There are many different types of windshield cracks, but most of them occur from an object impacting the glass. Often these are rocks which fall off of dump trucks, or objects which are kicked up by tires of another car. When the object hits the outside edge of the windshield it will usually result in one long crack, whereas objects that impact toward the center of the glass will cause starbust cracks. These are many small cracks emanating from the central point of impact.
The type of crack caused by impact is often determined by where the object strikes the windshield. For example, a floater crack starts anywhere away from the edge of the windshield (farther than two inches from the edge). These can start out small and then spread in any direction. An edge crack usually forms at the moment of impact, and is usually ten to twelve inches long. As the name implies, these cracks begin within two inches of the edge of the windshield or reach the edge.
Often a crack in a windshield began as a small chip. Generally speaking, cracks less than six inches can be repaired. Those which are longer or reach the edge of the windshield will usually necessitate replacement of the entire windshield.
These are most common windshield crack types:
- Bull’s Eye – Damage to glass caused by a rock (or other object) that is circular, typically with a cone in the outer layer of the glass. It is is similar to a chip, in the sense that a chunk of glass has been removed by the impact, but it is larger
- Chip – Damage to glass caused by a rock (or other object) that causes a small piece of glass to come off the windshield.
- Combination Break – When there are multiple types of breaks in a windshield, such as a chip with cracks coming off of it.
- Crack Chip – A single crack that can be covered with a quarter with an impact point.
- Ding – Terms used by general public to describe a chip
- Edge Crack – A crack that starts within 2″ of the edge of the windshield, or reaches the edge of the windshield. It normally forms immediately, and starts at 10-12″ long.
- Floater Crack – A crack that starts in the middle of the windshield (anywhere that is not within 2″ of the edge of the windshield).
- Half Moon – Damage to glass caused by a rock (or other object) that is similar to a bull’s eye crack, but not completely circular.
- Long Crack – A crack that is over about 6″ (15cm) long, which many windshield repair methods are unable to fix
- Partial Bulls-Eye – Same as Half Moon.
- Pit – An area where a small piece of glass is missing.
- Star Break – series of short radial cracks coming off of the impact point, resembling a star.
- Stone Break – A small chip that occurs when a stone (or other hard item) hits the windshield. It can then become a large crack over time.
- Stress Crack – A crack that occurs without anything hitting the windshield, typically due to a large variation in the temperature. One situation that might cause stress cracks is when a car becomes overheated from sitting in the sun, and then the air conditioner is turned on high or the car is washed with very cold water. The opposite example would be a very cold car suddenly being exposed to heat. This is why, in the winter, ice should be scraped or melted off the windshield with cold water, but never with warm or hot water. It almost always starts at the edge of the windshield. Stress cracks will normally be a straight (or slightly bending) line, and will not have any sign of impact. A “pen test” is often used to determine if there is a stress crack — a ballpoint pen is run along the crack, and if it dips anywhere, it is not a stress crack. That is because with a stress crack, no glass actually comes off the windshield.