Windshield Damage: When to Repair or Replace Auto Glass (Full Guide)

Repairing windshield damage is an unfortunate burden many vehicle owners have to bear. Your car, SUV or truck may be working perfectly, the interior may be spotless, yet what begins as a tiny star chip can continue to spread.

Soon, your vision is obscured, and you risk a police citation and your safety. In fact, a damaged windshield can be dangerous to the driver and all passengers, as weak auto glass threatens the integrity of your vehicle.

So that you can save time and money, and so that you can be vigilant about protecting yourself and your passengers in the case of an accident, here is the guidebook you require on auto glass replacement. The next time you see a chip, scratch, or crack, you will know how long to wait, and how fast to act, to mitigate the damage fast.

What Types of Windshield Glass Damage Should You Look For?

car windshield crack repair

– Chips

When you follow a vehicle too closely and a pebble or piece of debris hits your windshield, a chip in the glass can result. Chips almost always occur on the outer layer of the front windscreen. The screen – or windshield – is comprised of laminated glass and is actually several panes of glass separated by a layer of plastic.

This process makes the auto glass difficult to shatter. So, when that tiny rock or tin can flies up and hits your windscreen, tiny pieces of glass will flake off, and that’s when you get your chip.

Many vehicle owners are unaware that there are several types of chips your auto glass can sustain.

Different types of chips

Chip (pit)

What we refer to as a chip is a small piece of glass missing from the windscreen. We refer to the “pit” as the location where the glass is missing.


If the chip is on the larger side with a dark-colored, circular shape and impact hole, you have a bullseye chip.

Half Moon

A half-moon chip, otherwise referred to as a partial bullseye, resembles a typical bullseye, only the area where the damage occurs is only circular on one side.

Combination Break

A particularly severe chip involves a combination break, where the chip center has several cracks radiating from it.

– Cracks

When we speak of auto glass cracks, most of the time, we are referring to the laminated glass that makes up your front windscreen. However, any of your auto glass panes can crack, including the tempered glass that makes up your rear and side windows.

Here is another fact about auto glass damage most are unaware of. While chips are typically formed by small rocks and debris hitting your auto glass, cracks can form without any impact whatsoever.

Windshield Cracks Reasons

Cracks can form in the inner or outer layer of your front windshield or in any other piece of auto glass for a variety of reasons.

Temperature Changes

Anyone who has ever tried washing their car with super cold water on a really hot day can tell you all about the most common form of “stress crack,” a change in temperature. You can get a similar crack if you try using steaming hot water to melt an icy windscreen.

Pressure Changes

Many phenomena can cause pressure changes severe enough to cause cracks, including the weather. Wind pressure is a common reason for cracks to develop in the auto glass.

Auto Glass Defects

Your vehicle’s auto glass may have one or more manufacturing defects, which can cause cracks to develop. For instance, residual stress is the term we give to weakness along the edges of the windshield, which can lead to irreparable damage later on.

Different types of auto glass cracks

Edge Crack

An edge crack begins within two inches of the windshield and can sometimes reach as far as the outer edge.

Stress Crack

This is the crack you usually see when temperature changes lead to your windshield damage.

Crack Chip

If the crack can be covered by a quarter, we call it a crack chip.

Long Crack

If the crack is longer than six inches, about the size of a dollar bill, you are said to have a long crack in your auto glass.

Star Break

This damage presents itself as a series of cracks that radiate out from a single chip, which gives the auto glass damage the appearance of a star.

Floater Crack

A floater crack appears in the center of your windshield, not near the edges.


Your auto glass can become scratched by wiper blades that need to be replaced. As the rubber on the wipers wear away, the metal components that hold the rubber into place may begin scraping against the windscreen glass. Over time and with enough scraping, scratches can form and deepen.

Windshield scratches are usually shallow. You can determine the depth of a scratch by running your finger over the damage. Most scratches only affect the outer layer of the glass.

While scratches may not affect the structural integrity of your auto glass, they can take away from the attractiveness of your vehicle. Scratches can also reflect the light from the sun or headlights from oncoming cars, impacting your vision and leaving you susceptible to dangerous accidents.

Windshield scratch repair can usually be performed if the damage isn’t too deep, and involves buffing the damage out until it is no longer visible.

Can the Auto Glass Damage be Repaired? 

Other than protect you from the elements, your auto glass plays an important role in your safety and the safety of your passengers. Your windshield, in particular, is a vital component of your vehicle’s safety systems.

