Why did the glass in a plastic window crack?

Metal-plastic windows have become a part of our lives; it is impossible to imagine a modern home without them. They provide a microclimate in the room, do not allow outside sounds to pass through, and often have additional functions. The main part of the window is, of course, the glass unit; the barrier properties of the entire system depend on it. Such blocks are becoming more and more complex in design, including several chambers, and the internal space is filled with gases for thermal insulation. Therefore, it is especially unpleasant if the glass in a double-glazed unit is cracked.

Most modern windows are quite durable and often include tempered glass or triplex. There are videos on the Internet in which a window block is hit with a sledgehammer or a baseball bat, but not even a trace remains on it. However, this does not apply to the cheapest versions. An inexpensive single-chamber double-glazed window not only does not provide reliable protection for the home from the cold, but is also easily damaged or broken.

A glass unit cracked: reasons, what to do?

Agree, it’s quite unpleasant to see a crack on your window, especially when it comes to a recently purchased double-glazed window. So what, this could happen? Of course it can. A glass unit may crack at first glance for no apparent reason. That is, in order for a crack to appear in a double-glazed window, it does not necessarily need to be hit with something. But how so? If the plastic structure is used carefully, why did the glass unit crack and what to do in this case? There are a number of reasons that contribute to this. In this article we would like to consider all situations associated with the formation of a crack on the surface of a window structure. So let's get started.

How to replace a double-glazed window?

This is not difficult to do: just bend the beads holding the structure and pull it out of the rubber seal, after which you need to order a new glass exactly the same size as the damaged one. To insert it, just return the glass unit to the seal and insert the glazing beads in the same order in which they were placed.

A double-glazed window will last a long time if it is correctly selected, installed, and handled carefully. If cracks appear, this product cannot be repaired and must be replaced entirely.

Why does a double-glazed window crack: reasons?

According to experts in the installation of plastic windows, in order for a crack to appear in the window, it is not necessary to somehow mechanically influence it. That is, the cause of the crack formation may not be a blow or careless operation of the window.

This means that if your double-glazed window is cracked, the reasons may be different. Let's take a closer look at what can trigger the appearance of such a disease.

Conditions outside the window

Surprisingly, the temperature outside the window is a fairly common cause of cracked glass. More precisely, if the temperature difference in the house and outside is too great, then the windows may begin to sag. As a result, a crack is quite likely to form in the glass of the double-glazed unit. If this happens, then it is not external factors or the homeowner who are to blame. But who? All responsibility lies with the company that installed the metal-plastic structure. The fact is that it was she who incorrectly chose the installation method in accordance with the climatic conditions of the area.

Important!

Before blaming the window manufacturer for all your troubles, try to determine whether weather conditions are the cause, and as a consequence, the installer company.

Artificial temperature difference

A glass crack has appeared in a double-glazed unit, try to remember if you leave the electric kettle on on the windowsill in the winter. The fact is that in this way you will artificially create a strong difference in temperatures enveloping the double-glazed window on both sides. As a result, there is a high probability that a crack will develop along the window.

Important!

Multi-chamber double-glazed windows are more protected from the effects of temperature differences.

Wall displacement

You may have heard that shrinkage of a house can cause a crack to form in a double-glazed window. How true is this statement? In fact, the version with house shrinkage was created by unscrupulous companies that are trying to cover up their installation and technology selection flaws with such a global problem as building shrinkage.

Imagine, a stone opening changes its dimensions by 4 mm (installation tolerance) - the wall will crack. If the wall is not cracked, the cause of the problem lies elsewhere. The only exception to the rule “the installer is to blame” in this case is the installation of windows in log houses made of timber, logs, or laminated veneer lumber. There, skew of the opening is possible, but even in this case there is a time-tested technology - the window dimensions are designed smaller with a gap for the shrinkage of the frame. Here, of course, you can miss the forecasts, although the right installers will warn the customer seven times that all possible problems with the installation “with an expectation of future shrinkage” are his personal responsibility and will be eliminated at his expense.

