Primer for walls for painting - types and tasks

Gusevsky Andrey Anatolyevich

Drywall primer

Painting walls today is one of the most popular types of decoration of premises. Few people like to make repairs every year, so you need to keep the coating for a long time, while maintaining a fresh, pristine look.
This can be achieved only if the primer of the walls was carried out before painting, and the paint itself was selected high-quality, corresponding to the operating conditions.
Be sure, no matter how expensive and reliable it is, without proper surface preparation it is impossible to guarantee that it will not crack or crumble after a while, that dirty spots from walls will not come through it, mold will not appear, etc. The primer can protect against all this.

Purpose of use of primer

The task of the primer is to prepare the surface for the subsequent application of any finishing materials, including coatings.
What is the essence of preparation, what does it give:

• First of all - improving the adhesion properties of the surface of the base. Simply put, its ability to adhere to and hold paint or other coatings;
• Strengthening the base, binding its particles to each other. If the surface itself, intended for painting, is not able to withstand mechanical stress, if it crumbles or crumbles, then the paint itself is not able to stop and prevent this process - it will crumble along with the top layer. But the primer before painting the walls will cope with this task;

Crumbling surfaces - unreliable paint base

• Reduced absorbency. This is especially true for plastered, plastered and other porous surfaces that absorb moisture well;
• Save paint. If the base is primed and is not able to absorb a lot of coloring matter, most of it remains on the surface, immediately creating a uniform decorative layer;

Note. Where two or even three coats of paint would have to be applied without a primer, it often allows you to do one. Given that the price of good formulations is quite large compared to the cost of soil, the savings from its use are obvious.

• Protection against emerging stains. The uneven color of the base or colored spots on it can shine through the paint. Primer (seeDrywall primer for wallpaper - why is it needed) covers them with a thin and durable film, preventing them from seeping out;

The paint lays on the primer evenly and easily.

• Protect the base from moisture. When painting exterior walls or in rooms with high humidity, a special water-repellent primer will prevent the penetration of moisture into the thickness of the material, preventing its destruction;
• Protection against fungus (seeAntifungal primer - purpose and characteristics of the material) High humidity, poor thermal insulation and other factors can trigger mold on the walls. Primers with special fungicidal additives will help not only to prevent this, but also to cope with an existing problem.

One of the functions of a primer is mold protection.

As you can see, this operation has many functions. If you need a solution to at least one of the listed problems (you need to save paint, strengthen the loose base or protect it from moisture), then you can easily answer the question of whether it is necessary to prime the walls before painting.

Features of the choice of primer

The composition for priming is selected depending on the characteristics of the material in need of processing.There are many primers for general use, suitable for different surfaces, and there are special mixtures with special properties designed for specific materials and creating the basis for a certain type of paint.

Primers for walls

Let's see which priming preparations exist, and which of them are applied to different substrates depending on the operating conditions:

• Firming impregnation. These are acrylic water dispersion primers with various additives.
  They are mainly used for internal work on lime, cement-lime, gypsum plasters, drywall. They improve the adhesion of the surface to paint, strengthen unreliable bases, form a film on their surface that does not allow moisture to pass, but does not impede the passage of air vapor;
• Acrylic primers. They are used for external walls - they penetrate deeply into them, bind dust and surface particles to each other, create water-repellent protection;
• Acrylic and latex primers. Suitable for exterior and interior use, serve as an excellent base for acrylic and water based paints;

Front acrylic primer paint Acrylato Primer

• Primer for solvent-based walls. It is deeply absorbed, it binds well the dust and particles of plaster located on the surface, does not interfere with fumes, creates a hydroprotection.
  It is used for plastered, asbestos-cement, wood and previously painted surfaces both inside and outside the building;

Note. Such compositions are highly flammable; care must be taken when handling them.

• Silicate primers. An excellent choice for preparing exterior walls made of concrete, silicate brick, and also coated with lime or cement-lime plaster, silicate paint. Deeply absorbed in cracks and pores, clogging them;

In the photo - the processing of sand-lime blocks

• Two-component epoxy paints. They are used on concrete substrates in the interior. Before use, mix the contents of the two packages and dissolve with water.

It is important! You can not mix components from different manufacturers - they may not be suitable in chemical composition, and the finished product will lose its useful properties.

Primers for wooden substrates

Most often it is necessary to paint wooden surfaces, whether it be partitions, walls, facade decoration, doors or window frames.
A whole series of special tools is intended for them, which includes:

• Drying oil. The composition that penetrates deeply into the structure of the tree protects it from moisture and rot. Universal - can be used for indoor and outdoor use;
• Alkyd primers. They are used before painting wood with alkyd, oil and latex paints;

Alkyd soil is available in metal cans

• Water soluble acrylic primers. They give the base a uniform color before applying varnishes, paints, impregnations and stains;
• Styrene primers. Protect from decay, form an adhesive film on the surface that improves the adhesion of phthalic and alkyd enamels to it;
• Oil based primers. Apply after primary priming with drying oil. Suitable for processing any wood materials, as well as metal;
• Shellac primers. Their purpose is the processing of fresh coniferous wood that exudes resin.

Shellac

Priming nitrocellulose varnishes are also very popular, but they are more suitable not for walls, but for the floor - they protect the natural wooden flooring from darkening.

Tips for wall primers

Not all surfaces need thorough preliminary preparation. If they are durable, do not absorb water, have good adhesive properties, you can do without this stage.
You can answer the question negatively whether it is necessary to prime the walls before painting, if we are talking about dry storage and other utility rooms, which do not have high decorative requirements.
In all other cases, it is better not to neglect this operation. Especially if, after rubbing a finger against a wall, a dirty mark remains on it or on the surface itself.

Before you begin this work, study the following tips and tricks from experienced craftsmen:

• Freshly plastered walls can be primed only after the mortar has completely dried - after 2-4 weeks;
• When processing facades, you need to ensure that they are dry and not too heated by the sun;
• If it is necessary to dilute the primer, only those products specified by the manufacturer may be used. The instructions on the package contain both this information and the recommended proportions;

Always read the instructions for use carefully.

• If the treated surface is characterized by high absorbent characteristics, the primer should be applied in 2-3 layers;
• You can start staining after the time required for the complete drying of the primer. For different compositions it is different and can range from 2 to 24 hours;
• Before the primer of the tree, you first need to treat the knots - heat them with a thermal gun, collect the protruding resin with a spatula, wipe with a solvent and cover with shellac;
• Walls affected by mold, cleaned from it with a stiff brush, dried well, and only then covered with a special penetrating primer with fungicidal properties.

The primer can be applied in any way convenient for you - with a brush, brush, roller or spray. It is important not to leave unprocessed areas, but also to prevent the formation of sagging and puddles on the surface.

Conclusion

You can get more information on this topic by watching a short video on this page. But, based on the foregoing, it should already be clear that the walls need to be primed. Of course, if it is important for you that the end result is pleasing to the eye and does not require periodic alteration.