How to make concrete contact with your own hands

For many, the price of ready-made concrete contact seems high or such a product requires a minimum quantity and they do not want to buy a whole package. In such cases, you can use a homemade alternative composition. For it you need to take:

high-quality PVA glue;
cement.

In a container you should mix PVA with cement until a thick, homogeneous composition is obtained, and then treat the surface with it, wait until it dries completely and continue finishing work.

Concrete contact is necessary to increase the adhesion of materials used for finishing with various surfaces: walls, ceilings.

The product is a ready-made special mixture that is used to prime the required surfaces. Many people do not consider it necessary to use concrete contact during the repair process, which can subsequently lead to peeling of tiles, wallpaper, and plaster.

If the necessary material is not available, you should know what can replace the concrete contact, so that the repairs made do not disappoint in just a couple of months.

Connect the unconnected. Problem for concrete contact

The construction of any house always ends with surface finishing: plastering, painting, laying tiles or flooring.

Finishing may also be necessary in an old building if you want to make renovations.

Any finishing always involves the application of finishing materials. And it is at this stage that difficulties may arise, because not every surface provides acceptable adhesion to finishing materials: plaster, paint.

In old buildings, there may be surfaces that have already been painted or tiled previously, and if this finish holds up well and does not peel off, it is permissible to apply a layer of fresh finishing materials to it. But such surfaces are smooth and do not adhere well to plaster and new paint; finishing materials will slide off them.

In order to prevent possible problems, primers are used, which are applied to surfaces to give them the ability to firmly adhere to finishing materials.

Description and purpose

Concrete contact (BC) is a universal means for increasing the adhesion force of various bases to the finishing layer. The components of the primer make it possible to use it for processing concrete structures, brickwork, painted surfaces, tiled walls, plasterboard sheets, wood, and glass. Concrete contact is a polymer dispersion prepared on the basis of acrylic, to which quartz sand, cement, and additives are added to increase adhesion. The liquid mixture is released in buckets or barrels.

When performing repair and construction work, a universal primer helps solve the following problems:

prepare concrete floor slabs for installation of a wet screed or laying a self-leveling floor;
prime the walls and partitions before applying any plaster (cement, Venetian), especially if the finishing layer is thick;
reduce porosity and strengthen the structure of drywall before painting, wallpapering, tiling;
glue smooth finishing elements to glossy materials (even glass to metal);
treat the ceiling before whitewashing;
preserve plastered structures for the winter.

The scope of application of primer material in construction work is quite wide.
The use of concrete contact according to the instructions and in accordance with GOST requirements is mandatory for water-repellent surfaces (painted, tiled), as well as monolithic concrete. In this case, there is no need to dismantle the old finish: it is worth applying a layer of primer on top, which will make it sticky, rough (due to quartz particles), and ensure the adhesion of the new coating.

Advice: Before using an expensive product, experienced professionals advise testing the material for water absorption. The surface is sprayed with a spray bottle - if the water is poorly absorbed, it makes sense to buy BC. For rough, porous substrates, it is more profitable to use a cheaper deep penetration primer.

Composition of concrete contact

The primer contains:

styrene-acrylic dispersion as a binder;

quartz sand fractions from 0.3 (for putty) to 0.6 (for plaster);

Portland cement;
fillers.

The primer is a viscous liquid suspension, usually pink (sometimes blue or purple) without a distinct odor. The dye is added to the composition to make it convenient to control the application and not leave bald spots.

Concrete contact mixes with water, but after drying it becomes water insoluble.

The primer is non-toxic and does not require the use of protective equipment when working with it; but it is advisable to wear protective gloves and ventilate the room.

When frozen, concrete contact loses its qualities. There are types of primers that can withstand several cycles of freezing and thawing without loss of properties.

Homemade composition instead of concrete contact

A composition of PVA glue and cement can be used to treat metal surfaces before they are puttyed or painted. The surface must also be carefully prepared in advance, ensuring stronger adhesion to the applied composition.

Experts do not recommend using homemade compounds in construction and repair work. In their opinion, only high-quality concrete contact can provide the desired result.

There are only a few options for replacing concrete contact; the characteristics of the work being carried out should be taken into account. For ideal results, use the original product or consult a specialist.

What surfaces can be treated

Betonkontakt is intended primarily for treating concrete and brick walls for the application of gypsum plaster.

Hardened concrete, like brick, has a fairly smooth and low-porosity surface with low adhesion. Concrete contact does not penetrate deep into the base, but forms a thin film on its surface. Thanks to the addition of quartz sand, this film has a rough surface to which any finishing materials adhere well.

