Primer for plaster. Primer on plaster and before plastering: the choice of the optimal solution, taking into account the parameters, types Primer on plaster

What are the primers used for plastering walls? At what stages of work is it reasonable to use them? Which surfaces should be primed and which should not? Let's figure it out.

Soil types

To begin with, let's decide what, in fact, primers are used during plastering.

By functionality

Two main categories can be distinguished:

Firming(penetrating, primers), as the name suggests, impregnate the porous surface and make it more durable, preventing shedding and delamination.
adhesive designed to improve the adhesion of the plaster layer to the surface.

In addition: all primers noticeably reduce the absorbent properties of the surface.
This reduces the consumption of paint during the final finish and the absorption of water from the plaster at , which positively affects the resulting strength of the coating.

Composition

Depending on the main active component, one can distinguish:

Acrylic primers, which are an aqueous dispersion of acrylic resins.

Mineral - based on cement.

In both cases, various polymer additives can be used to correct soil properties.

How it works

Indeed, how exactly does the primer affect the properties of the coating?

Firming

When the surface is moistened, the main active ingredient (it can be either acrylic resin or cement), together with water, penetrates into its pores due to the capillary effect. When water evaporates, soil particles remain in the pores, penetrating the coating with a kind of strong threads stretching deep into the coating.

adhesive

There are two possible ways here:

Creation of a film with high adhesive properties on the surface.
In an advanced version - the inclusion of a fine mineral filler in this film, which will make the coating rough, thereby further increasing the adhesion of the plaster to the surface.

This is exactly the primer "Betokontakt" from Knauf: it is an aqueous dispersion of acrylic resin already familiar to us with the addition of fine quartz sand and auxiliary polymers. The price of a 20-kilogram package of soil is approximately 1,700 rubles.

Without primer

What surfaces can be plastered without prior priming?

The answer, in general, is quite obvious: on durable and porous, providing good adhesion to the plaster. It is enough to simply moisten these surfaces with water before carrying out plastering work.

The instruction, however, concerns, first of all, cement and lime mixtures. If gypsum is used, a primer is still highly desirable as the material itself has only moderate adhesion to most coatings.

Here are a few examples of surfaces that, when using cement plaster, do without soil without any loss of strength.

Shell masonry. Both the seams and the stones themselves provide excellent adhesion to the cement: their surface, when magnified, resembles a lunar landscape.
Masonry made of ordinary brick, made in a hollow (with partially hollow seams).
Masonry of cinder blocks, which, again, are quite porous.

plaster mesh

On complex surfaces, plaster is often laid in a grid pattern.

There is no opposition here: nothing prevents the use of a plaster mesh on a primed wall; however, it must be admitted that reinforcement solves the problem of poor adhesion of plaster to the base much more effectively.

For cement and lime plasters, galvanized steel mesh with a mesh of about 2 centimeters is traditionally used. With gypsum mixtures, a fiberglass mesh with a mesh of 5 millimeters and a density of 150 g / m2 is more often used.

Please note: with a plaster layer thickness of more than 3 centimeters, the use of mesh is strongly recommended, regardless of the quality of the base.

How is the plaster mesh attached?

In general, there is no regulation: improvised means are used.

The fiberglass mesh on the base of drywall is glued with PVA glue or simply pressed into the first layer of plaster.
On a wall made of face brick or monolithic concrete, the steel mesh is fixed with dowels driven into the base. Under the head of each dowel, a piece of knitting wire is wound in the shape of the letter Z.
Dowels can press the mesh against the wall using wide washers or profile sections.
Finally, no one will cancel plastic dowel-umbrellas. They are inserted into pre-drilled holes, after which the core is driven into the body of the dowel with a hammer.

Wooden partitions are often plastered on shingles - thin laths stuffed on a wooden frame.

Primer application

As a rule, primer of any type is applied in one layer on a previously prepared surface.

The method of application is determined by the size and number of pores of the base:

Monolithic concrete, drywall or aerated concrete blocks are possible.
For brickwork, a wide brush is more suitable, which will allow the soil to penetrate into all the irregularities of the base.
It is desirable to treat a shell rock wall with a sprayer. The primer applied with a brush obviously will not fall into the countless recesses of this material.

What is the preparation of the surface for a primer and subsequent plastering?

