A Primer For Walls Under Wallpaper: Is It Necessary To Primer Before Gluing, Which One Is Better To Choose For Liquid Coatings, What Else You Need To Remember In The Process Of Wor

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-18 12:09

Having started repairs, many neglect such an important stage of work as priming the walls. And completely in vain. The use of primers before finishing allows the coating to adhere more firmly to the surface of the walls, minimizing the risk of defects in the future.

However, you should not use any soil that is at hand. It is necessary to know and understand how to properly process the walls, what is needed for this, and what is strictly prohibited.

Why is this needed?

One of the most important steps in preparing walls before painting or wallpapering is priming.

Let's consider the main functions of the primer:

Adhesion . Increased adhesion between materials ensures tight adhesion of the layers and prevents the webs from peeling off. With insufficient adhesion, the new tile will soon fall off along with the glue, fresh plaster begins to crumble, and expensive wallpaper rolls off. However, the same fate awaits cheap wallpapers. And these manifestations are the stronger, the smoother and smoother the surface was before finishing. That is why the priming of the walls is of fundamental importance.

When processing, the walls become rough, due to which the top layer of finishing materials adheres to the walls as firmly and evenly as possible.

An example of a typical adhesive commonly used for the treatment of flat, smooth surfaces is concrete contact. It contains small particles of quartz in combination with an adhesive base. When applied, the surface remains fairly even, but acquires the required degree of grain, which ensures a high quality of further finishing and decoration work.

Strengthening the surface . The soil deeply (up to 15 cm) penetrates into the pores of the walls and sticks them together, thereby minimizing the likelihood of delamination of the base. The material becomes stronger and more homogeneous. The fewer internal defects on the walls, the higher the quality of the finish.

Priming reduces the likelihood of subsequent destruction of the material and this is very important for all types of walls, especially for porous and loose materials (plaster or brick).

Antiseptic treatment . Mold and mildew that appear on the ceilings and walls of a room is a hazard to life and health. Neither the owners of cottages, nor the inhabitants of high-rise buildings are insured against the appearance of such uninvited guests - they arise wherever there is high humidity and little air, where the temperature is not particularly high, and there are no opportunities for ventilation. This is why mold is most commonly found in bathrooms, but it can often be found in living spaces as well. Allergies, asthma, chronic diseases of the bronchopulmonary and nervous systems - these are just some of the dangers that await residents of affected apartments and houses.

To reliably protect walls from mold, special soils are used, which include antiseptics. They destroy bacteria and prevent the growth of these dangerous microorganisms, making the microclimate clean and healthy.

Reduced glue consumption . During the priming process, the wall is covered with a smooth film, which prevents excessive absorption of adhesives.

The use of a primer greatly facilitates the process of applying topcoats (glue, plaster or paint), which means that raw materials are consumed more economically. For surfaces treated with special compositions, just one single layer of paint is enough, but "bare" surfaces need two, three or even more layers. This leads to an increase in the consumption of paint (or glue), the cost of effort and time, since each applied layer must dry thoroughly before applying the next one.

That is why priming is not only high quality, but also tangible savings.

Disguise . Dark and yellowed spots are masked - this is especially important before applying light wallpaper or painting with white enamels. If you bought a house or apartment on the secondary market and started repairs, then after removing wallpaper or old paint, you may find greasy stains, as well as indelible traces of coffee, colored ink, corrosive soot, tobacco and similar unpleasant surprises. Such traces are more likely to shine through the new wallpaper, especially if you use light, uniform colors, and this will inevitably ruin the whole look of the room.

To combat such spots, special pigment primers are used, which effectively mask the spots once and for all.

Moisturizing . Uniform wetting of the treated surface is of fundamental importance before plastering. If the wall is not moistened, then in different areas the finishing hygroscopic layer will begin to dry at different rates - somewhere it will dry longer, but somewhere too quickly and you will have to wet the walls again and again. All this will invariably lead to the fact that the surface is covered with stains and looks unaesthetic. The reason for this is the heterogeneity of the material itself. Chips and small cracks can be located inside, and in addition, some areas warm up faster (near pipes and batteries). It is the priming that provides moisture and uniform drying of the coating, and therefore improves the quality of the finishing work.

Types of primers

All types of primers are divided according to three criteria: solubility, base material and scope.

