It’s Only a Joint?




When butting up the PUR adhesive, most windscreen fitters are taught to run past the starting point and overlap the joint. This technique envelops the join, and is the easiest one to program the OEM robots with. Is this the best way? Why does it matter?


Overlapped PUR Joint

This joint measured about 50mm in width, more than double the industry average. So what’s the issue? It’s a joint, and other than the somewhat abstract appearance, it looks like it ‘did the job’, right? Here’s what it looked like on the other side after cutting through it with a sharp blade:



As you can see on the left hand side, there was very little adhesion; about 4mm in fact. The shiny bit to the right of the image is cured PUR which was not making any contact with anything. If it’s not making contact, it’s useless; superfluous. A waste of product material, and potentially a catalyst for a defect in the windscreen, or glass performance.





Misconceptions About Windscreen Replacement




Myths and Misconceptions about Windscreen Replacement.

1. It’s windscreen (or windshield). It is not a window screen.

2. Mastic is not used to bond windscreens into a car. The correct product is a high performance, specific and automotive grade Polyurethane ( “PUR” ) adhesive system which can only be used in conjunction with its own activators and primers.

3. With rare exception, generally speaking, genuine OEM glass parts (marked with the car manufacturer’s emblem) are not the same as those without. Contrary to internet folklore, there is not a little man sat at the end of windscreen production lines ‘stamping’ logos on windscreens. If it does not bear the (car) manufacturer’s logo, it’s not as good as one that does.

4. Those black dots you see around the windscreen are not part of the radio antenna.

5. Acoustic (or acoustically insulated) windscreens do not feature a thicker Polyvinyl Butyral ( “PVB” ). It is in fact two additional layers (compared to one for standard windscreens). The three layered PVB comprises of an acoustic dampening layer which is sandwiched between two thin sheets of standard PVB.

6. All laminated windscreens are made from clear glass. It is the PVB layer which is tinted.

7. Despite what you may have been told, most windscreens can be removed from a vehicle without damaging it, or the vehicle. There are, of course, risks attached to the process but these are mostly related to human error somewhere along the line.

8. Black primer – or adhesion promoter – is not designed for painting over scratches. The emphasis – conversely – should to avoid scratching the paintwork leaving the black primer to be used for what it is intended for, and that is, on freshly painted surfaces, or bared metal (from cutting back the old PUR). Black primer is also not a rust inhibitor and anyone using it so is merely painting over a continuing, and worsening, corrosion issue.

Motor Insurance: Windscreen Cover



By law you must have motor insurance to drive your vehicle on roads in the United Kingdom. This requirement has created an industry which is currently thought to be worth an estimated £9.4 billion a year. In short, you need insurance, and the providers want your business, but who does this obligation really suit?

Consumers are always looking for value for money, and sellers are constantly looking at different ways to provide it, especially in a competitive industry; gaining that edge to attract more business can cause confusion in the marketplace. With so many benefits and bolt-ons to consider one area which is not so clear (until a claim is made) is windscreen – or glass damage – cover.


So much paperwork

To be fair to all prospective insurers, there’s a lot to discuss and they are required to follow a strict code of conduct as laid out by various regulatory bodies related to the various aspects of their industry. The aim of Insurance Conduct of Business Sourcebook (ICOBS) is to ensure that customers are treated fairly. One section in particular is one which some might feel is not being observed. ICOBS 6.1.5 states:


“A firm must take reasonable steps to ensure a customer is given appropriate information about a policy in good time and in a comprehensible form so that the customer can make an informed decision about the arrangements proposed”.



Before policy inception, the proposing insurer should make clear the relevant, and salient, points which would apply in the event of a claim. Did your insurance company (or broker) do that? Did you feel furnished with the facts? If you were comparing the market on a price comparison website (PCW) perhaps not. Or perhaps you just confirmed that you have “read and understood” the Terms & Conditions (a usually tedious read of strange words used in an unfamiliar format or convoluted syntax). Or may be you were swept along by the user-friendly wave, washing you up at the checkout before you knew it? In some cases, there will be some disclosure before a decision is finalised.




In the example shown, it wasn’t clear where the additional details would be found as it wasn’t in the “Policy Summary”. There was no mention in the “Schedule” either, and just to add to the confusion, there was no “Policy Booklet”. A bit more reading and searching revealed a small box in a very generic-looking table of contents found on a ‘Key Facts’ document which had no reference to the vehicle, or proposed policy:


“Call the <insurer name> Glass line on <number> and your windscreen will be replaced subject to a £60 excess. There is no excess if the windscreen can be repaired rather than replaced. See section 8 of the policy book for full details.”