Removes large irregularities. The thickness of the plaster layer affects both the final cost of finishing work and strength. The smaller the distance between the base plane and the most prominent point, the thinner the coating will be.
Remove paint, whitewash, peeling putty and plaster. If the new plaster does not belong to the same type as the old one (gypsum plaster over cement mortar, cement over lime, etc.), the surface is cleaned to a solid base - concrete or masonry.

Then the base is dedusted as much as possible. Sweep the outer wall enough; Vacuum the inside.

Please note: a penetrating primer is quite capable of ridding a wall or ceiling of dust residues by firmly gluing them to the base.

Questions and answers

Let's answer the most popular questions that arise among novice builders who are doing plastering work with their own hands for the first time.

What is the primer consumption per 1m2 of plaster?

It strongly depends on both the type of soil and the absorbency of the substrate.

For penetrating primers, you can focus on the following numbers:

On drywall or monolithic concrete, about 25-50 milliliters of soil are used.
When priming aerated concrete, the consumption increases to 70-100 ml/m2.
All 200-250 ml / m2 will go to cinder blocks or the notorious shell rock.

Please note: we are talking about the consumption of a ready-to-use primer.
Many manufacturers supply it in the form of a concentrate diluted with water.

Do I need to prime the walls after plastering?

The answer is determined by your future plans.

If any final coating is expected - painting, tile, etc. - a primer on the plastered surface is highly desirable.
If the layer of plaster remains in its original form or, as a maximum, will be whitewashed with lime, additional costs of money and time are not needed.

What is the primer of the walls after plastering?

Any acrylic-based penetrating primer. Adhesive primers are useless here: all plaster solutions give a fairly porous surface; but the increased strength of the base will not hurt.

Is a primer required after plastering if the surface is to be puttied?

Before applying putty of the same type (cement on cement base, gypsum on gypsum), this operation is not necessary. Under putty with a composition that does not correspond to the composition of the plaster, it is always necessary to prime.

Does the primer on plaster for outdoor work differ from the primer used in interior spaces?

Yes. The postscript "facade" on the packaging and polymer additives-stabilizers in the composition.

What primer for gypsum plaster can be used on a concrete or plasterboard base?

And here we are not in for surprises: all the same compositions based on acrylic resins are optimal. If we consider the products of the German company Knauf, which deserve all respect, which are widely represented on the Russian market, then in the first case it is better to use the already familiar Betokontakt, in the second - Rotband Grund.

Conclusion

The video in this article, as usual, will offer the reader additional materials. Good luck with the repair!

In the process of preparing walls for plaster, priming is one of the most important processes affecting the quality and durability of the decorative layer. However, for walls made of different materials, it is advisable to use different types of mixtures and technologies for their application.

The article will give an overview of materials, technical and operational characteristics of various types of primers. the need for their use. And also, the technology of priming walls before plastering.

Why prime the walls

Most general purpose primer formulations are used to improve adhesion between layers of plaster or between a wall and facing material. But the possibilities of the primer are not limited to this. Depending on the requirements and material of the walls, it can perform the following functions:

Increase the strength of the outer crumbling layer of rough plaster;
Improve interlayer adhesion;
Neutralize fungus and mold both on the surface and in the depth of the base;
Act as an anticorrosive and waterproofing coating or flame retardant impregnation when preparing walls for plastering.

The wall was not primed for exterior plaster work, the result is extensive peeling of the decorative coating

Varieties in composition

Primers on an organic solvent, they are based on alkyd and some other resins. Such compositions are applied to wooden surfaces, including those painted with oil paints, to fiberboard, chipboard, OSB and other wood-containing pressed boards. They are used to coat various metal surfaces, glass or plastic.
Water-soluble formulations are mainly silicate, silicone, and acrylic based. Such compositions are universal and are applied to concrete, brick, drywall and any type of wood.

Important: preparation of walls for decorative plaster includes the obligatory process of priming. Usually the name of the recommended composition is indicated on the packaging with plaster. But if there is no such information, then the base should be impregnated with a primer, which includes the same binders as for decorative plaster.

Water-soluble formulations are breathable and do not accumulate moisture. They are odorless and are the most common among universal primers.
Some specialized formulations use epoxy, polyurethane, shellac resins or cement.

Important: solvent-based primers are not used in contact with foam.

