Plaster for wet rooms: features of the material and its use. Cement waterproof plaster Plaster for damp walls

For finishing rooms with high humidity, a special material is used - plaster for wet rooms. This coating allows you to increase the level of protection of the walls of basements, rooms located in the basement of buildings and bathrooms. Waterproof plaster is not in vain considered a universal remedy that does not require special skills when using and investing large financial resources.

The main property of plaster for wet rooms is its increased moisture resistance. It is used both for leveling walls made of bricks and cinder blocks, and for leveling and decorating gypsum, cement and foam concrete surfaces.

There are several ways to apply plaster, depending on the material used and the surfaces to which the plaster will be applied. You can apply a ready-made special mixture, prepare a moisture-resistant plaster yourself or treat an already plastered surface with a special water-repellent solution.

Features of moisture resistant plaster

• It is made from environmentally friendly components, which makes it possible to use it even in residential areas. It does not contain harmful impurities, which allows you to apply plaster in places with high temperatures. Such mixtures are not radioactive and harmless;
• ease of use is due to the plasticity of such a mixture. When applying plaster, there is no need for any special technical devices; application on surfaces is carried out with ordinary spatulas;
• has increased strength, resulting in a smooth surface, without the formation of cracks. The ability to add a hardener before applying to the surface to be plastered will give the mixture resistance to cracking even in rooms that may not be heated for a long time or in which there are sharp temperature fluctuations, as well as where the temperature is often much higher than normal;
• protection against high humidity - allows the use of such mixtures for both internal and external finishing work. After the applied plaster dries, a waterproofing layer is formed that protects any surface from moisture penetration.

The process of preparing moisture-resistant plaster

You can also prepare a waterproof plaster mixture yourself; for this, hardeners that increase moisture resistance are used, which are added to the sand-cement mixture in proportions one to one. Lime or other substitute hardeners may be used.

If it is necessary to protect an already plastered surface, then waterproofing impregnations or mixtures will be needed for this.

Before proceeding with the application of plaster on the surfaces of interest to us, it is necessary to carry out preparatory work, which includes: cleaning walls and surfaces from old layers of paint, plaster and, most importantly, dust that has already been or may appear during repair work. This is done for better adhesion of the applied layer of water-repellent plaster to the treated surface. Therefore, the better the cleaning of excess stains, paint and plaster is done, the better and smoother the new layer will lie.

What to do with the surface on which whitewash has been applied? One can hope that the plaster will lie well on the lime surface, but it is unlikely that it will be possible to achieve the necessary adhesion of the new layer with the old whitewash. Therefore, it is also better to clean off or wash off such a layer. It is possible to use a special impregnation, which is also intended for the treatment of concrete surfaces. It should not be forgotten that the impregnation is applied several times, with pauses of about half an hour. Complete drying of such an impregnation will occur in ten hours. Drying times are approximate - observe ambient temperature and manufacturer's instructions.

The mixture for using wall plastering must be mixed well, regardless of whether you use ready-made or prepared yourself. In such a mixture there should not be any undissolved lumps - the quality of the work performed depends on this. A poorly mixed mixture will begin to crack very quickly, the waterproofing effect will be impaired.

In the process of plastering, the temperature regime should also be taken into account. It is worth using such mixtures at a temperature not lower than plus five and not higher than thirty degrees. Violation of technology when using such plaster can lead to its peeling and subsequent alteration of the work performed.

The work itself is carried out in several stages:

• the main layer of plaster is applied to the prepared surface with throwing movements;
• after some time (usually three hours is enough), a leveling layer is applied;
• after drying (five to six hours), final grouting of the surface.

How do you use wet room plaster? details in the comments!

Waterproof plasters are made on solutions with the addition of ceresite, liquid glass and sodium aluminate.

Waterproof plaster mortars on ceresite

Waterproof plaster mortars on ceresite are prepared by mixing a dry cement-sand mixture with ceresite milk. Ceresite plaster mortars are used no later than one hour after mixing. Solutions on ceresite do not adhere well to the previously applied layer, so they need to be applied in thin layers.

Waterproof plaster solutions on liquid glass

Plaster solutions on liquid glass set quickly, after 2 - 5 minutes. after closing. Therefore, they need to be prepared in a small amount, which can be used up before setting begins. For work, a dry cement mixture is first prepared, which is then closed with a solution of liquid glass. The coating is made from ordinary cement mortar, since liquid glass is destroyed by carbon dioxide contained in the air. Concrete on liquid glass.