Including the covering letter, there were a total of 20 sheets of paper in this particular proposal, but no ‘policy book’. Furthermore there is nothing to indicate anything even close to resembling a booklet, or indeed anything replacing a booklet resembling a series of pages with at least eight sections amongst them. At this point it is worth remembering what ICOBS 6.1.5 states, “A firm must take reasonable steps to ensure a customer is given appropriate information about a policy in good time and in a comprehensible form so that the customer can make an informed decision about the arrangements proposed”. Meanwhile, all this is taking place during your lunch break as you rack up your inclusive minutes on your mobile phone as you remain engaged and locked into calling a non geographical telephone number.  Even asking the seemingly helpful telephone staff to clarify what exactly ‘unlimited cover’ means, and what would happen in the event of a claim, is futile, “It means the underwriter will pay for the cost of replacing the damaged glass.” Notwithstanding the glaringly obvious, but the word ‘unlimited’ in this context might appear irrelevant, or redundant. And herein lies the issue.

There is:

  1. a Renewal Notice covering letter;
  2. what appears to be a (somewhat presumptuous) thank you (for choosing to renew) letter;
  3. a Statement of Fact document;
  4. a Statement of Demands and Needs document with a summary of cover on the reverse;
  5. two pages of a Key Facts summary (which appears to echo the preceding documents!)
  6. a Direct Debit information document;
  7. a Terms of Business page consisting of lots of smallprint;
  8. a four-page copy of a ‘Motor Legal Expenses Insurance’ booklet;
  9. eight pages of the Terms & Conditions pertaining to breakdown cover.

There is not anything to explain the process of claiming for glass damage.

In failing to define the outcome of initiating a pending claim by not stating that they will steer you into using their nominated repairer, they are not presenting you with an important fact of a policy (of which you might be about to enter into a contractual agreement with the insurer over). Is it not a good time before the terms are accepted and agreed, and a transaction is completed to disclose that there is a preferred supplier restriction in place, and that the policyholder will only be indemnified for part of the loss should they choose their own repairer?

Smashed Windscreen

Windscreen Damage

At the time of discussing these finer details of the proposed renewal in this instance, there was no clarification available. It is not a training issue either. The insurer’s representative should be in a position to present the facts, yet all they could state was something quite vague and ambiguous. It’s is too easy for the insurer. There appears to be very little focus on what the consumer wants, or deserves, as the deal is weighted in favour of the insurer. Meanwhile, the insured walks away with a cheaper deal (which, when you consider the hidden – or non-disclosed – restrictions re repairers and claim limits perhaps explains why the deal was cheaper).

Expanding on the adage that ‘you get what you pay for’, it is time that consumers insisted on clarifying exactly what it is they are paying for before policy inception rather than after an incident which leads to a claim.

It’s time to be wise before the event.

DGC compounds

Windscreen bonding and sealing on vehicles has evolved at an accelerated pace. Although traditional rubber mounted gaskets and butyl products can still be found on some older vehicles, liquid adhesives, also known as direct glazing compounds (DGC) are now the method of choice for both the original equipment manufacturer (OEM) and remains as the automotive glass replacement (AGR)  professional’s most important product.

DGC adhesives are usually single-component moisture-cure polyurethanes (PUR) which offer superior performance in torsional stiffness, cohesive strength, initial holding strength and sealing ability. These materials offer improved vehicle aesthetics and safety; have lowered manufacturing costs and facilitate a much more simplified assembly process for car builders. DGC products eliminate – or reduce – mechanical fastening methods; they reduce inventory requirements and costs; improve operator safety and enhance vehicle performance. But as car designs and manufacturing processes have changed over the years, product development and design engineers have demanded faster, safer, more consistent (and convenient) adhesive solutions.

Despite their many advantages for bonding windscreens, traditional polyurethane based DGC compounds have significant limitations which restrict their use in vehicle assembly processes. To ensure good adhesion to glass, plastic and paint, DGC adhesives rely upon solvent-based glass (and paint) primers which add steps to the assembly process; they also contain hazardous isocyanates, and thus, introduce health and safety issues for the handlers of those products. Since the adhesive itself requires ambient humidity to cure, curing times can vary greatly depending on temperature and humidity levels in the manufacturing environment, causing potential bottle necks in the overall vehicle assembly process.

