Do-it-yourself primer for walls under plaster – which one to choose

For a person who is not involved in professional repairs, it is not always obvious whether the walls need to be primed before leveling or for decorative plaster. What composition to choose for a particular surface, how long it will take to dry, what sequence of work, and many other questions may arise during the finishing process. We will answer most of them in this article.

What is a primer

This is a building composition in the form of a liquid, which is used to treat walls, floors, and ceilings. Performs the following tasks:

• enhances adhesion - the adhesion of dissimilar materials, in this case between
• processed surface and finishing;
• strengthens the foundation;
• levels the layer;
• protects against corrosion;
• saves paint consumption.

The composition of the mixture depends on its intended purpose and the type of surface. It applies to:

• concrete;
• brick;
• tree;
• drywall;
• old paint.

The primer composition must be kept in a well-closed container in a cool, dark room.

Rules for preparing the construction foundation

In order for the finish to last for a long period, it is necessary to properly prepare the surface. Do I need to knock down old plaster? Professionals advise dismantling any type of previous finishing. Remove the wallpaper, as in the photo below, knock down the plaster and tiles, wash off the paint and whitewash. If this is not done, the new finish will fall off along with the old coating.

Next, the construction base is tapped with a hammer to identify fragile fragments. If any are found, the shaky areas are removed, the defects are expanded and deepened.

The next stage of surface preparation is cleaning. Remove dirt and sweep away dust. If there are greasy and oil stains, treat the surface with a degreaser. After this, take a break to allow the base to dry.

If mold and mildew are present, it is recommended to perform antiseptic treatment. Only after this the primer is applied.

The meaning of priming

Man began priming surfaces at the beginning of his historical journey. Artists were the first to do this - without a special primer it is impossible to put paint on canvas. The primed surface not only held the paint firmly, but also allowed the master to work comfortably - the base of the painting became dense and uniform in roughness. The same functions are inherent in modern primers. Padding:

• saturates the wall surface with moisture before applying plaster, which prevents it from taking water from the solution;
• creates a film with deep penetration into the wall (up to 1 cm), which significantly improves adhesion between its surface and the plaster;
• removes dust, including in places inaccessible to a brush or vacuum cleaner;
• muffles color spots on the wall (but not a transparent primer), turning its surface into a more monochromatic one, which is very important when wallpapering concrete;
• creates a smooth, easy-to-finish surface.

Before plastering

When redecorating an apartment or house, you should not miss one important nuance: the walls must be treated with a primer before plastering.

And let some experts prove that previous generations did not prime, and the plaster lasted for decades. One cannot agree with them for one reason: in the past, walls were reinforced with plaster mesh (metal), which rusted, and traces of rust very often made their way through the decorative coating of the walls.

Today, even concrete can be plastered without reinforcement thanks to a properly selected primer. Priming walls allows you to:

• Saturate the walls with moisture, as a result of which the chemical reactions of hydration of cement or gypsum are not interrupted due to lack of water (as is known, a number of wall materials - concrete, aerated concrete, brick, etc. - have the property of capillary suction of water molecules from the solution);
• Increase the strength of the wall surface while simultaneously creating good adhesion with the plaster solution. Deep penetration primers are absorbed into the wall material up to 1 cm, leaving a continuous film on the surface. When applying plaster, the film adheres to particles of cement or gypsum, providing a strong connection between the wall and the plaster;
• Bind dust, which actively counteracts any connecting processes;
• Achieve savings in the family budget. A wall treated with a primer has a smoother surface and good adhesion, which allows layers of plaster to be applied evenly. Therefore, it will be required less when compared with the consumption of a wall not treated with primer.

When plastering concrete, you need to be very careful when choosing a primer. They have their own primers on sale here. So, under gypsum solutions you need to use only a “concrete contact” primer, which binds dust, saturates the wall with moisture, and forms a film with high adhesive properties (due to the presence of quartz sand).

For information: a primer with “concrete contact” properties can also be used when laying plasterboard with ceramic tiles; during plastering work on polystyrene foam; when leveling walls with plasterboard using gypsum-based glue.

It is not recommended to use “concrete contact” under cement mortars.

Preparation of wooden walls and concrete surfaces

Wood adheres well to many types of finishing materials, but not to plaster. Therefore, it is necessary to prime the brick before applying plaster. The preparation process consists of three stages:

1. Be sure to apply a water-repellent mixture;
2. Install the mounting membrane;
3. Install the plaster mesh.

There are such varieties of putties as bark beetle, Venetian and silk. In this case, you only need to remove dust and dirt from the surface and apply 2 layers of primer. In this case, you can do without smoothing out minor defects. If the type of plaster requires a flat surface, then first we level it using beacons, then apply an adhesive mixture to a dry, clean wall. We check the evenness of the wall.

