Features of concrete contact and calculation of its consumption per 1 m2

The parameter “ Concrete contact consumption ” significantly depends on the porosity of the surface on which it is applied.

Basically, Betonokontakt is used for priming concrete surfaces (hence its name), but can also be applied to other surfaces: brick, drywall, concrete and ceramic tiles, old paint, etc. But even for one type of surface (for example, concrete) the consumption concrete contact can vary significantly.

Price of concrete contact, properties and characteristics, application instructions: Concrete contact

Purpose of the primer composition

When combining two materials with different characteristics, problems arise in most cases. The use of primers can correct the situation even with the most problematic surfaces. Such compositions also include concrete contact. After its application, thanks to the special composition, the surface becomes rough, which significantly increases adhesion.

Manufacturers of concrete contacts use environmentally friendly materials. The mixtures do not have a pronounced odor and do not change the appearance of the walls.

The composition is applied after thorough stirring. The finished primer is used for the following purposes:

• Avoiding damage to the paint structure after painting the walls.
• Increased adhesion during plastering.
• Ensuring reliable adhesion of tiles during gluing to a concrete surface.
• Elimination of defects (small cracks, seams, etc.).
• Preventing destruction and shedding of finishing materials.

For example, primer from the manufacturer Knauf contains acrylic, which provides moisture resistance and high adhesion.

Composition and characteristics

Concrete contact primer has the following composition of components:

• Portland cement or cement;
• Quartz sand;
• Acrylic polymer;
• Technological additives that ensure its vapor permeability, hygroscopicity, protection from chemical and biological influences.

The composition of the concrete contact necessarily includes quartz sand with different grain sizes. For example, Ceresit soil contains a fine-grained mineral filler; it is used for treating smooth substrates.

The acrylic contained in the base of the concrete contact is a polymer adhesive that provides adhesion to the base. In addition, dyes are added to the concrete contact. They help determine the thickness of the covering layer and visually detect unpainted areas.

Concrete contact has the following technical characteristics:

• Environmentally friendly product. Does not emit an unpleasant odor or harmful fumes. Its use does not require additional body and respiratory protection;
• Resistant to aggressive environments;
• Forms a waterproofing layer;
• Allows air to pass through, which eliminates the formation of mold and mildew;
• Drying time at 20°C and 70% humidity is 3 hours;
• Manufacturers have established a service life of 80 years;
• Recommended temperature for indoor work is from +5 to +30°C and humidity 55-80%.

How long the concrete contact will dry depends on the temperature and humidity in the room. Under unsuitable conditions, additional heating can be used to speed up the process.

Consumption depending on surface

Concrete contact primer significantly simplifies working with different materials and allows you to reduce the consumption of finishing materials. Most often it is used for concrete surfaces, but good results have also been seen when applied to brick and drywall.

The consumption of concrete contact per m2 is calculated depending on the type of surface to which it is applied. Its porosity is of decisive importance - this will determine how quickly the composition will be absorbed. The higher the degree of absorption, the greater the consumption.

Surfaces have different absorbencies:

• Low porosity - metal ceramics, painted walls, rubbed concrete. In the examples given, soil consumption per m2 is minimal - 0.15−0.25 kg. The composition is applied in an even layer; no additional leveling is required.
• Average porosity. This is concrete of the highest grade, monoliths, cement screeds, bricks for cladding, concrete tiles. The consumption rate of concrete contact per 1 m2 is 0.2−0.35 kg.
• High porosity. This includes wall bricks, sand concrete and similar materials. For them, per m2 you will need 0.3−0.5 kg. To save primer, experts recommend pre-treating the surface with impregnations that slightly reduce porosity.

The user cannot always determine the degree of surface porosity. To establish the consumption of concrete contact in such cases, a test treatment is carried out. In the experimental area, the boundaries of 1 m² are determined using tape. Take a fixed amount of soil, for example, 1 kg. Begin to apply a layer to the selected area until a uniform coating is obtained. The remainder is weighed, then the consumption of concrete contact per 1 m² of wall is calculated.

Is it possible to reduce the consumption of concrete contact?

