How To Perfectly Putty The Walls For Painting And How To Prepare The Base

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• Wall leveling and preparation for filling
• Types of putty
• Filling technology step by step
• Starting layer application
• Finishing with finishing putty
• Cobweb reinforcement
• Grinding features
• Purchased tools
• Homemade grinding devices
• Work rules
• A selection of videos on preparing walls for painting

Proper preparation of walls for painting is the most important stage of decorative finishing, ensuring the aesthetics of the result. The work consists in leveling and filling the walls, and this can be done in several ways, differing in complexity and time. In all cases, the base is a starting layer of putty, which can be supplemented with reinforcement and decorative material in order to achieve a more smooth and durable coating. In addition, the surface must be sanded. What do you need to know to make the wall to be painted perfect?

Wall leveling and preparation for filling

In order to obtain perfectly flat walls, their surface must be pre-treated, eliminating even the smallest differences in height and all noticeable defects in the base. Depending on the initial state of the walls, you can align them in one of several ways:

1. Preparation of the rough coating.
2. Plastering.
3. Plasterboard finishing on the frame structure.

Sanding is a good option if a clean concrete base or old plaster layer does not have significant irregularities, cracks or other defects. In this case, it is enough to remove the old coating (wallpaper, paint, decorative plaster, etc.) and remove the thin top layer of rough plaster or concrete with a grinder or a bar with sandpaper. Before the walls are putty for painting, the base should be covered with two layers of primer, antiseptic and antifungal impregnation if there was mold. As a result of measurements, the differences in height should not exceed 2 mm.

If the irregularities are significant or the base has significant defects, it is necessary to completely plaster the walls or sheathe the walls with plasterboard. Previously, the flaws of the main surface are sealed with a solution. Old trim should be removed completely, not just damaged areas, even if part of it seems to be strong enough. Then a new layer of plaster is applied or sheets of drywall are mounted using the appropriate technology.

When the preliminary leveling is completed, the surface should be primed, as in the case of sanding. You can start further work in 5–6 hours, since you can properly putty the walls for painting only on a perfectly dry surface - it is better to wait a little longer than apply the putty to a wet wall.

Types of putty

There are basic types of putty. When choosing the best way to putty the walls for painting, one should take into account not only the advantages and disadvantages of these options, but also the features of the room.

Advantages	disadvantages
Gypsum	Health safety, no shrinkage, fast drying. The presence of additional properties - heat and sound insulating qualities, fire resistance. Plasticity, the ability to apply in a thick continuous layer (up to 60 mm).	Hygroscopic, not suitable for bathrooms, swimming pools, kitchens. Fast hardening - it will not work to prepare the mixture immediately for the entire wall, since it will dry in about 45 minutes. The cost of gypsum is higher than that of cement.
Polymer	High strength, resistance to temperature fluctuations, no shrinkage, high elasticity, excellent adhesion to any surfaces.	High price.

The best option, therefore, will be a polymer putty, since it is ideal to putty the walls with it in any conditions. It is also the easiest to work with. However, the choice can be limited by budget.

Filling technology step by step

For filling, you need to prepare:

• a container with a volume of 15-25 liters;
• construction mixer or perforator with a paddle attachment;
• putty knife;
• roller with suitable hairiness;
• grinding tool.

The floor along the walls should be covered with paper or plastic, because putty on the decorative flooring will not be easy to remove.

Starting layer application

It may seem that a plastered or concrete wall itself is quite suitable for applying paint. However, even ideal wall plaster is not suitable for painting, and it is necessary to figure out how to prepare the walls for painting. This is due to the fact that concrete and plaster are porous and hygroscopic materials - they quickly absorb all the moisture from the paint, which will not allow the finishing material to be applied in a uniform layer. Because of this, the shade of the wall will change, even small irregularities will appear. The putty will not allow all these shortcomings to appear.

First of all, a starting putty is applied to the prepared wall surface. According to its structure, it is located between the plaster and the putty - it is no longer so porous, but still does not allow you to make perfectly smooth walls. The composition of this material includes gypsum and coarse lime, which makes it possible to make the coating layer quite thick - up to 5 mm, and finally hide all the irregularities. In this case, the putty does not crack even without reinforcement.

Putty is applied with a wide spatula. Without experience, they may be inconvenient to use, but this is recommended due to the fact that the sharp corners of the tool and the joints of the treated sections of the wall form small irregularities on the surface - the more there are, the more difficult the grinding process will be. A narrow trowel is useful for working on hard-to-reach areas and smoothing out small flaws in the coating. The tool should be held at an angle of 20 ° –30 ° to the wall.

It is also important to consider how many times the walls are putty. The answer is simple - until perfect evenness is achieved. Usually two layers up to 3-4 mm thick are enough; the second should be applied after the first has dried, displacing the joints of the finished sections. Drying should take place naturally, without using a hair dryer, heat gun, etc.; Avoid direct sunlight on fresh putty. When the last layer is dry, which will take 6-8 hours, the surface should be sanded to remove any minor irregularities.

The starting putty can already be painted, but the result will not be very high quality due to the graininess and porosity of the material, although these parameters are less than those of plaster. If you need an ideal wall finish for painting, the technology will be complicated by applying a finishing layer.

Finishing with finishing putty

The finishing putty of walls for painting does not have coarse-grained inclusions, therefore, it allows you to achieve a smooth and uniform surface. Due to the fact that the constituent components of the mixture are very small, its hygroscopicity is reduced - the paint will not be able to penetrate deeply into the surface and will lie in an even layer.

The technique of applying the finishing putty is similar to the usual method, the only difference is in the layer thickness - it should not exceed 2 mm, otherwise the finish will crack. In addition, it is more difficult to make mistakes with such a thin layer, and irregularities and dents will definitely not appear on the surface. However, flaws associated with the corners of the trowel and joints will also be present upon completion of the work. Therefore, after applying the putty, sand again with less abrasive emery paper.