What types of primers are there?

Types of wall primers are specifically designed for treating vertical surfaces, interior and exterior. They can be different in characteristics, method of application, basis, level of protection from negative factors.

Acrylic

It is a mixture of acrylic and latex. It increases the fixation of finishing materials on the surface. Widely used by professionals and beginners to perform construction and repair work. Varieties of acrylic primers have appeared that are in great demand - impregnating, penetrating deep into the layer, special, universal and others. Each drug has its own spectrum of action - enhancing the adhesion of materials, penetrating into the thickness of the surface, provided that non-standard materials are used in the work. It is used for surfaces with a reduced absorption coefficient of liquids.

Deep penetration before plaster

The first class of primers is a deep penetration primer.
Visually reminiscent of milk with a weak neutral odor. After application and drying, it leaves a durable film on the surface, thereby strengthening and removing dust from the layer.

A deep penetration primer is suitable for treating loose surfaces, which allows you to strengthen the wall and reduce paint consumption.

It works best to create a reliable base for heavy types of wallpaper.

Mineral

A primer based on mineral components is used for the initial treatment of surfaces for the purpose of leveling.

A primer based on mineral components works with surfaces made of specialized mineral materials: concrete, brick, plaster, as well as gas silicate and expanded clay concrete blocks.

Cement is used as a binder in such cases.

Adhesive mixtures

The use of such a primer will help improve the adhesion of the finish and the base. It is advisable to use adhesive primers when working with plastic, steel, tiles, and glass.

Antifungal primer

Types of primers differ from each other in the way they act on the surface. The primer is a liquid mixture that is applied to the required base - wall, floor, etc. - in order to improve adhesion to finishing materials (wallpaper, paint, putty). A finish without primer will last much less time. It strengthens old and loosely structured surfaces. Some modern paints will not adhere to the base without first applying a primer.

Fungus and mold have caused significant inconvenience to humanity for many years. Antifungal primer will become your faithful assistant in the fight against them. To avoid undesirable consequences, if you find mold on the wall, stock up on antifungal primer. It has proven itself to be an excellent means of prevention, used during the finishing of a room - in cases where fungus appears in the layers of thermal insulation. It is produced on an acrylic, mineral or alkyd base. The main component of the primer, the fungicide, prevents harmful microorganisms from forming in the treated surfaces. Among such primers there are also products with concentrated substances. They will help remove fungus, mold, and lichens from concrete or brick surfaces. Before applying any of the primers, dry and clean the required surface. Mold can be washed off with a cleaning agent or warm water. It is recommended to use a blowtorch or a hair dryer when cleaning. The primer is applied with a roller, natural bristle brush or airbrush. Wear protective clothing and a respirator for work, and gloves on your hands.

Isolating for color matching

This substance makes it possible to even out the colors of the final paint. In addition, during operation it will allow you to maintain the brightness and saturation of the applied color longer. It is used for both internal and external surfaces subject to painting or plastering.

Universal for plastering and painting

A universal, deep-penetrating primer designed for indoor and outdoor use and in areas where strong adhesion is expected. A universal option is used for walls before painting or plastering, as well as wallpapering. Additionally, it can be used for treating facades and floors.

Properties of solutions

The compositions used to prepare the surface before finishing perform several functions.

With their help it is provided:

• cleansing;
• reliable grip;
• resistance to mechanical load;
• additional protection from moisture;
• prevention of fungus and mold.

Thanks to the adhesive properties of the primer, the plaster adheres well to the surface, allowing you to save on the consumption of finishing material.

Primers contain film-forming components, resins and fillers. Dye can be added to many solutions. It allows you to process the entire surface, i.e. all areas that will not be painted over can be seen.

After applying the composition, a thin film forms on the wall. The loose and porous surface becomes durable. The film prevents excessive moisture absorption, which facilitates the plastering process. The liquid contained in the construction mixture will not quickly drain into the work surface.

Selection parameters depending on surface type

An important factor when choosing can also be the type of surface itself on which the primer will be applied.

Concrete

Concrete contact or primer for concrete is designed to ensure sufficient adhesion to concrete. This is important for the subsequent application of putty or plaster on concrete and other surfaces that do not absorb moisture.