Definitely not. Firstly, it is quite cheap, so there is no need to skimp. And secondly, the consequences can be sad: the strength of the primer will decrease, it will crack or completely peel off.

As the primer consumption decreases, the surface's ability to adhere will correspondingly decrease, which can lead to peeling of the coating from the base. Another important consequence of such savings may be a reduction in the waterproofing of a given surface.

An important feature that should not be forgotten when finishing walls and ceilings is the drying properties of many coatings. Why is this happening? For a large number of finishing materials, before application of which it is recommended to prime with concrete contact, a characteristic feature is the presence of Portland cement or gypsum in their composition.

When using them, immediately before application they are diluted with water. And during the drying of solutions such as plaster, sand concrete and others, with the rapid evaporation of water, drying out can occur.

Drying occurs when the amount of water in the solution sharply decreases. This leads to the fact that the reaction of the cement is suspended, which causes a decrease in the strength gain of the material. With a further decrease in the amount of water in the solution, while the strength remains the same, stress may arise, which will lead to cracks in the coating. In the worst case, the base may rupture.

This once again confirms that there is no need to engage in amateur activities, but rather follow the instructions. If you try to reduce the consumption of concrete contact primer for the surface, the result can be cracks throughout the entire wall and pieces of fallen plaster on the floor. If you do not take all this into account, you may end up with problems: you will have to redo everything from scratch and, accordingly, spend extra money and effort.

The use of concrete contact, as it turns out, is a rather scrupulous task, which has a lot of nuances, but you cannot do without it when finishing concrete walls or ceilings. Therefore, do not forget about the basic rules for processing various surfaces using concrete contact primer. And then, your repair will become an easy and enjoyable task.

Famous brands

The primer mixture from different manufacturers has its own characteristics. This also applies to consumption indicators:

1. Knauf. The substance is classified as an economical option. The cost of 5 kg of container is 500 rubles. One of the components is quartz sand, which provides surface roughness. Use the mixture for concrete surfaces. Consumption of Knauf concrete contact per 1 m² as a primer is 0.2−0.35 kg.
2. Ceresit - ct19. The substance is based on environmental components, which allows it to be used for interior work. Characterized by increased density. The sand included in the composition increases the degree of adhesion. The consumption rate per 1 m2 is 0.2−0.5 kg. The cost of 15 kg is 1 thousand rubles.
3. Prospectors. Universal primer mixture. Used for various surfaces, including concrete, gas silicate, and plasterboard. Using this type of soil, you do not need to purchase additional materials. Costs depend on the type of surface. On average, the figures are 0.2−0.3 kg per square meter. m. Price for 20 kg - 1200 rubles.
4. Bolars. It is developed on an acrylic basis, which allows the primer mixture to be used for both external and internal work. Thanks to its characteristics, it can be used even on uncleaned surfaces. Of all the options presented, Bolars is the cheapest primer. Concrete contact consumption per 1 m² of wall is 0.3 kg.

What not to do

If you wish, you can find reviews or videos that say that the plaster/tiles have fallen off from Betonkontakt. To prevent this from happening, apply primer only to recommended substrates. In addition, you should not do the following things:

• Dilute the plaster or putty composition with more water than indicated on the package. Yes, it’s easier to work with, but as a result, the putty may collapse.
• Do not apply the composition to frozen ground.
• Do not apply Betonokontakt to an unprepared surface (remove all detachable parts, degrease, remove dust).
• Do not apply BC on a damp base. Dry only.

  
  Eskaro produces a primer for non-absorbent rigid substrates with increased water resistance

• When working, do not forget to periodically mix the contents, as sand particles (granules from some manufacturers) fall down.
• You cannot continue work until the primer layer has completely dried (indicated in the instructions).
• Do not work at temperatures below +5°C. This does not mean that it cannot be used for outdoor work. It is possible, but it must be applied at positive temperatures.
• Do not allow dust to enter. It sticks very well to the adhesive surface, but then falls off along with the plaster. If the surface is dusty, another treatment is necessary.
• Do not use a composition that has expired or has been frozen. The exception is frost-resistant compounds (there are such). Before use, they must be defrosted, wait until the temperature rises above +5°C, then you can work. By the way, the inscription “frost-resistant” does not mean that it can be applied at sub-zero temperatures. It can only withstand several defrost/freeze cycles before application without loss of properties.

