Windscreen Repair Or Replacement, What is the difference
The sound of a stone flicking against the car’s windscreen is one that car owners dread. A small chip, left unattended, can eventually extend into cracks that split further and further across the windscreen.
The question is, how do you know when the damage is repairable with resin, or when the entire windscreen needs replacement?
Let’s start by looking at how the windscreen is made.
Three layers in the car glass
Windscreens consist of three layers: two sheets of regular glass with an inner layer of plastic (PolyVinyl Butyral – PVB) between them. This lamination layer holds the broken outer panes of glass together in the event of an accident, protecting the car’s occupants from dangerous glass shards.
Usually, when a stone or debris chips the windscreen, the damage doesn’t go through all three layers. It makes minor repairs so much easier.
Assess the windscreen damage
Fortunately, most minor chips and cracks are repairable without needing to replace the entire windscreen. When assessing the damage, it’s important to consider four factors:
There are many different types of cracks, depending on what caused the damage and the speed at which it hit. Some are fixable, others not.
This circular crack has a clean centre break and usually happens when a round object (e.g., stone) hits the windscreen. If caught in time, it is easy to fix bullseye cracks, and it typically doesn’t require a complete windscreen replacement.
This crack is half a bullseye, often has a dull edge, and is easily repairable.
Edge cracks are the most common. They start close to the edge of a windscreen and tend to move inward over time. The windshield will need replacement if the damage is flush with the frame or longer than a few inches.
Floater cracks tend to occur in the middle of the windscreen and often obstruct the driver’s view. The crack lines spread quickly and usually requires total windscreen replacement.
Star breaks start with an impact hole with one or two small cracks leading outward. These cracks tend to grow and spread. It is easily repairable, while the star is small and debris-free.
Combination breaks are mostly the result of serious damage, such as an accident or severe impact to the windscreen (e.g., falling rocks and branches). Due to the sheer of number chips and cracks, replacing the windscreen is the more affordable option.
Most auto glass repair technicians will be able to repair chips that are less than 1 inch in diameter (or about the size of a £2 coin), and cracks that are no longer than 3 inches.
If the chip or crack has gone through all three layers of glass, it likely is unfixable. Even if it is just a small hole, it will be an area of weakness that undermines the strength of the entire windscreen.
Chips and cracks in the driver’s line of sight require a complete windscreen replacement. No matter how good the repair job is, there may still be some mistiness, discolouration, or unevenness which can distract the driver. It will also result in MOT failure – something you certainly don’t need.
Damage near the windscreen’s edge (where it meets the metal frame) is also an essential consideration. Even a minor crack in this position will weaken the integrity of the windscreen and compromise your safety. This is because part of the crack or chip may be out of sight beneath the frame and impossible to repair safely. Anything closer than 7cm to the edge will require a windscreen replacement.