Based on this, we can conclude that plastic windows in new buildings crack not at all due to shrinkage of the house. The problem needs to be looked for elsewhere.

Mechanical impact

Of course, perhaps the most common causes of cracks in double-glazed windows are related to mechanical stress. Moreover, it is far from a fact that a crack will become immediately noticeable after hitting the glass. It can form over time. In addition, the wind outside the window quite often lifts something into the air, and it also has a habit of breaking branches and trees. That is, a mechanical impact that can cause a crack to appear on a double-glazed window can be applied both inside and outside the room.

Installation error

Yes, sometimes installers’ mistakes are not cheap. It happens that the team installing plastic windows, for some reason, was in a hurry and hastily carried out the installation, as a result, an error was made that could not be immediately identified. You are wondering why the glass unit cracked, but the fact is that the plastic structure was initially installed at an angle.

As you can see, in some cases the fault lies with the owners of plastic windows, in some cases with the company that carried out the installation, and in some cases with the manufacturer of metal-plastic structures. It is important to understand who is to blame. And to do this, it is necessary to correctly determine the cause of the crack. This is exactly where the specialists from the Teplo Doma company can help. Our technician will quickly identify the cause and offer several options to solve the problem. You can call a specialist right now.

Related article: Framing windows on the facade of a house made of polyurethane

Equipment and tools

Depending on the nature of the damage, the following tools and devices will be needed:

Polisher and buffing wheel – Used to remove streaks, scratches and to finish repairs of chips and cracks. Do-it-yourself repairs are often limited to soft fabric.
Scriber . It is convenient to use for removing small fragments and dirt. They also mark the place for drilling so that the drill does not slip. But for simple defects you can do without it.
Electric drill for drilling - stops the spread of cracks and gives access to internal cracks.
Bridge with injector - their purpose is to fill the defect with polymer. For constant use, buy a metal one - it is reliable, but expensive. Or they use disposable plastic devices that are attached to an adhesive base and used together with a syringe.
A mirror and a flashlight are necessary to determine the boundaries of the defect and determine the presence of air bubbles in the polymer.
Blade for cleaning off excess polymer after it has hardened.
Ultraviolet lamp - accelerates the hardening process of the polymer mass. If this is not available, you can use UV film, which is included in one-time glass repair kits.

In isolated cases of DIY repairs, you can do without some devices by replacing the polishing machine with a cloth, the scriber with a needle, the UV lamp with film, and the injector with a disposable plastic device.

A glass unit is cracked: what to do?

If the glass on a double-glazed unit cracked, you were unable to prevent it, and the disaster occurred through no fault of yours, then you don’t need to immediately go in and figure out what the reason is. First you need to see if this design is covered by a warranty. If the warranty period has not yet expired, you should contact the company that installed the windows. She should send a technician to you who will take the necessary measurements and fix the problem.

But what to do when the warranty period has expired. This will require some repairs. It is worth immediately noting that the repair of a cracked double-glazed window consists of replacing it. The fact is that you won’t be able to repair a crack in a double-glazed window.

, you don’t even have to try. After its appearance, the double-glazed window depressurized and moist air got inside. Now, no matter how hard you try, the window will not be able to fully perform its functions.

That is, if a crack forms on a double-glazed window, you will have only two solutions to the problem:

Change it yourself.
Call a specialist to carry out all the necessary work to replace the glass unit in the window.

We recommend calling a specialist. Everything is simple here: if you do not know how metal-plastic structures are structured and are not able to accurately determine the cause of the crack, then by starting a repair yourself, you can waste your time, money and nerves.

You can find tips on the Internet on how to seal a crack in a double-glazed window. Some people recommend using regular tape. “It may not be aesthetically pleasing, but it’s still practical,” these people say. As we have already said, a sealed window will not work as before. First, condensation will appear inside, and then, with the onset of cold weather, the entire window will be filled with ice.

