Dry mixes used in construction

The number of dry mixes currently offered is in the hundreds, and the amount of advertising information about them, perhaps, in the thousands. However, it is not easy to find objective information about the quality of dry mixes..
Imported mixtures remain the leaders in quality and prestige. They are also leaders in development and technology. True, there are significant differences among imported manufacturers: Scandinavian and German quality is incomparable, for example, with Turkish or Bulgarian.
Imported mixtures are followed by products of professional domestic manufacturers, obtained, as a rule, with the use of imported equipment and technologies. However, according to our manufacturers, these mixtures “are in no way inferior, and even surpass foreign ones in some characteristics, because imported additives, modern technologies, quality control, etc. are used in production. There is no doubt that domestic mixtures are more cheap. But – alas, many builders claim that the quality of Russian mixtures is still unstable, and significantly depends on the batch.

So, in order not to be mistaken in the quality of the dry mix, you should go to a good – large, long-working and reputable – hardware store. It is there that the products undergo “natural selection”: a reputable trade organization that cares about its image will not offer goods with which buyers have problems.

Whether block parquet, ceramic tiles or linoleum are laid in the premises – in any case, they need flat bases. It is such a base that is provided with the help of self-leveling self-leveling floors. The principle of such a floor is clear from the name: a thick solution spreads within acceptable limits and hardens, forming a flat surface.
For floors, dry mixes are used on a cement basis with additives that provide the necessary strength, viscosity, and hardening time. These can be reinforcing fibers that improve surface tensile and fracture strength..
Sometimes manufacturers offer a system of several types of mixtures for the installation of self-leveling floors. This is a mixture for rough leveling: filling gaps, cavities, etc., and a finishing compound poured over an already formed solidified surface, as a rule, is thinner and more expensive. Another option for combining mixtures is to use one of them for manual sealing of cavities and crevices, before pouring the finishing mixture. A special case is compounds for repairing stairs and sealing cracks, chips, irregularities, bare reinforcement. As a rule, such mixtures are used in small amounts, they are distinguished by their strength, wear resistance, and a high degree of adhesion to the repaired surface..
In general, the application of dry mixes for floors is the same: preparation of the substrate, preparation of the mix, pouring and hardening. All recommendations and requirements – how much water is needed, after what time the mixture will be ready for use, etc. – are set out in the instructions from the manufacturers. The general in all instructions is the following. The surface should be free of dust, exfoliating areas. Sometimes it is recommended to use a primer (primer) to prepare the base for pouring, which reduces the absorption of water by the base, which increases the adhesion with the mortar. For the same purpose, it is recommended to moisten the base with water. If an old plank floor is used as a base, then a reinforcing mesh can be used..

The instructions also include parameters such as recommended layer thickness, use temperature and mortar shelf life. These recommendations should not be taken lightly. For example, if the mixture to be used in a thin layer is cast in a thick layer, the surface may harden before the inner layers and break when trying to enter a seemingly hard area. It is not recommended to use a thin layer of “thick” compounds: it will dry too quickly, which does not contribute to strength. The air temperature at which the mixture can be applied is also important: as a rule, this is room temperature, but problems can arise in unheated rooms. There must be no drafts, sunlight and other factors that can lead to uneven drying of the mixture and, as a result, cracks on the surface. It is also impossible to overheat the water used for mixing; so in hot water the mixture will set faster, without having time to properly spread on the floor.
One of the best floor mixes is ABS Grosso mix, manufactured by Optirok (Finland). The mixture is used as a leveling layer for subsequent finishing coat of any type. An important advantage of the mixture is its quick setting, which allows walking on the surface in 2-4 hours. ABS Grosso is suitable as a direct substrate for the final finishing and as an underlay for the final ABS Pronto mortar. Among Finnish products and mixes for floors Scanfloor (“Scanmix”), they can also be used to arrange floors in rooms with different requirements – they will be durable, resistant to abrasion.
Domestic self-leveling floors are represented by a number of brands: “Glims”, “Plitonit”, “Petromix” and others. Mixes for repairing stairs are produced by the St. Petersburg enterprise ANTC “Alit”.
Get rid of the “wet” plastering work will help “dry plaster” – drywall. But conventional plastering technology is not a thing of the past. Perhaps this was largely due to the development of the production of plaster mixes. Their advantages in plastering are undeniable: you can adjust the viscosity and setting time, create textured surfaces, etc..