Primers for various surfaces

Priming of walls before plastering is carried out in various ways, depending on the material of the wall, its porosity, moisture absorption capacity, density and other factors.

Mineral bases

These walls include: concrete, brick, plastered with a cement or gypsum mixture, plasterboard, etc. For their processing, the compositions are used:

Universal - general purpose. This is an exclusively adhesive mixture designed to improve the connection between layers. It is applied both on a new base and on old plaster or its defective parts. An additional function is to reduce the absorbency of the material. Substrates with stains of paint, grease, oils or bitumen must not be treated.
Deep penetration - applied to crumbling surfaces. Is it necessary to prime the plaster before puttying if the facing layer is strong? Without fail, to strengthen the decorative or technical base of any type. In most cases, the treated wall receives a significant increase in moisture resistance. There are special mixtures for deep penetration into loose layers to strengthen them. Such compositions are not recommended for processing dense materials. Without being absorbed, they form a polymer film on the surface, which can peel off along with the plaster.
Adhesive with a filler of fine quartz sand. This is a well-known mixture of concrete contact.
Antiseptics - contain fungicidal substances that prevent the development of fungus and mold in the thickness of the walls.

Wooden bases

These include not only an array of various types of wood, but also chipboard, fiberboard, OSP. They are also treated with fungicidal and flame retardant impregnations. However, there are also special formulations to protect against insects.

Metal bases

If you plan to plaster a metal surface, then you can not do without a primer. For metal, several types of compositions are used. Firstly, it increases adhesion, and secondly, it isolates from corrosion. Separately, it is necessary to mention rust converters. They are used to remove its stains while protecting the metal and improving adhesion. Such universal compositions are quite expensive, but when using them, there is no need to apply impregnations in several layers, each of which has its own function.

Non-absorbent surfaces

These include laminate, glass, ceramic tiles. For processing, primers with increased adhesion are used. Usually used as a preparation of walls for decorative plaster or textured paint.

Absorption surfaces

These include all types of lightweight foam and aerated concrete. Aerated concrete primer under plaster performs a waterproofing function. Substances create a thin but durable polymer film on the surface of the wall blocks, which does not allow moisture to pass into the blocks and the room.

Anti-stain primers have the effect of paints, neutralize rust, age spots and can tint the surface in any color that will become the basis for textured paints or various types of thin wallpapers.

Primer application technology

The priming process is in many ways similar to painting and does not present any difficulty. The composition is applied with a small brush, a roller on a telescopic handle or an ordinary wide paint brush. If the wall has a large area, it is divided into 2 parts, and horizontally. First, the upper part is processed, then the lower part. A small brush is passed through hard-to-reach places: in corners and slopes. Video on how to prepare walls for decorative plaster:

Reinforced concrete surfaces:

brick walls:

After such preparation, any type of decorative coating can be applied: bark beetle, silk or Venetian plaster.

Applying the primer to the wall with a roller

It is considered optimal to apply a primer in two layers. The drying speed of the first can be different. It depends on the dryness and porosity of the substrate surface. It is strictly forbidden to apply the next layer when the previous one has not yet dried. In addition, different materials absorb the substance in different ways. For example, for the full processing of foam and aerated concrete, a significantly higher primer consumption per 1 m 2 for plaster will be required. Typically, the consumption for the most common materials is indicated on the container.

Priming - surface preparation for plastering, painting, wallpapering

Preparing walls for decorative plaster, video using a roller:

December 11, 2016
Specialization: facade finishing, interior finishing, construction of dachas, garages. The experience of an amateur gardener and horticulturist. He also has experience repairing cars and motorcycles. Hobbies: playing the guitar and much more, for which there is not enough time :)

This time I decided to devote an article to such an important topic as priming walls before plastering. It is from this procedure that the durability of the finish largely depends. Therefore, further we will consider how and in what cases walls should be primed, and how to do it correctly.

Do you need a primer at all?

Many beginners mistakenly believe that the purpose of a primer is merely to improve the adhesion of plaster to smooth surfaces such as concrete. Therefore, they doubt whether it is necessary to prime the walls before plastering, if the base, for example, is brick?

