How to Stop Windshield Crack from Spreading

That small crack in your windshield might seem harmless at first. But without proper attention, it can quickly spread across your entire windshield. This not only affects your visibility but also compromises your safety on the road. The good news? You can take immediate steps to prevent windshield cracks from spreading while you arrange for professional repair.

In this comprehensive guide, we'll walk you through everything you need to know about stopping windshield cracks from spreading, from temporary fixes to permanent solutions.

Understanding Windshield Cracks

Before diving into solutions, it helps to understand what you're dealing with.

Types of Windshield Damage

Windshield damage typically falls into three categories:

1. Chips: Small pieces of glass missing from your windshield, often caused by rocks or debris hitting the glass.

2. Cracks: Lines that run across part of your windshield, which can be:

   • Edge cracks (starting from the edge of the windshield)
   • Stress cracks (appearing without impact, often due to temperature changes)
   • Floater cracks (starting from the middle of the windshield)

3. Combination damage: Both chips and cracks together.

Why Cracks Spread

Cracks don't stay the same size forever. They spread because of:

• Temperature changes: Extreme heat or cold makes glass expand and contract
• Pressure: Driving at high speeds creates air pressure on the windshield
• Road vibrations: Bumpy roads shake your car and stress the glass
• Dirt: Debris getting into cracks can force them wider
• Water: Moisture can seep into cracks and freeze, expanding the damage

Immediate Steps to Stop a Crack from Spreading

When you notice a crack, time matters. Here's what you should do right away:

1. Clean the Damaged Area

First, clean the cracked area gently:

1. Use a mild glass cleaner or a mix of dish soap and water
2. Spray it on a microfiber cloth, not directly on the crack
3. Gently clean the area, avoiding pushing on the crack
4. Dry completely with a clean cloth

Keeping the crack clean prevents dirt from working its way in and making the damage worse.

2. Apply Clear Nail Polish as a Temporary Fix

One of the oldest emergency fixes is clear nail polish:

1. Make sure the crack is completely dry
2. Apply a thin layer of clear nail polish over the crack
3. Allow it to dry completely (about 1-2 hours)
4. Apply a second coat if necessary

The nail polish fills the crack temporarily and creates a seal that helps prevent dirt and moisture from getting in. This isn't a permanent solution but can buy you time until proper repair.

3. Use Super Glue for Small Cracks

Super glue works similarly to nail polish:

1. Clean and dry the crack thoroughly
2. Apply a very thin layer of super glue along the crack
3. Let it dry completely
4. Gently wipe away any excess with a clean cloth

Warning: Only use this method for very small cracks as a temporary measure.

4. Apply Windshield Repair Tape

Windshield repair tape provides a physical barrier over the crack:

1. Clean and dry the cracked area
2. Cut a piece of clear packing tape or specialized windshield repair tape slightly larger than the crack
3. Apply the tape over the crack, smoothing out any air bubbles
4. Make sure all edges are sealed

This method helps prevent dirt and water from entering the crack. The tape also provides some structural support to prevent the crack from spreading due to vibrations.

DIY Windshield Repair Kits

If you can't get to a repair shop immediately, windshield repair kits offer a more reliable temporary solution than household items.

How to Use a Repair Kit

Most kits follow a similar process:

1. Clean and dry the damaged area thoroughly
2. Attach the repair device (usually a suction cup with a syringe or pedestal) over the damaged area
3. Inject the resin into the crack following kit instructions
4. Allow the resin to cure (often requires sunlight)
5. Remove excess resin and polish the area

These kits work best on chips and small cracks (typically under 12 inches). They fill the damaged area with a clear resin that hardens to restore structural integrity.

Limitations of DIY Kits

While useful, DIY repair kits have limitations:

• They won't make large cracks completely disappear
• The repair may not be as clear or strong as professional work
• They're not suitable for cracks longer than about 12 inches
• Deep damage may still require professional repair

Prevention Tips to Keep the Crack from Spreading

While arranging for permanent repair, these measures can help prevent further damage:

1. Avoid Extreme Temperatures

Temperature changes cause glass to expand and contract, which can worsen cracks.