Tree

A primer for wood is also necessary, since it often acts as an antiseptic, which allows you to protect the wood from all sorts of destructive influences. This is most relevant for wooden surfaces located outdoors.

Gypsum

Gypsum putty or gypsum coating is a surface characterized by increased absorbency, which requires the use of a specialized primer.

Brick

There is an opinion that it is possible to apply plaster or paint to a brick wall without prior priming, since high-quality adhesion will be ensured. However, it is recommended to prime the brick base, since not all building mixtures include primer additives, which can lead to accelerated cracking and destruction of the entire layer.

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• Thursday, December 12, 2022 1:07
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Previously, plaster was applied without the newfangled primer, but now all sellers recommend it. In what cases can you save money and do without it?

Previously, plaster was applied without the newfangled primer,

It is extremely important to understand the following:

The very “previously” that you write about is not a standard of quality.

Quite often I remove “previously” (old Soviet plaster from different surfaces), it falls off on its own only from the “sound of a working hammer drill”.

The primer that is called “100 years at lunch” was simply in the USSR, there was a terrible shortage and it (PVA + water) was most often made “from what was available.”

Nowadays, technology and the composition of plasters have changed for the better; before plastering surfaces, priming is a mandatory process, and not only the base surface is primed, but also layers of plasters.

The quality (including the strength of the plaster on the surface) today is many times better than “before”.

Primer is not an expensive material, so you shouldn’t skimp on it.

Primer for plaster: in what cases can you do without it?

On this point, it is important to know whether you are plastering for yourself, or “for sale?” (that is, you complete the order).

It is important to know what kind of plaster we are talking about.

It is important to know what surface you are talking about.

You can, for example, plaster a brick with cement-sand plaster, without a primer, but the brick must be moistened.

For lovers of vintage (everything Soviet), you can, for example, plaster wood without a primer, but you need to stuff nails and tie them with wire, you get the Soviet version of a plaster mesh, which was in short supply back then.

We add clay to the solution for viscosity, lime (this is an ancient antiseptic found in modern primers) and also slightly moisten the surface.

How to calculate primer consumption

The required amount of primer depends on many indicators - the concentration of the solution, the type of primer, the type of surface being treated, as well as its ability to absorb liquid. For example, the consumption of a deep penetration primer mixture is 1 kg per 5-7, and a strengthening mixture is 1 kg per 5-15.

In order to calculate the amount of soil to treat the surface, you need to measure the area of ​​the walls being treated and multiply this figure by the material consumption rate provided on the label. Usually the surface needs to be primed 2-3 times, so this figure needs to be multiplied by the number of layers.

It is also necessary to check how the wall absorbs moisture; to do this, you need to spray water on it from a spray bottle; if it is immediately absorbed, then the degree of absorption is very high, and 1.5-2 times more primer will be required than normal, and if it immediately drains, then very low and less soil will be required.

Price of finished work

Very rarely, priming of walls is carried out separately from other finishing work; usually the package of services also includes plaster or putty. The cost of finished priming work includes the cost of material: the average price of strengthening soils for 10 liters is 300–500 rubles, and deep soils are 500–700 rubles per 10 liters, as well as the work itself. The price of services for priming walls from repairmen ranges from 50-100 rubles per hour.

Instructions for applying primer

Preliminary priming occurs in several stages:

• 1. The walls are cleaned of remnants of the previous coating and dust;
• 2. If the wall is uneven, it is first leveled using putty and plaster;
• 3. The plaster is allowed to dry completely within 24 hours;
• 4. The primer is applied first in the corners with a brush, then with a roller on large areas of the walls.

Preparation for application

The primer goes on sale in a dry and ready-to-use state, which can be applied immediately. They also sell concentrated solutions, which are brought to readiness by diluting with water.

A ready-to-use product (for example, an acrylic primer) is stirred so that all components are correctly distributed throughout the composition, and then the required amount is poured into a container and processed.

Water-dispersed soil concentrate is diluted in a ratio of 1:4 (add 4 parts of water to one part of concentrate). The required amount of concentrate is poured into a clean container, and then water is added - thus obtaining the necessary portion of soil to treat a certain surface area.

The two-component primer is diluted in the following sequence: first, the hardener is introduced, and then the thinner is added to obtain the desired viscosity.

Dry soil is diluted with water in a ratio of 1:4. Alkyd primer compositions are diluted with solvent 649, 650, xylene, solvent (the proportions are indicated on the packaging). Oily soils are diluted with drying oil.

