When should you replace a damaged windshield?

There are certainly some instances where it becomes very obvious that your windshield needs to be replaced. For example, if a truck hauling bowling balls accidentally lets one loose and it punches a hole through your windshield, you'll need a new one.

But it isn't always as clear cut as the above example. Sometimes, much smaller cracks and even chips can require a new windshield to be installed. Generally speaking, you will need to replace your cracked windshield if:

The glass is tempered.

As we have discussed, most windshields are a type of layered glass with a plastic layer in the middle called "laminated glass." Rather than shattering or breaking into fragments, laminated glass tends to hold together when damaged. However, side and rear windows are often tempered glass, which is made through a different process that causes glass to break into small, granular pieces when broken. Because it breaks in this fashion, replacement is the only real option.

The crack is too large.

Although there are situations where longer cracks can be repaired, those that are longer than a dollar bill usually require replacement. Similarly, if a chip is larger than a quarter, the windshield needs to be replaced.

If the crack is too deep. Any chip or crack that penetrates both the outer and inner layer of a laminated windshield requires replacement. Even if the crack only penetrates the outer layer, this can often expose the plastic layer within, causing it to become discolored if left in the elements for too long. For this reason, you may actually want to replace the windshield even if repairing it is an option.

If there are too many cracks or chips. 

Generally, if you have 3 or more cracks anywhere on your windshield, you'll probably need to replace it. After they take a certain amount of damage, they begin to lose their ability to withstand further impacts.

If the crack is in a bad spot. 

Damage to the driver's side of the windshield usually requires a full replacement because repairs often leave at least some residual markings behind. Cracks that span from one edge to another can weaken its structural integrity, which usually means a replacement is needed.