Waterproof plasters with sodium aluminate

Waterproof plasters with sodium aluminate are used to make surfaces waterproof, to seal holes in concrete and to plaster on damp surfaces made of concrete or brick. Before work, sodium aluminate is diluted with water. To obtain a solution of 2-, 3-, and 5-percent strength, you need 1 wt. dilute part of sodium aluminate in 15, 10 or 6 parts of water.

To obtain a waterproofing solution, first prepare a dry cement mixture with a composition of 1: 3 by weight (cement: sand), then the mixture is closed with a solution of sodium aluminate. Acid-resistant and alkaline concretes.

Ironing of cement plaster

To obtain a dense and smooth waterproof film on the surface of cement plaster, the plaster is ironed. Before ironing, a layer of cement plaster is leveled and rubbed. There are two ways of ironing: dry and wet.

Only horizontal surfaces can be ironed using a dry method. To do this, a sieve with holes of 0.6 - 0.7 mm is stuffed onto a small frame. and clean cement is poured on it. If the sieve is hit, the cement will lay down in a thin layer on the freshly grouted cement plaster. After applying a layer of cement with a thickness of 1.5 - 2 mm. it is leveled and compacted with a cutting, plastering spatula or trowel. It is necessary to level quickly, because after a while the cement begins to draw moisture from the raw plaster, turning into dough.

The decoration of premises with difficult operating conditions must be treated very carefully, avoiding the use of materials that may not withstand the aggressive effects of moisture and temperature changes. For example, it is not recommended to use gypsum putty or wallpaper in the bathroom - they will not last long. But cement and polymer moisture-resistant plasters are highly resistant to such influences. They will be discussed.

Moisture-resistant plaster mixtures can be different both in composition and purpose:

• Some are intended solely for leveling surfaces and preparing them for applying a decorative coating. For example, moisture resistant paint or tile.

• And the latter are themselves a decorative material that does not require subsequent finishing.

Note. Moisture-resistant decorative plaster for the bathroom is applied in a thin layer, therefore, with uneven walls, it requires preparation of the base with leveling compounds.

Of course, you can also level the walls with the help of sheets of moisture-resistant drywall (see Finishing ceilings and walls with drywall: tips from the master). It will perfectly cope with this task, it can be applied to any coating, and it will serve reliably. But only until the neighbors from above flood you. Such a possibility cannot be ruled out if you live in a high-rise building, so it is better to use more reliable materials.

Leveling compounds

Leveling is the removal of the surface into one plane without drops, holes and bumps. The material that is used for this should adhere well to the walls and serve as a solid base for decorative finishes.

Since the air humidity in the bathroom is high, it uses moisture-resistant plasters (see Consider which plaster to choose for the bathroom), the main binder of which is cement or polymer resins. These are ready-to-use or dry mixtures that require mixing with water, the proportions of the components in which are carefully selected.

But gypsum plasters should be used with caution, since they withstand such operating conditions only if the surface is tiled with careful grouting, which excludes the penetration of moisture under the cladding.

Note. There are moisture-resistant gypsum mixtures with special additives that make the plaster more resistant to moisture. But not to direct exposure to water! The instruction to them says that they can be used for plastering walls and ceilings in wet rooms.

If you nevertheless decide to use gypsum plaster (see Gypsum dry plaster mixture: features of use), as it is more convenient to use and does not give shrinkage cracks, experts advise you to play it safe and protect the surface leveled by it with coating type waterproofing materials. However, with a flood from above, it will not save you, because water will penetrate to the coating from the unprotected side.

We offer you a comparative price analysis of the most popular plasters intended for wet rooms. The cost may change over time or depending on the region, so we advise you to take it just as a benchmark for comparison. It is given for a bag of 25 kg.

The specified consumption of the finished mixture is designed to create a leveling layer with a thickness of 10 mm.

Compositions for decorative finishing

If you need moisture-resistant decorative plaster for the bathroom, then the selection criteria are the same: it is advisable to avoid gypsum-based compositions, using cement and polymer mixtures. In principle, there is nothing complicated: you just need to look for a note on moisture resistance on the packaging.

• Such a characteristic is possessed, for example, by polymer plasters STUC DECO and STUC GRANITO, which can be given different textures, acrylic plaster with the effect of "orange peel" Dufa Kratzputz aussen. They cost much more than leveling compounds, but they are applied in a thin layer, so a 20 kg package is enough for 10-30 square meters of surface.

• Also, decorative moisture-resistant Venetian plaster can be used to finish bathrooms. But it is desirable to cover it with a protective layer, which is often used as a special Optimist wax for plastered surfaces, which creates a protective moisture-resistant film.

Advice. Venetian plaster is one of the most difficult to apply. Therefore, if you do not have experience, do not risk applying it yourself. Many other decorative compositions are much easier to work with.

