How To Stop A Windshield Crack From Spreading – Repairs & Prevention

Driving home from work, you got stuck behind a gravel truck. A little stone hit your windshield as the truck turned off onto a construction site. Now you’ve got a chip in your windshield, but you can still see out just fine. So it’s no big deal, right

Unfortunately, the situation is more complicated than it seems at first glance.

cracked windshield

Your car’s windshield is far more than just protection from wind and rain. It is an integral part of your car’s ability to protect you in a crash. As a matter of fact, as much as 30% of your car’s structural strength comes from an intact windshield. So, the strength of your windshield plays a huge role here.

Although it seems like it’s just a large expanse of glass, your windshield helps support the roof in a rollover crash, provides support for the airbags should they deploy, and – along with proper seat belt use – prevents you and your passengers from being thrown clear of the vehicle during a serious collision.

Let’s a take a closer look at just how big of a deal small cracks and chips in a windshield can be, knowing that pretty glass is doing more than just keeping the wind out of your eyes and holding your oil-change reminder sticker.

But It’s Only a Tiny Chip! And It’s Not Blocking My View!

Surprisingly, Small Cracks And Chips Can Spread

As the glass is subjected to extreme temperature changes, chips can become cracks that creep across the glass.

This can happen when a blast of cold air conditioning hits a window heated by the summer sun or when a full-blast front defrost cycle hits an icy windshield on a chilly winter morning.

One study found that chips were likely to spread into cracks 80% of the time when temperatures plummet to winter’s extreme lows.

Also surprising: even potholes and other stresses on your car’s frame such as a particularly bumpy road or aggressive cornering can pose a danger to a windshield already compromised with a small crack or chip.

Protecting You During Car Crashes

Due to the way that small cracks or chips can worsen into large cracks, it’s important to know when small damage to a windshield is a problem requiring professional repair – and when it’s something you can repair yourself instead.

Either way, it’s very important to take action quickly.

For a successful repair, cracks and chips must be very clean and dry. Protect the damaged spot with a piece of clear packing tape as soon as you notice damage, to keep out dirt and moisture which can prevent repair materials from properly bonding.

Windshield Glass Is Not Just Simple Glass!

Your windshield is a highly engineered sandwich of two layers of glass bonded to an inner layer of vinyl.

It’s important that moisture is not forced between the laminated layers through a crack or chip (by means of washing or rain) to cause possible fogging or discoloration.

Protect the damaged spot and get it repaired or looked at as soon as possible!

The longer you drive with the damage unrepaired, the higher your chance of jarring the car somehow and causing a simple repairable ding to grow into a serious crack that will require windshield replacement.

Until you schedule an appointment and get the car into a shop for experts to deal with it, or attempt to repair the damage yourself, drive carefully.

Avoid sudden temperature changes as much as possible. Close car doors gently. Bring interior car temperatures up or down slowly, rather than blasting the defrost or A/C against the glass.

How To Stop A Windshield Crack From Spreading

Wait, Did You Say Small Chips or Cracks Can Be Repaired?

Yes, sometimes small chips and cracks can be repaired – depending on the size, location, and complexity of the damage, either by a professional auto glass technician, or with one of the products from our best windshield repair kits guide.

Consult an auto glass specialist about your windshield crack if

  • the chip or crack is larger than a dollar bill.
  • there are three or more chips or cracks.
  • the damage is in the line of sight of the driver.
  • the damage is more than a hairline crack and is a spiderweb of damaged glass.
  • the chip or crack is near the edges of your windshield.
  • if the damage happened due to a rather serious accident.

Uh-Oh. It Looks Like My Damage Might Need Professional Windshield Repair

Here are some common-sense guidelines for choosing a reputable repair shop for proper service if it appears you’ll need to have a professional take a look and you can’t stop the windshield cracks from spreading yourself.

  • Look for a technician accredited by the Auto Glass Safety Council or listed with the National Windshield Repair Association.
  • Choose a shop which offers a warranty on their work.
  • Be leery of a technician who finds damage you weren’t aware of or cannot see yourself. Scammers and unscrupulous shops may try to pressure you into having them replace the windshield with promises that your insurance will cover all of the expense. Laws regarding insurance deductibles on auto glass vary from state to state and among different auto insurance policies. Always check your insurance coverage or check with your agent so that you know what will be covered and what your share of the cost may be before work begins.

