The practice of leveling walls with rotband plaster

Installation of beacons

The next stage of plastering is the installation of beacons. Lighthouses are special metal profiles installed vertically along the wall surface. They serve as the plaster level. Beacons up to 6 mm thick are removable, over 6 mm are left on the wall. Removable beacons are removed after the main layer of cement-sand mortar has dried, and the remaining seams are rubbed with a float.

Installation of beacons for plaster

The first beacon is installed about 15-20 cm from the edge of the wall. With a trowel or spatula, apply a small layer of gypsum with dots vertically at a distance of 40-50 cm from each other. We apply the lighthouse to the plaster and press it lightly. Further, using the level, we set the beacon strictly vertically, for this we press the beacon into the plaster of Paris harder at certain points. The next beacon is installed according to the same principle at a distance from the first equal to “the length of the aluminum rule” minus “20 cm”. For the second and subsequent beacons, we apply the level not only vertically, but also horizontally and diagonally, observing the level of the entire wall.

Preliminary work with the base

Cleansing from the previous coating

The planes to be treated are pre-dried, the required temperature is from + 5 degrees Celsius. This contributes to less plaster consumption and better application. It is also necessary to clean from the previous coating (whitewash, plaster, paint, tiles or wallpaper). Remove irregularities and protrusions of the base. Be sure to treat metal elements with an anti-corrosion liquid. Otherwise, corrosion can come out.

Primer

• Substrates with increased moisture absorption must be covered with a primer. This is done with the aim of uniform adhesion of the plaster to the base. Priming can be done with brushes, rollers or sprayers. According to the instructions, it is recommended to use Knauf-Grundirmittel primer.
• Surfaces that do not absorb moisture by their technical characteristics should be coated with Knauf-Betokontakt primer. This is done to increase adhesion.

Exposing beacons and corners

Apply Rotband plaster to the wall with gaps of 40 cm. Press the beacons into the moldings and align them in one plane. The alignment rule should be 20 cm longer than the beacon spacing. Corner profiles are set in the same plane with the beacons. The moldings are applied to the side inside the profile. Rotband plaster, consumption per 1m2 with a layer of 10 mm.

• Knauf Rotband plaster - 30 kg; consumption 8.5 kg per 1m2.
• Knauf-Betokontakt - 30 kg; consumption 0.3 kg per 1m2.
• Knauf-Grundirmittel - 30 kg; consumption 0.1 kg per 1m2.

You can make a detailed expense using the calculator on the manufacturer's website KNAUF.

Kneading

Pour 18 liters of water into a container made of metal or plastic and add 30 kg rotband plaster to it. First, put 6 spatulas of the mixture and stir everything until thoroughly mixed, only then pour the entire bag into the water. Stir the entire composition with a construction mixer until all lumps are gone. The mass should be homogeneous. If the composition is too liquid, then add more dry plaster. After mixing everything, you need to wait 5-6 minutes, then stir again. Specifications require a little ripening time.

Application

Apply the matured mixture to the base to be treated for 20 minutes. You need to work on the ceiling as a "falcon", making movements towards yourself. The surface is covered by scribbling with a spatula. This does not affect the consumption, since in the future everything is leveled.

After sketching, everything is aligned with the tool - usually, making a wave-like motion.

When it is necessary to increase the thickness of the coating, repeated layers are applied, having previously created roughness on the first layer. Which will serve to adhere the layers. The second coating can be done only after a day. This is the drying time for rotband plaster.

Leveling and grouting

The setting period according to technical characteristics is within 50 minutes, after which it is leveled with a large spatula or metal lath. Excess is removed by covering up all the irregularities. In this way, less consumption is achieved. The wall for painting or wallpaper is additionally rubbed with a trowel tool. To do this, they are abundantly moistened with water and make circular movements, this makes the surface perfectly smooth.

Creation of structure

If a relief is necessary, it can be easily implemented, for this, simply still on a soft surface (after leveling with a rule), you need to draw it with a roller with a relief on the wheel. Structures can also be created using a trowel.

Do not forget that the dried structure is very difficult to remove, so wash the used tool beforehand.

Comparison with other plasters

Among the products of the Knauf brand there are other plasters based on mineral and polymer substances with leveling properties. They have some peculiarities in their purpose:

• Knauf Eisberg - white plaster for light finishing coatings;
• Knauf Goldband - mortar for leveling walls with rough defects (has less adhesion to smooth surfaces);
• Knauf HP Start is a starting mixture for creating a plaster layer with a thickness of 10-30 mm.

