Windshield Cracks – types, causes, and reasons for the spread


By  admin

Category:  Cracked Windshield

Did you know that only auto glass chips that are less than 40mm in diameter can be repaired? It might have come as news to you, but not all windshield damages are repairable. For this matter, you must seek professional help in case of a cracked windshield.

If the windshield integrity is compromised, it is imperative to consult auto glass experts without any postponement. Depending on the severity of the damage, the technician will suggest you get it repaired or replaced.

However, you may wonder why it is necessary for you to identify the types of windshield cracks. Windshields incur several chips and cracks due to several reasons. Knowing about the types of cracked windshields lets you gauge the extent of damage you are dealing with.  It will enable you to make an informed decision and act swiftly as some cracks are more severe than others.

Types of cracked windshields

Stress Crack

Have you ever encountered a cracked windshield even when it has not suffered any known damage? Experts term this crack as a stress crack. The reason can be sudden and extreme fluctuations in temperature or pressure. Glass windshields tend to expand under hot weather conditions and contract in cold weather. If the windshield is simultaneously subjected to both, the resultant is a cracked windshield. For instance, stress crack occurs when the car is overheated but with the air-conditioning on blast.

Other reasons that contribute to stress cracks include the age of the windshield glass. Old windshields are more susceptible to these kinds of cracks, and replacement is the advised remedy in such instances.

Floater Crack

This special crack is named so as it always occurs away from the edge of the windshield. A floater crack can be spotted in the middle of the windshield or at least two inches away from the windshield’s edge. This kind of damage extends across many cracked windshields, and thus, they usually have varying lengths. Floater cracks tend to spread very fast; therefore, they need immediate attention.  A professional will determine the crack’s width and depth before prescribing a repair or a replacement. Besides, if a tiny floater crack is not in the driver’s line of vision, a trained technician can effectively tend to it.

Crack Chips

When small rocks or pebbles strike your car windshield, the kind of damage sustained by the windshield is called a crack chip. This damage is usually relatively minute and can be fully repaired by an expert. Moreover, chips are further divided into several types, and determining the type is essential to take the appropriate repairing route.

Due to the tiny size of this damage, a majority of car owners often ignore it. Such cracked windshields are exceedingly vulnerable to developing more chips which may spread across the entire windshield over time. So, what can be corrected with a simple repair procedure might require replacement later.

Edge Crack

You can spot an edge crack within two inches of the windshield edge and usually extending and touching the edge. In fact, an edge crack is the contemporary of a floater crack. The length of these cracks varies between 10 to 12 inches in length. A cracked windshield with an edge crack needs to be replaced, and a new windshield has to be installed by expert technicians. It is not feasible to repair an edge crack as it compromises the original seal of the windshield. The chances of the windshield glass heighten, exposing you to the risk of further mishaps.

Combination Break

A combination break is a common type of damage that any car windshield can sustain. Multiple cracks and chips on the car windshield are collectively known as a combination break or crack. The cause of the same can range from foreign objects to sharp particles to extreme temperature changes. However, the remedial solution for such cracked windshields is only determinable after a thorough examination of the sustained damage. Besides, it is possible to prevent a combination break by seeking timely, professional help. A repair should be enough to treat minute cracks, but when the damage aggravates, replacement is the only solution.

Sometimes, your windshield may develop a crack. Windshield repairs to put off replacements become a hassle. Avoiding conditions that cause your windshield to crack is the most convenient and safest option. What causes this to happen? Let’s take a look at the top perpetrators.

Causes of Windshield Crack:

Existing defects

Some defects, either in the manufacturing process or installation, can make the glass sensitive to damage. Such faults can become a safety hazard staring you in the face. If a crack develops, opt for a quality glass replacement service.

Gritty roads

Driving on gravel paths causes your wheels to grind on pebbles. Frictional forces between the two surfaces cause the stone to bounce off and possibly hit your windshield. What starts as a chip eventually turns into a crack. Maintain a safe distance from the vehicle in front of you if you have to travel on such roads.

