Recommendations for choosing a sealant for working with plastic windows indoors and outdoors

Why do we need sealants for PVC windows?

What exactly is sealant for plastic windows used for?
Where to use it? Which one should you choose? What's the difference between them? To answer these questions, we first consider how windows are installed, and where “critical” points arise during installation.

Most often, when installing a frame, it is installed on anchors, and the space between the frame and the opening is foamed. Expanding after application, the foam fills the entire space and provides good thermal protection.

However, this material quickly deteriorates under the influence of sunlight and ceases to perform its functions - heat and wind protection, protection against freezing and water leaks. The porous structure of the foam, moreover, contributes to the accumulation of excess moisture, and this, in turn, can lead to the appearance of mold.

Hence the need to protect the foam from exposure to UV rays and moisture. This is done in various ways and materials. One of the most effective among them is protection with special sealants.

When installing window sills and slopes, cracks inevitably appear at the joints. They not only reduce the aesthetic appearance of the structure, but also contribute to the accumulation of moisture and dirt. These areas are also subject to sealing.

The flashing reliably protects against rain and water leakage into the room during rain and snow only if it fits tightly to the surface of the frame. Its complete tightness can be ensured only with the use of special materials.

In addition, sealants help improve the noise protection properties of plastic windows. For example, the sound of raindrops is effectively dampened with the help of sealants applied between the opening and the ebb.

Which putty to buy

Stores offer us a wide range of sealing pastes. All of them are divided into neutral and acetate. Acetate mixtures are used to increase the tightness of a smooth surface (glass). Neutral sealing compounds are used to seal seams between glass and frame.

The most popular compositions are:

• acrylic sealant is a new replacement for the old, conventional putty for wooden windows. It interacts well with other building materials, hardens quickly, plasters well, and paint adheres firmly to it. The composition perfectly retains heat and prevents air from entering through window joints. It is harmless, does not require special protection when working with it, and does not ignite easily. However, it has some disadvantages - it is not resistant to water and over time it loses its whiteness and turns yellow;
• butyl sealant - used for PVC windows. It is used for glass connections (2-3) in double-glazed windows. Does not allow water vapor to penetrate between the glasses;
• rubber sealant – has the highest strength indicators. However, it is also the most expensive;
• polyurethane - used to increase the strength of PVC structures. It lends itself well to painting, is resistant to temperature changes, and does not respond well to the aggressive effects of various chemical compounds. However, it itself is unsafe for health, since it contains caustic chemicals;
• Silicone sealant is an easy-to-use material that is used for any work with glass and frames. Due to its consistency, the paste easily flows into the very depths of cracks and joints, hardens and creates reliable protection against air penetration. It is used as a fastening agent between glass in double-glazed windows, and also as an external sealant. Used in working with plastic and wooden windows. Has high insulating properties. However, silicone putty for windows also has disadvantages: when working with it, a sharp vinegar smell is felt. Over time, this sealant begins to fall off, but it lags behind the window in a whole strip, just as it was applied, so an impressive gap immediately appears. It is impossible to paint such sealant.

Something to remember! There is a wide range of window sealants available. Each substance has its own pros and cons, so before purchasing you should be sure to familiarize yourself with the composition of each sealant.

Choosing the right sealant

To seal windows, compositions of all of the above compounds are used in practice.

To understand which sealant is best for plastic windows specifically in your case, you need to clearly define the range of problems that need to be solved. In addition, it is necessary to take into account the weather conditions under which installation work will be carried out and in what climate zone the window will be used.

Based on the performance properties of sealants outlined above, the conditions of sealing work and operating conditions, some conclusions can be drawn that will help you make the right choice of sealant.

• For sealing and sealing external seams, it is optimal to use acrylic, acrylate (STIZ “A”), thiokol and polyurethane sealants
• In cold and rainy times, polyurethane and thiokol compounds are suitable for sealing
• For internal sealing, the best choice would be white silicone or polyurethane sealants, STIZ “B” acrylate composition, liquid plastic
• When sealing the window blocks themselves and sealing cracks in double-glazed windows, butyl materials are the best choice

How to apply and coat with your own hands?

When applying sealant on their own, beginners often make a number of mistakes. To prevent this from happening, experts often share useful tips and tricks with them. To correctly apply the sealing composition, you must follow a certain technological map :

• First of all, beginners should use exclusively sealant from cylinders with a volume of 280 to 310 ml.
• The cylinder is inserted into the mounting gun.
• The plastic tip of the cylinder diffuser is cut off using scissors, after which an extension with a dispenser is screwed onto the threaded connection.
• Before applying the sealant, the surface to be treated is cleaned of dust, dirt and grease deposits, and then dried until completely dehydrated.
• The sealant is applied by pressing the handle of the mounting gun.
• When extruding, the master moves the balloon along the seam, which ensures continuous and uniform application of the substance.
• After application, the substance is carefully smoothed over the surface of the seam or crack with a special spatula or fingertip.
• It is necessary to wait from 30 minutes to 2 hours, depending on the composition of the material.

After applying and polymerizing the sealant, it is necessary to inspect the uniformity of the material and the absence of mechanical defects on its surface.

How to apply sealant correctly is shown in the video:

Difficulties and errors when sealing

When applying sealant, a home craftsman may encounter a number of problems and make mistakes that will affect the result:

• Choosing a low-quality sealant, or a substance whose functional purpose does not include operation under the temperature and humidity conditions characteristic of the room or environment.
• Errors during application when the sealant falls into the installation gap with interruptions and an uneven line.
• The consistency of the substance is too thick, which requires the use of another tool, or cutting a hole with a large diameter in the diffuser.
• Poor surface preparation - the sealant loses its adhesive properties upon contact with a dusty, greasy or wet surface.
• Installation of sealant at sub-zero temperatures, which is unacceptable according to the manufacturer’s recommendations.

Before you start using the material, you must read the instructions for use, which are printed on the body of the cylinder.

Video description

In this video, the master shares his personal experience of working with cork sealant:

Silicone

The basic component of this group of sealants is organosilicon silicone polymer. The combination of quality, ease of use and cost justifies the leading position of the material in relation to user demand.

Specialized composition for finishing windows Source uralmegaprom.ru

The advantages of the composition include the following characteristics:

1. Waterproof . On the outside, the main “pests” for sealant in window joints are natural precipitation, which the coating copes well with. Inside, the composition retains its quality after prolonged contact with water and household chemicals.
2. UV resistance . Sunlight often causes cracks and drying out of the finish, which is not the case with silicone filler over a long period of time.
3. Biological inertia . Synthetic material does not support or provoke the formation of fungus or mold.
4. Plasticity . This property is retained by the mass even after hardening. At the same time, under the influence of temperature changes, the shape from repeated compression and expansion remains unchanged.
5. Adhesion . The composition is used to fill joints between plastic and concrete, ceramics, wood or a homogeneous base.
6. Range . The material goes on sale in various versions regarding color and composition.

Characteristic features of the varieties of silicone sealant are:

• antiseptic or sanitary ones cope better with high levels of humidity, resist the appearance of fungus, mold, bacteria, but are unsafe for humans;

Example of sanitary sealant Source megastroi-market.ru

• neutral ones are inert to chemical reagents, have excellent contact with various types of bases, but contain methyl alcohol;

Sample of neutral composition Source bsteel.by