  
  The German company Bergauf also has an acrylic primer Beton Kontakt

• Do not add water, even if it seems that the composition is too thick. Unless the manufacturer described this possibility in the instructions. But so far we haven’t seen any of them.

Features of application

The effectiveness of concrete contact depends on a number of conditions . First of all, it depends on the correct execution of several steps:

1. Preparing the surface, removing dust and dirt, removing old finishes. If the defects are minor, then plastering is not necessary.
2. Treating walls with impregnation or a simple primer mixture before using concrete contact.
3. Waiting for complete drying.
4. Prime the surface with a thin layer of concrete contact using a roller.
5. Allow the mixture to dry within 2 hours.
6. Applying the second layer (their number depends on the condition of the surface, and each subsequent layer must dry well).

The surface is ready for puttying or finishing work.

Compared to other primer mixtures, the consumption of concrete contact per 1 m² is about 0.25−0.3 kg. Calculating the required amount is not difficult at all: the consumption rate is multiplied by the quadrature of the surface being treated.

Applying primer

There is no need to use special tools to apply concrete contact. A brush, roller or spatula will do.

• The surface to be treated is thoroughly cleaned of dust, dirt, etc. Concrete contact should not be applied to a wet surface, it will not stick!
• The primer is applied in a thin, even layer.
• After application, the primer must be left to dry. This usually takes several hours. At average room temperature and normal humidity, drying time takes 3-4 hours.

After just an hour, it may seem that the primer has dried, but there is no need to rush. It is best to treat the surface in the evening, and calmly proceed to the next stage of repair work in the morning.

The more time passes after applying the primer, the more dust will form, which will significantly reduce the bonding properties of the concrete contact.

If, for some reason, more than 2 days have passed, then the surface must be additionally opened with an ordinary deep penetration primer.

Online calculator for calculations

Online calculators are available on specialized websites, and their use is completely free. Qualified builders took part in the development, so the likelihood of error is reduced to zero. By going to the desired website and opening the online calculator, you just need to enter the necessary parameters:

• type of primer mixture;
• type of surface material;
• planned number of applied layers.

Many consumers do not believe that priming with concrete contact is necessary, and in order to save money they refuse this procedure. But if quality and the elimination of further problems are a priority, then applying a primer is necessary. The savings are insignificant, and it is sometimes very difficult to eliminate unpleasant consequences.

How not to get into trouble when choosing a concrete contact

Concrete contact from "Holzer"

Today in construction stores it is possible to “run into” a fake. Therefore, it is worth sticking to the choice of popular brands in large well-known construction supermarkets, where there is a high probability of choosing the best concrete contact for yourself.

Necessarily! Before purchasing from the seller, check whether there is a quality passport and a certificate indicating GOST for concrete contact. When purchasing a low-quality product, there is a high risk of losses and extension of repair and construction time.

Certificate of conformity for concrete contact, which must also be up to date

If you find a pungent odor or an incomprehensible color in the purchased composition, you should not wonder what it is; as a rule, you have all the “witnesses” of the low quality of the product. The original soil mixture, whether it is “Knauf” or “Starateli” 6 kg, it always has a pinkish color without an unpleasant odor with a uniform structure. Always check expiration dates and storage conditions.

Concrete contact of normal consistency

If the soil mixture accidentally gets on the surface of the skin, it must be removed with running water before it dries. Otherwise, doing this later will be more difficult, painful and with possible damage to the skin epithelium.

Having understood why concrete contact is needed and its characteristic features, we can safely talk about its indispensability and the need for use when carrying out repairs. Depending on taste preferences, requests and “wallet”, everyone makes a choice in favor of concrete contact from the company they like. But not a single professional will advise you to save on priming surfaces - follow the recommendations of specialists.

Betonokontakt: reviews

As you would expect, reviews of concrete contact are in most cases positive. There have still been no disputes about which mixture manufacturer is better. But occasionally there are negative reviews, but they are more likely about sellers, not about manufacturers.

