7 things that crack windscreens here
Almost every windscreen we replace across Brisbane, Ipswich, Logan and Bayside was killed by one of seven things. Six of them are avoidable.
This is not a general list copied from somewhere colder. It is what we actually see on South East Queensland roads, in roughly the order we see it — including the two that surprise people, which are the air conditioner and the driveway.
Seven causes, in order of how often we see them
Each one with the thing you can actually do about it. Number five is the only one nobody can prevent.
Gravel off a truck on the motorway
The Ipswich Motorway, the Logan Motorway and the Bruce Highway north of the city are where most of our chip repairs come from. A stone off a tipper at 100 km/h carries enough energy to break laminate on contact. What to do: leave a genuine gap behind anything with an open tray or a load of aggregate — four seconds, not two — and move out of the lane behind it rather than sitting there.
Roadworks and unsealed shoulders
Loose blue metal on a freshly prepped surface, and the gravel that gets dragged onto the seal at either end of a works zone. Both throw stones from your own tyres as well as other people’s. What to do: the posted speed through works is about the stones as much as the workers. Slowing to it genuinely reduces impact energy — it goes up with the square of speed.
The demister, straight onto hot glass
This is the one that surprises people. A car parked in a Queensland car park has a windscreen well over 60 °C. Getting in and putting the air conditioner on full cold, aimed at the glass, drops the inner face fast while the outer face stays hot. If there is an existing chip anywhere in the screen, that is the moment it runs. What to do: vents to the footwell first, windows down for thirty seconds, then bring the screen vents in gradually.
Heat cycling with a chip already there
Even without the demister, a dark dashboard behind glass in summer sun puts the laminate through a large temperature swing twice a day. The tip of an existing break is where all that stress concentrates, and it advances a little each cycle. What to do: this is the argument for fixing a chip the week you get it. An unfilled chip in a Brisbane summer has a life measured in weeks. A filled one has none of this problem.
Hail
The one you cannot do anything about. A South East Queensland storm cell can write off glass across a whole street in ten minutes, and hail damage is rarely just the windscreen — rear glass and sunroofs go too. What to do: under cover if you have the warning and the option, and check that your policy covers storm damage before the season rather than during it.
Body flex — driveways, speed humps, kerbs
A windscreen is a structural part of the shell, bonded in and carrying load. Every driveway crossover taken at an angle, every speed hump, every kerb, twists that shell slightly and works the glass with it. It rarely starts a crack on its own; it very reliably extends one that already exists, and it is the usual cause of a crack that appears to start at the edge for no reason. What to do: take crossovers square and slowly, particularly if there is damage in the screen already.
A previous fit that was not done properly
The one we see and other people do not. Urethane laid at the wrong bead height, a pinchweld that was not primed and has begun to rust underneath, mouldings forced back on, or glass that was never the right part for the car. All of it puts uneven load into the new screen, and it cracks from the edge months later for no apparent reason. What to do: ask what urethane is being used and what happens to bare metal on the pinchweld. Anyone doing it properly will have an answer ready.
Six of the seven come down to one habit.
Get a chip looked at the week you notice it. Almost everything on this list only turns into new glass because there was already a break in the laminate for it to work on.
Where our work actually comes from
Twenty years of jobs, sorted by where the damage happened rather than where the car lives.
Motorway commuting
The biggest single source. Ipswich Motorway, Logan Motorway, Centenary, Gateway. Chip repairs from stones, usually noticed the following morning as a small star break low on the passenger side.
Depots, yards and haul routes
Heavy vehicle work — trucks and buses. Larger screens, more exposure, and a much higher cost of downtime, which is why we come to the yard.
Acreage and gravel driveways
The western suburbs — Anstead, Bellbowrie, Karalee, Mount Crosby. Stones from your own driveway and from unsealed side roads, plus a lot of body flex over rough tracks.
Car parks and break-ins
Side and rear glass rather than windscreens. Tempered glass shatters into the door cavity and the carpet, and vacuuming it out properly is most of the job.
Caravan parks and long trips
Motorhomes and campervans. Big flat screens, thousands of highway kilometres, and glass that often has to be brought in — worth booking before you leave rather than from the road.
What to do the day you get a chip
Four minutes of work that decides whether this costs thirty minutes or a morning.
Look at it with a 20-cent coin
Smaller than the coin, out of your line of sight, not touching the edge — that is a repair. Any of those untrue and it is new glass. The full test is here.
Keep water and dirt out of it
A strip of clear tape over the chip until we get there keeps grit out of the break. A contaminated chip does not take resin as well, and the finished repair is more visible.
Go easy on the temperature
No cold demister blast onto hot glass, no hot water on a frosty morning. Both are asking the break to run.
Ring the same week
Not the same month. Most comprehensive policies cover a chip repair with nil or reduced excess, so in a lot of cases the fast option is also the free one — see insurance claims.
Keep reading
Why do windscreens crack in hot weather?
Because the inner and outer faces of the laminate end up at different temperatures and expand by different amounts. A dark dashboard behind glass in Queensland sun creates a large swing twice a day, and the stress concentrates at the tip of any existing chip. Aiming a cold demister at hot glass does the same thing much faster.
Can a windscreen crack on its own with no impact?
Effectively, no — but it can appear to. Almost always there was already a small break, or damage at the bonded edge, and temperature change or body flex over a driveway extended it. A crack that seems to start at the edge for no reason is usually a sign of a previous poor fit or a rusted pinchweld.
Where do most windscreen chips in Brisbane come from?
Gravel off trucks on the motorways — the Ipswich, Logan, Centenary and Gateway in particular — followed by roadworks and unsealed shoulders. Leaving a four-second gap behind anything with an open tray removes most of that risk.
Should I tape over a windscreen chip?
Yes, a strip of clear tape over the chip until it can be repaired is worth doing. It keeps water and grit out of the break, which means the resin bonds to clean glass and the finished repair is stronger and less visible. Do not use anything that will leave adhesive inside the break.
Does hail damage get covered by insurance?
Storm and hail damage is usually covered under comprehensive policies, and hail rarely affects only the windscreen — rear glass and sunroofs commonly go with it. Check the storm cover in your policy before storm season rather than during it.
Caught a chip this morning?
Ring the same day and it is usually a thirty-minute repair. Leave it a few hot afternoons and it is new glass. No call-out fee anywhere in Brisbane, Ipswich, Logan or Bayside.