Why windshield chips in Arvada turn into cracks every winter
The freeze-thaw cycle, road sand on Wadsworth and I-70, and what to do before the first cold snap.
Every December the calls change. Through the fall we repair chips. By mid-December we are replacing windshields where a chip has run into a crack overnight. The pattern is predictable enough that it is worth explaining.
What is happening
A windshield chip is a small void in the outer layer of glass. When the car sits overnight in Arvada at 10 degrees and you start it in the morning with the defroster on high, the inside of the glass warms fast while the outside stays frozen. The two layers expand at different rates, and the chip is the weakest point. The stress releases as a crack that runs toward the nearest edge.
Why Arvada sees so much of it
- Road sand. Jefferson County and CDOT sand Wadsworth, Kipling, Ward Road, and I-70 heavily. Trucks throw it at windshield height.
- Big daily temperature swings. Sunny 50-degree afternoons and single-digit nights are routine from November to March.
- Outdoor parking. Many Arvada homes have the second car in the driveway, exposed all night.
What to do before the cold
Get any chip repaired before the first hard freeze. A repair takes half an hour, is often free under comprehensive coverage, and almost always holds through the winter. Once the crack has run, the only option is replacement.
If you already have a crack, scrape the outside of the glass rather than blasting the defroster, and get the replacement scheduled. A crack that reaches the edge of the windshield can compromise the bond that holds the glass in during a collision.