On one of the forums, a man told a terrible story that after applying concrete contact to the ceiling and then whitewashing it, the result was not satisfactory. At first, pinkish reflections could be seen under the layer of white. And after a week, the whitewash began to chip off along with the primer.

Professional builders in this case explain that either the composition was purchased with an expired expiration date or after repeated freezing, or a fake was purchased.

Such cases, unfortunately, do occur. Therefore, if the purchase of concrete contact occurs not in a specialized store, but in the market, then it is better to open the container and check the homogeneity of the mixture. If the solution is not homogeneous, the purchase should be abandoned.

What general properties does concrete contact have?

In a nutshell, the function of concrete contact is to create conditions for gluing foreign materials without the use of complex adhesives. The very composition of this type of soil allows it to “stick” to any surface. Unique adhesive ability is achieved by combining many elements.

Primer Lakra betonokontakt for external work

Concrete contact primer has quite a wide range of applications:

• It perfectly bonds finishing and building materials with smooth, glossy surface textures.
• Improving the quality of adhesion of plastered walls.
• Finishing surfaces without preliminary cleaning of previously applied materials. As an example: a high-rise building with a tiled facade is easier to treat with concrete contact than to clean everything down to bare walls.

Visualized technical characteristics of concrete contact primer

The concrete contact primer has characteristics of a higher class - they turn it into an indispensable independent material for finishing work:

1. Long service life. Some manufacturers provide a guarantee of up to 80 years for the preservation of the properties of their products. Who will check the truth of such “speeches of the Reds”, because, most likely, during the specified time, restoration work will be carried out in the premises more than once.
2. Drying speed. A correctly applied concrete contact layer needs no more than two to three hours for it to dry and work with it can continue.
3. Moisture resistance. When it dries, a film forms on the surface of the concrete contact. It is absolutely waterproof and serves as waterproofing, thereby protecting the main surface of the wall from adverse influences.
4. Low consumption. There are certain standards according to which a specific amount of substance is required per unit area. But, due to a number of circumstances, they cannot always be observed. Therefore, everything here is individual. Much depends on the surface being treated. Porous or rough texture will require a thicker layer of primer.

Traditionally, concrete contact primers are divided by type of surface and can be treated with a specific composition: for metal, wooden walls, and so on. However, in practice this is not always taken into account, since the classification is conditional.

Concrete contact primer, the composition of which is not always the same, must be purchased for specific work from a specific brand.

Basic data: primer consumption rate per 1 m2 area

Photo from website: Refite.ru

Typically, non-professional craftsmen refuse materials such as primer, wanting to save their own money, since repairs are already a costly and labor-intensive process. However, this can lead to rather disastrous results. Professionals strongly advise that you always treat walls and ceilings, as well as floors, with special primers that provide special benefits, for example, they can significantly reduce the consumption of glue, paint, putty and other substances that are applied to them. But how to correctly calculate the primer consumption per 1 m2 of surface so as not to make a mistake? This is exactly what we will talk about today.

You need to know that primer, the consumption of which per 1 m2 is quite small, has a cost much lower than putty, glue or paint that is used for the final finishing of surfaces. That is why it is worth priming walls, floors and ceilings with special care, as this will significantly reduce your home renovation costs.

In order to correctly calculate the primer consumption per m2, it is necessary to take into account a number of certain conditions and factors, which are worth discussing separately.

• The type of surface that needs to be treated plays a primary role. For example, plaster will require more substance than a concrete wall, and metal will require less than brickwork.
• The components and components of the primer you have chosen, as well as the proportions of its application, are in accordance with the manufacturer’s recommendations.
• The type and type of substance that will go over the pre-applied primer.
• Time of year, as well as climatic and weather conditions at the time of application of the soil.

The type of primer application will also play a role, since a roller, a brush and a spray gun are completely different things and the material consumption will be varied. Oddly enough, the consumption will be the least for an automatic spray gun, if it is configured and working well, and the most for a foam roller. But the main thing that needs to be considered is the type of primer mixture itself, which you will choose in the store. Let's figure out together how much soil is needed per square meter, after which calculating the total amount will not be difficult even for a schoolchild.