• Park in the shade or a garage when possible
• Avoid using defrosters at high settings
• Don't blast hot air directly at the windshield in winter
• In summer, open windows slightly before turning on AC to gradually adjust temperature
• Use a sunshade when parked in direct sunlight

2. Reduce Pressure on the Glass

Pressure changes and stress can cause cracks to spread rapidly.

• Avoid slamming car doors, which creates air pressure changes
• Drive at moderate speeds until the windshield is repaired
• Take smooth roads when possible to avoid vibrations
• Don't power wash your car until the windshield is fixed

3. Apply a Temporary Seal if Needed

For longer cracks or during bad weather, consider:

• Using clear packing tape over both sides of the crack if possible
• Applying a thin layer of clear silicone caulk for a more water-resistant seal
• Covering the crack with a clear plastic sheet secured with waterproof tape during heavy rain

When to Seek Professional Repair

While temporary fixes help in the short term, professional repair is always the best solution. Consider these factors when deciding between repair and replacement:

Repair is Usually Suitable When:

• The crack is shorter than 12 inches
• Damage is not in the driver's direct line of sight
• There are three or fewer cracks/chips
• The crack doesn't reach the edge of the windshield
• The damage doesn't penetrate both layers of glass

Replacement is Necessary When:

• The crack is longer than 12 inches
• Multiple cracks cover a large area
• Damage is directly in the driver's line of vision
• The crack extends to the edge of the windshield
• Both layers of glass are damaged
• The glass is very old or has previous repairs

The Professional Repair Process

If you're curious about what happens during professional windshield repair:

1. Assessment: The technician examines the damage to determine if repair is possible.

2. Cleaning: The damaged area is thoroughly cleaned to remove debris.

3. Resin injection: Special equipment creates a vacuum over the damage, and clear resin is injected into the crack.

4. Curing: The resin is cured using UV light to harden it.

5. Finishing: Excess resin is removed, and the area is polished to match the surrounding glass.

Professional repairs typically take 30-60 minutes and are much more reliable than DIY solutions.

Cost Considerations

The cost difference between repair and replacement is significant:

• Repair: Typically costs $50-$150 depending on the damage
• Replacement: Can cost $200-$500+ depending on your vehicle make and model

Many insurance policies cover windshield repair with no deductible since it prevents the need for more expensive replacement later. Check with your insurance provider before paying out of pocket.

Safety Implications of Cracked Windshields

A cracked windshield isn't just an aesthetic issue—it's a safety concern:

• Structural integrity: Your windshield provides up to 30% of your car's structural strength
• Airbag deployment: A proper windshield ensures airbags deploy correctly
• Visibility: Cracks can distort vision, especially at night or in rain
• Legal issues: In many states, driving with a cracked windshield is illegal if the damage obstructs the driver's view

Frequently Asked Questions

How quickly will a windshield crack spread?

It varies widely. Some cracks may not spread for months, while others can expand rapidly within hours, especially during temperature changes or when driving on bumpy roads.

Can I drive with a cracked windshield?

Yes, but with caution. If the crack doesn't obstruct your vision and isn't spreading quickly, you can drive to get it repaired. However, avoid high speeds, rough roads, and extreme temperatures.

Will my insurance cover windshield repair?

Many comprehensive auto insurance policies cover windshield repair with no deductible. Some states even have "zero deductible" laws for windshield claims. Contact your insurance provider to check your coverage.

How long does professional windshield repair take?

Most professional repairs take 30-60 minutes. The resin cures quickly, and you can usually drive immediately afterward.

Can all cracks be repaired?

No. Cracks longer than 12 inches, those in the driver's direct line of sight, or damage that penetrates both layers of glass typically require windshield replacement rather than repair.

Conclusion

A cracked windshield requires prompt attention, but you don't need to panic. By taking immediate steps to stop the crack from spreading, you can buy time until you can get professional help.

Remember that temporary fixes are just that—temporary. For safety and visibility, professional repair or replacement is always the best solution for windshield damage.

Don't wait until a small crack becomes a major problem. By addressing windshield damage early, you save money, maintain visibility, and ensure your vehicle remains safe to drive.

For more detailed guides on windshield care and maintenance, visit Windshield Repair Guide. Our experts can help you understand your options and find the best solution for your specific situation.