Why is glass broken for cars?

Despite the fact that the composition of the car glass is stronger than that of a normal glass panel, shavings and cracks inevitably form on the windshields. The windshield of a car consists of two thick pieces of glass separated by a thin layer of plastic, which has been designed to prevent the windshield from shattering in an accident. While a crack usually begins with the blow of a stone, there are certain factors that contribute to its spread.


Hard material waste is a constant danger for drivers on busy streets or on motorways. Even the smallest stone represents a serious threat to the windshield. A stone or a piece of gravel driven by another car can create visible damage to the car’s glass. Sometimes, the damage is not visible. A small dent created by this waste can be enough to ruin the integrity of a windshield. The result is weakened glass and prone to more extensive and visible cracks.


Once a dent exists, water vapor can cause cracks in the windshield. The water penetrates the smaller nicks and cracks in the glass. This moisture causes extensive cracks in the glass. As the temperature of the water varies due to external climatic conditions, its properties also vary. The expansion of the water helps it to make its way through the glass, resulting in a damaged windshield. This factor is difficult to block once there are gaps in the windshield because water vapor is constantly present in the air.

Low temperature

A windshield in cold weather tends to become concave, which leads to the appearance of cracks that extend horizontally. The existing nicks and cracks are subjected to more stress at this temperature. In addition, the two sheets of glass that make up a windshield often have different temperatures, because the temperature inside the car is different from the outside. On a cold day, the outer leaf of the windshield contracts; while the warmer temperatures expand the inner leaf. This leads to the appearance and propagation of cracks in the glass. On the contrary, the same principle is true on a hot day. The heat from outside, combined with the cold indoor air by the air conditioning make the glass change shape. You may have heard of someone who poured hot water on a frozen windshield and the result was a crack in the windshield. In this case, hot water expanded the windshield glass, while cold temperatures contracted the inner layer.

Bad roads

A trip on a road in poor condition increases the likelihood of a crack of considerable size. Potholes, unpaved roads and other obstacles on the road help to separate the glass. Melbas and small pre-existing cracks extend while driving your car on uneven terrain.

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