Burning sunrays

When direct sunlight strikes your windshield, the molecular bonds in your glass loosen, and the surface expands. Gradually, this can result in cracking while allowing heat to pass through, signing you up for an unexpected sauna. Cracks particularly begin in the outer edges of the windshield because the centre is the thickest part. Cover your vehicle with a car shield or park in a garage in extreme temperatures.


In places that experience extreme weather, the winter season can sometimes bring hailstorms. The stones that fall during such storms are much like someone deliberately throwing stones at your windshield. As a result, it has a higher chance of breaking.  Halt your vehicle in a safe place and wait for the storm to settle.


When you park on the roadside, day-to-day activities become menacing affairs. A shuttle, ball, or can come hurtling towards your car. Not only does it risk damage to your windshield, but also your vehicle.

Following heavy-duty vehicles

Garbage trucks, tractors, construction vehicles, and the lot carry materials that could crack your windshield if they happen to fall on it. Also, there is a higher risk of the truck unloading suddenly — owing to the road conditions, faulty latching securement, or overloads. Steer clear of such vehicles on the road by switching lanes or by maintaining a reasonable distance.

Crack under pressure

Just like the human body, changing altitudes and air pressure will disturb the balance of your windshield. If you frequent speed up on the road, your windshield could develop cracks. Drive at the right pace and observe extra care in hill stations.

Alternating temperatures

While an extremely cold or hot environment affects your glass health, fluctuating temperatures from within will do the same. The sudden expansions and contractions caused by these extremities will wear out the windshield. Manage the heater and defroster settings in your vehicle with care.

Stumbling wreckage

The next time you park under a shade, ask yourself – is it safe? To answer that, most of them become perils for your windshield. Trees that shield from sunlight might throw the stray branch or fruit on your car glass. Parking in open spaces reduces the likelihood of such events.

Aged windshield

Glasses have a lifespan and die after serving their purpose. If they have withstood years of hardships, they will be frail and prone to the slightest hit. With time, such windshields tend to become thinner and brittle. Thus, if you are driving around with an old vehicle, consider replacing the windshield.

Now, windshield cracks can be a result of stones, debris, accidents, heavy tree branches, etc. However, do you know that cracks can steadily spread, becoming huge safety hazards? Let us find out what causes cracks on the windshield in cars to spread:

Causes of cracks on the windshield in cars to spread

Extreme Alterations in Temperature

The difference in the temperatures between the interior and exterior of your car can add pressure on your damaged windshield, causing the cracks or chips to get aggravated. When a windshield is exposed to direct sunlight for hours, it gets heated and tends to expand. This can cause the windshield crack to widen or spread quite considerably.

If you turn on the air conditioner after your car has been standing under the sun, windshield cracks can expand. In the same way, if you turn on your heat on high and direct it at the cold windshield during winters, the cracks can spread. This is because glass tends to contract in cold weather and expand under hot temperatures, which is why if you expose your windshield crack to harsh weather conditions or extreme weather fluctuations, it will spread.

A Bumpy Ride

Driving on bumpy roads or over a pothole, shutting your car doors loudly, or even slamming on brakes a little too harshly can make your windshield damage much worse. Speed bumps, sudden brakes, etc. put additional stress on your car that can lead to more spreading and worsening of the windshield crack. Even if the windshield crack is small, it can potentially expand to a great degree if you don’t get it handled by professionals and continue driving in a way that causes unnecessary jerks or movements.


Your car windshield is made of two sheets of glass with a layer of plastic in between. A crack, no matter how small, can trap moisture in between the layers, be it from rainfall, snowfall, or a car wash. This can weaken the structural integrity of your windshield in the car. Moreover, when the temperature drops, the moisture inside the crack freezes, causing internal pressure and worsening of the crack.


When dirt gets into the windshield crack, it can weaken the windshield’s structural integrity and compromise its strength. To avoid getting dirt into the windshield crack, you can put a piece of clear tape over the damage as a temporary solution till you get your windshield fixed. Keep in mind that the tape is just a temporary solution, and it cannot repair the damage in any way.