A cracked window will still have to be replaced. Or maybe repairs will be cheaper? Repairing double glazed windows is virtually impossible. No, in theory it can be done, but it will be more expensive than a replacement. A good article has been written on this topic - “Is it possible to repair a double-glazed window?”

So, let's summarize. If the glass in a double-glazed unit is cracked, then first you need to establish the cause. To do this, a complete diagnosis of the metal-plastic structure should be carried out. If any additional fault is found, it must be eliminated. Once all this is done, the cracked glass will need to be replaced. It’s better not to do it yourself, as this is not the easiest task.

Will they register with the traffic police if the windshield breaks?

Technical inspection is regulated by regulations, in which everything is described in great detail. Regarding our question, we conclude:

They will not register a car if the windshield on the driver's side is cracked in the area cleared by the windshield wipers. We are talking about cracks, not chips and other types of damage.
When an inspection specialist sees a broken glass, he will most likely write that there is a crack, regardless of whether this is actually the case.

You can challenge this decision only in court, which will take a lot of time. Therefore, it is easier and cheaper to install new glass or repair it before registering with the traffic police.

As you can see, there are many reasons why a windshield can crack. However, following the advice from the article, you can significantly reduce the risks of their occurrence.

The glass in a double glazed unit is cracked - what are the causes of the defect?

A rather unpleasant but common problem faced by owners of apartments and houses is damage to the glass unit . Even a small crack can significantly reduce the comfort of staying in the room: cold air will begin to enter the room, the window will freeze in winter, and will not be able to contain the noise. It is not necessary to completely change the window structure if the double-glazed window is cracked: replacement can be done separately.

What to do if your windshield breaks?

If the damage is minor (crack), then seal it on the outside with tape. This way you will reduce the risk of dirt getting inside, which is important for subsequent repairs.
Try to get your windshield repaired as quickly as possible. Cracks tend to spread if they are not repaired in time.
Try to avoid getting into potholes or hitting curbs until the problem is fixed.
If the windshield has broken badly, then it is worth replacing it, and the sooner the better.

What to do if a crack appears?

When a double-glazed window is cracked, many cannot decide what to do. This question becomes relevant if, for example, the window has been damaged. The simplest, but most expensive way is to call a specialist who will replace the double-glazed window with a new product. However, replacing such a design is not the most difficult procedure, and you can save a lot by ordering a similar system and fixing it yourself.

The double-glazed window has a structure consisting of several glasses, between which there is a frame for strength and drainage. The parts are fastened together using sealant: it is located inside and outside. It is important that the glass unit does not allow air to pass through. Glass of different properties and quality can be inserted into the design; the quality and cost of the product depend on this.

The strength of the glass unit depends on the thickness of the glass, how it was produced and whether it is covered with a film. Spacer frames are most often made of galvanized steel: it is an inexpensive, durable material that is not afraid of corrosion. Aluminum is used less frequently, as this metal is softer. In cheap windows you can find plastic frames.

To prevent the glass from fogging up and to remove excess moisture, the frame is filled with a special desiccant. Thanks to small holes, the spacer design allows moisture to pass through to the dehumidifier and heat to pass through, which prevents the product from freezing. The dehumidifier protects the system from freezing and fogging; it is made from molecular sieve and silica gel. Some double-glazed windows are filled with inert gases for better insulation of heat and sound, so if such a double-glazed window is damaged, its restoration is no longer useful. Before installing a new product, it doesn’t hurt to find out why the previously installed glass unit cracked.

Related article: Flexible windows for verandas

Weather conditions as a destructive factor

In a previously published article entitled “Design of a plastic window,” all the components of this light-transmitting solution were described in detail. Let us briefly recall that a double-glazed window includes several glasses that form chambers and are separated by a spacer frame. The space in the chambers of a double-glazed window is filled either with inert gas (a more expensive version of windows) or with dry air (the most popular due to the optimal price/quality ratio). At the joints, to ensure the tightness of the structure, the chambers are sealed with a special substance.

