Our Windscreen Replacement Process
A windscreen replacement takes eight steps: identifying the correct glass from your registration, protecting the vehicle, removing trim and wipers, cutting out the bonded screen, preparing the bonding surface, positioning the new glass, checking sensors, and confirming your safe drive away time before you move the car.
Why does the process matter more than the glass?
Because a windscreen is structural. It is bonded to the body shell and contributes to the roof holding its shape in a rollover, and it gives the passenger airbag something to deploy against. It is not a window that happens to be at the front.
That means the bond does the work. Two fitters can use the same glass and produce very different results, and the difference is entirely in preparation: how the aperture was cleaned, how the surface was primed, and whether the adhesive was given the conditions and the time it needs.
This is also why the failures show up later rather than on the day. Wind noise at 60mph, a damp footwell after heavy rain, a rain sensor that stopped reacting: none of those are visible when the car is handed back.
The eight steps, in order
The correct glass is identified
Your registration gives the build specification, not just the model. Heating, rain sensor, acoustic layer, camera bracket, Head Up Display and tint all change which screen your vehicle takes.
The vehicle is protected
Dashboard, seats, paintwork, wings and trim are covered before anything is cut. Removal generates glass dust and the tools work close to the paint.
Wipers and trim are removed
The technician needs clear access to the full bonded perimeter. Scuttle panels, wiper arms and mouldings come off first.
The damaged screen is cut out
The old bond is cut through with wire or a cold knife. The aperture is then inspected, including for corrosion, which is more common on older and working vehicles.
The bonding area is prepared
The old urethane is trimmed back to a thin even bed, the surface is cleaned, and Sika primer is applied where the system requires it. This is the step that decides whether the job holds.
The new glass is positioned
Set in one movement and aligned so mouldings sit flush, sensors line up with their housings, and the glass is square in the aperture. A screen that goes in crooked cannot be nudged after the adhesive grabs.
Sensors and equipment are refitted
Rain sensor gel pads, camera brackets, heating connections and mirror mounts are reconnected and checked rather than assumed.
Safe drive away time is confirmed
You are told the actual figure for the adhesive used and the conditions on the day, before you drive.
What happens after the fitting
The job is not finished when the glass is in. Trim gets refitted and checked, wipers are run through their arc, the demister and rain sensor are tested where fitted, and the interior is cleared of glass and fitting waste.
If your vehicle has a windscreen camera, calibration is carried out where the manufacturer specifies it. Pilkington notes that even a small change in camera position can affect how the system performs, and that a camera can run on incorrect parameters without lighting a dashboard warning.
| Checked before we leave | Why |
|---|---|
| Glass position | The screen should sit square in the aperture with even gaps |
| Mouldings and trim | Loose or lifted trim points to a rushed fit |
| Wipers | Correct arc, correct park position |
| Rain sensor | Automatic wipers should respond where fitted |
| Demister and heating | Where the screen carries heating elements |
| ADAS | Calibration where the manufacturer requires it |
| Interior | No glass or adhesive waste left behind |
| Safe drive away time | Confirmed to you, not assumed |
Common questions about the process
How long does the whole thing take?
The fitting itself is usually one to three hours depending on the vehicle and what is fitted around the screen. Calibration, where needed, adds to that.
The part that cannot be compressed is the adhesive reaching drive away strength afterwards, which is separate from the fitting time.
When can I drive the car?
When the technician confirms it, not before. We bond with Sika polyurethane, and Sika are clear that their glass adhesives have different minimum drive away times depending on which product is used and the conditions on the day. That is why you get a figure for your installation rather than a number from a leaflet.
Advertised flat figures like “drive away in 30 minutes” belong to a specific product under specific conditions. They are not a universal rule.
Is there anything I should avoid for the first day?
Do not slam the doors. A closed car is a sealed box, and the pressure spike from a slammed door pushes against a screen that has not reached full strength. Leave a window slightly open if you can.
Avoid jet washes and leave any retention tape in place for as long as you are advised.
What should I look for in the days afterwards?
Wind noise that was not there before, damp in the footwells or headlining after rain, wipers catching on the trim, or a rain sensor that has stopped reacting.
Any of those means the screen should be looked at again. Say something rather than living with it, because a leak gets worse and a leak into the electrics gets expensive.
Do you do chip repair as well?
Our core work is replacement rather than chip repair. If your damage is small and well placed, a repair may be possible and is cheaper, so it is worth asking about before committing to a new screen.
Send a photo and we will tell you which of the two you are looking at.
What we guarantee
Our fitting is guaranteed against water leaks, wind noise, bonding failure and workmanship. If any of those appear after we have replaced your glass, call us and we will come back and put it right. Read the guarantee.
This process applies across all the glass we replace, not just front windscreens.
Ready to book?
Send your vehicle registration, your postcode, which glass is damaged and whether the vehicle has a camera, rain sensor or heated screen.
AI Auto Glass, 248 Meadway, Birmingham B33 8NN. Monday to Saturday, 08:30 to 20:00. See mobile windscreen replacement or all windscreen services in Birmingham.