Concrete contact: what is it and what is it used for?
In the process of self-repair in the apartment there may be an unforeseen problem of poor adhesion of finishing materials with the surface to which they are attached. In order not to face these troubles, it is recommended to pretreat the base coating with a concrete contact. To properly use the composition, it is enough to understand what it is, and most importantly how and why it is used.
Concrete is a special deep-penetrating primer mix based on fine quartz filler in the form of sand, with a particle size of 300-600 microns. With the help of the inclusion of this component in the solution creates a strong rough surface, on which you can perform finishing work with absolutely any material.Concrete contact firmly seizes with the base due to the presence in the composition of special polymer bonding agents.
The scope of the material is very wide. For interior work they are treated with absolutely all surfaces: the ceiling, walls and floor.
At the same time, there are only two requirements for the material being processed:
- clean base without dust and oil stains;
- The temperature of the base is above the zero mark of the thermometer.
The basis may be different. Concrete contact suitable for work on concrete, wood, metal, glass, tile, painted and many other surfaces. For almost every type of coating, manufacturing companies offer their own version of products with minor differences in the composition of the mixture. But such a separation is rather conditional and in most cases the solution can be used for work both on glass and on concrete with the same kind of mixture.
If priming with concrete-contact is more recommended for interior work, then such treatment is a prerequisite for exterior work. Without its use, it will be impossible to achieve the desired adhesion between contacting building materials. At times of severe weather conditions, lining materials can quickly peel off from the base.This not only leads to a deterioration in the appearance of the building, but also to separation from the surface: if the decoration was made with tiles or stones, there may be cases of injury to passersby.
Why do you need?
The main purpose is to provide a strong bond between the two materials and strengthen the base. Improving adhesion is necessary not only on the ceiling and walls, but also when constructing a floor screed. Concrete contact is applied both under a concrete and cement-sand screed, and under a bulk floor. As a result, the finished surface is not a separate layer, but a solid and solid construction.
On concrete wall plates, which are distinguished by a special smoothness of the surface and poor absorption of moisture, the use of such a solution is necessary. Without it, work on plastering or painting the wall will not work. Finishing materials will not stick or quickly crack and crumble from such a surface, and the wallpaper simply will not hold.
Betonokontakt is a convenient modern replacement for bandaging of walls, which was used in the Soviet and post-Soviet period. For the device of this design, the entire surface of the walls was covered with a mesh of fabric.For glueing, ordinary PVA glue was used. This method was not only difficult, but did not always lead to the desired result.
With the help of the use of concrete contact, it is also possible to save yourself from time-consuming and expensive work on cleaning the surface from the old coating. This mixture can be applied to the oil paint and tile. At the same time, the quality of the final result will be no worse than when applied to the surface cleaned from them. It remains only to strictly follow the manufacturer's instructions, comply with the technology of use and perform all the work within the designated time frame.
In addition to good adhesion with the surface, improving adhesion and versatility, concrete contact has another important feature. After the composition dries, a waterproofing layer forms on the surface, which will not be superfluous for both interior and exterior works. But this quality is especially important for the preservation of plastered surfaces for the winter period. Under a layer of concrete-contact coating plaster will remain as smooth and dry as it was before the frost.
Types and characteristics
The main difference between the types of concrete contact is the particle size of quartz sand, which determines the choice of surface for processing this mixture. In addition, there are primers that are intended only for indoor use, and a combined primer for exterior and interior work. On the packaging of the primer composition is always indicated instructions describing suitable materials for processing. It is worth trying to take into account the recommendations of the manufacturer, this will reduce the consumption of primer and get the desired result.
The composition of the concrete-contact must contain the following components:
- Cement or portland cement;
- Fine quartz filler;
- Polymer, most often acrylic, component;
- Special technological additives.
The technical characteristics of the composition do not depend on the manufacturer, the type of mixture and are always the same:
- Environmental friendliness. The composition does not have an unpleasant smell and harmful fumes. To work with it do not need personal protective equipment for hands and respiratory tract.
- Resistance to alkalis and aggressive media.
- The waterproofing properties.
- Transmits gases, which creates proper air circulation in the room and prevents the formation of mold.
- Resistant to parasites, mold and fungi.
- Drying speed at room temperature and moderate humidity is only 2-3 hours.
- The term of operation declared by manufacturers is 80 years. After this period of time, the concrete contact layer begins to break down.
- The air temperature for work is 5-35 ° С, the recommended humidity is 60-80%.
To make the layer thickness and coating uniformity easy to control, manufacturers add a white or pink dye to the mixture, which can be clearly seen on the treated surface. Without a dye, concrete-contact is a clear liquid.
Apply the solution on any surface can be either manually or mechanically using a compressor or spray gun. There are options for the use of mechanical devices, it is necessarily indicated in the instructions. In addition, in specialized stores there is a choice of a mixture in aerosol cans.
Any type of concrete contact must comply with GOST 28196: according to its characteristics, it refers to water-dispersionacrylic copolymer formulations. If the number of the GOST indicated on the packaging is different, it is better to refuse such a purchase.
The mixture consumption per 1 m² depends not only on the size of the sand particles, but also on the porosity of the treated surface:
- for a smooth and slightly porous surface, such as a painted wall, metal and glass bases, ceramic tile, the mixture consumption will be about 150 g / m².
- for medium porous surfaces of concrete slabs or finishing bricks, consumption will vary between 300-350 g / m².