Such a finish is good in that it creates an integral seamless coating, which, in terms of its strength and moisture-resistant characteristics, is not inferior to tiles. In addition, both of these materials are perfectly combined with each other, allowing you to create an interesting and original design.

The only limitation concerns the texture of the surface: it should not be very embossed. In the depressions, recesses and grooves, water will definitely accumulate and mold will appear. In addition, washing such a surface is very problematic.

You should not hope that moisture-resistant plaster for the bathroom will save you from all the problems associated with high humidity and direct contact with water and detergents on the walls. You can count on this only if the finishing technology was strictly observed during the work.

Namely:

• Both the base and the already dried plastered surface must be treated with a waterproofing compound (see Waterproofing primer for wet rooms) or a deep penetration primer;

• It will not be superfluous to treat with fungicidal agents that prevent the formation and development of fungal microorganisms, mold;

Advice. You can immediately look in stores for a primer with antifungal additives.

• If the plaster is carried out on beacons, fixed on the walls with gypsum mortar, then when removing the beacons, after the plaster has set, it is necessary to thoroughly clean the places of their fastening on the walls from gypsum;

• If you are preparing a mortar for plaster with your own hands, do not spare cement, strictly follow the proportions recommended for this brand. Adding liquid glass to the solution will help make the coating more durable and waterproof;
• If the walls are leveled for tiling, try to do the job as efficiently as possible, not hoping that minor flaws can be corrected by the thickness of the tile adhesive layer.

Conclusion

Increasingly, traditional tiles in the decoration of bathrooms are giving way to decorative plaster. But even under the tile it is necessary to level the base, and for this you can use only moisture-resistant plaster mixes. You know the basic principles by which they should be chosen. And how the application process itself takes place, the video in this article will tell.

Modern materials for wall decoration, one of which is moisture-resistant plaster for the bathroom, allow the use of this finishing technology in wet rooms on a par with traditional options - tiles, painting, panels. And, if you follow certain technologies in using this type of plaster, it can be a worthy replacement for painting or tile, since the material is quite original, durable and diverse.

Wall preparation

A feature of the use of moisture-resistant decorative plaster in rooms is the preparation of walls. The main ability to resist moisture just depends on the materials that are used to level the walls and form the basis for the decor. Special moisture-repellent cement-based mixtures or gypsum plasters, such as Rotband, are well suited for this.

Today, there are also more modern materials, such as sanitizing plaster for the bathroom. This is a type of cement-sand mixture, to which certain components are added, due to which it has, over other plaster options, a number of advantages:

• Creation of a moisture-proof layer;
• The ability to regulate the microclimate of the room, absorbing and releasing moisture;
• Resistant to salt precipitation, which destroy most building materials, especially in a humid environment;
• Crack resistance;
• Environmental Safety.

Options for decorative plaster for bathrooms

There are a lot of types of decorative plaster, so it is difficult to subject it to a certain classification. Consider the main options and the possibility of using them in a humid environment.

Depending on the substances that make up the plaster, there are: mineral, silicate, silicone and acrylic. In order for the moisture-resistant decorative finish for the bathroom to please for a long time, it is necessary to choose the right look for it, and for this it is important to know the features of each.

mineral plaster

Mineral decorative plaster in its composition includes cement and lime. To give texture, crushed marble is also added. The larger the pieces of marble, the deeper the surface relief of the plastered wall will be. This type of wall decor is waterproof plaster for the bathroom, because it contains waterproof components. It is convenient to take care of such a finish - pollution is easily washed off with ordinary water;

Waterproof decorative mineral-type bathroom plaster has good water vapor permeability. This creates comfortable conditions in the room due to the fact that the walls can "breathe". Also, the mineral finish is not affected by time, endurance only increases with aging. Almost all types of this type of finish have a light shade.

For your information: The disadvantages of this type of plaster are intolerance to constant vibrations and low elasticity. When choosing it to work in the bathroom, you should take this into account.

Polymer plaster

Acrylic (polymer) plaster is a water-based mixture that is ready to use. It contains synthetic resins and ash elements, as well as glass, crushed marble. The color scheme of this type of finish can be selected at will, since it can be tinted.

Before using this type of finish in the bathroom, you should consider all the positive and negative sides. The positive thing is that acrylic plaster has a high resistance to water, on the other hand, it has practically no ability to pass steam, like any polymers, so it is better not to use it in rooms with poor ventilation. Also, water-repellent acrylic-based bathroom plaster can last up to fifty years;

silicone plaster

The composition of this type of plaster includes silicone resins. For those who plan to make repairs in the bathroom forever, this type of wall decoration is the most suitable. The durability of silicone plaster is more than sixty years.