It is important to remember that the instructions for diluting the composition are consistent with the requirements of GOST; deviation from the proportions may lead to a violation of the work technology, and the base will not acquire the necessary qualities.

Briefly about the price-quality ratio

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

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

If finances allow, then it makes sense to use the primer composition of the second and third groups in various combinations.

General application technology

Priming the surface before finishing is an indispensable condition for successful repairs; this procedure cannot be skipped. Before you start working, you need to prepare the following tools: brushes, a roller with a telescopic extension, a primer tray. A stepladder will not hurt - it is convenient to work on the walls in the upper part and the ceiling.

Next, prepare the surface: wash off the whitewash, remove old wallpaper, clean it of dust, dirt, and oil stains. After reading the instructions for diluting the primer, prepare it and, after pouring a small amount into a tray, begin priming. You can work with soil at temperatures from 5 to 30 degrees and air humidity up to 75%.

The surface is coated thoroughly, leaving no gaps and no smudges. In places that cannot be reached with a roller, they work with brushes. After treatment, the surface must dry (the drying time of the primer is indicated on the packaging). If necessary, apply a second coat of primer.

Sequence of work

All finishing work occurs in the following order:

Base primer - leveling plaster (gypsum or cement) - primer - putty - primer again - decorative coating (wallpaper/paint/plaster).

Important! Between the plaster layers, if they are not leveled at once, they are also primed.

Before work, you need to prepare the surface:

• completely remove all peeling old coatings
• clean with a brush, remove dust from the surface with a damp cloth or vacuum cleaner.

The walls are primed as follows:

1. If a concentrated primer is used, it must be diluted in accordance with the instructions. The proportions depend on the percentage of dry matter of the polymers in the solution.
2. The primer is poured into a cuvette (tray) or other container.
3. A paint roller is dipped into the solution and the excess is squeezed out.
4. Roll the roller along the wall from bottom to top so that a thin film is formed. Liquid should not drain or accumulate.
5. In corners it is more convenient to prime with a brush.
6. The treated wall is left to dry. If necessary, apply a second layer no earlier than after 4 hours. This is true for aerated concrete and foam blocks, which are primed twice to close all pores. Further plastering can begin after 12 hours, when it is completely dry.

Primer Application Methods

The primer is applied to the surface to be treated in different ways: manually (brush, roller) or using automated means (spray gun, spray gun). The choice of method depends on the scope of work. If we are talking about processing one or two walls, it is better to prime with a roller. When you have to do a lot of priming, you can’t do without a spray gun. On the primer package, the manufacturer indicates acceptable methods of use. The user himself chooses a method of surface treatment that is convenient and accessible to him.

How to apply with a brush

Brushes for applying primers are used in cases where it is necessary to treat minor areas of the surface. The tool is not effective over large areas. As a rule, brushes are used to prime areas that are difficult to reach with a roller or sprayer.

The technology of applying primer to the surface is no different from the same work with paint. The brush is dipped into the soil, then pressed against the walls of the container to drain off excess material. On the surface, use a brush to fill the space, without smudges or gaps. You need to work carefully so that the primer does not drip onto the floor, splash on other walls, windows, clothes, or get on open areas of your hands or eyes.

If the material gets into your eyes, immediately wash them with plenty of water. If during work the soil gets on the window glass, then the drops are also immediately removed with a damp cloth, otherwise, after drying, difficult-to-remove stains will remain on the glass. Applying primer over large areas with a brush is labor-intensive and time-consuming work. It is better to do it with a roller.

How to apply with a roller

Working with a roller is much faster than using a brush. The tool covers a large area in one pass and applies the primer evenly to the surface. Roller processing has its own characteristics.

To work, you need a special tray into which primer is poured in portions. The roller is dipped into the liquid and rolled on the ribbed part of the tray so that the excess material drains off and the roller itself is evenly saturated. Then they transfer the tool to the surface and roll a section of it, trying to apply the primer evenly. At the same time, omissions and smudges are not allowed.

The next batch of soil begins to be applied next to the previous one, gradually entering the previously treated area. To avoid any gaps, add a little color to the primer that is close in color to the main color of the finish. This way you can control the priming process and avoid omissions.

To reach the ceiling and upper parts of the wall with the roller, a telescopic extension is attached to the tool. In places where it is impossible to reach with a roller, cover the base with a brush.

When working with the tool, make sure that the primer does not drip onto the floor, clothes, body, or get into your eyes. Gloves and goggles are used to protect the body and eyes. The floor is covered with plastic film, paper, cardboard.