Deep penetration primer: consumption per 1m2

As you already know, primers are divided into two main types: superficial and deep penetration. The latter are preferable to use on loose and unreliable surfaces in order to strengthen them as much as possible. Such mixtures reliably seal the pores, making the surface much stronger, more reliable and durable. Therefore, the consumption of a deep penetration primer per 1 m2 will be much greater than that of a surface primer, because it penetrates and is absorbed deeply.

Photo from the site: pobedit-msk.ru

Such mixtures are most often used for pre-treatment of plaster, wood, chipboard and fiberboard, MDF and OSB, as well as foam concrete, cinder blocks, brickwork and similar surfaces. Depending on the composition, you will need from 80 to 150 grams per square meter. At the same time, the price of a deep penetration primer, with a consumption per m2 within such limits, will be quite affordable for everyone, so there is no need to skimp on matches.

Consumption of acrylic primer per 1m2 area

Despite the fact that these types of primers are based on acrylic resins, they are diluted with ordinary water and do not require any special solvents. This type of soil is produced ready for use in plastic buckets or in bags, in the form of a powder mixture that requires dilution. The consumption of acrylic primer depends primarily on the form of release.

Photo from website: Refite.ru

Most often, the acrylic primer mixture is white, like whitewash, so it is hardly suitable for application on dark surfaces. It is used as a base for paint, wallpaper, laying tiles, porcelain stoneware and other finishing materials, mainly on plastered walls. The optimal consumption per 1 m2 of acrylic primer will be about 120-180 grams, which will also depend on the thickness of the substance itself and the thickness of the applied layer. It is better to use this soil indoors, as it is resistant to moisture, which must be taken into account when purchasing.

Mixture consumption

The consumption of high-quality Knauf concrete contact per 1 m2 is a very important and pressing issue. Professionals, and even those who have at least once worked with similar compositions, will definitely say that this indicator is determined by the type of surface, its initial condition and the level of moisture absorption.

When analyzing construction practice (on average), the following figures were obtained:

• Consumption for brick, sand concrete and porous concrete is 500 g per 1 sq. m. Costs can be reduced if you use impregnations that penetrate deeply into the material.
• First-class monolithic concrete is primed in an amount of 350 g per 1 sq. m, provided that the pore size is average.
• When there are few pores or the surface is already covered with paint, you can use only 150-250 g of primer to cover 1 sq. m.

In order for adhesion to be fully ensured, the condition of the original wall surface must also be taken into account. If gaps are discovered during the work or the base very greedily absorbs the finishing material, it can be coated again, but only after the initially applied mixture has completely dried.

Determining exactly how much primer will have to be spent is not so difficult. Its small volume is weighed in a pallet and distributed over an area of ​​1 sq. m on walls and ceilings.

Home craftsmen and even experienced professionals are naturally interested in whether it is possible to deviate from the recommended figures and use less concrete contact. As practice shows, this is a big mistake: the cost of purchasing a primer is relatively small, and its lack impairs the quality of preparation. The layer created will be fragile - it can crack and delaminate. The worst thing is that then it will not be possible to achieve a normal level of adhesion with the main finish.

Then even the best primer will not be able to prevent the plaster from falling off or the paint from cracking. We will have to redo all the work and again invest in the purchase of finishing and preparatory materials.

First, concrete contact can be mixed with deeply penetrating mixtures, and then it can only be used in its pure form. When using a spray gun, the total primer consumption increases slightly. The manufacturer recommends waiting 12 hours for drying (this time is the maximum). If the temperature and humidity conditions are favorable, you can wait only 3-4 hours. When using hand tools, concrete contact should not be diluted with water, but if it is sprayed mechanically, the solution is made in a ratio of 2: 1.

conclusions

1. When purchasing, check the authenticity of Betonokontakt. There is a risk of buying “water”. Ask the seller for documents. The inscriptions on the container must be visible and clear.
2. Prepare the surface correctly - this will reduce consumption.
3. Do not dilute Betonokontakt with water.
4. Apply primer when all dusty work in the room is completed.
5. If the soil is completely absorbed, go over again. Don't leave untreated spots.
6. Always smile!