Careful adherence to the instructions is also necessary when working with dry mixes for plaster. It should be added that for a quality repair using decorative plasters, you need to have simple special tools for applying mortar, leveling. The base for plastering must be dry, hard, free from dirt, dust, oils, grease, etc. Smooth surfaces are provided with a “notch” before plastering. In order for the plaster layer to lay down qualitatively, sometimes the base is recommended to be moistened with water or primed.
Plasters can be applied both with a spatula and with a special spray (this must be specified in the instructions). The first layer is usually applied with a thickness of 4-5 mm, the subsequent ones – up to 7 mm. If the wall surface has significant irregularities, several layers of the composition can be applied (each subsequent layer is applied after the previous ones have hardened). For full surface treatment, a steel ruler is used with which the surface is leveled. To make the surface even smoother, the slightly dried layer can be wiped off with a damp sponge.
One of the examples of high-quality products on the Russian market is Rotband plaster, manufactured by TIGI Knauf. The material is a one-layer, adhesive gypsum-based plaster, most suitable for hand plastering of walls and ceilings. The mixture is intended for application to ordinary hard substrates (brick, concrete, etc.) indoors. Its consumption is 8.0 kg / m2 with a layer thickness of 10 mm. From one bag of dry mixture (30 kg), about 38 liters of ready-made solution is obtained.
The products of the company “Atlas” (Poland) are also interesting: the plaster composition is a good basis for applying plaster, mineral or acrylic plasters. The mortar is frost and water resistant, therefore it can be used for finishing in unheated rooms. Manufacturers recommend determining the amount of water based on the desired consistency of the solution. With one package, you can make about 1.6-1.7 m2 of plaster. The solution is usable within 4 hours.

An important place in the final finishing is occupied by decorative plasters, with the help of which various textured surfaces can be obtained. Such compositions are applied to the prepared layers of plaster, then rubbed with special tools: depending on the grinding technique and fractional composition of the composition, various surfaces can be obtained – “bark beetle”, “rustic”, rough, etc..
Putties are widely used in construction and repair work. It is a thick, viscous mass designed to fill irregularities and smooth surfaces. As a rule, putties contain gypsum, drying oil, cement or glue as a binder. Usually putty mixtures are packaged in smaller volumes than plasters and self-leveling floors: in packages of 3 or 5 kg.
The putty mixture is applied with a spatula perpendicular to each other. Excess putty is removed and then reused. If it is necessary to align in several layers, then before applying the next layer, make sure that the previous layer is completely dry.
An example of a putty for plasters is Ceresit CT 29, from the venerable family of German dry mixes Ceresit, manufactured by the Henkel concern, Germany. The putty is presented in packs of 5 and 25 kg. Material consumption is 1.8 kg / m2 of wall at 1 mm thickness. The putty allows you to repair cement-lime plaster, fill cracks and grooves on walls and ceilings.

For leveling walls and ceilings in dry, damp and wet rooms, as well as for outdoor work, Plitonit-K cement-based putty mixture can be used. It can be used on concrete, aerated concrete, over masonry or lime-cement plaster. A mixture of white, “super white” and gray colors is made.
A special family of putties is produced for working with drywall (Gyproc, Knauf): these mixtures allow to close gaps and traces of fasteners in the “drywall”, providing a perfect surface.
In general, dry mixes are an expensive pleasure, so the use of high-quality products in tens of kilograms for plastering or self-leveling floors is not available to everyone. More economical mixtures – dry adhesives, solutions for laying facing materials.
Among dry mixes for tiles, two important “families” can be distinguished – for laying and for grouting joints between ceramic products..

The most important parameter of dry mix for laying is load-bearing capacity. The fact is that the facing materials used now vary in weight from several kilograms to tens of kilograms, and the mixture that successfully holds the tile may be powerless in front of a granite slab 25 mm thick. Attention should be paid to such a parameter of the masonry mixture as the setting time. Another important nuance is whether the mixture can be used for wall and floor cladding, or “specializes” in only one of these areas.
When working with marble tiles or other coarse-grained rocks, it is necessary to use a special mixture, in particular, this can be found among the German Ceresit mixtures mentioned above. When using conventional mixtures, color change and the appearance of stains on the stone are possible.
When laying tiles on walls, the base must be firm and level, free from dust, dirt, lime and paint residues. Large irregularities must be corrected using fillers. If the surface has the ability to absorb water, it is advisable to apply a primer emulsion.
On the prepared, primed base, using a notched trowel, apply an adhesive solution, if possible in one direction. It is not recommended to apply the solution on too large a surface, as it retains its adhesive properties, on average, for half an hour. The larger the tile, the larger should be the size of the “teeth” on the spatula.