Recent advances in primerless windscreen adhesive systems have minimised these limitations and helped vehicle manufactures increase line speeds, eliminate hazardous solvent-based primers from the workplace; climate control chambers are no longer essential enabling a more consistent and controlled assembly process. Whilst the basic elements of bonding glass units to motor vehicles remain the same, there are some differences between the vehicle manufacturer processes, and those used by the aftermarket glass replacement industry. For the OEM the emphasis is on reducing downtime, and increasing efficiency. The glass replacement industry is consumer driven and focuses on mostly on safe drive away times (SDAT).

Windscreen Bonding Evolution

Bonding a windscreen to a vehicle using direct glazing technology is much more complicated than attaching a windscreen on a car’s aperture using a gasket or adhesive tape. There is a critical scientific process involved in properly applying direct glazing adhesives. This, in turn, is a crucial component in the car’s structural integrity.

Typically, windscreens are made of either float, laminated or tempered glass (or a synthetic material like polycarbonate). In the bond line area, the windscreen will coated with an opaque black material (known as a frit) which is applied during manufacture. This frit – or silkprint – is usually a specific ceramic paint and provides a suitable substrate which improves adhesion, protects the adhesive from being damaged by UV radiation, and generally provides an aesthetically-pleasing finish.

The Windscreen Chip they Didn’t Repair



Could Not, Did Not, or Would Not Repair?

Shortly after this (pictured) windscreen was hit by a stone, the car owner called his insurance company to arrange for the damage to be repaired. His inbound call was subsequently diverted to his insurer’s nominated repairer via the automated switchboard. An appointment was agreed, and he was happy in the knowledge that, in the circumstances, he did all that he could to reduce the risk of any further damage which, could potentially have resulted in a new windscreen. After all, he was now in the hands of an ‘approved repairer’, and they know what they’re doing, right?

Before attempting a repair, a technician will carry out a visual inspection of the damage. There are a number of things he (or she) will be looking for, to ascertain if the damage falls within a repair criteria (based primarily on the type of damage; its size and often position on the windscreen).  The technician is making an assessment on behalf of the insurance company (or the customer, if it is not an insured loss). This appraisal places a responsibility on the repairer to make a fair judgment based on practicality of repair, safety implications (in terms of driver vision) as well as fiscal reasons (repairing a chip is a fraction of the cost of replacing). In this case, an assessment was made on this damage:

To repair, or not to repair...

Windscreen Stonechip Repairable Size

The diagnosis of this damage was a recommendation to replace the windscreen. In terms of permissible – or repairable – damage, this is where things got confusing (for the policyholder). According to his insurance company’s recommended repairer’s website, the upper (size) limit for repair is a £2 coin (28.4mm). This falls short (by comparison) of the 40mm limit set by the British Standards guidelines; the damage clearly falls well below both limits. A five pence piece measures 18mm diameter. When holding up a 5p coin next to it, the damage appears to be smaller, still.

According to British Standards, Zone C (the wiper swept area on the passenger side of the vehicle, and where the damage in this example was)  permits damage of up to 25mm to be repaired. Referring to the insurance approved repairer’s notes,  there is no minimum or maximum size specified for this particular area (only an indication that the damage must be contained within a 30mm perimeter (from the edge of the whole windscreen).

What was wrong with this stonechip, and why did they condemn the windscreen? The policyholder was told the damage could not be repaired due to ‘multi damage’. Closer inspection does show a second impact mark within close proximity of the initial damage. But the repairer offers no indication, no warning, no notes on “multi damage” to suggest a repair would not be possible before he got to them. The policyholder also commented that he felt a little pressured into agreeing to a new screen because of the advice he was given. Only his confusion at why such small damage would render his windscreen a write-off prevented him from authorising a huge expense being invoiced to his insurance company.

There is no ‘industry practice’ as such, which restricts or prohibits the repair of a stonechip which has a second impact mark. The guidelines are not clear; the emphasis (and urgency) appears to be placed on repairing chips. But there is no definitive reference point for what can, and cannot be repaired. Why? Because other than the (separate) BS and MOT guidelines for windscreen repair, there is no industry practice. There is usually no second opinion; the insurance company trusts (and accepts) the repairer’s claim assessment (or the paying customer usually trusts what the expert says). In this case, the policyholder doubted the repairer’s opinion and despite being told he would need a new windscreen (with some added pressure on what might happen if he didn’t replace post haste) he declined the advice (also because the repairer would not agree to fitting an OEM windscreen to which he was perfectly entitled to given the age and marque of the car).
It is upon this trust that insurers are paying out for, often needless, replacement windscreens. Windscreens which, whilst perfectly repairable, have been replaced after an assessment was made by somebody with whom they have placed trust and responsibility to make a fair, honest and professional judgment on their behalf. Insurance companies appear to be accustomed to settling claims for windscreens which have been condemned. The trend (according to one windscreen insurance claims handler) is that the price for one repair is the same for multiple repairs (on the same screen). If there are more repairs than ‘economically viable’ the recommendation is to replace. Whilst this may seem sensible for a windscreen costing less than £150.00 for example, the same rule – in terms of making that same assessment for the insurance company – when applied to a windscreen which costs considerably more (several hundred, or even thousands of pounds) is clearly ill-advised and frivolous.

