You hear that dreaded "thunk." A nice fat rock just hit your windshield and made a small chip right in the middle. Now what? Your best bet is to quickly head for a windshield repair shop and get that chip repaired before it grows. Here's an explanation on how little chips become large ones, and whether that windshield needs to be repaired or replaced.

Windshield Basics

A windshield is made of laminated safety glass. It's really a glass sandwich, with a plastic-like layer sitting between two pieces of glass. That plastic keeps the windshield from shattering when a rock hits it. Instead the rock creates a hole or chip in the glass, often with small cracks. Depending on where they are, small chips and cracks can be repaired. If the damage is too extensive, the windshield needs replaced.

How Little Chips Become Big Problems

Those small chips and cracks can become big problems. Sometimes called "spider webbing," the tiny cracks around the damage may spread. Hitting a bump in the road, like a pothole, is enough to cause cracks to expand. Changes in temperature, either outside or inside your car, can also cause expansion. If left unattended, that small chip grows into a maze of cracks that interfere with your vision of the roadway.

Repair or Replace?

Each state tends to have its own rules about when a windshield becomes unsafe. In California, for example, it is illegal to drive with a cracked windshield or rear window that obstruct the view of the roadway. The determination is often made by a traffic officer on the spot, who may or may not issue a "fix-it" ticket. Many insurance companies do offer windshield protection riders to help with replacement costs. Some insurance firms may even cover the entire cost of repair. Replacing the windshield may or may not require you to pay a deductable.

Repairing Your Windshield

A windshield can usually be repaired if:

  • The damage is not in the driver's main viewing area. Dings and cracks near the edges of the windshield are usually repairable if they haven't reached the seal. That seal is the part that holds the windshield in place and keeps out moisture.
  • The chip is still small. If it has large cracks spider webbing out from it, no matter where it is on the windshield, that chip is not repairable.
  • The repair can be made without removing the glass. Pulling the windshield typically increases the damage.

Replacing Your Windshield

A windshield needs to be replaced if:

  • The damage is in the driver's line of sight.
  • The chip has damaged both layers of glass. The laminate will keep it intact, but won't stop potential leaks.
  • Some cars have rain sensors and antennas embedded in the windshield. If either of these are damaged, the windshield must be replaced.
  • You'll need a new windshield if the damage originated inside the vehicle. This could happen during an accident if your head hits that windshield. Wearing seat belts can help prevent this scenario.