In fact, all of these materials can be interchangeable, there are no significant differences between them. "Rotband", as well as the three mentioned plasters, are often applied manually, although mechanized application is also possible. If you have to finish on large areas, it is better to buy other building mixtures, for example, Knauf MP 75 or Knauf MP 75 Ultra. They are ideal for use in professional plastering stations and other aggregates. The range of the company's plasters is large enough to easily find the most suitable one for a specific situation and perform high quality finishing work.

Performing work with and without beacons

Many craftsmen plaster walls without the use of beacons. This method is most often suitable for those surfaces in which the defects are insignificant, and if you only need to level the base under the decorative layer. In this case, the deviation of the plane from the desired level is determined. This is done using a rule that is pressed against the wall.

First, large cavities are sealed with a mixture, then the solution is distributed throughout the entire area, leveling it. Then the surface inspection is repeated. If there are no gaps between the rule and the wall, then the work is done correctly, and you can proceed to plastering the next section. When the base is completely hardened, it must be sanded and covered with a decorative finish.

Installation of beacons simplifies the work with plaster. Finishing is carried out similarly to the previously described method, but in this case, special guides are attached to the wall, along which the base is leveled.

What is Knauf gypsum plaster

The specialists of the German company "Knauf", traditionally producing high quality dry plaster, still keep the main components and the method of making the gypsum mass a secret. By law, they are only required to confirm the sanitary safety and environmental friendliness of gypsum plaster, but they have the right not to disclose production technologies, which they regularly do. How much gypsum rotband is used, so many questions arise about its composition.

It is only known that the composition of the dry plaster mass rotband includes:

1. Gypsum mass with additives that improve the setting of water and prevent shrinkage:
2. Plasticizers that increase the fluidity and hardness of the gypsum surface after setting;
3. Dusty inert filler based on silicon oxide with a fine crystalline structure.

To prepare a ready-made gypsum mix, rotband "Knauf" with your own hands, you just need to add pure water, exactly as much as required by the instructions, and mix the mixture with a mixer nozzle. 0.6 liters of water is consumed per kilogram of dry gypsum rotband powder. After activation and mixing with a mixer, the rotband gypsum mass remains in working condition for another 40 minutes, the plaster dries quite quickly. During this time, it is necessary to complete most of the finishing operations. How much Knauf rotband material will set exactly depends on temperature, air humidity and the presence of a draft.

The advantages of the universal plaster mass "Knauf" rotband over cement plasters can be formulated in four points:

• High surface quality, no deformation and cracking of the gypsum mass, subject to the rules for preparing the solution defined in the instructions;
• The consumption of gypsum plaster is almost twice reduced in comparison with sand-cement compositions;
• The versatility of the Knauf rotband allows using the same mass both as a plaster and as a filler.
• Environmental friendliness and safety. The use of gypsum binders, according to the developers, makes the room more comfortable for a person to stay. In addition, the gypsum material has better thermal insulation, dries faster and is immune to open flames.

They produce a dry gypsum mix of Rotband "Knauf" in soft packaging weighing 30 kg. The name gypsum universal plaster is often confusing when, opening the bag, a person sees in front of him a gray, cement-like mass. In fact, the "Knauf" rotband dry mix has long been produced not only in Germany, but also in a number of CIS countries, including the Russian Federation. Therefore, the dry mass can be gray, white or pink. As it dries on the surface of the walls, the plaster gradually brightens, becomes almost white.

There are a lot of fake Knauf rotband plasters on the market, so you can easily get screwed up, not knowing how to distinguish a fake from the original.

Advice! When filling ready-made mixtures on the line, the date and exact time of the bag sealing are stamped on the packaging by a mechanical automatic machine. If there are packs with the same packing time on a pallet with tared plaster, then, most likely, you have a fake "Knauf" rotband in front of you.

Ready-made mixtures in packaged form are stored for up to six months, dry plaster cannot be stored in an opened container for more than a week. The instructions and storage rules are always given on the packaging of the gypsum plaster.

Tips & Tricks

Most homeowners prefer budget repairs, in which most of the construction work is done by hand. Wall plastering is no exception to this.

This process is not difficult, but in order to do everything right, the following recommendations of experienced craftsmen can help:

• Plastering is necessary only for those walls that have significant defects and irregularities. This will help not only speed up repairs, but also save money on finishing. Therefore, first, the surfaces are checked, and if the lighting falls on them at an oblique angle, then alignment is done. It is also necessary to cover the walls on which the skirting boards are to be attached.
• To ensure good strength of the coating, you can use a primer made from water and PVA glue.
• If the plaster is applied to brickwork and the room temperature exceeds 23 ° C, then the base should be thoroughly moistened.

