How many layers of glass are in your windshield? Why doesn’t it fall apart when that crack takes off from end to end? A windshield is NOT as it appears: a single piece of glass that is attached to the front of your car placed there to conveniently prevent the wind from getting on you and to block dirt and debris from taking out your face.
In reality, windshields are actually far more involved than just one piece of glass used as a windbreaker, which is probably a good thing since they are put into many situations where they have been responsible for many saved lives.
Your windshield is made up of not one, but two identical sheets of glass that are pressed together. Why two pieces you ask? Good question. Two makes for better insulation – just like your house glass – two panes are better than one right? They also make for a more stable surface. When you get that pesky chip on the freeway, the two sheets prevent you from getting hit in the face by it. Your windshield will also remain air and watertight even when one layer is cracked.
In between the two sheets of glass is a layer of laminated plastic. The purpose of this plastic is to hold the two sheets of glass together. This plastic keeps objects from breaking through to you while driving. We like plastic! This then makes the glass much safer.
The glue used is polyurethane. This glue helps bond your windshield to your car. The seal should be water and airtight. It helps keep you safe in case of a rollover or crash. The glass keeps the structural integrity of your vehicle. It helps keep your roof intact in order to help you get out if there is an accident.