According to the criterion of solubility, there are:

• water-based - acrylic, as well as silicone and silicate;
• based on natural minerals (gypsum, cement);
• compounds dissolved by organic matter - polyurethane, latex, alkyds.

The components used are:

• alkyd - versatile mixtures, equally effective on wood, concrete or metal surfaces;
• acrylics are used mainly on brick and plastered walls; they perform well on surfaces such as fiberboard and chipboard;
• polyurethane - optimal for coatings with low absorbency, as well as on dirty and dusty walls;

• latex - effective suspensions, suitable for all types of walls;
• silicate mineral - suitable for concrete and plastered surfaces;
• glyphthalic - the most effective for the preparation of bases made of metal or wood, are used in rooms with high levels of humidity;

• perchlorovinyl are considered universal soils, optimal for the preparation of poorly and rarely heated premises. Keep in mind that perchlorvinol formulations have an unpleasant odor, so processing should only be done in a well-ventilated area;
• aluminum is effective for surfaces affected by fungus;

• epoxy ones are optimal for metal surfaces, they reliably protect corrosion and increase adhesion to finishing materials;
• shellac compounds prevent the appearance of resins, therefore they are used when working with wooden surfaces.

According to their purpose, primers are divided into the following types:

• Universal designed for all surfaces and for any coating. As a rule, they are used for small volumes of work in cases where a specialized composition is not available, or for processing surfaces that consist of materials of a mixed type.
• Antifungal agents are recommended for the kitchen and bathroom. They contain ingredients that prevent the growth of mold and mildew. Provide adhesion of such strength that the coating adheres firmly to the substrate and no microorganisms can penetrate.
• Anti-corrosion ones are used to work with metal elements, extend their service life, and prevent the appearance of rust.
• Deep penetration mixes are an excellent option for porous, insufficiently strong and loose substrates. Such a wall is thoroughly strengthened, therefore it is often used when working with plaster, drywall and foam concrete.
• Covering primers with insulating properties.
• Pigmented ones are suitable for light materials.

By the way, some craftsmen prefer to make a primer with their own hands. There are several common recipes:

From laundry soap and copper sulfate . To prepare such a composition, water is taken and brought to a boil, after which grated laundry soap is added to it. For 7 liters of liquid, 1 briquette of 65% soap is required. There it is also necessary to add 100 g of copper sulfate and 50 g of glue for carpentry work. The composition is cooked over low heat for half an hour, after which it is filtered and cooled.

The second composition is easier to prepare . It will require 1 liter of PVA glue and 5 liters of water. The glue is diluted with water to a homogeneous consistency, after which a little cement should be added to it, stirred and filtered.

Both formulations provide deep penetration and guarantee high adhesion. All components of the mixture are available and have a low cost. Their only drawback is the lack of antiseptic characteristics.

Wallpaper glue or PVA diluted with water is also used as a primer.

Specifications

In times of scarcity, ordinary glue was used as a primer. Now, when the assortment of the proposed compositions is wide and varied, it is not so easy for the consumer to answer the question - which primer to prefer? Let's try to understand the intricacies of the choice.

In order to correctly determine and choose a suitable primer, first of all, you need to know on what type of surface the composition will be applied, as well as study the characteristics of the room (humidity, temperature) and the type of finishing material.

The choice of primer is based on several aspects:

By type of wall covering

A wide selection of dry and liquid primers for hardboard, OSB plates, brick, metal and wood is presented in hardware stores. It is very important to take into account the condition of these surfaces. When they pour, it is worth purchasing a suspension with deep penetration, if the walls are affected by fungus or dangerous mold, it is better to treat them with a quick-drying mixture with fungicides.

Different surfaces require different primers. For example, drywall will not "accept" every primer: it absorbs moisture, and if the composition for processing is chosen incorrectly, then the wallpaper layer in the future will be removed only together with the cardboard. That is why special requirements are imposed on primers for this type of materials: a solvent is unacceptable in its composition and it must have moisture-resistant properties. The best choice is an acrylic primer, which will protect the material and ensure maximum adhesion to the surfaces.

Not every soil is suitable for plywood due to its porous structure and high water absorption rate. The best choice would be an alkyd suspension based on drying oil or water-acrylic compositions.

For fresh untreated wood, as well as fiberboard and chipboard, it is better to purchase improved alkyd soils, they strengthen the pores and prevent the swelling of the canvases. However, they contain an organic solvent, so the primer cannot be used in residential premises. In houses and apartments, it is worth giving preference to acrylic soils - they have the same properties, but are completely safe for human life and health.