In addition to a concrete or brick base, the following surfaces can be treated with concrete contact:

In addition, surfaces with an already applied layer of paint or old tiles are treated with a primer. If these finishing materials hold tightly, a new coating can be applied over them. Neither paint, nor tiles, nor plaster will stick to a smooth painted or ceramic tiled surface, but if you first treat it with a concrete contact primer, adhesion will increase and it will be possible to apply new finishing materials.

Thanks to the use of concrete contact, it is possible not to use a mesh under the plaster and not to prime the surface with PVA glue; The plaster will hold up just fine. Thus, the use of concrete contact significantly reduces the labor intensity of plastering work and the time spent on it.

It is not recommended to apply cement plaster to concrete contact. It can tear the primer layer and peel off.

Betonkontakt is also used to prime the surface of a concrete screed in order to bind residual dust before laying the floor covering.

Main applications of concrete contact

Good adhesion and high soil strength have led to the fact that the composition, originally designed to work with a cement wall, is increasingly used:

For gluing ceramic tiles directly onto the concrete contact layer. In this case, either a composition for a gas silicate surface is used, or a double layer of primer with filler for heavy plasters is performed;
For rooms built from porous or foam materials, it is necessary to use waterproofing coatings; the concrete contact layer practically does not allow water to pass through;
As a fixing or insulating primer in basements or rooms with concrete or cement tile floors that produce large amounts of dust and dirt.

The majority of primer manufacturers produce concrete contact in two versions - for use under putty and for plastering. The first composition has a finer filler and produces a thinner layer of soil. With some experience in using the primer, its consumption can be reduced to 180 g per m 2. For heavy plasters, the use of concrete contact with a filler grain size of at least 0.5-0.6 mm is considered mandatory. If the walls presumably have old hydrophobic impregnations or contamination, sometimes, before applying the primer, the surface is treated with a special latex-based deep penetration solution.

How to apply concrete contact

In order for the primer to perform its functions, you must adhere to the rules for its application.

There are always instructions for use on the packaging. You must read it carefully and adhere to these rules. The properties and methods of applying primers of different types from different manufacturers may differ, for example, some types of concrete contact can only be applied with a brush, while others are designed specifically for application by roller. These nuances must be taken into account.

Preparatory work

Before applying the primer, it is necessary to remove debris and excess dust; if there is old paint or plaster that does not adhere well, it must be knocked down and cleaned with metal brushes; Wash dirty surfaces with soapy water or soda solution and dry thoroughly.

When storing the material, sand settles to the bottom, so before work it is necessary to thoroughly stir the primer so that the sand is distributed evenly.

It is the sand that is part of the concrete contact that makes it possible to give the surfaces a roughness that ensures adhesion.

Applying primer

There are two main ways to apply primer:

with a brush or roller;
spray gun.

Applying concrete contact with a brush or roller is a rather slow and labor-intensive process.

It is necessary to apply it so that the sand is distributed evenly over the surface of the base.

It is much more productive to apply the primer with a spray gun. In this case, the air flow beats the residual dust and distributes the sand evenly over the surface.

In addition, the spray gun allows you to significantly save time.

Sometimes it is recommended to apply concrete contact using a roller, which is certainly faster and more convenient than applying it with a brush.

To do this, the primer will have to be diluted with water, but adding water will weaken the adhesive composition. As a result, the sand will not adhere well, which is noticeable even when applying the primer: the sand crumbles directly onto your hands. In addition, the fleecy surface of the roller absorbs large amounts of sand. The primed surface acquires an uneven, bald, crumbling texture.

There are types of concrete contact that are designed specifically to be applied with a roller. Such primers have a more liquid consistency, which allows you to use material more economically, while they provide surfaces with increased adhesion.

Concrete contact is applied to the base in one or two layers. After drying, a durable film appears on the surface of the base, resembling sandpaper to the touch. It is this structure that allows you to reliably hold finishing materials.

After working with the primer, the instrument must be immediately thoroughly washed with water, since the composition dries quickly, and after that it can only be washed off with a solvent.

Features of applying concrete contact for outdoor work

Concrete contact can be used at ambient temperatures from +5 to +25°C. When performing finishing work in the cold season, you need to use special frost-resistant types of primer intended for outdoor work.

What is a primer?

Looking at the label in the store, seeing what the primer consists of, it becomes clear that it is a rather simple and easy-to-make substance. But it is indispensable in the construction business. The main task of the primer is the formation of an adhesive film on the surface being treated. Simply put, the mixture makes the surface more sticky for applied decorative materials.

