Primer for plaster and before plastering: choosing the best solution taking into account the parameters, types

The correct primer can make a big difference when plastering. Plaster needs a strong foundation in order to bond and produce a smooth, long-lasting finish. It is not only about adhering to the surface.

Selecting the best primer can be challenging because there are many different kinds available. Every primer has unique qualities that work well with various plaster types and surfaces. Selecting the ideal primer for your requirements is made easier when you are aware of your options.

We’ll walk you through the important things to think about when choosing a plaster primer in this post. You will discover all the information required to make an informed choice, from comprehending primer types to knowing when and how to apply them.

Type of Primer	Best Use
Acrylic Primer	Great for most surfaces, quick-drying, easy to apply.
Alkyd Primer	Ideal for wood, provides a strong base.
Epoxy Primer	Best for areas with high moisture, offers strong adhesion.
Polyurethane Primer	Perfect for metal surfaces, protects against corrosion.

The need to apply a primer

The most widely used primer application tool is shown in the picture.

Plaster requires a high-quality primer that is carefully chosen, and there are several clear reasons for this, such as:

• ensuring high adhesion of the base to the applied finishing materials;
• ensuring the resistance of the base to mechanical loads by filling the micropores with an impregnating composition and strengthening the entire structure;
• ensuring the resistance of the base to the negative impact of environmental factors due to a dense polymerized film on the surface and, as a result, an increased degree of hydrophobicity.

Plaster seems to have a composition similar to putty. However, there is a notable distinction in the fillers’ grain size and composition. Putty can now be applied in a thin layer and polished with sandpaper after drying, thanks to an order of magnitude improvement in adhesion.

Such benefits are not present in plaster mixtures. The plaster layer is viscous when it’s wet, but as it dries, it’s possible for some areas of the finishing material to peel.

The base of the plaster mixture’s extensive moisture absorption is the cause of these unfavorable effects. Consequently, the finishing material does not have enough time to properly set and adhere to the base in the areas from which the moisture was removed the quickest. A primer, which is widely available in specialty construction stores, can solve this problem.

When finishing walls that have already been plastered, a primer is still required. For instance, the base needs to be strengthened and made more hydrophobic before painting or gluing wallpaper with your hands after it has been leveled with a layer of putty or plaster.

This can be explained by the fact that most plaster mixtures and putties do not form a uniform layer covering the whole surface with the same density after drying. Because the glue is absorbed unevenly, the paint will lie unevenly on such a base and the wallpaper may come off.

Applying a primer layer, which creates a microdillor with uniform properties across the base’s entire surface, will be a successful solution to this issue.

Important: Using a primer both before and after plastering will ensure the best possible finishing work.

Choosing the best solution

Painting pre-primed decorative plaster is seen in the picture.

As was previously mentioned, there is a large variety of impregnating compounds available on the market, so you can select the ideal option for a variety of surfaces.

Certain primers, for instance, fill the pores and strengthen the material by penetrating the base’s thickness. Other materials form an external hydrophobic film, but behave differently and essentially do not penetrate deeply. Plaster application requires the use of products that also serve as disinfectants or antiseptics.

The issue with using the aforementioned compositions is that, in order to achieve specific operational characteristics, they must be used in conjunction with other materials. Conversely, there are universal primers that serve multiple purposes simultaneously when applied to the plastered base.

Using universal compounds can help you save money by eliminating the need to buy multiple compounds and shorten the time it takes to complete tasks.

Parameters that should be taken into account when choosing a primer

This is how a country house’s walls are primed for gypsum plaster.

Important: Not all primers work well with all bases. The accuracy with which the primer is chosen prior to plastering will determine the final product’s quality.

Depending on the kind and properties of the base, primers fall into the following categories:

• Strengthening compounds are used if the plastered base is unstable or loose with an excess of micropores;
• Deep penetration impregnations are relevant if the base has recently been plastered or if the surface is made of asbestos cement or materials of similar density;
• Anti-corrosion compounds are used if finishing materials are to be applied to bases with metal inclusions;
• Antiseptic impregnations are relevant when finishing old walls or when working on wooden bases;
• Primer compounds with increased adhesion are used if the base is covered with difficult-to-remove contaminants, both organic and inorganic in origin.
• Universal impregnations are used when some of the above conditions are typical for one type of surface.

Once the criteria for choosing a plaster primer have been established, we will take into account the primary categories of compounds available in the market.

Types of primers for plaster

Using an acrylic primer before painting is seen in the picture.

There are two primary categories into which the whole primer range that is marketed can be separated:

• strengthening;
• adhesive.

Primers of both kinds are available for purchase as dry mixtures that can be diluted with water or organic solvents, or as ready-made liquids.

A roller, brush, sprayer, or other conventional painting tool can be used to apply either type of coating. The type of tool that is appropriate to use is usually indicated specifically in the instructions on the packaging.

Products called strengthening primers are used to treat bases initially. As a result, these compositions are generally referred to as primers.

Primers’ primary purpose is to fuse the base’s top layer’s structure into a uniform coating down to a maximum depth of three centimeters. Up to 10 cm of the plaster and base’s micropores are penetrated by deep penetration primers.

These are, of course, average indicators that may vary depending on the type of base and the properties of the plaster layer. For every square meter of plaster, 50–120 grams of primer are typically used. Prior to applying decorative plasters or tile adhesives, the base must be prepared using deep penetration primers.

The purpose of adhesive primer for decorative plaster is to enhance the adhesion properties between various finishing material layers.

Primers are categorized as follows based on the properties of the binder component:

• alkyd;
• acrylic;
• mineral;
• polystyrene;
• phenolic.

Although there are more compositions in the list, it is best to stick to the first three when remodeling residential property.

We will go into further detail about each of them with you.

The image shows alkyd primer-enamel.

• Alkyd primer is used to treat a wide range of bases, including wood, concrete, tile and even glass surfaces. Before applying the plaster layer or decorative finishing layer, the primer must dry for 10-15 hours.

A ready-to-use acrylic primer is seen in the picture.

• Acrylic primer is a universal product, as it can be applied to both old and new plasters, as well as to brickwork, concrete, wood, etc.d. In addition, a primer for decorative plaster, made on the basis of acrylic copolymers, can be used to process dry plasters based on gypsum boards and chipboards.

Standard packaging of mineral primer for aerated concrete underneath plaster

• Mineral primer is used exclusively in construction and serves mainly to strengthen old plaster coatings and other porous and unstable surfaces.In addition, such impregnation has proven itself as a material for processing concrete, expanded clay concrete and gas silicate blocks, brickwork, etc.d.
  Primers are made on the basis of lime, gypsum, cement and a number of other materials of mineral origin.

Selecting an appropriate primer prior to plastering is essential to attain a robust and long-lasting surface. The important things to think about, such as surface type, plaster compatibility, and environmental conditions, will be walked through in this article. You can make sure your plaster adheres correctly and lasts longer by being aware of the various primer types and their unique advantages. This will ultimately save you time and effort when it comes to future repairs.

Plastering requires careful primer selection in order to produce a smooth, long-lasting finish. It prolongs the plaster’s life, improves adhesion, and guards against moisture.

Take into account the particular requirements of your project, including the kind of surface, the surrounding circumstances, and the plaster type you’re using. Aligning these elements with the appropriate primer will simplify and improve the quality of your work.

Choosing the right primer will save you time and effort in the long run, as well as enhance the quality of your plastering.

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