The use of silicone plaster for finishing bathrooms is facilitated by water repellency and ease of cleaning from dirt, and mold and fungus do not start on such walls.

Important to know: Moisture-resistant silicone-based bathroom plaster is quite resistant to ultraviolet radiation. If the room is open to the sunny side, this type of plaster will be ideal.

Silicate decorative plaster

The basis of this type of wall decoration is potassium glass, also called liquid glass. Walls covered with silicate plaster perfectly repel water, resistant to the spread of fungus and mold. At the same time, this finish has a high vapor permeability.

The choice of colors is unlimited: the moisture-resistant silicate-based decorative plaster for the bathroom has more than 250 different shades. Among the shortcomings of this plaster, a rather high price can be noted.

Types of plaster by application technique

All of the above options for bathroom plastering allow you to realize different design ideas using different application techniques:

• "Goose skin" or "fur coat". This technology is performed with a piece of newspaper crumpled in a lump or a sponge wrapped in cellophane, with which the relief is stuffed on the surface of wet plaster;
• "Bark beetle". This decor is implemented using a construction grater and plaster with inclusions of a large fraction. Furrows are formed as a trace of these coarse-grained inclusions in the process of vertical or horizontal alignment of the plaster with a float;
• Decorative grooves are applied to the wet finish with a conventional or special spatula. In this way, you can imitate masonry made of stone or brick;
• Venetian technology is currently the most popular way of decorative wall decoration. It is implemented by applying mixtures of different colors in layers, with constant grouting and scraping off the layers. The result is an imitation of masonry or marble.

Conclusion

The sphere of repair is constantly developing and pleases us with new opportunities for a creative approach to interior decor. For example, quite recently, decorative plaster for the bathroom seemed to be a very exotic way of finishing, but today it is used very widely. We introduced you only to the main options for this type of coating. We hope that this information will be useful to you.

Today, along with other options for finishing bathroom walls, the use of decorative moisture-resistant plasters is in demand.

Walls covered with such plaster acquire the texture of natural stone, marble, while they perfectly resist moisture and are not afraid of high air temperature in the bathroom.

And, if the laying of tiles on the walls requires special training and knowledge of the technological features of the work, then you can easily finish the walls with decorative plaster on your own.

Moisture resistant bathroom plasters are made on the basis of lime with the addition of Portland cement, clay and polymer binders.

Depending on the components included in its composition, it is possible to obtain a very different surface texture - from rough to absolutely smooth. Such plasters are also called "Venetian".

Advantages of moisture resistant decorative plaster

The main advantages of moisture-resistant plaster for the bathroom include:

• lack of hygroscopicity. Such plaster does not absorb moisture.
• resistance to the spread of mold and mildew. Quality is very important for materials used in wet areas.
• vapor permeability allows the plaster to "breathe" without accumulating water vapor.
• variety of colors. Allows you to choose the desired shade of plaster. Does not require painting.
• sufficient cost-effectiveness of finishing.
• very high adhesion to any surfaces. It is possible to apply moisture-resistant plaster on concrete, MDF, drywall without preliminary preparation and surface priming.
• high aesthetic qualities. The appearance of decorative moisture-resistant plaster allows you to give the interior of the room a very special, noble look.

The main areas of application of such plasters are the repair of walls and ceilings, the solution of design problems in a given style, the restoration of interior coatings.

What decorative plaster looks like in the interior, you can see in the photo below:

You can watch a video about the advantages of decorative plasters below:

Applying Venetian plaster

Before applying the plaster, you need to level the walls, as the layer of decorative plaster is too thin to hide the existing defects.

Only after the surface is completely ready, you can proceed directly to the decorative finish.

A primer (primer) is applied to the surface to be finished with plaster, which improves the adhesion of the plaster material to the surface material.

The primer is best applied with a paint roller.

Decorative plaster is diluted with water from a dry mixture. To do this, pour water into a container of a suitable size, add a coloring pigment to give the desired shade to the plaster, and then pour in the dry mixture.

The proportions of dye, dry plaster and water are approximately 5-6 liters of water per 16 kg of dry mix and up to 3 cans of 400 ml of dye.

The mixture is properly stirred with a mixer until a homogeneous consistency and then proceed to its application.

Moisture-resistant plaster can be applied with a small trowel or spatula.

Application takes place in two layers. In this case, the first layer sets the main texture of the surface, and the second layer fills in some irregularities and is applied over the slightly dried first layer (after 1-2 hours).

If a rough surface is not required, then the dried plaster is polished after application with a fine, non-crumbling sponge or spatula.

When using two colors, you can create interesting artistic effects that stylize the surface of the walls like natural materials.

A video of applying moisture-resistant Venetian plaster is presented below.