Reviews are different. But problems usually arise due to inattention or failure to follow the manufacturer's recommendations. Be careful when purchasing and read the instructions before use - then the consumption will be as expected and the quality will be high.

Area of ​​use

Primers are used to improve adhesion properties, as well as to improve the strength of the base, which is processed using the material. For each type of soil there is an instruction that specifies the composition, material consumption per m2, as well as for what work, external or internal, it can be used.

Concrete contact primer is used for the following purposes:

1. The properties of the primer make it possible to use it before screeding or self-leveling floors, which is why it is often called a primer for concrete floors
2. Primer for concrete is used to treat surfaces before finishing with plaster or putty.
3. To reduce the porosity of plasterboard slabs before gluing trellises or laying tiles
4. The composition allows you to use betokontakt before whitewashing the ceiling

The technical characteristics of the concrete primer can be used for work with non-absorbent surfaces. These can be bases coated with varnish or paint, or tiled. The most important thing is that for this there is no need to dismantle the old coating, because a penetrating primer is applied over these materials, forming a rough surface that adheres well to the new finishing elements. It is worth clarifying that the concrete contact primer has an environmentally friendly composition, and this allows it to be used in any room. Although GOST specifies what composition the primer should have, many manufacturers may deviate slightly from the list of elements, although this does not in any way affect the quality of the material.

Let's look at the technical characteristics and properties of the primer:

Epoxy and polyurethane mixture

Among concrete primers, several materials can be distinguished. Epoxy primer is characterized by improving the strength of the surface after its application. In addition, the composition can be one-component or two-component. Let's look at the benefits of these solutions:

Polyurethane primer is very similar to epoxy mixtures and has the same excellent properties. Typically, polyurethane primer is used for work in industrial areas. It is chemical resistant and perfect for garage use. Despite its price, this primer is very economical, because to acquire the necessary properties, applying one layer is enough.

Classification of surfaces and impact on Concrete Contact consumption

The main influence on primer consumption is not the nature of the material, but its ability to absorb water. According to this criterion, all types of foundation can be divided into several groups:

The minimum primer consumption is indicated. It is not difficult to assess the adequacy of the amount of Concrete Contact. To do this, you need to make sure there are no gaps, uniform application, and the quality of sand adhesion to the base. Primer soaked into the wall and crumbling sand indicate the need to apply an additional layer of Concrete Contact.

Determine with high accuracy the consumption of Concrete Contact per 1 sq.m. possible with a test application. To do this, mark out a square with a side of 1 meter on the working base using masking tape. The primer is mixed, a small volume is taken - from 0.5 to 1 kg. Concrete contact is weighed on scales and applied in accordance with the recommendations. The sand should not crumble, the primer should not be completely absorbed. After making sure that there are no gaps, the remaining Concrete Contact is weighed. The difference between the obtained values ​​is the exact consumption when working with a given base.

How to reduce Betonkontakt consumption

The desire to increase the profitability of construction work leads to attempts to reduce the consumption of materials used. The base primer is often not given much importance and people try to use Concrete Contact as little as possible. This cannot be done! The low price of the material will not allow significant expenditure of funds, and the consequences of poor-quality priming can be significantly higher than the savings achieved. Cracks may form in the finish coating, and peeling may occur on complex substrates.

Reducing the amount of primer leads to poor adhesion and drying out. Concrete contact is used before applying cement and gypsum plasters. These building mixtures are mixed with water. The Betonkontakt layer plays the role of waterproofing, preventing water from the plaster from penetrating into the base. As a result, reactions in the finishing coating proceed in a normal manner to gain strength. Preserving water allows you to avoid shrinkage due to loss of mass, and prevent stresses arising in the structure of the plaster. As a result, there are no cracks or peeling on the surface.

It is recommended to adhere to the Betonkontakt consumption specified by the manufacturer for this type of base. This will allow the work to be completed efficiently, without increasing the cost of rework.