So that you yourself can answer this question, next I will talk about all the functions that the primer performs, in addition to improving adhesion:

strengthens the surface, gluing dust, grains of sand, loose pores, etc., thereby preventing its delamination;

ensures uniform absorption of the plaster into the surface of the base;
prevents the appearance of mold, and also protects them from other biological influences, due to the content of antiseptic compounds in the composition;

prevents the appearance of salt stains on the surface.

To summarize all of the above, the primer increases the durability of the finish, regardless of the type of base. I hope that now you will not think about whether it is necessary to prime a brick wall before plastering.

Soil selection

Before proceeding with priming, it is extremely important to choose the right primer. Let's see what primers exist and what primer to use before plastering walls.

So, on sale you can find the following compositions intended for priming:

Universal primer

The name of these primers speaks for itself - they are universal. They can be applied to any type of wall, except for wood and metal.

Universal compositions have all the functions necessary for a primer:

increase adhesion;
strengthen the base;
have an antiseptic effect.

It should be noted that universal primers are water-based, due to which they have the following properties:

practically do not have;
dry quickly.

Therefore, before plastering, most often, these types of soils are used.

You can find the cost of these compositions from the table below:

deep penetration

Deep penetration compounds are able to penetrate into the porous structure to a great depth (up to 10 cm), while they stick together the pores. Thus, the main task of a deep penetration primer is to strengthen the surface of the walls.

Such a composition can be used if the surface of the walls, for example, is a shingle covered with clay. Also, a deep penetration primer will be needed if you plan to apply new plaster over an old layer of plaster that is “dusting” and crumbling.

Deep penetration compounds, like universal primers, are water-based, so they have the same advantages - no odor and high drying speed.

Below is the cost of some well-known deep penetration primers:

adhesive

As you might guess, these compounds are designed to improve adhesion between materials. Therefore, they should be used on smooth surfaces with poor adhesion, such as concrete, old paint or even tiles.

The principle of operation of adhesive primers is based on the fact that they give the surface some roughness due to the presence of quartz sand and other abrasive in the composition. Thus, after treatment with adhesive primer, smooth surfaces feel like sandpaper to the touch. As a result, plaster, putty and other coatings adhere well to them.

It should be noted that adhesive primers exist both on a water basis and on the basis of organic solvents. The latter contain alkyd resins in their composition. They can be used to process wooden walls.

You can find the cost of adhesive primers below:

Priming technology

So, we figured out how to prime the walls. Now let's get acquainted with the technology of processing walls.

This procedure can be conditionally divided into several stages:

Preparation of primer and tools

First of all, you need to determine the amount of soil. To do this, you need to know the quadrature of the walls and the consumption of the composition.

Consumption depends on the surface of the walls and the type of primer itself. Therefore, manufacturers usually indicate this parameter on the packaging.

Also, don't forget to add 10-15 percent stock. When buying soil "back to back", you most likely will not have enough of it.

In addition to the primer itself, you also need to prepare inventory:

paint roller - the choice depends on the type of surface that you will be processing. So for brick walls it is better to use a roller with a long or medium pile. Concrete walls can be treated with a foam or velor roller;
cuvette for roller;

paint brush - needed for processing hard-to-reach areas.

Wall preparation

It is necessary to start work with your own hands by preparing the walls. This procedure is carried out as follows:

if the wall is not prepared for plastering, it is necessary to get rid of the old coating. To remove the plaster, you can use a perforator with an appropriate nozzle.
It should be noted that you can only partially clean the walls of old plaster, i.e. remove only those areas that exfoliate. In this case, be sure to “grab” a few centimeters of plaster around the perimeter, which holds well;

then the walls must be cleaned of dust with a brush or even a vacuum cleaner;
Dust-free walls should be wiped with a damp cloth and dried.

This completes the preparation.

Padding

The instructions for priming the walls look like this:

First of all, you need to prepare the primer, having read the instructions for use on the package. When the composition is ready for use, you just need to shake it thoroughly.

Some primers are sold concentrated and require dilution before use. In this case, add water to the soil in the proportion indicated on the package;

then pour the primer into a special compartment of the pallet. The rolling platform must not be covered with liquid;
then dip the roller into the ground and roll it slightly on the site so that excess liquid is drained from it;

now roller the wall. Roll it out so that the soil lays down in a uniform thin layer. There should be no streaks and areas with a large accumulation of liquid on the walls.
As necessary, dip the roller into the ground and wring it out on the rolling platform;

treat hard-to-reach areas with a primer using a paint brush;
after that, you need to wait for the soil to dry. Under normal conditions, i.e. at a temperature of 20-25 degrees, it will take 3-4 hours to dry. If the room is cold, drying may take 12 hours or more;
after the walls have dried, the primer must be reapplied in the same way.