The same question arises - how many times to putty the walls for painting? If necessary, you can apply a second coat of finishing putty, but usually one is enough. After grinding, the work should be checked with light - the beam from the lamp is directed at an obtuse angle to the wall, while all irregularities will cast a shadow. They are easy to spot and grind off with a sander

When the wall is completely dry, it should be cleaned of fine dust with a dry cloth, broom or vacuum cleaner. After that, two layers of primer are applied to the surface. When it is dry, you can start painting. What is the best finishing putty to choose?

Cobweb reinforcement

To create a high-quality painted wall, it is recommended to use a cobweb to protect the wall from cracking. To prevent this, you can strengthen the finish - for this, a spider web is used for walls for painting.

The cobweb is a glass-fiber painting in the form of a fine mesh; it is glued to a layer of starting filler before applying the top coat. In addition, the starting putty should be reinforced, as it shrinks, which can lead to cracking.

Fiberglass is made of fiberglass threads, which makes it immune to moisture, chemicals, temperature changes. It is durable and ideal for strengthening a layer of putty. In addition, it is very thin and has no relief, so that no irregularities will show through on the surface of the finished wall.

Glueing the spider web is quite simple; to get perfectly smooth walls for painting, you need to follow the technology exactly:

1. Glue is applied to the wall surface in an even thin layer.
2. The fiberglass strips are applied to the wall. They can be of any size, the main thing is to correctly determine the front and back sides of the cobweb, otherwise the material will adhere worse to the surface.
3. The painting canvas is then spread out with your hands and rolled to remove air bubbles from underneath. It is important to make sure that the edges of the cobweb are exactly docked with the corners of the room. Extra edges are cut off if necessary.
4. From above, the cobweb is coated with glue until the entire canvas is saturated. The glue will play the role of a primer, which will reduce paint consumption, as well as provide better adhesion of the finishing plaster to the reinforcing layer.
5. The following strips are glued overlapping; it is recommended to glue them parallel to the floor.

Complete drying of the adhesive takes a day, after which you can start applying the finishing putty. In addition, you can paint directly on the fiberglass - in this case, an aesthetic relief will appear on the surface of the walls. A good finishing putty for walls is only needed to get a perfectly smooth surface for painting.

Grinding features

The main rule of sanding is to work on a perfectly dry surface before priming it. The secret is using a wide trowel when applying the putty and using light when sanding. Details about the technique of grinding walls.

First of all, you need to decide what is the best way to grind the walls after putty - the choice of tool will depend on the type of material (starting or finishing), as well as the type of surface. Based on the area of the wall, one of the following tools is selected:

• a wooden block with sandpaper - for small areas that are easy to handle by hand;
• electric sander - for large surfaces, while it should be borne in mind that the joints of the walls in any case will have to be processed by hand;
• if there are protrusions, bas-reliefs and other areas with complex geometry on the wall, a machine with an eccentric will do.

Purchased tools

If the wooden block seems too uncomfortable, for manual work, you can use a special device with a handle and clamps, which allows you to quickly change worn out sandpaper. An abrasive mesh can be used instead of paper.

The mesh is preferable due to the fact that, unlike paper, it is not clogged with dust and wears out more slowly; however, it is more expensive. The difference in price is offset by the amount of paper required - in order to get perfect walls for painting, you will need many sheets. To save money, you should not buy cut paper - cutting it yourself is easy, and at the same time sharpening scissors.

The grain size of the sanding block depends on the type of finish: for a starting putty, a mesh size of 120 is suitable, for a finishing putty - 80 or 60. Most likely, you will have to try several options for the grain size - start with a coarse one, removing the most noticeable surface flaws, then use an increasingly fine one, while at shadows will not stop appearing when lighting the wall.

The grinder is more convenient to use and allows you to finish repairs faster; in addition, with its help you can get a really flawless surface. However, purchasing a power tool for processing a small area is not always cost-effective.

Homemade grinding devices

You will have to make a device with your own hands if you need to sand the walls for painting in hard-to-reach, small areas that cannot be reached with a bulky bar. A homemade tool is made as follows:

• a piece of plastic profile is cut in such a way that a strip about 70 mm wide is obtained;
• on one side, sandpaper is glued to the profile using double-sided tape;
• the end of the line is trimmed at an arrow-shaped angle.

If desired, you can cut and glue several strips of paper with different grain sizes. You need to work with an angle, and cut it off as the sandpaper abrades - the principle is the same as when sharpening a pencil.

Work rules

Before starting sanding, you need to protect the room from dust - furniture, window and door openings, decorative flooring are covered with polyethylene film. You need to work in a protective suit, mask and always with a respirator.

Sanding starts from the corner of the wall, then you should move downward, processing a strip about a meter wide. In this case, you need to make movements in a spiral, slightly pressing on the tool. You should not press too hard, since in this case it will not work perfectly to align the walls - the top layer of putty will simply be erased

If in the process some kind of depression is found, the work should be completed, and then the defect should be repaired with putty. All work should be done with single-grit sandpaper or mesh - it can be changed when the entire wall has been finished.

Thus, the technology of filling walls for painting is not difficult - the main thing is to observe all stages of work and select the right materials. To achieve a flawless finish, it is also important to paint the smooth prepared wall correctly - for this you need to choose the appropriate hairiness of the roller. The rule is simple - the less the surface roughness, the shorter the pile. So, if the filling is carried out correctly, the pile will be minimal, because the wall will turn out to be perfectly smooth. And how to paint without streaks, that's in the next article.

A selection of videos on preparing walls for painting

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