How to apply by spray

The most effective way to prime large areas is to spray with a spray gun. The primer is prepared in the usual way described above. The main thing is to choose a nozzle that matches the grain size, viscosity and fluidity of the material. To apply primer, use nozzles from 1.4 to 1.8 mm and a needle along the diameter of the nozzle.

The next step is to adjust the shape of the torch (with a special screw) and the volume of applied primer on the sprayer. Set the supply air pressure within 3–5 bar. Apply the composition to the probe and evaluate the quality of the spray. The prepared primer is poured into a paint sprayer and, taking precautions, the material is applied to the base. They work quickly with the spray gun, apply the primer evenly, and do not stay in one place for long, otherwise there will be smudges. After coating, wait for the soil to dry and begin further processing.

Materials for plastering surfaces

Since it is impossible to do without plastering the surface when restoring a building foundation, you need to know what is needed for plastering walls. The following materials will be required:

• plaster;
• primer;
• an industrial mixer if a dry mixture is used to prepare the solution;
• container for dispensing primer;
• brushes, roller or spray bottle for applying primer;
• a clean bucket for preparing plaster mortar;
• paint bucket for spreading the solution onto the surface;
• set of spatulas;
• industrial trowel for grouting the material after hardening;
• rule for leveling the product.

How long can it take to plaster?

It all depends on what kind of primer you used.
Thus, acrylic primer dries in 8 hours, while oil, glyphthalic or contact primer takes a much longer time to dry, about 24 hours. Mineral soil dries in different ways, it all depends on the thickness of the applied layer - from 3 hours to a day. Phenolic soil takes approximately 15 hours to dry. Quick-drying primers are also sold; after treating them, walls can be plastered in 6-7 hours. Alkyd primer dries in 10-12 hours. And perchlorovinyl primer, when applied in 1 layer in summer in hot weather, dries in 60 minutes.

Polyvinyl acetate primer dries in half an hour.

You can treat the walls with a primer yourself. It’s better not to be lazy and spend a little extra time so as not to be disappointed with the result. Moreover, applying a primer is not so difficult; minimal skills in working with a brush or paint roller are enough, although for large-scale work it is better to use a professional spray gun.

Drying time

Before using the primer mixture, it is important to read the instructions on the package. There you can also find the time it takes for it to dry, since this parameter differs for different soils. But it may be that there are no technical specifications on the packaging. In this case, the experience of professionals suggests that the acrylic version dries in about 3 hours.

For contact and oil soils this time extends to 24 hours. However, everything depends on air humidity and temperature. For example, if the room is more than +25 degrees, the mixture will dry faster, but if at this time the humidity exceeds the threshold of 65%, you will have to wait 3 times longer.

Making your own primer

There are 3 recipes for preparing primers. All of them are easy to make with your own hands.

To improve adhesion

It can be applied to any glossy surface, for example, metal pipes, sheets of tin.

1. Bring 1 liter of water to a boil in an enamel bowl, place 250 g of potassium alum.
2. Pour 200 g of dry paint glue into a separate bowl and pour in 2 liters of water.
3. Place the dish with glue on the stove, light the burner, add a grated piece of laundry soap (70%), mix thoroughly.
4. Grind 2 kg of chalk to a dust state.
5. After dissolving the soap, pour in 30 ml of drying oil and 2 kg of chalk powder and mix.
6. If the primer is too thick, add water.

To increase strength

1. Pour 7 liters of water into an enamel bucket or pan, place it on the stove, light the fire and wait for the water to boil.
2. Rub 1 piece of laundry soap (65%) on a grater.
3. Pour soap into boiling water and turn the heat to low. Continuously stir the mixture with a wooden spoon.
4. After the soap has completely dissolved, pour in 500 ml of wood glue and add 100 g of copper sulfate.
5. Mix the mixture thoroughly for half an hour. It is impossible for lumps to appear.
6. Then strain the hot mixture through a sieve and cool.

This primer can be applied to walls made of concrete and brick.

Deep penetration

1. Pour 1 liter of PVA glue into an enamel bowl, gradually add 8 liters of water, stirring until the mixture becomes homogeneous.
2. Add 1 trowel of cement and mix thoroughly.
3. Strain through gauze folded in 2 layers and prime the walls.
4. The prepared mixture is immediately applied to the walls.