In the unfortunate case of a roll-over accident, for instance, your auto glass keeps your vehicle’s integrity intact, preventing the roof from caving inward.

Your windscreen is also designed to deflect the passenger side airbags upon deployment. If the windshield is damaged, the airbags may deploy through the glass, rendering them useless in the case of an accident, and putting your passengers at risk.

Because auto glass is so critical to safety, some damage is irreparable. Generally speaking, any windshield damage that starts from the edge of the screen and travels into the driver’s line of vision or exceeds the length of a dollar bill is not considered a candidate for repair. 

What Types of Windshield Damage Can Be Repaired? 

When we assess a vehicle’s auto glass for damage, we follow strict criteria for auto glass repair and replacement. Those criteria are twofold.

  1. Is the damage all the way through the glass?

    Here we are assessing the depth of the auto glass damage. If just the outer glass of your windshield is damaged, we may be able to repair the damage instead of replacing the windscreen outright.

    Conversely, if the damage can be felt with your finger on either side of the glass, replacement is the only option for ensuring safety and protection. 

  2. Is the length of the damage larger than a dollar bill?

    Scratches and chips are small and typically shallow enough to be repaired. If caught early, these defects in the glass can usually be contained before they begin to spread. Leave a chip or crack too long, however, and a crack can develop, which can quickly spread across your entire windshield.

    If the crack is longer than six inches, your windshield can only be replaced. The same is true if you have several chips or scratches affecting your vision or threatening the integrity of the glass. 

Methods of Windshield Repair

If your auto glass damage is roughly the size of a quarter or smaller, if there are fewer than three chips, and if your crack is tiny and hasn’t reached the edge of your windshield, the damage can usually be repaired. 

Sir Glass experts use a variety of techniques to mitigate the damage while bolstering the strength of your auto glass in the case of an unfortunate accident.

Patch with Windshield Resin

For tiny defects in the glass, such as a chip, we apply a peel-and-stick patch that goes over the damage. The patch keeps the damage from spreading as we apply an auto glass resin. The resin is used to fill the damage before it is cured and hardened. And that is all it takes for a fully repaired and stronger piece of auto glass. 

How do the Experts Go About Replacing Your Windshield or Tempered Auto Glass?

When the damage to your auto glass is too large to repair or when your glass is shattered entirely, replacement is your only option. 

Auto glass is held in place by a powerful adhesive. The seal on this adhesive must be broken before the old auto glass can be lifted away. In some cases, the trim, clips, fasteners, and retainers that hold the auto glass in place must be removed before the auto glass replacement can be continued. 

The windshield is removed with a specialized device, taking great care not to damage the pinch weld, which will be used to hold the new windscreen in place. 

With the damaged screen removed, the old urethane is scraped away to make room for new urethane and glass. 

In some cases, when removing the old urethane, it is common, even for experts, to cause some damage to the pinch weld. This damage, which usually amounts to tiny scratches, is minimal and can be mitigated by applying a urethane primer to the outside of the windshield, inside the edge, and on the window channel. 

Applying the primer allows the urethane glue to hold more effectively while simultaneously keeping rust from forming on the window channel, particularly when scratches are present.

If rust has already formed on the channel, every bit will have to be sanded and then primed before the new urethane is applied. 

The new urethane is applied around the perimeter of the screen and then the auto glass is set into place. Auto glass professionals use strong suction cups to lower the windscreen into position.

The screen must be placed just right before it is secured into place with clips.

The clips help to prevent shifting and allow the urethane to cure. The urethane takes around three hours to cure and harden, whereby the car can be driven away without issue, with the windscreen completely intact. 

This process is more or less the same when replacing all types of auto glass, including the back glass, review glass, and quarter panel auto glass. 

Get a Windshield Replacement Quote by Auto Glass Experts in Portland, Oregon 

Repairing your windshield is easy when you let the professionals do the job. When performing a DIY project like auto glass repair or replacement, you leave yourself open to making a few mistakes.

Air bubbles can form in the auto glass patch and your windshield may be improperly set, leaving you and your passengers at risk of serious harm. 

When you need auto glass repair or replacement, trust your windshield, back and side glass to SIR Glass in Portland, Oregon. We can come to you with our mobile auto glass repair, wherever you are located in the area, for fast service and convenience. Call now for a free quote and get your auto glass damage repaired today, before the damage becomes worse tomorrow.