Due to the impact of environmental manifestations on the glass unit, such as a sharp jump in atmospheric pressure, or a change in temperature values (extreme heat, cold), mechanical stresses are likely to occur on the glass, which is one of the reasons why the glass unit burst.

Why can chips and cracks appear?

If the glass in a double-glazed unit is cracked, the reasons may be different. The most common is mechanical damage: most often such a crack is located on the outside of the window. This means that someone threw a stone or some not necessarily large object accidentally hit the glass, causing a crack to appear. In rare cases, birds may crash into glass.

Such damage to the inside of a double-glazed window usually occurs when it is handled carelessly, for example, if there was a heavy flower pot on the windowsill that was carelessly moved and hit the glass. If such a double-glazed window was filled with gas, it will have to be replaced, since it will lose the gas, and with it all its qualities. There are other reasons for cracked glass. These include the following:

Pressure on the glass by any object or when opening.
Incorrect assembly during manufacture.
Deformation of the window frame.
Incorrect installation or incorrect size, resulting in a leak in the product.
Sudden changes in pressure and temperature outside.
There is a large difference between the temperature conditions outside and indoors, and the room becomes very hot.

If the mechanical causes of damage do not raise questions, then the rest should be considered more carefully.

Causes of cracks on the windshield

The main reasons are as follows:

Mechanical. Hit by stones and other objects, birds, hail, branches (in case of parking under trees). The actions of hooligans also cannot be ruled out.
Thermal, associated with a sharp temperature change. For example, turning on the heating at full power in winter or sudden cooling from the air conditioner in summer.
Manufacturing defect. As a rule, it appears some time after purchasing the car. The windshield may break for no apparent reason, but obtaining a warranty replacement at the dealership may be difficult. We'll talk about this below.
Violation of body geometry after an accident. Poor-quality body repairs cause cracks in the windshield when hitting a small hole or bump, parking on a curb, etc.
Low quality glass or poor quality replacement. It is better to install glass on a car in specialized services where experienced specialists work and have the necessary equipment and high-quality materials.

How to prevent glass damage?

In order for the glass unit to last as long as possible and not crack from accidental impacts, a number of measures can be taken to help extend the life of the product. First of all, when choosing a window design, you should not strive for cheapness: the thinner the glass and plastic, the lower the cost of the structure, but also the higher the vulnerability. Thin glasses can react to the slightest load and crack; they freeze easily, since the frame is not thick enough to retain heat sufficiently.

Make sure that the glass does not touch each other: this can lead to dire consequences. When ordering a double-glazed window or the window itself, measure the space several times or invite a specialist from the company from which you will order the product. This will protect you from mistakes; in addition, in the event of a defect on the part of the company or an incorrect measurement by a specialist, you will be able to demand a free replacement of the double-glazed window with a new one.

Often, crooked walls or shrinkage of the house can increase the pressure on the window frame. It can be severely deformed or, conversely, unnoticed by the eye, but this is enough to render the structure unusable. In order to prevent the double-glazed window from cracking, causes of this kind must be eliminated immediately. To do this, they usually strengthen the window opening, preventing the structure from sagging, or they do not install windows in a house under construction, but wait until it shrinks.

When the temperature outside is below freezing, heating devices begin to be used indoors. If you heat a room too quickly and too much, thin glass can crack. In order to avoid this, it is advisable to initially order double-glazed windows with tempered glass. In addition, the heating of the room must be done smoothly: this is especially true for houses heated with a fireplace or wood stove. The room should not be allowed to cool down to outside temperature, as windows do not like such changes.

The crack may not become noticeable immediately. When pressure is applied to the structure, it can form for quite a long time and be invisible to the naked eye. Pay attention to the location and shape of the crack: if it appears in the center of the glass unit and is shaped like the letter C, this means that the glass unit was stored incorrectly by the manufacturer and the room was not heated.