Recommendations for choosing a primer

In order to choose the right primer for plaster and get a quality repair, it will be useful to learn how to properly mix different types of material, how to make a primer mixture yourself, and when it is better to use only ready-made compounds. Recommendations from professionals will help you obtain this important information:

• Having purchased any type of primer, strictly follow all instructions for diluting the primer mixture, which are given in the instructions for the material by the manufacturer. Proper dilution of the mixture will allow you to achieve economical consumption of the composition;
• It is possible to make a primer mixture yourself: at home, any high-quality wallpaper glue can replace it. The product needs to be diluted, treated with it on the walls and immediately begin wallpapering. You can also make a mixture by mixing soap, wood glue and vitriol.

All subsequent work is carried out only after all layers of primer have completely dried.

The best primers from the store

1. Acrylic - it is applied to wooden, concrete, brick, plastered walls, and chipboard.
It has no odor; after applying it to the walls, they “breathe.” It is not suitable for smooth surfaces. 2. Alkyd - it is used to treat wood surfaces, which then swell somewhat, so wallpaper sticks well to them. It may contain mixtures that prevent corrosion and mold from appearing.

3. Glyphthalic - suitable for metal. But it is only suitable for dry rooms.

4. Perchlorovinyl - it is universal, suitable for wooden, brick, plastered and metal walls. It is toxic, which is why only outdoor walls are treated with it.

5. Polyvinyl acetate, it includes polyvinyl acetate dispersion and latex. It can be used to cover any surface, but only polyvinyl acetate paint can be applied to it.

6. Phenolic - it is applied as the first layer on walls made of metal and wood. But since it is poisonous, it can only be applied to external structures.

7. Polystyrene - it is also used to cover external walls; it cannot be used indoors. It is applied to plaster and wooden walls.

8. Aluminum, it is used to treat wood surfaces and protects them from fungus.

9. Epoxy is applied to concrete surfaces for better adhesion and to protect the metal from corrosion.

10. Shellac is used to treat wooden walls to prevent resins from escaping from them.

11. Mineral is made of cement, gypsum, lime. It is covered with concrete and brick.

12. Universal.

Treating walls before plastering

Builders have long noticed that walls coated with film-forming substances contribute to the reliable connection of the plaster layer to the wall. The product was prepared from materials of natural origin: soap solution, bone glue and copper sulfate. Modern solutions for treating fences are made based on various chemical compounds. It's called a primer. There are many types of primer for plaster. For each type of base and composition of the plaster mortar, a specific type of primer is selected.

Why do you need to prime walls before plastering?

What to prime the walls with? Do I need to prime the walls before plastering? There should be no doubt about this. Of course, surfaces must be primed for the following reasons:

1. The loose surface layer of wall fences is strengthened.
2. A reliable adhesion of the plaster to the base occurs.
3. Antiseptic additives prevent the formation of mold and fungal formations.
4. Fire retardants help increase the fire resistance of the coating.
5. The primer for plastering walls performs waterproofing functions.

Consequences of plastering without a primer
From seeing the photo, no one will have the question: “Do I need to prime the wall before plastering?”

Types of primers

Impregnating compositions differ in their purpose:

1. For surfaces with a wood structure (wood, chipboard, fiberboard and OSB), liquids consisting of organic solvents based on alkyd and other resins are used. They are also applied to surfaces painted with oil paints.
2. Universal impregnation is a water-soluble product based on acrylic, silicone or silicate. This type of primer is applied to concrete walls, brickwork, wood surfaces and plasterboard cladding.
3. There are special coatings using epoxy, polyurethane and shellac resins and cement. They are rarely used in construction.

To treat walls before plastering, mainly universal liquids are used. Coatings based on various solvents are not used for impregnation of foam and polyurethane foam fences.

Wall railing bases

Each base has its own type of primer. According to their structure, vertical fences are divided into mineral, wooden, metal, hydrophobic and absorption bases:

Mineral

Such structures include concrete, brick and plasterboard walls. They are impregnated with universal products. Deep penetration liquids are applied to loose, crumbling substrates.

Do I need to prime a wall before plastering a dense surface? This must be done, because under the top layer there may be a fragile layer of material. The deep penetration agent saturates the base several centimeters deep. This applies especially to concrete and brick fences.

Deep penetration impregnations should not be used to treat dense substrates. Due to the inability of the product to penetrate deeply, it forms a polymer film on the surface, which can contribute to the peeling of the plaster.

For concrete bases, a solution called Betonkontakt is used. The component of fine quartz sand in Betonkontakt significantly increases the adhesion of concrete.