Concrete surfaces, as well as bricks, are treated with mineral compounds based on cement or gypsum.

If the walls are covered with old putty, then in addition to the primer, it is advisable to cover the walls with diluted glue. Otherwise, the wallpaper will first stick, but after a while it will fall off along with the top layer of putty.

By type of wallpaper

When choosing a primer, one should take into account what material it is applied under - under wallpaper or painting. In theory, you can use universal mixtures, but it would be more correct to focus on specific types of wallpaper (vinyl, non-woven or paper), as well as a type of paint and primed walls just for them. Many people apply diluted wallpaper glue, but it can leave stains and cause the wallpaper to turn yellow, so this option cannot be considered the most successful.

An acrylic primer will work well for all types of wallpaper. However, non-woven "require" alkyd suspension. Due to the high number of pigmented particles, as well as the property of forming a thin semi-matt film, it perfectly masks dark spots on the walls and forms an ideal base for shimmering wallpapers, emphasizing the color.

For water-based paint, which is mainly used in interior decoration, it is desirable to use polymer compositions.

How to treat the surface correctly?

Correct preparation of the walls is the guarantor of the quality of further finishing work. Before starting work, remove old wallpaper or paint, remove the crumbling layer of plaster, wash away the whitewash, degrease and level the wall.

If they have old wallpaper, they are removed with a spatula. Before starting dismantling, the surface is abundantly moistened with water or a special liquid. To remove simple paper wallpaper, a soap solution will suffice, but small cuts should be made on denser washable cloths so that the liquid can penetrate into the base and facilitate their removal.

If you cannot remove the coating the first time, then it is worth repeating the operation.

Tip: for tough wallpaper, you can use an ordinary iron. The heating surface is applied to the desired place through a damp cloth and pressed for a few seconds.

After all the old wallpaper has been removed, the wall is washed and cleaned with a spatula.

If the wall is plastered, then there is no definite answer to the question of removing the old layer - it all depends on the condition of the coating. It is quite simple to check it - you just need to tap the wall. If the coating is loose and has cracks, then the putty will simply sprinkle, such a coating should be removed and a new layer applied.

Painted walls are cleaned in a variety of ways. If an ordinary scraper is enough for a water-based emulsion, then enamel paints may require special solvents. The cleaned wall should be sanded with coarse-grained sandpaper.

Any surface cleaning must be carried out in a safe manner. When carrying out work, a universal respirator and protective goggles should be used, the room must be ventilated. If removers are used to remove the old paint layer, then you should protect the skin with a special paste from the adverse effects of solvents.

It is imperative not to remove old coatings with a soldering iron and gas torches.

If mold or mildew is found, sanitize with bleach or specialized preparations.

Only after pre-treatment should you proceed directly to the application of the primer. And remember - the mixture is applied only to completely dry walls!

To prime the wall, you need the primer itself, as well as tools: a paint roller, a container (pallet) and a brush.

Please note that soils are sold in liquid and dry form. The first one can be used immediately, but the second one should be diluted with water in the proportions indicated by the manufacturer on the package.

Instructions for applying primers are as follows:

• with a special brush, brush off the dust left after removing the old coating;
• degrease the base - this will ensure good adhesion of the soil to any base, as a rule, white spirit or ordinary acetone is used for this;
• apply the primer to the wall with a special paint roller, avoiding the appearance of "puddles", splashes and drips;
• hard-to-reach places (ledges, corners, decorative elements) treat with a brush.

The coating layer should not be thick. After the first layer has dried, the primer should be reapplied.

If you use glue as a primer, there are several features of this composition to be taken into account. It is very important to dilute the composition with water to a milky consistency. This is especially true if you use PVA glue (it is used in rooms with high humidity) - otherwise, before the next gluing, you will not be able to tear off the wallpaper, even if you wet it abundantly.

How long does it dry?

After all the primer has been applied to the wall, you need to wait until it dries completely. Wallpapering or painting is possible only after the wall is completely dry.