For information about single-chamber double-glazed windows, read the article “Single-glazed double-glazed windows: also cool!”

Replacing a double-glazed window with your own hands

If you still decide to save money and replace the glass block yourself, then pay attention to a few points:

Installers do not recommend installation at air temperatures below -20 degrees, but even at -15, rubber seals can become fragile.
When replacing the bag on the window sash, it must be removed completely.
Working with damaged glass requires special care. Prepare gloves and, if possible, special suction cups that can be used to safely move the bag.

Removing the glass unit from the frame is quite easy. To do this, pick up the glazing beads that hold the block down with a thin spatula or knife and remove them from the grooves in the direction from the middle to the ends. First you need to remove the long side clamps, then the bottom, and finally the top. After this, carefully remove the glass using suction cups and place it on a flat surface covered with a cloth.

Visually check the new block for chips, peeling of the sealant around the perimeter and other damage. Clean the installation site from debris and dust. Place the lining on the lower profile and install the glass unit. Check the size of the gap between it and the frame; it should be the same around the entire perimeter.

Secure the structure with glazing beads in the reverse order. First, place the upper and lower clamps in the groove until they click, then the side ones. Use a rubber mallet for this. Once the fasteners are in place, the repair can be considered complete.

What causes double glazed windows to break?

If a double-glazed window has burst, the reasons should be looked for in the following:

Temperature fluctuations. Changes, especially if there is a noticeable difference between internal and external temperatures, have a bad effect on the strength of the product. Under certain conditions, the glass begins to bend inward or outward. You should be wary of cracks if your area experiences low pressure in hot summers and high pressure in frosty winters.
Human factor. For example, you force the window sill with heavy, rigid objects, and then inadvertently press hard on them, not taking into account the distance. Then don’t be surprised if you see that the double-glazed window has burst from the inside.
Loads generated by the building. If you installed a “glass package” in a new house, and then it shrinks and the window opening is compressed, the result will be broken glass. Can a double-glazed window burst in old buildings? Quite. For example, a glass set in a log house, the walls of which are gradually deflected, is capable of cracking due to the loads on the structure created in this case.
Incorrect installation or manufacturing defect. The glass will crack, for example, if the installers installed the “packages” incorrectly or there was some kind of manufacturing inaccuracy from the beginning.

But there are also factors that may raise doubts, but in fact will not affect the integrity of the glass. For example, can a double-glazed window burst due to an LED strip? In fact, you can safely attach some lights to it. LEDs do not emit even a thousandth of heat, which could damage the glass.

It's all about pressure

As we know from a school course in natural history, atmospheric pressure, due to the movement of large air masses over the surface of our planet, cannot remain the same for a long time. It either rises or, on the contrary, declines. The normal value of atmospheric pressure is usually fixed at 760 mm h.s.

When a double-glazed window is manufactured at the factory, it is sealed at one pressure value. During operation, atmospheric pressure reaches different values. The difference between the pressure outside and the pressure in the cavity of the glass unit contributes to the appearance of mechanical stresses on the glass, causing the glass to bend. Since the base of the fixed glass is stationary, the double-glazed window acquires rounded shapes that are invisible to the eye, but can have a dramatic impact on the integrity of the glass structure.

Precautionary measures

Instead of wondering whether a double-glazed window might crack in your case, it is better to be on the safe side in advance. There are some rules that will reduce the risk of being left near a broken window. Almost all the reasons why double-glazed windows burst are known.

For example, when ordering installation, make sure that the frame ratio is not higher than 5 to 1.
In addition, installation of such products cannot be performed at room temperatures below +5 degrees.
You should also handle the window with care and avoid the occurrence of significant mechanical stress.