A professional auto glass technician will assess your cracked windshield in person and advise you as to whether a chip repair can be done or the crack can be filled and repaired, or if the whole windshield will need replacing.

A shop can also assist you in filing a claim with your automotive insurance to cover part – or all – of the cost of the windshield crack repair or even file the claim on your behalf. (As advised above, though, be sure you know what your policy covers!)

My Chip Is Very Minor. I’d Like To Try A Windshield Repair Kit. Where Do I Start?

If you’ve got just one or two small chips or cracks, they’re away from the edges of your windshield, and aren’t in the driver’s field of vision, you may be able to take on a small repair yourself.

Avoid “hacks” such as filling the crack with nail polish or super glue! At auto parts stores and online, you can buy a windshield repair kit with detailed instructions, an applicator, and an epoxy resin that can be used to fill and stabilize the chip to prevent it from worsening into a larger crack.

The DIY kits vary in the size of chip or crack that they can repair, so read the package information carefully.

Note that a repair done with a do-it-yourself kit is not going be as strong or as permanent a repair as what a shop with a trained technician can do.

Regardless of the size of the crack or chip, if you need to be absolutely sure that no further damage occurs, or if you want to be covered if it does, it’s best to go straight to a professional who will guarantee their work.

Professional repair costs range from under $100 to over $200, but they will still be less costly than a full glass replacement, which can cost between $200 and $1,000.

The exact procedure for any given do-it-yourself repair kit will vary by manufacturer, but the basic process will be similar regardless of which brand of kit you choose.

The tools included in the kit will help you force an included liquid epoxy into the crack or chip. After it hardens, you’ll use a razor to carefully shave the surface smooth so that your windshield wiper blades won’t catch on the repair.

Some points to consider:

  • You’ll need to work at a moderate temperature, so park your car in the shade or in a garage to do the repair.
  • Plan on an hour or two to complete the job.
  • After completion, the damaged area is not likely to be perfect, but will be much improved over leaving the crack or chip unrepaired, and the glass should be better stabilized against further cracking.

Is There A Way To Prevent Chips And Cracks In My Windshield?

It’s impossible to completely prevent accidental damage. There are, however, some steps you can take to give your windshield the best chance of lasting the life of your car.

  • Keep your windshield clean and change your wipers regularly. Damaged wipers and dirty windshields contribute to hazy glass and tiny surface scratches that can weaken the glass, making it more susceptible to breaking or chipping when something does hit it.
  • Drive defensively! Maintain proper following distance from trucks, construction equipment, pickup trucks carrying gravel or other loose debris, and any vehicles with double rear wheels. Slow down when traveling on gravel roads, in construction zones, or on roads in poor repair.
  • Use only plastic snow removal tools, never metal. Never use hot water to melt ice or snow. The sudden temperature change can crack the glass.
  • Keep the harsh chemicals away from your car’s glass. Choose a glass cleaner which does not contain ammonia, which can streak on automotive glass.

I’ll Never Look Through My Windshield The Same Way Again!

Besides adding shape and style to your car, protecting you from rain and wind, and giving you a handy place to put an oil-change reminder, windshields play a critical part in keeping you safe on the road.

Give them the respect they deserve and address damage promptly, with tools designed specifically for the job or with help from a professional automotive glass technician.

Then that wide expanse of glass that lets you see the world around you can continue to do its most important job: protecting you from the hazards of the open road and ensuring you have maximum visibility!

In the mix of a male dominated industry, Jennifer is our go-to gal for all your car related questions. Besides all the valuable work and insights she contributes to, Jennifer runs a website - and an active Facebook community - called 'Ask Jenny About Cars' where she helps many people with their car-buying and car ownership decisions – providing advice, reassurance and research help to friends, family, and clients on all topics concerning cars. She has a wealth of knowledge and you can rely on her to explain everything in simple language that even a novice can understand.

1 thought on “How To Stop A Windshield Crack From Spreading – Repairs & Prevention”

  1. You got me when you said that it’s best to choose an auto glass technician that’s listed with the National Windshield Repair Association to make sure that they are reputable. My car’s windshield was damaged when my son accidentally hit with a stone while playing. The cracks are getting severe, and I want the damages to be repaired in the best possible way. I will consider all your tips because I want to ensure my safety while driving.


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