Primers for brick walls under plaster can be used for cement surfaces.

Wooden

Wooden bases include not only wood, but also surfaces made of chipboard, fiberboard, and OSB. For such bases, impregnations with fire retardant and fungicidal additives are used. These components increase fire resistance and prevent the appearance of mold and fungal formations in the wood structure under the plaster.

Metal

If it is necessary to plaster metal fences, special-purpose coatings are used. These products include a rust converter, which is used on metal as a primer for plaster. In addition to cleaning rust stains, the liquid provides high metal adhesion. The universal coating of metal structures includes this substance.

Hydrophobic

Glass, laminate and ceramic tiles have the quality of being hydrophobic. For walls of such a structure, it is best to use special coatings based on polymer resins. They are often used as a preparatory layer for decorative plaster or before textured painting.

Absorption

Walls made of foam blocks and aerated concrete have such surfaces. Is a primer necessary before plastering masonry walls made of these materials? It is necessary in order to, in addition to increasing adhesion, prevent moisture from penetrating into the walls. The coating forms a durable waterproof film on the surface of foam concrete and aerated concrete blocks.

Pros and cons of using primer

So why do you need wall primer? To answer this question, you need to understand what advantages and disadvantages this procedure has.

The benefits of using a primer include:

• Walls treated with primer are well protected from damage that may occur, for example, when removing old wallpaper.
• The primer layer increases the moisture resistance of the walls, reliably protects the treated surface from destructive processes, the appearance of dampness, mold, and mildew.
• The antiseptic components included in the composition have a specific odor that repels harmful insects and microbes.
• The final layers applied over the primer will be more resistant to various influences and will last longer.

Is it possible to plaster over old paint?

Most instructions for finishing materials say that before applying them, it is necessary to remove the old surface coating, since the new one may fall off soon after the repair. Especially when it is already poorly held or can be easily removed with a spatula. This rule applies to old paint. But there are cases when it holds up well for now, but removing it will be quite labor-intensive. As a result, even the most experienced specialists find themselves at a dead end in finding a way out of this situation. Under these circumstances it is quite possible to apply plaster over paint.

Old paint, especially oil paint, has already lost its adhesive properties. Thus, when putty or plaster is applied to it, these finishing materials will fall off and crumble after some time. But there is one way in which it is quite possible to solve this problem. And this secret is that a special primer is applied to the old paint under the plaster:

• Betonokontakt primer is very suitable;
• you can use a special composition from Neomid.

When using this method, the surface becomes rough. Strength is achieved thanks to the liquid component of the primer, which is absorbed into the old coating, in our case, into the paint. And adhesion is improved by containing small particles, for example, quartz sand.

Common Mistakes

Even though the task is not too difficult, common mistakes are common. The first of them is the use of dispersion and water-emulsion pigmented paint. It does not perform all the functions that are required. Also, you should not use it even as a second layer - this leads to the formation of various stains. The main mistake is applying one layer, because almost always two are required.

Not everyone knows whether it is necessary to prime a wall before plastering, so they do not do this work. This approach is also wrong.

Remember that priming the walls always precedes plastering. This is the only way the walls will be able to keep the coating for years. Treating the surface with a strengthening mixture is a common practice for many advanced builders.

Why plaster walls?

Amateurs often have a question: why do you need to plaster walls? This finishing stage is performed for the following purposes:

• Leveling the building base. This manipulation is performed before further painting or wallpapering. The procedure is carried out so that the appearance of the finish meets the aesthetic needs of users. For this reason, to the question: “Do I need to plaster before wallpapering?”, the answer will be positive.
• Masking of defects. If there are cracks, depressions or potholes on the surface, then decorating the surface will not work. First, the defect is masked and only then the finishing is applied.
• If we talk about whether it is necessary to plaster monolithic walls, craftsmen do not recommend abandoning this stage of finishing. This manipulation is performed to seal the joining seams of the slabs if wallpaper or paint is used as a decorative coating. When tiling, plastering may not be necessary.

Useful tips

Arm yourself with useful recommendations from professional craftsmen: this will help you achieve the highest quality results when carrying out finishing work. Plastered surfaces will be reliable and durable if the material is selected correctly:

• When purchasing, choose water-soluble formulations. They have a breathable texture and do not accumulate moisture.
• If the composition contains solvents, they are not suitable for processing foam.
• Before applying primer, it is important not only to clean the base, but also to wipe it with a damp cloth to remove dust. Otherwise it will be on the surface, which will affect the color of the base.
• The primer must be diluted in strict proportions. Do not compromise the consistency: this will affect the consumption and absorbency of the walls.
• The layer of application of the composition should not be dense. It is important to maintain uniformity over the entire surface being processed.
• The primer can only be applied to a dry base.

