If you have a cracked windshield it is usually not caused by a defective windshield but was caused by a rock that hit your windshield. Your windshield has two layers of glass with a thin layer of plastic between the two layers of the windshield. When a rock hits your windshield it does one of two things. It either hits the first layer of the windshield and bounces off, this will only cause a small pit in your windshield and no windshield repair is needed. However, if the rock hits your windshield hard enough the rock chip will separate the two layers of glass between the plastic. This gives your windshield an appearance of a black circle or lines coming off the rock chip. No matter how small these rock chips are on your windshield you will need a windshield repair. Even if the rock chip does not bother you and is on the edge of the windshield you will still need to have your windshield repaired because here is what will happen.

When you have a temperature change on the windshield that little rock chip will spread across the windshield. While we can repair windshields up to 30 inches, if the crack in the windshield spreads across the windshield we can not repair your windshield and you will need to replace your windshield. The temperature change can be caused by turning on your defroster or when you park your car in the sun with your windows up, pressure will build up inside your car like a hot air balloon This is why so many people will come out from work or at lunch and see a crack in their windshield. Also, you may be driving your car and hit a pothole or go over a railroad track and suddenly there's a crack across your windshield. Even the pressure from the wind hitting your windshield while you are driving can cause a crack in your windshield.