If it turned out that you do not have enough soil, you can increase its amount by adding water. The only thing is, do not add water in the amount of one part to two parts of the soil.

Now wait for the second layer to dry. To make sure that the priming is done well, run your hand along the wall. If the hand remains clean - you can safely proceed to the application of plaster.

Conclusion

From the article, you learned the detailed technology of priming walls, and you can easily do the job at home or in an apartment. Also follow the recommendations above regarding the choice of soil and be sure to watch the video in this article. If any of your questions on this topic remain unanswered, leave them in the comments, and I will try to answer you.

December 11, 2016

If you want to express gratitude, add a clarification or objection, ask the author something - add a comment or say thanks!

The primer is, without exaggeration, the basis of a quality repair. This is a special liquid composition that serves to treat any substrate before applying the subsequent coating. The primer removes dust and strengthens the surface, and also enhances the adhesion of the applied coating to it.

Remember, a primer is necessary for any base:

concrete
foam blocks
tongue-and-groove blocks
brick
drywall
cement screed and plaster
gypsum plaster
putty...

The difference will be only in the type of soil.

You ask, what are the consequences if you ignore this rule? Well, as a maximum, the tile will fall off, the plaster will fall off in a layer, the wallpaper will peel off, the paint will fall in terrible spots ... But we are talking about the primer before the plaster (gypsum). So, if you do not prime (especially concrete), then the chance that everything will fall is quite large. Moreover, the plaster will fall from the concrete ceiling immediately. In the case of walls, if you're lucky, the plaster will visually hold. But any tangible vibration will cause it to move away from the base, and it will begin to curl and crack. And later, it will probably still fall.

Repairs are a lot of money. You will spend several hundred rubles on the soil (about $ 20 for 10 liters). But if you decide to save money, you risk losing thousands and tens of thousands. The miser pays twice. Believe me, in the decoration - it is.

To perform plaster work, we need two classes of primers.

The first is deep penetration soil.

It looks like milk, has a slight neutral smell, leaves a resistant film when dried. Due to this, it strengthens and removes dust. When dirt gets into the container with it, as well as when overheated, it tends to emit a fantastic stench. When it dries, it disappears.

The second class of primers for plaster is a special composition for smooth surfaces, in particular for concrete. It is usually called that - Betokontakt.

There are options: betonkontakt, bettokontakt and more. The essence is one. Such a composition is a suspension of solid particles (quartz sand) in a sticky substance. For some reason Betokontakt has a pink color. Probably standard. But do not think that this is simple sand mixed with PVA! It's not so simple when it comes to a really serious product from a well-known manufacturer. Normal Betokontakt even penetrates into the pores of concrete, preventing the formation of efflorescence. This is a fairly complex composition.

Indeed, not every soil of this type is worth using. For many masters there is only one authority - Feidal. It is also the most expensive. A 20 kg bucket costs more than 2,000 rubles (almost $60), while soil from Osnovit costs 1,300 rubles (less than $40). But, nevertheless, it is a reference. At least, because it visually has the largest size of solid particles in its composition. And this is an important factor. After application and drying, Faydal's Betokontakt gives such a rough surface that it is really possible to tear off the skin on it. The plaster sticks "with a bang." Here is a recommendation. If you don't find Faidal, take Knauf.

Betokontakt needs to be stirred before each use, because solid particles go to the bottom of the bucket in a fairly short time. Nowhere do they write that before applying it, the surface should be treated with a conventional primer, but this should be done when there is a suspicion that the ceiling or wall is very dusty. It is enough just to run your palm over them and see if it gets dirty. If yes, then it would be better to use a regular primer first.

The word "normal" refers to deep penetration compounds. Three leaders can already be distinguished among them - these are Knauf, Bergauf and the same Feidal. They are called Tiefengrund or Tiefgrund. These soils have a low consumption, because they foam well. The price is about the same - about 700 rubles ($20) for 10 liters.