• The most difficult to reach places can be treated with a spray bottle.
• If the surface being treated consists of several materials of different composition, use a universal primer or separate compositions (if you have the finances).
• Wear protective glasses and gloves when working. If liquid gets on your skin, wash it immediately, otherwise it will be difficult to remove.
• If the soil has an odor, buy a respirator. Special clothing is recommended: if it gets on it, it will leave stains.
• When finished, wash your roller and brush immediately. If the primer dries out, you will have to change the roller coat and throw away the brush.

Sources

• https://otdelkasten.com/pokraska-sten/kak-nanosit-na-steny-gruntovku
• https://StroyGuru.com/remont-kvartiry/steny/zachem-nuzhna-gruntovka-sten/
• https://otdelkasten.com/pokraska-sten/luchshaja-gruntovka-dlja-sten
• https://stenamaster.ru/vidy-gruntovok-ih-primenenie-261.html
• https://mastremont.ru/kakoj-gruntovkoj-obrabotat-steny-pered-shtukaturkoj/
• https://cozzyroom.com/remont/gruntovka-sten.html
• https://odissey2000.ru/staty/kak-gruntovat-steny-instrukciya-po-pravilnomu-naneseniyu-gruntovki
• https://otdelkasten.com/shtukaturka-sten/gruntovka-sten-pered-shtukaturkoj
• https://diy.obi.ru/articles/gryntovka-dlya-sten-pravila-vibora-i-ispolzovaniya-20910/
• https://GidPoKraske.ru/gruntovanie/gruntovochnye-raboty/gruntovka-sten-pered-shtukaturkoj.html
• https://dekoriko.ru/gruntovka/pered-shtukaturkoj/

Why do you need a primer for putty?

Plaster is capable of absorbing moisture more and has a fairly rough surface that requires further processing. And when the question arises whether it is necessary to prime the plaster before puttying, it should be taken into account that the density of the former is much lower than that of concrete, and the porosity is greater.

These conditions indicate that the surface needs to be puttied for further finishing. This way you can avoid a rough coating that will show its marks through the finishing material. And the more intense the layer of plaster, the weaker it will adhere and the faster it will peel off.

However, in the process of laying putty on a porous and moisture-absorbing surface, the composition instantly loses its plasticity, and as a result it becomes difficult to level.

In addition, in such a situation, particles often separate from the spatula, which will leave damage and gaps on the base prepared for the putty. Priming allows you to avoid these problems and will help strengthen the layer of future putty to a fairly impressive depth, as well as avoid porosity and moisture penetration.

Interesting! The composition of the primer differs from concrete in the absence of impressive penetration and the ability to saturate the wall to a sufficient depth.

Carrying out the work yourself?

While building a house and finishing work can be done on your own without any problems, installing electrical wiring in a wooden house in most cases requires the hands of a specialist. Although quite often the owners of country houses (meaning the male half) carry out such work on their own.

This is understandable. A real owner needs to be able to understand such things. For novice “electricians”, there is a step-by-step method for carrying out the process of installing electrical wiring, taking into account the necessary requirements, following which you can carry out the relevant work efficiently.

Tools

We already know which primer is better. In addition, we found out what is the best way to prime a brick or block wall before applying plaster. The amount of material has been determined, all that remains is to prepare the tools that will be needed in the work:

• To perform cleaning you will need a dustpan and a broom; you can use an industrial vacuum cleaner;
• when working at height you will have to use a stepladder;
• gloves, a cap, and goggles will be needed as protective equipment;
• To remove drips from the walls, prepare a damp cloth;
• To remove defective areas, you should have a hammer, chisel, and sandpaper at hand;
• roller - selected taking into account the material from which the wall is built. For example, priming a brick wall is best done with a roller that has a long or medium pile. Concrete walls are easier to handle with foam or velor rollers;
• to work in hard-to-reach places you will need a paint brush;
• cuvette for rolling and squeezing the roller.

It is more convenient to work with a brush in small areas. With its help, you will treat even small cracks and small recesses with primer as much as possible. The roller is used on large, flat surfaces because it has a certain contact area.

There is another option for applying primer - a sprayer. Its use is justified over large areas. In addition, in the accompanying instructions, the manufacturer always indicates how this or that primer is applied.