Car windshields can often crack for no apparent reason at all. You might wake up one fine morning and find a deep crack sitting on the windshield of your car and staring right at you. However, it isn’t a simple crack; there can be several underlying reasons for the damage. Some obvious reasons why you might have a cracked windshield are stones, debris, broken tree branches, a ball that a kid might have hit unintentionally towards your car, etc. These are all relatively straightforward incidents that could cause your car to have a cracked windshield. However, there are other, less apparent reasons which could have been enough to cause damage to your windshield. Here are a few lesser-known reasons which can cause your windshield to crack for no “apparent” reason.

Changes in Temperature

Temperature changes can cause the windshield glass to expand and contract. Different glass portions heat up at different speeds, faster around the edges and slower in the middle. Due to this inconsistency, the glass expands and contracts at different rates. A crack could be triggered by washing a car with cold water during a sweltering day or by trying to defrost an icy windshield with hot water. Using a defroster or a car heater does not prevent this from happening either. Thermal expansion and contraction are one of the most common reasons for a cracked windshield.

Pressure Changes

Changes in pressure can be caused due to heavy storms and winds or by putting heavyweights on your windshield. These might be enough to make a stress crack appear on your windshield, seemingly out of nowhere. If a crack begins to appear on the edge of your windshield, it might not be immediately noticeable, so that a crack might come as a surprise a few days later. You can also identify the difference between stress-related cracks and cracks due to impact by touching the centre of the crack. If the centre is smooth, the crack must have been caused due to stress.


Exposure to sunlight can cause the metal and other materials around the car to heat up. The edges of the glass heat up faster than the middle portion causing cracks to appear on the windshield. This could, however, be prevented by keeping the car in the shade.

Structural Defects

Your windshield might have manufacturing defects. Annealing the glass during manufacture, might cause changes in pressure and result in stress cracks or residual stresses along the windshield edges. Due to this manufacturing defect, your windshield might have a structural weakness and would thus be prone to fractures and cracks.

Imperfections in the Glass

The glass installed in your vehicle might be defective. However, this might slip your eye completely because these defects can only be detected by professionals. This can cause a cracked windshield in your car without prior warning.

Poor Installation

Your windshield might be imperfectly installed, even if it was done by professionals in a factory. Although that might be a rare case, if something like that happened, vibrations due to a loose fit might cause stress on the glass, leading to a cracked windshield.

Mechanical Stress Loading

Excessive body flex or distortions in the structure of the car can cause mechanical stress loading. This can happen due to improper lifting of the vehicle with a floor jack which might twist the car's body excessively. This might cause the windshield of your car to crack.

Prior Minor Damages

A tiny chip or a hairline fracture on your windshield might expand with time, causing cracks to appear on the glass’ surface. The small cracks might get bigger, and with sufficient diagonal chassis twisting, there might be enough displacement to lead to a cracked windshield.

Past Accidents

If your car had been in an accident in the past, it could have caused stress to the internal structure of your car. The windshield provides structural support to the car, and the accident might reduce the strength of the windshield. It might not have been visible for a while after the accident, but with time, cracks could appear on the glass due to the weakening of the structural integrity of the windshield. This could especially happen if the car is not properly repaired after the accident. Uneven forces on the windshield and the slightest of stress, like running the car fast over a speed bump, could trigger the windscreen to crack.

A cracked windshield calls for immediate professional help. Since the car windshield is the crucial safety feature of the car and provides structural integrity to the car — it should be fixed as soon as possible. It is best to seek professional help and opt for the best windshield repair services to avoid faulty installation. AIS Windshield Experts is India’s largest automotive safety glass repair and replacement network in India. We are the only company in India providing chip repairing services on car windshields. Our 90+ centres in over 50+ cities are offering fast, safe and professional service with well-trained professionals and top-of-the-line equipment. We also give a 1-year extended warranty on our products and workmanship. So, if you have a cracked windshield and need immediate assistance, get in touch with AIS Windshield Experts today!

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