When leveling the walls, it is advisable to use beacons, they allow you to set the correct level and determine the optimal thickness of the finish.In the event that the base is single-layer, it must be leveled immediately after coating with a solution. You can also use special trowels for this, they are used after the coating has set to the surface.

The mixture hardens quickly and cannot be used afterwards. Before the start of plastering, the working area must be calculated and the level of all differences and slopes is determined. Thanks to such calculations, it is possible to calculate in advance the consumption of material and make estimates.

Small and large cracks can appear after finishing if the mortar is poorly mixed or dries quickly under the influence of drafts. Therefore, the mixture should be thoroughly mixed and plastered only indoors. In addition, the surface must be well sanded, and if the mixture is applied in several layers, then a construction mesh should be used. Putty allows you to eliminate only minor irregularities reaching 5 mm, since its layer cannot exceed 5 cm.Therefore, if the walls have large drops, then it is best to first hide them under drywall, and then apply the mixture

Technical characteristics and composition of gypsum plasters

Plaster mixes based on gypsum have the following technical characteristics:

• bulk density - (kg / m3)
• water-solid ratio W / T (weight of water / weight of dry mixture), otherwise called dilution proportions;
• mortar mixture output - the ratio of the volume (weight) of the dry mixture to the volume of the solution (l / l or kg / l);
• processing time of the applied mixture (min) otherwise - setting time;
• density of the mortar mixture, kg / m3;
• density of the solution (kg / m3).

Also, the characteristics of the SGShS include:

• maximum thickness of the applied layer (up to 6 cm);
• drying time;
• set of strength;
• consumption rate kg / m2;
• air temperature during operation.

The manufacturer indicates these parameters on the packaging. The specific gravity of gypsum plaster is two times less than that of cement plaster - 1500 kg / m3. This ultimately determines a lower load on the structure.

As part of the SGShS, a binder, fillers and modifying additives are isolated.

Gypsum

The common word "alabaster" refers to two different minerals - gypsum and calcite. Gypsum with a fibrous structure is called selenite, and granular - alabaster. Gypsum is used as a raw material for the production of various types of gypsum, obtained by drying (partial dehydration at different temperature conditions) with subsequent grinding.

Therefore, gypsum happens:

• construction (also called alabaster);
• molding (has a finer grind);
• medical (highly pure raw materials);
• high strength (lower drying temperature).

When combined with water, gypsum hardens quickly, generating heat and increasing its volume. However, the "made" stone has a microcrystalline structure, microporous and loses its transparency.

Gypsum, as an astringent, is divided according to:

• strength (12 grades from G2 to G25 - (breaking load in compression 2-25 kg / cm2);
• fineness of grinding (3 groups - I coarse, II medium, III fine grinding);
• setting time (3 types - A fast-hardening, B - normally hardening, C - slow-hardening).

For plastering works are used gypsum grades G-2 ... G-25, grinding; II, III groups; normal and slow hardening. The density of loose gypsum powder is about 900 kg / m3, in a compacted state - up to 1450 kg / m3. The color of the mineral is often white. It also happens gray, yellowish and with a pink tint.

Plaster and alabaster are available for sale. For gypsum plaster, the use of gypsum grades 4-6 can be replaced with alabaster.

Excipients

To prevent cracking, as well as to reduce the cost, impart new properties, fillers are introduced into the plaster compositions.

fillers for gypsum plaster

In gypsum mixtures, for this they use:

• sand (quartz, limestone, river, etc.);
• sawdust (the so-called "Armenian plaster" contains sawdust sifted through a 5 mm sieve);
• flour (limestone or dolomite);
• ash;
• chalk;
• perlite (light solutions);
• mica, etc.

The type of mixture dictates the fineness of the aggregates (the ratio of the surface area of ​​the particles to the volume occupied by the particles): limestone and quartz sand with a fineness of up to 0.8-1.0 mm is used. The ratio of aggregates by fractions should be approximately equal.

Additives

Modifying additives increase the mobility, bond strength, plasticity of the mixture, slow down the setting rate, and reduce the possibility of cracking.

СГШС have too early setting. Therefore, retarding additives are introduced into the mixtures. One of the retarders is hydrated lime. Its addition also improves ductility and reduces shrinkage deformations.

