How to seal a crack in glass + stages of work

Glass is a popular material. It is inserted into windows, doors and cars, made into dishes and used in furniture. However, glass is quite fragile and often cracks. To correctly and quickly fix the problem, it is important to know how to seal a crack in glass. The choice of material for repair depends on many factors: the width of the hole and its length, the location of the glass itself. In some cases, the glass can only be completely replaced, in others you can handle it on your own.



Previously, it was believed that a crack in the glass of a window occurs as a result of mechanical stress. There are a number of factors that lead to structural damage.

Adverse environmental conditions

The temperature difference between outside and home is a common cause of surface damage. When the difference is large, the windows begin to sag, which creates a high load on their fragile elements.

In such cases, all responsibility falls on the company that performed the installation. Correct installation prevents deformation of the window structure under the influence of temperature.

Sudden temperature change

Artificial temperature changes negatively affect structural elements. This is especially true on winter days. If you heat up cold glass suddenly, it will crack. Therefore, it is recommended to avoid such influence.

Placing electrical appliances that emit a lot of thermal energy will sooner or later lead to such consequences.

Wall displacement

Home shrinkage is quite common. This is especially true for wooden buildings. In masonry buildings, the risk of shrinkage is minimal, although possible.

If the glass suddenly cracked and there was no negative impact on it, the reason for this is the displacement of the walls.

Of course, if you install the windows correctly, taking into account possible changes in the opening, then nothing threatens the structure.

Mechanical influences

One of the most common causes of cracks on windows. This may be due to the owners themselves, strangers, or unfavorable weather conditions.

Careless handling of the structure leads to damage not only to the glass, but also to other structural elements. These include damage to the handles and locking mechanism.

In frequent cases, the culprit is a strong wind, which can lift something into the air or break a branch. All this can compromise the integrity of the glass.

To avoid such troubles, you need to treat your windows with care and install them well.

Stained glass film

Stained glass film is made translucent, so it only partially protects from curious neighbors and passersby - it does not allow you to see what exactly is happening or is in your apartment. But people moving around the rooms appear to the eye as blurry silhouettes.

Please note: stained glass film is used only if the distance between your window and the intended “spectators” is at least 3–5 meters. The fact is that, coming close to the glass, a person can easily see everything that interests him.

• Beauty - such a film will become part of the interior and can serve as a separate accent in it. • Variety of colors - There are hundreds of films on sale with patterns in different styles and with a rich range of colors. • Low price and long service life - these parameters for stained glass film are the same as for mirror film. • Does not block ultraviolet and infrared radiation. • Half transparent. • Does not fully imitate stained glass - from a close distance it is clearly visible that this is a drawing, not a pattern made of colored glass.

The stained glass film is fixed to the glass with water and is easily removed without leaving marks.

How to fix

How to repair a crack in window glass? This is the first question that arises for home owners who are faced with such a problem. There are 2 options.

  1. Replace only one glass.
  2. Install a new double glazed window.

The disadvantages of the first method include the labor intensity and complexity of the process. When replacing, you will need to dismantle the package and carefully separate the damaged glass.

They carefully select the fabric. At the same time, difficulties arise with the assembly of the double-glazed window. After unpacking, the seal is broken. It is not always possible to restore it at home.

If the window is under warranty, it is better to contact the company. If the cause of a crack is a design defect or a violation of installation technology, replacement is free of charge.

In any case, it is recommended to seek help from specialists, as this will significantly speed up the repair work. The technician will be able to easily determine the thickness of the glass unit and select a suitable replacement.

Common Mistakes

The work of sealing wooden or plastic windows is usually not difficult. But many make mistakes, because of which everything has to be redone again.

  1. Using a regular medical plaster. Once spring comes, it will be difficult to remove.
  2. Using masking tape. This method is quite popular, but the tape comes off quickly.
  3. Foam tape is not suitable for covering old wooden frames.
  4. Pasting energy-saving film onto dirty glass.
  5. Ignoring external insulation of slopes.

Any method of insulating windows, depending on the material from which the frame is made, has its own characteristics and nuances. Therefore, sometimes it is better to turn to craftsmen who, using a special tool, will complete the work quickly and, most importantly, with high quality.

Insulating a room for the winter is not that difficult. To do this, you can use available means, for example, strips of fabric or paper, foam rubber, cotton wool, etc. If there are large gaps, you may need to purchase spray foam or sealant. In particularly serious cases, when you need to insulate a window sill or slopes, you can use the services of specialists.