Repair materials

In addition to tools and devices, you will also need consumables, including:

Photopolymer for filling cracks and chips . For different types of damage, the polymer density is selected individually. There are varieties that are better suited for repairing different types of cracks: narrow, wide or long. Also pay attention to the color of the polymer so that it matches the surface being repaired.
Glass cleaner to gently clean the repair area.
Moisture remover . You can do without it by waiting for the moisture to evaporate naturally or by drying it with a hair dryer at low power.
Degreasing agent - alcohol or acetone.
GOI polishing paste - used to eliminate streaks, scratches and final polishing of surfaces after repairs.

Alternative remedies available at home to combat minor scratches and streaks include:

toothpaste, preferably with a whitening effect;
furniture polishing liquid;
a mixture of mustard powder and vinegar;
colorless manicure varnish.

What to do in case of cracks?

If the glass in a double-glazed unit breaks, you can do one of two things. First, replace the cracked element. This is the most budget option, but sometimes it leads to a deterioration in the aesthetic appearance of the product. However, please note that it is not the specific glass that will need to be replaced. What to do if a double-glazed window bursts - you will have to replace it entirely due to the peculiarities of the technology.

Secondly, if a double-glazed window bursts from the inside, you can completely replace the window. If there was initially a product or installation defect that affected the functionality of the product, this is often the only possible option.

Critical temperature effect

Like the pressure of the earth's atmosphere, the temperature of the environment is constantly changing. Under the influence of sunlight, the glass of the double-glazed window heats up, thereby transferring almost the same temperature to the dry air or inert gas located inside the chambers. Those who have diligently studied physics and remember the properties of an inert gas have probably already guessed what an increase in temperature in relation to gas pressure leads to - the gas pressure on the walls of the glass increases. When the temperature drops, the gas pressure in a closed volume drops. This is reflected on the glass - it can “play” due to the pressure of the gas, either inward or outward. This fact may well be the reason why the double-glazed window bursts.

It is also worth considering the fact that in nature, changes in temperature and pressure can either neutralize or complement each other. A striking example of such an overlap: high pressure in cold weather and low pressure in warm weather. These critical cases have the greatest impact on the deflection of glass in a double-glazed unit.

Preparatory stage

Before starting repair work, it is necessary to prepare the site. You can lay everything out on the table or on the floor. The main thing is that there is enough space for laying the window frame or double-glazed window.

The work surface should be covered with a blanket, which will prevent damage to the structure during repairs.

Manipulations with double-glazed windows must be carried out very carefully. This is especially true for glass separation. If the complete replacement method is chosen, the process is much simpler.

Tips and tricks

To avoid such troubles as a crack in the window glass, you should adhere to the following recommendations:

carefully select the window design (multi-chamber windows withstand temperature changes more easily);
entrust installation to specialists;
avoid mechanical damage to the window;
do not use an electric kettle or other household appliances that generate a lot of heat on the windowsill (this is especially true in winter, when a large temperature difference is created).

When making repairs, you should be careful. All work is carried out carefully and slowly. When dismantling the sash, it is worth enlisting help, as it weighs a lot.

Streaks and scratches

Shallow damage can be successfully “treated” with GOI paste: for this you need:

Clean the glass surface with glass cleaner or warm water and dry;
heat the GOI paste in a water bath;
Apply the warm paste to a lint-free soft cloth or polishing pad and let it soak in slightly;
walk the disc or cloth with paste over the area to be repaired and then rub it manually or using a grinder on the desired area, moving in one direction.

Treatment with paste is usually repeated several times, especially when manually processing the surface, until the desired effect is achieved. Then the remaining paste is removed, the surface is washed with warm water and dried.

For glass surfaces, only fine abrasive paste No. 2 or No. 1 is suitable and only in a warm, melted state. Also, when polishing, you should avoid putting too much pressure on the glass sheet.

If, when testing a defect, the nail clings to the scratch, then it is considered deep. Removing it by polishing will result in distortion in this area - a lens effect. This is acceptable for a glass door, window or partition, but not for a car windshield. To get rid of deep scratches on the windshield, use a colorless compound to fill the deepening of the scratch.