glass, the nature of the break, the size, the depth and the location of the damage.

The most common forms of damage are:

The bullseye: Which, as it sounds is a small hole with cracks extending outward from the center.
The half moon: Half a bullseye crack

Edge crack: Starts a few centimeters from the edge of the windscreen and usually travels the entire width if not treated. This is the most common form of windscreen damage.

The chip: A small piece of glass that is chipped out of the window.

These four types are usually caused by rocks or small objects impacting the windscreen and can be repaired quite easily if caught early.
Stress Cracks: Don’t necessarily form from an impact; but rather from factors like sudden or dramatic temperature variations. They are almost always straight, and can be repaired if they’re tended to quickly, and are not too substantial.
Floater Cracks: Start in the middle of the windscreen. They are riskier because they can obstruct the driver’s view and cause further cracks in vulnerable spaces. These may still be repaired if taken care of early.
Combination Breaks: Several chips and cracks within one windscreen as a result of serious damage. Combination breaks may be too extensive to repair; typically, in this case you’d be better off having your windscreen replaced.
Repair vs Replacement

The cost for repairing a windscreen can be as little as $60 depending on the placement and extent of the damage. If damage is less than the size of a dollar coin and not in a critical vision area (CVA) repair is possible; but if damage is in the CVA, repair may obstruct the driver’s view of the road and replacement may be necessary. The CVA is the part of the windscreen 90mm from the top of the windscreen to 65mm from the bottom and directly in front of the drivers line of sight.

Replacement costs run from $200, depending on make and model of car, and into the $1,000’s for windscreens with costly electronic features.

When possible, having a professional technician repair your windscreen under warranty using a high quality epoxy resin is the better option. Not only is it quicker and better for your pocket, it helps the environment too. The materials used in producing a windscreen are not recyclable, therefore they sit in landfill, never breaking down.

So, if you’re ever in the common position of choosing between replacement or repair, investigate repair first. Your local Novus windscreen professional will come to you, and is always willing to lend a helping hand.

Novus Auto Glass are the windscreen repair experts. Specialising in windscreen fixing, windscreen replacements, glass restoration and other services, Novus can help you get back on the road. Call 13 22 34 to bring Novus to your door.

These four types are usually caused by rocks or small objects impacting the windscreen and can be repaired quite easily if caught early.