For laying ceramic floor tiles, the adhesive solution is applied to the prepared base surface. Then, using a smooth float, a thin layer is made that is in good contact with the base. The mortar is applied to the fresh contact layer with a suitable notched trowel, in such an amount that the tiles can be laid within 30 minutes; it is placed on the mortar and easily pressed to the base. The most important nuance of floor laying is the absence of air “bubbles” in the adhesive mixture: after drying, the voids under the tiles will give themselves away by breaks in the cladding. Therefore, as a rule, mortars for laying floor tiles are diluted more elastic. At the pinnacle of elasticity are the tile adhesives that allow a layer of tile to be laid over an old layer of cladding. These compounds have very high adhesion and ensure adhesion of the cladding even to glossy surfaces..
Dry mixes for tiles are presented by almost all leading manufacturers – among “Vetonits”, and “Ceresites”, and “Atlas” and other manufacturers.
It should be noted the St. Petersburg family of dry mixtures Plitonit, in the name of which there is a hint of the main “specialization” of these mixtures. In the composition of Plitonites, in addition to leveling mixtures and compositions for the floor, there are also: Plitonite A mixture – for interior work in dry and wet rooms; Plitonite B is also suitable for outdoor use, as well as for facing swimming pools; Plitonite C allows laying natural stone tiles on ceramic tiles and surfaces painted with waterproof paints.
An important aspect of facing work is the finishing of surfaces whose temperature is constantly changing (fireplaces, stoves, etc.). Without delving into the nuances of the difference between tiles and tiles, it is simply recommended to consult with experts. For the information of consumers: a dry mixture based on clay for laying stoves and fireplaces is presented in the Vetonit family.

The use of grouting (jointing) for the joints between the tiles can increase its waterproofing properties, improve the appearance. It is important to know when choosing grout: what thickness of the seam they can cover, can they be used in places where reliable waterproofing is required.
Grouting is carried out after the mortar has hardened, on which the tiles are laid, that is, 1-3 days after the end of the facing work, otherwise microcracks may form. When applying the mortar, the joints must be clean. After the grout dries, you can sand the resulting surface with a cotton cloth.
One of the important properties of grouting mixtures is the color that is in harmony with the color of the laid tiles. In the Sopro system (“Stern”, Germany), several different mixtures are presented for filling tile joints. Sopro MFs is suitable for filling joints up to 5 mm wide and is available in 25 colors. Sopro MFs + b blend allows seams from 3 to 20 mm in width, it is available in 10 colors.
When using tiles on elastic substrates, elastic grouting is recommended. Such grouts are used to process joints on deformable substrates, for example, on flexible partitions, heated “floating floors”, etc., for example, Ceresit CE 37 grout, which allows you to join joints with a width of 4 to 15 mm.

As for ceiling works, there are probably no special mixtures for them. For work with ceilings, wall compositions are used, which is usually indicated in the instructions for them.
Mixes used for ceiling work must have good adhesion and a thick consistency. With their help, puttying works can be performed: repair of small defects in the ceiling before painting or pasting, plastering, gluing finishing materials. One of the typical tasks for putty is filling the gap in the joint between ceiling slabs.
For plastering work on the ceiling using dry mixes, fast-setting plasters should be used. One of them is dry mix M-150 (“Knauf”), which can be used for work both in heated and unheated rooms. The Rotband mixture of the same manufacturer is a one-layer adhesive gypsum-based plaster suitable for hand plastering of walls and ceilings, intended for application to ordinary hard substrates (brick, concrete, etc.) indoors.
When using adhesive mixtures, one should pay attention to their “bearing capacity” in a diluted state. If we are talking about gluing ceiling polystyrene tiles, then the “performance” of the mixture is easy to verify empirically; if the ceiling is wallpapering, then only such glue should be used, the instructions of which indicate the possibility of using it for ceiling work.