To perform glass repair you will need the following set of tools and materials:

  • Screwdriver Set;
  • stationery knife or chisel;
  • gloves;
  • rubber suction cups;
  • sealant.

The sealant is chosen very carefully. The quality of the connection of the glass unit elements and its throughput capacity depend on this.

Cracks on windows due to cold weather

This defect is not typical for structures installed in the middle zone and southern regions of Russia, since in these regions there is no severe cold in winter.

Little-known companies that produce economy-class windows often do not include in their products the ability to withstand low street temperatures. Therefore, among their products you can often find specimens that, when used in the northern part of our country, simply crack. Often the plastic profile or frame suffers.

Expert commentary

Vladislav Dobronravov

Leading technical specialist at Okna-Media company

This problem with a plastic window can only be solved by completely replacing it.

In order to prevent cracking of the components of the PVC structure, which is caused by severe frost (from -25 C and below), it is necessary to choose a window model from a well-known manufacturer: Rehau, KBE, Kaleva, etc. Moreover, it is desirable that it includes a triple-glazed unit and a five-chamber profile. Only then can we say with confidence that such a structure will not crack at low temperatures.

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.

Emergency measures

If such a problem happens to you, and you put off repairs until later, follow these recommendations:

Cover the damage with transparent tape to prevent any kind of contaminants from getting into the cracks.

  • Do not clean glass with chemicals. If it gets into a crack, it will worsen the hardening of the polymer adhesive during sealing.
  • Drive at low speed. Various vibrations and shocks contribute to the growth of the problem area.

Using silicone glue

It is best suited for glass repair. If the silicone is in a tube with a wide neck, draw it into a medical syringe, but if the tube of glue is small and its neck is tiny, you can apply it directly from the tube.

Slowly fill the entire crack space with silicone glue. Make sure that it fills its internal volume.

If the crack is quite wide, more than 1 mm, seal it on both sides from the bottom and almost to the very top with tape, which will be removed after the silicone dries.

Different types of silicone dry differently, so allow the repaired area to dry thoroughly. This usually takes from 12 to 24 hours.

Take the time to remove excess glue from the surface, this way the result of your work will look much more aesthetically pleasing.

Gently apply a thin layer of clear nail polish to the surface of the glass where the crack occurs. Once the varnish has dried, the repair can be considered complete.

Repaired glass can be safely washed; it is not afraid of water.

Homemade glue

You can make the glue yourself. In a glass jar, mix acetone and turpentine in equal proportions.

Constantly stirring the mixture, add crushed polystyrene foam to it little by little. The smaller the foam crumbs, the faster they will dissolve in acetone and turpentine.

Having brought the viscosity of the transparent homemade glue to the viscosity of honey, put it in a syringe and use it to seal the crack in the same way as with silicone glue.

Elimination methods

Before you begin to repair a crack in a double-glazed window, you need to choose the appropriate method. The choice largely depends on the location of the crack and the size of the crack.

If the glass is damaged in the corner, you can use glue. Of course, this method will ruin the appearance of the structure.

If a crack has formed at the edge or in the middle, then replacement is indispensable. In the future, such a crack can spread over the entire surface. The work can be done in 2 ways.

  1. Glass replacement. To do this, you need to remove the glass unit and separate the glass. Choose a suitable canvas taking into account the thickness. Clean the surface. Connect the elements using sealant. After hardening, put the glass unit in place.
  2. Replace the glass unit. Remove the old unit and install a new one in its place. However, they must be identical in size. This method is less labor-intensive and ensures the preservation of the insulating properties of the structure.

If it is not possible to unpack the window on site, it is recommended to remove the sash and carry out work on a prepared surface.

What should the glass unit itself be like?

Energy efficiency is not the only requirement for double-glazed windows. By default, they should have a stable design and, as far as possible, a high degree of resistance to external influences. Two- and three-chamber modifications, as well as products made from triplex or tempered glass, have these qualities to a greater extent. The rigidity of the spacer frames chosen for production also plays an important role. You can learn more about these important elements of double-glazed windows in the thematic review on OknaTrade.

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.

Precautionary measures

I am a supporter of preventative measures, and instead of wondering why the glass in a plastic window burst from the inside, I prefer to prevent trouble. The following simple rules will help you save money, time and effort:

  • Order the profile from a reliable manufacturer. The miser, as we know, pays twice.
  • Reschedule installation if temperature drops below +5°C.
  • Train yourself to use windows carefully. Open them smoothly, without sudden movements, and periodically lubricate the mechanism.
  • Avoid excessive or uneven heating of the structure. For example, if you plan to work with a hair dryer, make sure that hot air does not hit the glass surface.


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