Paint or putty adheres better to a primed surface because the primer fills its micropores and irregularities. Because of this, the area and force of adhesion of finishing materials to the surface increases greatly. Soil also performs other functions:

Securing the foundation. The composition impregnates the loose prepared surface, preventing it from shedding and cracking after applying decorative coatings;
Leveling the absorbency of the material. The prepared surface may have uneven thickness and uniformity of application. The mixture densely covers the entire surface, creates a uniform adhesive film over the entire surface;
Protective and decorative function. Some types of primers are designed to protect the surface from exposure to weather conditions and solar radiation. Wood treated with a special primer reveals the grain structure and looks more beautiful.

Priming at home is really easy. How to replace the primer from an expensive hardware store will become clear below.

Carrying out finishing work without preliminary priming will lead to peeling of the applied material. All the work will have to be redone. Priming the work surface is a dust-free job that will help avoid the appearance of defects.

Concrete contact consumption. Is it possible to reduce it

Considering that concrete contact is more expensive than other primers (concrete contact is one of the most expensive types of primers), the desire to save material is understandable. For this purpose, it is sometimes diluted with water, which leads to a significant decrease in the quality of the coating.

The standard consumption of concrete contact applied in one layer is from 0.1 to 0.5 kg per 1 square meter of surface.

What determines such a large scatter?

Depending on the ability of the base to absorb moisture, the primer consumption will differ.

For example, for monolithic concrete, concrete slabs it will be 0.2-0.35 kg, for tiles - 0.1-0.2 kg per 1 square meter. On average, smooth surfaces will require 150 g of primer per square, and porous surfaces with a cellular structure - up to 500 g for the same area.

How to tell if a surface is smooth or porous:

Smooth surfaces include painted, metal, and ceramic surfaces.
Surfaces made of facing bricks or concrete slabs are considered medium-porous.
Concrete, brick, and cellular surfaces are called highly porous.

The following factors also influence primer consumption:

Fraction of quartz sand included in the composition of concrete contact. The larger the particles, the greater their surface area, which means that more base adhesive is needed to cover these grains of sand. A primer with coarse sand is applied in a thicker layer, as a result its consumption is greater than that of concrete contact, which contains fine sand.
Method of applying primer. When applied manually (brush, roller), the concrete contact layer is thicker. The spray gun applies the primer thinner and more evenly, reducing its consumption.
Temperature and humidity in the room. The higher the ambient temperature and the lower the humidity, the greater the primer consumption.

And, of course, material consumption increases when applied in two layers.

Types of primer mixtures and their properties

Primer compositions are distinguished by the type of binder and by purpose. The first classification is more understandable to professionals; it is more convenient for beginners to use the second. In addition, mixtures differ in the presence of additives that give the composition additional properties, for example, antiseptic or fire-resistant. The composition may contain substances that facilitate work: coloring pigments for applying an even and dense layer, drying accelerators.

Types of primers by type of binder

The chemical composition of the primer determines the scope of application. This applies not only to the type of surface, but also to the location of the repair work. Some are suitable exclusively for external use, as they have improved properties, but can cause harm to health, others are suitable only for interior decoration, for example, due to a long drying time.

Depending on the binder, primers are classified into the following types:

Mineral - used for preparing surfaces made of concrete, brick and expanded clay blocks. They contain cement or gypsum (sometimes it is replaced by lime). Drying time – 24 hours.
Acrylic - almost universal in use, not suitable only for metal surfaces. They dry quickly (only 2-5 hours) and have almost no odor. Suitable for external and internal work. The basis of acrylic primer is water.
Alkyd - used for treating wood, fiberglass, glass, plastic and metal surfaces. They add rigidity to wood fibers and prevent rotting and mold. Protect metal from corrosion. A uniform rough layer is created on a smooth surface. Drying time – 10-15 hours. Used for exterior and interior decoration. Manufactured on an oil basis.
Phenolic – suitable for wood and metal. Dries in 12 hours. Used when working indoors and outdoors.
Griftal - used only for interior work. Suitable for processing wood and metal. Drying time – 24 hours. At low temperatures they lose their properties.
Polyvinyl acetate primers are special-purpose primers, suitable only as a base for polyvinyl acetate paints. Dries in just 30 minutes.
Perchlorovinyl - used for mineral and metal substrates. Toxic, therefore suitable only for outdoor use. Dries quickly even at low temperatures - about 1 hour.
Polystyrene - suitable for wooden and plastered surfaces. They emit harmful substances and for this reason are not recommended for interior decoration.