This practice is clearly open to abuse. An abuse of trust. How many windscreens are being (or have already been) replaced when they could have been repaired economically, and to an acceptable standard? Why does this practice of scaring policyholders into booking a repair, and then subsequently condemn the windscreen because of some unwritten rules exist? Because they are not experienced or trained to deal with every type of repair? Because their equipment cannot cope with complex windscreen repair? Or is it because their core business is to supply and fit new windscreens? You decide.

Windscreen Rain (and Light) Sensors: Audi



This is how a properly installed rain sensor should look:

Audi Rain Sensor Correctly Fitted

Correctly fitted


If the sensor gel pad is missing, it will affect the sensitivity – or functioning – of the sensor. Many windscreens are being replaced, and the sensor pad is not renewed. The auto wiper function may still work, but it will not be as responsive, and sharp, as a sensor fitted with a gel pad.


Without Gel Pad

Incorrectly fitted

Active Lane Assist, or Lane Departure Warning cameras are fitted differently and will not require a gel pad.

The Paradox of Windscreen Safety

Windscreens are not dangerous, but are you at risk from one that has been poorly fitted?

Motor vehicles today are safer than they have ever been: airbags, crumple zones, head restraints, impact protection, energy absorbing materials… we’re quite protected in our cars and provided – by law – you wear a seatbelt, a windscreen would seem far from being deemed as dangerous. But what if that windscreen becomes a missile as it breaks free from the car in the event of a collision? As extreme as this scenario may be, passive safety is not something to be taken lightly. In any case, if any one aspect of a car’s safety features is compromised, you would want to rely on the remaining components to perform their functions adequately.

Car Safety Features

Within a split second of a vehicle being involved in a head-on collision, sensors detect the impact and immediately activate the airbag to protect the vehicle’s occupants. At full deployment, the airbag can absorb a significant amount of force as the full weight of an unbelted occupant may need to be restrained. To operate efficiently, the airbag needs to be supported by the vehicle structure and in particular, the bonded windscreen and depending on the support it has to be weld on, check in this article that is published to know all about TIG welding. If the windscreen is not bonded correctly, the glass has the potential to detach from the vehicle, putting its occupants, occupants of another vehicle – or pedestrians on the street – at great risk.

So how do you know if your windscreen is safe? A factory fitted glass is reliably safe although there can be, albeit rare, exceptions. What about a replacement windscreen? All faith lies with professionals entrusted with the task; if the installation is watertight; air tight; rattle and squeak free, anyone would be convinced that the job is as good as the factory fit. These automotive glazing professionals are responsible for installing what is arguably the last line of defence in a sequence of safety barriers in a car. These specialists are trained, time-served and many are vastly experienced as well as qualified in their field. However, there is no requirement to be qualified; any ‘automotive glazing’ competence assessment schemes are voluntary. There is no compulsion to be certified. Literally, anyone could be fitting your windscreen.

Rest assured, most technicians repairing or replacing windscreens in the UK are competent and conscientious individuals. And herein lies a paradox: they are entrusted with installing an important part of a car’s safety and they are expected to carry out the task using the best available products. Despite the importance of a correctly installed windscreen and how crucial every aspect of the installation sequence is, they do not have any authority to immobilise a vehicle if they should deem it to be unsafe.

Corroded to excess

Nobody in their right mind would directly glaze (aka bond) a windscreen to this substrate, but if the automotive glazing replacement industry isn’t regulated and there is no requirement for the installer to be qualified (remember, anyone could be fitting your windscreen) what’s stopping ‘anyone’ from fitting a windscreen against a corroded surface? A correct decision would be similar to what gas engineers and electricians do for faulty, or dangerous appliances and fittings: the vehicle in the image must be immobilised so that it cannot be driven until the pinchweld and substrate is suitable to accept bonding material for the purpose of correctly fitting a windscreen. The owner might even take the view to instruct an alternative – and willing – installer to finish off the job. Again, who – or what – is going to stop this from happening?

