Types of Windshield and Rear Auto Glass Damage for Portland Area Drivers

As a driver of our Portland area roads, it is important to learn about the various types of windshield and rear windshield damage you could end up dealing with at some point in time. A stray rock or kicked up piece of debris could damage your auto glass. Do you know what auto glass damage looks like and what to do about it? You soon will.

Here are the various types of auto glass damage you could endure, and what to do when your auto glass chips, cracks, or shatters. 

Windshield Damage

Windshields are specialized pieces of glass that are created through a process known as lamination. Laminated glass is created by bonding several layers of glass together under immense pressure and heat. The glass is bonded with a resin called polyvinyl butyral or PVB. The result is a single sheet of glass that contains multiple layers. The PVB resin produces excellent sound insulation and helps keep the glass together in case of an accident. The glass will not shatter upon impact like the other auto glass panes in your car and will instead bend and flex. Laminated glass also blocks around 99% of UV light.


Most people are familiar with windshield cracks, but you can get cracks on any vehicle auto glass, including your rear window. Cracks typically occur when something hits your auto glass, like a rock thrown from the car in front of you. When the object hits the outside edge of the windshield, the result is usually one long crack. Other cracks form near the center and cause starburst cracks. 

Unlike chips, cracks can also form without any impact with a rock or debris whatsoever. Here are the most common types of cracks we deal with in our auto glass repair shop.

Stress Crack

This type of auto glass crack can happen after a sudden variation in temperature. An example is when you might try to pour hot water on your windshield to melt ice in the winter, which is a common mistake we see. Stress cracks can also appear if your car gets overheated in the sun and you then turn on your air conditioner or you wash your car with cold water. 

Stress cracks are typically straight or slightly bent, and with no visible impact points. Some stress cracks can be repaired. We typically conduct what is called a pen test, whereby we lay a ballpoint pen along the crack. If the crack dips anywhere, it is not a stress crack, as stress cracks don’t cause glass to come off the windshield. 

Edge Crack

This crack begins within two inches of the edge of the windshield, or it can touch the outer edge in some cases. 

Floater Crack

This crack starts somewhere in the center of the windshield and not near the edges. 

Crack Chip

The crack chip isn’t really a chip at all; it’s a crack that can be covered by a quarter. 

Long Crack

This is a crack that is longer than six inches in length, which cannot be repaired.

Star Break

A star break can be classified as a chip and a break, but it does consist of a series of cracks, which is why it also belongs in the crack category.


These auto glass defects usually happen when a small rock of flying piece of debris collides with your windshield. Instead of forming cracks, small pieces of glass are removed, causing a chip. You almost always find chips on the outer layer of your windshield, where the debris has caused tiny pieces of the laminated glass to flake off.

Auto glass chips come in several different types.

Chip (Pit)

This type of auto glass chip is characterized by a small piece of glass that is missing from the windshield. We call the area where the glass is missing the “pit.”


Bullseye chips are larger than regular chips. You can tell this type of auto glass damage by the dark-colored and circular shape with an impact hole.

Half Moon

A half-moon is like a bullseye, but the damage isn’t circular all the way around. 


Windshields occasionally get breaks that resemble stars. The star shape is created by small chips that contain multiple cracks that radiate outward, resembling a fireworks explosion. Star patterns can usually be repaired, but the defect will still be slightly visible after the affected area is filled. In some cases, star breaks and their remnants can lower the value of your vehicle when it comes time to sell.

Stone Break

This is a small chip that occurs when a hard item, such as a stone, hits the windshield. These breaks can become cracks over time.

Combination Break

A star is a good combination of a combination break, which consists of a chip and several cracks.

You should get chips fixed immediately because a chip left unrepaired can weaken your windshield and cause cracks in the auto glass to form. It would be a shame to allow a tiny chip to become a significant crack that would then require a complete windshield replacement. It is far better to repair small defects in auto glass to save time and money while also keeping you safe. 

Shattered Auto Glass

While a front windshield doesn’t shatter like the other panes of auto glass in your vehicle, it does its own form of shattering. The shattered glass is still held in one piece, thanks to the lamination process. And you shouldn’t have to worry about the glass collapsing into your vehicle or onto your hood in the case of an accident. Thanks to the strong urethane adhesives that hold the windshield in place, the entire windshield will remain in its frame, keeping you and any occupants in your vehicle safe. 

If your windshield ever shatters while driving, it is important to take immediate action.

First, pull over to the side of the road. Never hit your brakes suddenly, since the driver behind you might not have fair enough warning to slow down, leading to an unfortunate collision. Instead, gradually reduce your speed and put your turn signal on, then pull over. Contact the legal authorities if someone threw something that broke your windshield. When driving your vehicle to the auto glass repair shop, wear glasses in case stray pieces of glass fly off the windshield. 