What properties does concrete contact give to surfaces?

Applying concrete contact provides many advantages:

Strengthening surfaces.
Giving surfaces waterproofing properties. (In addition to concrete contact, there are other waterproofing impregnations. If subsequent plastering with cement mortar is planned, it is advisable to use other impregnations rather than concrete contact).
Formation of an adhesive film that allows high-quality application of finishing materials to the surface.
The concrete contact coating does not interfere with gas exchange (primed walls “breathe”).
The surface is protected from mold and mildew.
Preventing the absorption of water from the plaster mixture, which reduces the strength of the plaster layer, by the base material.

Advantages of concrete contact:

availability;
easy application;
added dye to control the uniformity of application;
quick drying and the ability to continue finishing work without wasting time;
safety, absence of harmful effects on the human body;
ease of use (convenient consistency, concrete contact primer is supplied ready for use and does not require dilution with water);
fire and explosion safety;
durability.

How to choose concrete contact correctly

The question arises: how not to make mistakes when buying?

Choose a primer produced by well-known companies that are sensitive to their reputation. If you see an expensive brand of concrete contact at a too low price, this is a reason to be wary.

You can evaluate the quality of the primer visually. High-quality material always has a pink, blue or purple color to control the evenness of the coating. If the primer is almost white, this is a sign that it may have been heavily diluted with water.

Video: Primer: types, mistakes, how to deceive? Secrets of materials and advice from a professional

Concrete contact is one of the types of primers that cannot be avoided when carrying out finishing work. In addition to adhesion, it gives surfaces additional characteristics: strength, waterproofing properties, resistance to mold and mildew, and also provides dust removal from concrete surfaces. The use of concrete contact allows finishing work not only on new surfaces, but also on those that have already been previously painted or tiled. To obtain a reliable and durable coating, it is important to use high-quality material and not try to save money by diluting it with water.

Useful tips and tricks

In addition to the basic rules, there is a huge amount of advice from professionals on working with concrete contact. Let's look at the main recommendations.

You cannot use concrete contact on bitumen mastic. The increase in adhesion will be minimal; the use of the solution in this situation is unjustified.
Under no circumstances should you dilute the composition with water or add any components by hand. It can be diluted with water only if the manufacturer has indicated this on the packaging, and in the dosage indicated on the packaging.
It is better to apply the composition not to the entire surface at once, but only to that part on which you will quickly have time to carry out further finishing work.
The solution can be used for a long time only if the storage rules indicated on the packaging are observed. If you notice that the composition has thickened or is not drying well, it is better to buy a new package of concrete contact.
This material can be used when working with any surface: it is suitable for floors, walls or ceilings.
When working with this solution, you should not carry out additional surface treatment.
You can use concrete contact only after you have fully studied the instructions.

If you follow simple rules, you can make repairs easier. In many cases, concrete contact is a necessity and can be used as an alternative to primer.

Subtleties of the process of applying concrete contact to walls

Often during the construction or renovation process, it becomes necessary to glue two materials that cannot adhere to each other. Until recently, this was an almost unsolvable problem for builders and finishing craftsmen. However, these days such problems can be solved using a special primer called concrete contact.

How to work with concrete contact – recommendations for application

The manufacturer of the special primer guarantees the effectiveness of its use subject to certain conditions:

while maintaining the room temperature in the range of 5–35 degrees Celsius;
when performing work on impregnation of the base at a humidity of no more than 60%.

There are certain restrictions when using primer. Prohibited:

use the primer mixture after defrosting;
cover the base with a negative temperature.

What is it used for?

Concrete contact is a type of primer on a sand-cement base with a large number of polymer additives. The main task of this material is to increase adhesion (adhesion of surfaces to each other). In a few minutes you can increase the adhesion of any material to the wall. To do this, you just need to apply concrete contact.

It is very difficult to apply plaster on a completely flat wall - it will peel off and then fall to the floor. After treatment with concrete contact, the wall becomes slightly rough. Any finish will fit easily onto such a base.

How to prepare the mixture?

Often there is no need to prepare this mixture - manufacturers are ready to sell a completely ready-made solution. When purchasing such a concrete contact, it is enough to stir all the contents until smooth. It must be remembered that it can only be stored at positive temperatures.

Nowadays, few people prepare such mixtures with their own hands, because you need to know exactly the proportions, buy all the necessary materials, and also dilute them correctly with water. Then you need to wait and watch how the solution thickens. This is extremely energy-consuming, so everyone buys ready-made concrete contacts. You just need to read the instructions for use and work with this composition correctly.