How long you have to wait depends on many factors, not least the type of soil itself:

• acrylic primer dries in about 2-3 hours;
• alkyd dries after 20 - 22 hours;
• it will take about a day to solidify the glyphtal soil;
• drying of polyurethane suspensions will take about a day;
• for a silicone primer, it takes about 5 hours;
• the latex primer dries quite quickly - you can start finishing work 2 hours after its application;
• silicate and mineral compounds dry the longest - they will need more than a day;
• but water-based mixtures dry instantly - you can apply paint and glue the wallpaper after 20-30 minutes.

The speed at which a wall dries can be affected by other factors, including:

• air humidity - the higher it is, the slower the soil dries;
• temperature conditions in the room - excessively low and high temperatures reduce the rate of drying of the coating;
• layer thickness - the denser it is, the longer you will have to wait;
• base structure - the deeper the coating penetrates into the wall, for example, for drywall, the longer it will take to wait for the cover to dry completely.

In the process of drying the primer, it is very important to comply with several requirements:

• avoid temperature fluctuations in the treated room;
• do not allow drafts to appear;
• do not try to dry the wall artificially.

Any deviation from these norms causes uneven strengthening of the layer, and, accordingly, reduces adhesion in certain areas of the surface.

Important points

Priming the surface of the walls before finishing is mandatory - it ensures high quality and durability of the subsequent gluing of wallpaper or painting the wall. Work with soil does not require special equipment and can even be carried out by a non-professional.

However, it is important to adhere to some principles:

• Choose a primer suitable for your surface.
• Follow the manufacturer's instructions carefully, the entire procedure is indicated on the outside of the package. The product should only be diluted in the proportions specified by the manufacturer. If you make the mixture more or less concentrated, then the primer will lose its performance and its use will lose all sense.
• Use a roller - it provides an even application of the layer, but hard-to-reach areas should be treated with a small diameter brush.
• Treat the porous base several times, treat damaged surfaces with solutions of two types: antiseptic at the first stage, and universal at the second.
• Take your time, wait until the surface dries naturally.
• Do not dilute the entire mixture at once (if you purchased dry soil) - most often only part of the raw material requires work.
• If during the work the primer gets on the floor, window or clothing, wipe the place of contamination with a cloth soaked in water. The sooner you do this, the easier it will be to get rid of unsightly stains.
• Rinse rollers and containers immediately.

These rules are simple, but it is their observance that will guarantee that all subsequent work will be done quickly, efficiently and efficiently.

Well, in conclusion, we recommend that you familiarize yourself with the best primer manufacturers in the world. Hardly anyone will doubt that the primer of a well-known brand is of excellent quality. But a product from an unfamiliar company is always fraught with risk: you may be lucky, and the product will have all the declared characteristics, or it may turn out to be much worse than expectations.

If you do not want to play roulette, then we advise you to give preference to the products of one of the leaders in this market segment:

• Ceresit - the absolute leader in the building mixtures market. A world-famous company with a century-old history. For more than 100 years, this manufacturer has been offering the consumer high-quality goods in a wide range. To date, Ceresit has opened its factories in Russia, which made it possible to significantly reduce the prices for products for the domestic consumer. The production of soils of all types has been established, and, of course, under the wallpaper.
• Knauf - a well-known German holding, formed in the 30s of the last century. The brand has been known on the Russian market since 1993. The products are represented by universal compounds, deep penetration agents, soils for absorbent substrates. The constantly growing quality of products here is ensured by the relentless introduction of the latest technologies and the improvement of the management system.

• Tikkurila - a company from Finland that has been successfully selling its products since 1862. The giant's production facilities are represented in several countries, where the production of paints and other materials has been established. The category of primers here is represented by acrylic compounds, as well as suspensions with moisture-insulating parameters and increased adhesion properties.
• Caparol - a brand with a worldwide reputation. The company began its work back in 1885, today the products are sold in dozens of countries around the world. The manufacturer offers a variety of soil types, including frost-resistant compounds and under wallpaper.
• Weber - a manufacturer that produces construction mixes under the Vetonit brand. Here, the production of primers for facade and interior finishing works has been established.

• Ivsil - Russian manufacturer. The company is relatively young - it is only 20 years old, but it has firmly established itself as one of the leaders in the building mixtures market. It is engaged in the production of universal soils and compounds for maximum penetration.
• " Prospectors " Is another domestic factory that started in 1992. The basic principles of its work are based on the introduction of scientific and technological progress, improving technology and relentless quality control. Now "Prospectors" offer the Russian buyer concrete contact primers and suspensions for surfaces with high absorbency.