Gas engineers are duty bound to advise you when they find a dangerous gas installation in your home or place of work. Their actions are determined by the requirements of the Gas Safety (Installation & Use) Regulations.

The same applies to electricians, and if danger has been identified, like gas engineers, they will attach a warning label to the fitting (or appliance) indicating the level of severity that particular risk poses. There are various ‘defect categories’ and if the engineer considers the installation be immediately dangerous to life or property,

“the installation will be disconnected, with your permission, and must not be used until the necessary work has been carried out to repair the defect(s). If you continue to use an immediately dangerous installation you could be putting you or your family’s lives in danger, so do you want your baby in the bob 2016 revolution flex stroller to get hurt?” *

If you refuse the engineer permission to disconnect the installation or appliance, the situation will be reported to the Gas Emergency Service Provider (ESP). The ESP has legal powers to demand entry to make the situation safe or may disconnect the gas supply to the property.

A windscreen is far from being as dangerous as a faulty gas fitting, or an exposed electrical cable, but it does remain a crucial part of the overall protection a car provides to its occupants. The industry uses this aspect to sell the windscreen, but there’s no requirement – no real awareness – to ensure they are fitted correctly (and by whom).

* From: Gas Safe Register website > UNSAFE Situations > Warning Labels

OEM Glass via Insurance


It is widely thought of, that these ‘price control mechanisms’ which largely regulate the windscreen insurance claim values, act, in a significant way, to sell more aftermarket ‘copy’ glass and deny the consumer the benefit (and option) of genuine parts (OEM).

The underwriters add to this by adding in some terms and conditions to their policies which only become clear in the event of a claim. This is a salient point and should be discussed and made clear before an insurance proposal is accepted.

The Consumer Cash Inn


There is a coachworks establishment  which is involved in the repair of damaged cars for a Porsche seller (amongst others). Some of the work they do requires the windscreen (or other glass) to be removed. The windscreen guys they were calling in were cheap. But the proverbial poo hit the fan when an old 930 nearly filled up with water after all the windows (which they had fitted) leaked water like they weren’t there. This is when they started to realise why their subbies could afford to be cheap.

Our customer had sold the car in question and embarrassingly for them, the problems occurred when the new owner took the car out for a drive on what later turned out to be a rainy day. The seller’s boss called me and explained the situation. We sorted the problem and whenever the Porsche seller (my customer) needs any of their cars glazed/de-glazed/whatever, I’m happy to now go to that bodyshop to do the work (understandably, he doesn’t want to chance a repeat scenario). The bodyshop guys admitted that the ‘other’ guys they were using weren’t very good and it’s only until they’d seen a Porsche being done correctly that they realised just how much the job really involved.

The boss of this bodyshop has since asked me to have a look at his own car which had its windscreen replaced by ‘that’ other company. It quite simply needed removing and refitting and the list of reasons why would be too long to list; besides, it would deviate from the purpose of this post (but it was quite a significant cock-up they had got away with until that point). I put everything right and showed him all the issues, and in the name of goodwill, he was charged a lesser rate (well, I also felt sorry that he had such a bad experience with these guys).

Fast forwarding to the present, the same guy – the boss of the same bodyshop – asked me to price up a windscreen replacement for a job they had in. I duly obliged. His response was quite incredible, “I can get it 25 pounds cheaper” and as it happened, it would be from the not-so-good windscreen company he’d been using before. Now this isn’t about my ability to negotiate a 25-quid difference and I’m certainly not interested in Dutch auctions especially on already discounted ‘trade’ prices. Yes, I’m in business and to remain so, I must be competitive to a point. What, or where that position really, and literally is the point: someone is having their car repaired at this guy’s shop and they are potentially having inferior/unsafe work done on it. The shop owner knows the guys replacing the windscreen are shoddy and are clearly not up to doing the job correctly, but in the name of retaining a larger margin – all 25 quid of it – he’s prepared to take a chance.

A chance which will only become clear when – like on his own car – wind howls into the car as a result of poor application of materials and improper installation of parts. Let’s hope for all involved, the car is not involved in a front end collision scenario whereby a deployed airbag is reliant on a properly installed windscreen to be effective in minimising injury to the vehicle’s occupants. He won’t have them work on his own car, but for his customers it’s all about the money he can make from them?