Despite the fact that concrete is rightfully considered one of the most durable building materials, due to exposure to high humidity, high temperatures and other factors, it can be destroyed. To avoid this trouble, it is customary to use concrete sealants. What they are and features of application - in the article.
Why is sealant needed?
If the concrete is mixed incorrectly or when external adverse factors are applied, the material may begin to deteriorate. At the same time, microcracks form in it, which increase in size over time. Sealants for concrete are necessary to prevent cracking of the material and the loss of its qualities.
In this case, the product should easily tolerate temperature extremes, extreme heat or frost, and also be moisture resistant. To seal cracks in concrete, experts recommend using a concrete sealant for outdoor use, the main component of which will be polyurethane. Such varieties of material are also suitable for processing external seams.
Varieties
According to the method of exposure, the materials are divided into two main types:
- Surface, which cover the surface of concrete with a moisture-resistant film.
- Penetrating, which protect the material from cracking, penetrating the entire depth of the solution.
According to the variety of the main component, there are:
- silicone - contain silicone, the amount of which is 45% of the total mass, they are used to seal aquarium, window joints, in bathrooms;
- Acrylics are used mainly for internal work, as they lose their properties when exposed to low temperatures;
- bituminous are used for installation and repair of roofs, as they easily come in contact with roofing;
- polyurethane are the most versatile, as their properties allow you to use them both for indoor and outdoor use;
- rubber is used for processing roof seams and for facade work;
- polymer;
- silicate.
There are also specific concrete sealants with two components that must be thoroughly mixed before use.
Areas of use
The choice of sealant depends on the purpose of use. When choosing, you should pay attention to the information that is indicated on the package. There is information about moisture resistance, frost resistance, heat resistance and other parameters that must be considered when choosing a product. It is also not recommended to use joint sealants in concrete for internal work in filling cracks on the outside, as this will lead to rapid destruction of the material.
When filling seams or cracks that are below the water level, it is necessary to use sealants that are designed for some pressure, this will also be written on the packaging. To fill the voids in the roof or other movable structures, it is recommended to use sealants that have some mobility. In addition, for window panes and aquariums there are separate varieties of sealants that are designed exclusively for such purposes.
Application temperature
Sealants for joints in concrete for exterior or interior use have different frost resistance indicators. They must be taken into account when purchasing this or that material. Typically, the temperature stability of universal sealants is from -50 to +200 degrees.
Shade selection
Acrylic, silicone or polyurethane concrete sealants are available not only in the classic transparent or white version, but also in color. Certain types of materials have the ability to stain after solidification. This is relevant for cases where the shade of the sealant does not match the color of the base material.
Benefits
The positive aspects of the building material depend on the particular product selected, but most of them have similar advantages:
- preventing the penetration of dirt, dust, grease, chemicals and moisture, which significantly increases the service life of concrete and simplifies maintenance;
- increase the wear resistance of the concrete coating;
- long service life;
- Ease of use;
- prevention of defects, cracks.
Quality products have practically no drawbacks, except for the presence of harmful impurities in the composition of some mixtures. With the correct application and compliance with the solidification conditions, the internal or external concrete sealants have a sufficiently long service life.
Necessary tools
In order to process the joints with a waterproof sealant for concrete, it is necessary to stock up with tools, without which the use of mixtures is not possible.
- Pistol. There are a great many varieties. There are pistols with mechanical and automatic control, closed and open type. The most affordable open source tools with manual control are often used for home sealing concrete joints.
- A spatula is necessary to level the sealant. They can be metal, plastic and rubber, and also have a relief to form a beautiful seam.
When repairing sutures with tools, it is important to avoid contact with the skin of the hands, since most compounds contain substances that can cause skin surface irritation or even a chemical burn.
Removal Tools
In some cases, the joint sealant in concrete must be removed from the surface. This may be necessary in case of inaccurate application of the material. Two main methods are used for this:
- Mechanical, which involves the removal of excess sealant from the concrete surface with the use of rough exposure, namely by scraping the mixture with scrapers, spatulas and other tools. Large frozen pieces of material can be cut with the help of an office knife.
- Chemical, which consists in the use of compounds that soften the sealant and make it possible to remove it from the surface of concrete. Unfortunately, this method is applicable only for silicone materials, the rest require rough mechanical action.
Experienced experts agree that it is much easier to prevent the sealant from getting onto unwanted surfaces. To do this, use masking tape, which is attached along the entire length of the crack or joint on both sides. After applying the composition, it is removed, leaving behind an even strip of sealing compound.
Sealant Application
To start working with sealant, you must carefully study the instructions for use. If the product is one-component, then it must be used immediately, if it is two-component, then they must be thoroughly mixed. It is recommended to apply sealant to concrete using a manual or automatic spray gun, thus uniform distribution of the composition can be achieved.
To ensure good adhesion to the surface, thoroughly clean it from possible contaminants, dust, debris, paint or oils. Only after cleaning can sealant be applied.
It is not recommended to apply a sealing compound in the presence of weather precipitation, such as rain, snow, hail, since in this case it is impossible to ensure a good adhesion of the sealant to concrete. Because of this, after a while, chips, cracks can occur. To seal interpanel-type joints, it is allowed to apply concrete sealant directly to the insulation material.
The drying time of a particular type of sealant is indicated by the manufacturer on the packaging and varies from several hours to several weeks. All this time, it is strictly forbidden to allow the composition of atmospheric precipitation to hit the surface, as this will adversely affect the durability and strength of the sealant.
Sealing and Injection
To close small surface cracks it is often enough to apply a small layer of concrete sealant, but if the crack is deep, you can resort to the injection of concrete. This procedure is the introduction of a sealing compound deep into the defect using high pressure. Inside, it spreads evenly, filling with itself internal voids.
This method is quite expensive, because for the implementation of the injection you need equipment that will provide the necessary pressure, also increases the consumption of sealant. However, the results are impressive, since this method can eliminate even the deepest and largest defects.
Conclusion
Before you buy a sealant for concrete, you need to decide for what kind of work it will be required, since different types of materials are used for various purposes. Experienced builders are always advised to study the instructions from the manufacturer, which is indicated on the product packaging, so you can find out all the nuances of working with a particular composition. The procedure for sealing joints or cracks is not particularly difficult, but it requires minimal skills to work with concrete and sealants.