- for highly porous surfaces, such as concrete or building bricks, the consumption may be 500 g / m² or more; To reduce the consumption of concrete contact surface is coated with a deep penetration primer.
Subtleties of use
Concrete is sold in finished form in containers of 3, 5, 20 and 50 liters. In order to get to work, you just need to open the lid and mix the composition so that the quartz filler is evenly distributed throughout the mixture. Stirring also needs to be repeated periodically and in the process.
Before proceeding with the application of the mixture, the surface to be treated is carefully prepared:
- a coating that doesn’t hold well on the substrate should be repulsed or scraped;
- remove grease stains, glue and bitumen drips;
- clean the surface of dust and wait for it to dry completely.
It should be noted that it is necessary to process the base with concrete contact immediately after it has dried. If a new layer of dust settles, cleaning from it will have to be repeated anew. Concrete contact does not adhere only to dusty and greasy surfaces.
Tool for applying the mixture you need quite a bit:
- wide brush, roller or spray;
- stick for mixing;
- container with concrete contact.
Apply concrete-contact can be roller, but it is better to replace it with a wide brush. So you can achieve a more even coating and better penetration of the composition into all the cracks and pores in the base. The mixture can be diluted with water, but only in cases where mechanical methods are allowed for application: this is indicated in the manufacturer's instructions.
On the painted wall or drywall primer on the contrary is better to produce a roller. With other methods, you can get too thin and weak layer.Brush and soiled surfaces should be thoroughly rinsed immediately after the completion of all actions. Uncured concrete contact is very easy to wash, and the cured composition cannot be removed.
After 3-4 hours after applying the soil will not be superfluous to check the quality of the resulting coating. From the dried layer, it is easy to determine if there are gaps or where the primer has been completely absorbed. If such defects are found, the surface must be covered again with the same composition. You also need to check the strength of the layer that you need to scrape with a knife or spatula. Qualitatively applied material does not fall off and is not deformed.
It is recommended to begin to apply gypsum plaster to the surface or to make pasting tiles no later than 12 hours after the surface has dried. Dust quickly settles on the finished rough layer and affects its penetrating properties. If after drying two or more days have passed, the surface must be further treated with a deep penetration primer.
In the conditions of the modern market, many manufacturers offer their version of concrete contact.There are both very cheap and very expensive offers. The final decision on which composition to use always remains with the consumer. But still, it is better to understand in advance the main suppliers of such goods.
AT concrete contact Axton In addition to the standard set, marble crumb is included. Used for application indoors and outdoors. Among consumers, the composition is in good standing. The only drawback is complaints about the high consumption of the mixture. The average price is 300 rubles for 6 kg.
Concrete contact from the company "Optimist" it is intended for works on an old tile, on strong layers of alkyd or oil paint. It is applied both to external, and to internal works. Mixture consumption 200-300 ml / m². The average price is 500 rubles for 6 kg.
Concrete production the company "Bolars" also suitable for work both inside and outside the building. Suitable for both concrete and smooth tiled surfaces. Available in fractions of 0.3-0.6 mm and 0.6 mm. Price per pack 5 kg in the range of 300-350 rubles.
Concrete contact "Bitumast" not much different from their fellows. It is made by the Himtorgproekt company in the city of St. Petersburg.Suitable for work on the street and in the house. The average price of 700 rubles for 7 kg.
Concrete contact from Kreps Company It has a 0.4 mm quartz sand fraction. Mixture consumption from 170 g / m². Suitable for both indoor and outdoor use. The average price is 400 rubles for 4 kg.
Bettocont from of the “Osnovit” company also suitable for any work, but differs in the increased consumption of the mixture. Manufacturing company denotes consumption of 450-500 g / m². The cost of 6 kg of the composition will not exceed 450 rubles.
The most important thing when buying a mixture is to shop only in specialized stores and choose products from well-known manufacturing companies. For greater confidence, it is recommended to read the reviews on the Internet.
As one would expect, the feedback on concrete bricks in most cases is positive. Disputes about which manufacturer of the mixture is still not found. But occasionally there are negative responses, but rather they are about sellers, not about manufacturers.
At one of the forums, the man told a terrible story that after applying a concrete-contact to the ceiling and the subsequent whitewashing, the result was not pleased. First, under a layer of white, you could see the pinkish reflections. A week later, the whitewash began to break off with the primer.
Professional builders in this case explain that either the composition was expired or after repeated freezing, or a fake was acquired.
Such cases, unfortunately, occur. Therefore, if the acquisition of concrete contact occurs not in a specialty store, but in the market, then it is better to open the container and check the homogeneity of the mixture. If the solution is heterogeneous, the purchase should be abandoned.
Concrete cannot be applied before cement mix plaster. The tensile strength of the film after such a primer is 0.1 MPa less than that required for cement-based solutions. Therefore, plastering cement compositions should be made only on concrete
When buying a primer you need to pay attention to the date of production and storage conditions. It is recommended to use only the formulations, less than a year has passed since the day of production. If concrete contact was stored incorrectly and was subject to freezing, it makes no sense to use it. After defrosting, such a mixture loses its adhesive properties.
To reduce the consumption of concrete-contact,the surface is pre-coated with a deep penetration primer. If the base is too dry and porous, after drying the first layer, you need to apply a primer again. Processing by concrete contact is possible only after complete drying of the soil.
What is concrete contact, see below.