Or, call Sir Auto Glass wherever you are pulled over to the side of the road, and we can have your windshield replaced by coming to you.

What if Someone Broke Your Auto Glass?

You walk to your car only to find that one of your auto glass panes is shattered. Whether someone vandalized your vehicle or broke in, here are some steps to take.

First, call your insurance company and file a police report. If your car has been broken into, do not touch anything until a claims adjuster or police officer is able to assess the damage. Make sure you also take pictures of the scene that shows the auto glass damage before having anything cleaned or repaired.

When cleaning up the auto glass, use a shop vacuum. You always want to suction the glass as opposed to sweeping it up, as glass can harm leather seats and scratch other interior parts of your car. Most auto glass repair shops will include shop vacuuming as part of the glass replacement process. 

When driving to the auto glass shop, secure the window to keep the elements out. Many people use cardboard and duct tape, but the better method is to use clear packing tape that is run vertically from the top of the window to the bottom while inside your vehicle. 

Or, call Sir Auto Glass for mobile auto glass replacement, and we can come to wherever your car was damaged to make your vehicle and auto glass good as new.

Is It Safe to Drive with a Cracked Windshield?

Driving around with a crack in your front auto glass is never a good idea. If the damage is a chip, those kinds of defects can usually be repaired. A crack is different. A crack can limit your vision or cause light effects that can distract you when you are driving. A crack can also weaken the integrity of your windshield and, ultimately, the frame of your vehicle in case of a rollover accident. 

Small cracks can become larger cracks over time. Moisture can get into the crack and ultimately into the layers of your laminated glass windshield. Along with temperature, the crack will quickly spread. Dirt can also get inside the cracks, causing the cracks to widen and spread. Finally, bumps in the road may be all it takes for that small crack to get just a bit longer. 

As soon as you notice a chip or crack, we recommend that you bring your vehicle to an auto glass repair shop for a chip repair or complete windshield replacement for your peace of mind.

10 Reasons Why Not to Wait to Get Your Windshield Fixed.

Back Windshield Damage

The rear glass of your vehicle is located opposite your windshield and acts as a counterpoint to help your vehicle retain its rigid frame in the case of an accident, while also protecting the vehicle occupants. Just like windshield damage, you should take rear auto glass damage very seriously. A single chip or crack could put you and your passengers at risk.

Unlike layered windshield glass, back auto glass is made in a similar fashion as all the other forms of glass in your car. The side windows, vent glass, sliders, quarter glass, and sunroof are all made with the same material, which is known as tempered glass. Unlike the other forms of glass, however, the rear auto glass is strengthened by thermal treatments so that it can withstand blunt force. After heating the glass to around 1200 degrees in a tempering furnace and then rapidly cooling the glass in a process called quenching, the back glass pane becomes four to five times stronger than before the tempering process. 

While the back glass is strong, the pane can shatter. Don’t worry about sharp shards of glass, however. When the back auto glass breaks, the pieces are tiny and sand-like, giving it the common nickname “safety glass.”

In some cases, back auto glass, like the other panes of glass in your car, can seem to shatter as if something hit it when nothing actually hit it at all. This is a rare occurrence but usually happens when a crack occurs and then gets worse over time. It’s only when temperature variation of some other type of stress factor occurs that the glass finally gives way.

Repair Auto Glass or Have it Replaced?

In many cases, windshield or back glass repair is covered by your insurance. Your auto glass repair shop should be able to work closely with the insurance company to get your windshield or rear auto glass repaired or replaced. 

If your auto glass can be repaired, which is often the case for cracks less than the length of a dollar bill and small chips, this will usually be free of charge if the insurance company picks up the tab.

If your windshield or back auto glass needs to be replaced entirely, you may encounter some costs, such as paying the insurance deductible. The total out-of-pocket expenses you could incur for replacement depends on your policy and type of auto glass being replaced. 

The only way to determine if your auto glass can be repaired or if you need to have a complete windshield or back windshield replacement is to have your vehicle assessed by a qualified auto glass repair expert.

Get a Free Estimate for Auto Glass Damage

When your auto glass bears a chip or crack, seeing the defect can quickly ruin your day. If the chip or crack is left too long, you could face even more damage. Cracks that lengthen can obscure your vision, leading to accidents. Some police officers will even give you a ticket for cracked auto glass, as it is considered a driving impediment. Cracked auto glass is also a safety hazard, which is why you should always have auto glass damage taken care of as soon as you can.

At Sir Auto Glass in Portland, Oregon, we offer mobile auto glass repair service. We can provide you with chip and crack repair and complete windshield and back auto glass replacement for fees you can afford. We can work with you and your insurance company and guarantee a quality installation to ensure your auto glass always holds up as it should. Improve the value of your vehicle and keep yourself and your occupants safe with auto glass done right. Have you sustained auto glass damage? Call now for a free estimate, and we can get you back on the road with your auto glass intact in no time.