Windscreen Chip: Repair vs Replace in NZ

The windscreen chip repair vs replace question in NZ depends on the chip's size, depth and position, and on how quickly you act, because a chip can spread into a crack with a hot day, a cold night or a bump.

This guide explains how repairers and WOF inspectors judge damage, which positions are worst, and what to do in the first hours after a stone hits the glass.

Windscreen chip repair vs replace: what decides it?

Repairers judge three things: the type and size of the damage, where it sits on the glass, and whether it has spread. A small stone chip or star break that is clean and has not cracked outwards is the usual candidate for repair. A long crack, heavy contamination from dirt or moisture, or damage that has reached the edge is more likely to need a new windscreen.

Repair is a structural and optical fix, not a cosmetic one. Resin is injected into the damage to stop it spreading and restore strength, though a faint mark often remains. The aim is stability, not invisibility.

Where on the windscreen is damage most serious?

The driver's critical vision area is the most restricted part. The NZTA vehicle inspection requirements for light vehicle glazing say a windscreen fails when its critical vision area is damaged, apart from scratching, surface pitting, small stone marks and certified visible repairs that do not affect the driver's vision. Elsewhere on the glass, a windscreen fails if damage exceeds the permitted type and size in NZTA's table, or if any damage goes through more than one layer of glass.

Damage near the edge is also a concern, because the edge is under stress and chips there are more likely to spread, even when the inspection rules do not set a distance. Because the exact tables are in the NZTA manual, ask a repairer or WOF inspector to measure your damage rather than relying on a coin comparison.

Should you repair or replace? A quick guide

These are general indicators, not a substitute for a professional assessment.

• Small, clean chip or star break with no cracks: often repairable if not in the driver's critical vision area
• Chip in the driver's critical vision area: assume replacement is likely, unless a certified repair leaves vision unaffected
• Cracks that are lengthening, or any crack running to the edge: usually replacement
• Damage through the inner layer, or deep pitting that has weakened the glass: replacement
• Old chip that has been dirty, wet or driven on for weeks: repair is less likely to succeed

Will a chip fail a WOF?

It can. According to NZTA, damage in the critical vision area is a fail, as is damage over the size limits in the table or damage through more than one layer of glass. NZTA also says damage that stops wiper blades working properly is a fail. A certified repair can pass, and a repair must be certified to a recognised standard, with the repairer's receipt as proof.

If your WOF is due soon, have the glass assessed beforehand, because repair is much quicker and cheaper to arrange than a failed inspection and a rushed replacement.

What should you do in the first hours after a chip?

Act early, because dirt and moisture reduce repair quality and changes in temperature can spread the damage. Cover the chip with clear tape to keep dirt out, avoid slamming doors, avoid blasting the demister or air conditioning directly at it, and avoid car washes until it is assessed.

Check your insurance too, because some policies cover windscreen repair or replacement, and the excess or claim rules differ between insurers. TopChoice checks each listed business against the NZ Companies Office and NZBN register, its Google Business Profile and its reviews, and excludes lead-generation sites. Our Top 5 windscreen and auto glass lists are a vetted place to start.