Set retarders or inhibitors include citric acid. To slow down the setting to 30-40 minutes, when mixing with water, add 10-20 g of food or technical citric acid.

Other retarders can be found in the kitchen or utility store:

• milk with a fat content of 3.2 (replaces 10% of the amount of water);
• PVA glue (glue 1 part, water 3-4 parts);
• washing powder (for 5 kg of gypsum - 100 g);
• wallpaper glue;
• liquid soap or faerie;
• putty Vetonit (part of vetonite is taken into four parts of gypsum, mixed dry, or first vetonite is diluted in water, and then gypsum is closed with this liquid);
• plasticizer for concrete mixes.

To reduce shrinkage and cracking, cellulose fibers are introduced, and polymers are introduced to increase the adhesive forces and reduce water absorption.

Bleaching additives are also used - lime, whitewash (zinc or titanium).

Water

Clean tap water is necessary for breeding GSH. Only cold water is taken. The quantity is indicated on the package.

Types of mixture and its features

Most often, plaster is used to level surfaces. This mixture is cheaper than plaster for decorative work. Common types of mixtures (by composition):

Cement. In the composition - cement and sand. Such plaster is most often used during rough finishing work. To properly dilute such a mixture, it is recommended that you first read the instructions given by the manufacturer (printed on the packaging). There will be indicated the proportions of the mixture and water for specific tasks.

Attention
After applying the solution, it must be carefully leveled with a spatula or rule before it dries, since it is difficult to achieve an even surface with this type of plaster.

Limestone. Contains cement, sand, lime

Lime gives the material plasticity and lightness. It is easier to work with lime plaster, but it is inferior in strength to the previous version.

Plaster. It contains gypsum. It features a high absorption rate and fast drying. Such plaster is used for interior decoration work. Since the solution dries quickly, it is recommended to prepare it in small portions. Unlike other types of plaster, you can immediately apply a decorative coating on top of gypsum plaster.

More expensive types:

1. Acrylic. It contains acrylic resins. Pros: climatic resistance, moisture resistance, ease of application. Acrylic plaster can be applied to all mineral substrates, even old ones.
2. Silicate. In the composition - "liquid" potash glass. Sold as a dry mix or diluted. Has increased vapor permeability. Applied only to silicate primers.
3. Silicone. Contains silicone resins. Differs in good vapor permeability, rich palette. The material is non-marking, breathable and durable.

It is worth highlighting the following types of dry mixes:

1. Coating room. This mixture is used when you need to prepare the surface for applying a decorative layer: decorative plaster, wallpaper, tiles, etc.
2. Finish. Finishing coating. This plaster has a different texture or structure. It is more often used for external work than for internal work.

We offer you to watch a video about the types of plaster for finishing work and the features of its application:

What it is?

Gypsum is a burnt gypsum stone that is crushed to a powder state.

Important

Environmentally friendly natural material lays down in a thick layer on the surface of the walls, hiding visible defects well.

Gypsum plaster contains a large percentage of this material and various additives. They are necessary so that the mass does not freeze on the surface too quickly and it would be possible to carry out the finishing coat, drawing without haste.

Gypsum decorative plaster, in addition to the main component, contains:

1. Fine-grained fillers. They lighten the weight of the mortar. Most often, expanded polystyrene, foam glass and perlite are added.
2. Elasticizers increasing the elasticity.
3. Whitening particles. Lime or similar materials may be added.
4. Retarders.

Thanks to fillers, thermal insulation properties increase, adhesion is enhanced.

This gypsum plaster can easily adhere to any kind of surface. It:

• brickwork;
• concrete walls;
• glossy surface;
• expanded clay concrete;
• aerated concrete;
• cellular foam concrete.

Gypsum decorative plaster can be used to level surfaces before finishing - horizontal or vertical. It can form walls, ceilings, but in conditions of normal humidity. Recommended for embedding:

• pits;
• cracks;
• cracks.

Suitable for residential / non-residential premises. But you only need to carry out interior decoration.

Material characteristics

If you compare several bags of dry mixes from different manufacturers, you will be surprised that their composition will be approximately the same. The secret lies in the ratio of the components, which determines the properties of the solution and the finished coating.

And now we will consider the range of gypsum leveling mixtures from five companies, whose products are in demand in Russia. The table below shows the approximate cost of materials that are required to level 1 m² of the base. Despite the "approximately equal" prices, when recalculated for the entire area of ​​walls and ceilings, the total costs will differ significantly.