The application of soil is a simple process, at least in the case of plastering work. You just need to evenly “wet” the surface with it. It is most convenient to do this with a roller. If the base surface is cement or gypsum plaster, one coat is sufficient. But if it is brick or foam concrete, once may not be enough, because these materials absorb moisture very well. And too rapid withdrawal of water from gypsum plaster leads to its cracking. We don't need this. Just primer once, wait for complete drying (2-3 hours) and repeat the process. Before applying the solution, again, do not forget to wait for the soil to dry. Application temperature should not be below +5 degrees.

Betokontakt is applied to a dry and clean base with a wide brush or a long-haired roller. Do not save, apply fatter, preferably in different directions. It usually dries in 2-4 hours. Don't even try to start applying mortar until the primer is COMPLETELY dry! It's just pointless.

The primer before plastering is very important, never neglect it before plastering walls and especially ceilings. This can cost you dearly.

May 21, 2014 ADMIN

Pre-treatment of surfaces before plastering is provided by building technology to improve adhesion of further wall coverings with other materials. The primer of the walls under the plaster prevents its subsequent cracking and peeling.

If the plastering technology is not followed, the end result is doomed to rework.

What is the purpose of priming surfaces?

The primer is necessary to improve the parameters of the walls before finishing work.

Primer coating allows you to:

remove sand grains from the surface and plug small cracks;
ensure uniform absorption of subsequent material;
improve the adhesion of the base with further finishing;
significantly save the plaster mixture;
apply a modern product with antifungal properties;
extend the service life of the finishing material several times.

When finishing, specialists use soil mixtures before each stage of work. Compliance with simple technological rules significantly affects the quality of the finish and increases the service life.

Which surfaces should be primed

A beautiful and even wall can be obtained using simple plaster. However, there are walls that are not ready for plastering, and the primer is the composition that should be used to treat surfaces.

If there are walls made of various materials and of different quality in the room, you will have to stock up on several types of primer material. So, you need to cover with a primer:

strengthening - porous surfaces (concrete, brick);

deeply penetrating - asbestos-cement walls and freshly plastered walls;

anti-corrosion - metal structures;
antiseptic - wooden surfaces;

against stains - surfaces made of organic and inorganic material.

Choosing a primer for a specific base

Building practice confirms that in order to obtain a strong and durable finish, it is necessary to prime the walls before plastering.

The consumer building materials market offers a wide range of primer products, making it easier to choose for each substrate. Each package indicates the materials that need to be treated with this primer.

The constituent components of each mixture are: adhesive mass, resins, oils, coloring pigments, substances that accelerate hardening and drying. The composition of the soil depends on the adhesion to the surface for which the treatment is provided.

A primer with a mineral base should be impregnated with ordinary concrete and its analogues: foam-gas-slag-claydite concrete.

Acrylic primers attract with a wide range of applications and affordable price, which are well compatible with drywall, cement and concrete surfaces with synthetic paints.

In addition, alkyd compounds are a good impregnation for chipboard and fiberboard with a painted or untreated surface.

Enhanced properties of soils for special purposes (to retain moisture, prevent the formation of stains) are given by special additives that are introduced in certain proportions.

A primer with a high penetrating effect should be used on porous and loose substrates in order to significantly increase the strength of the layer. A high-quality penetrating liquid composition should be cloudy, but leave no traces, completely absorbed into the surface.

The choice of method depends on the cultivated area.

About the features of interior decoration

High-quality interior finishing involves applying a primer to each layer of the treated area. So, the surface should be primed to, then before putty, then to.

Before applying the paint, it is necessary to apply an acrylic primer, and not an alkyd one, then the paint will be better (without bubbles) to lay down on the surface.

Long gone are the days when one type of primer was used for all types of finishing work. Today, the building consumer market is supplied with a wide range of modern primers in dry form and ready for use.

Briefly about the ratio "price-quality"

All primers supplied to the market are conventionally divided into 4 groups:

inexpensive materials, more often used in the decoration of public spaces, when cost is more important than quality;
high quality materials of a domestic manufacturer or jointly with foreign production;
primers provided by well-known international companies (ATLAS, JOBI, DUFA, TIKKURILA, OPTIROC);
elite imported materials supplied on order with additives that can be used to control the drying speed of the composition.

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