Plaster mixture on cement, gypsum and lime-based: ready-made dry mixes, composition and proportions. Do-it-yourself mortar for plastering walls: what mixture to use and in what proportions? Why You Should Use Supplements

Question: which plaster is better - gypsum or cement is relevant when carrying out capital and repair construction works. These binders are a popular basis for ready-made mixtures for leveling, cladding and preparation before finishing decorative surfaces. Each material has its advantages and disadvantages, choose correct option not easy. The main guidelines are: price, operating conditions, ease of installation and timing of its implementation.

Being universal, cement-sand plaster is well suited for both exterior and internal works. It is not afraid of dampness and temperature changes and is often used to level walls, slopes and other surfaces (up to unheated and basements), finishes in conditions of high humidity, processing concrete structures to increase thermal insulation properties. This perfect option masonry mortar when erecting buildings from aerated concrete or foam block. Distinctive features cement mixture is high adhesion, durability and strength, it should be chosen when conducting capital construction or for restoration old surface(subject to material compatibility). This point is important: cement does not adhere well to plastic, wood or painted surfaces.

Significant limitations of the application include difficult process application and long drying time. The work is carried out in several stages: spraying, throwing, rubbing and grinding. Get perfect flat surface through the use of cement plaster is difficult, not everyone has the necessary skills, while with gypsum such problems do not arise. It dries for a long time - up to 3 weeks, even if a thin layer is applied. The resulting surface is porous and not well suited for subsequent decorative finishes(dark, needs filling and polishing). In general, cement mixtures are not decorative, with the exception of species with special additives.

Gypsum-based plasters are more plastic and do not shrink, as a result - this is an ideal option for leveling internal walls. They dry much faster, additional puttying is not necessary, their structure is already quite smooth without it. The main color of gypsum plaster is white, it does not show through under wallpaper or paint. At the same time, it easily comes into contact with coloring pigments, it can be chosen as an independent decorative finish, in addition, it takes the desired shape, including three-dimensional patterns. Light weight allows applying gypsum mixtures without the risk of overloading structures, and only poor water resistance prevents them from being called universal. Under the influence of moisture, gypsum is destroyed, so this plaster is not used for outdoor work.

Comparative overview of benefits

To the advantages of solutions on cement base include:

• Strength and durability. They are best suited for restoration and finishing outdoor work and withstand mechanical and other external influences well.
• High quality adhesion to aerated concrete, smooth surfaces of natural or artificial stone previously plastered walls. This is an ideal plaster for foam blocks (both masonry and finishing), its consumption on porous material is minimal.
• Low cost, cement types plasters are 1.5–2 times cheaper than gypsum plasters. This applies to both ready-made building mixtures and those mixed independently.
• Moisture resistance is the main advantage of cement mortars. It is this property that allows them to be used as plaster for slopes, facing bathrooms, bathrooms and kitchens. Gypsum under the same conditions is permissible only with subsequent protection of the surface with tiles. This ability also allows cement compositions for outdoor work.

The advantages of gypsum plaster are:

• Quick and easy installation. They dry twice as fast as cement, with the same layer thickness, and are easy to process.
• No shrinkage processes. When hardening, the risk of cracking is minimal, in comparison with cement plasters.
• Plasticity: solution without special efforts accepts certain form or distributed along the wall with desired thickness layer.
• Environmental friendliness and vapor permeability. This is a "breathing" plaster, safe for humans and favorable for the indoor microclimate.
• Sound and heat insulation abilities. The porous and lightweight structure retains heat better than others and prevents the penetration and spread of noise.

Due to the listed properties, gypsum mixtures do not need reinforcement (with the exception of layers from 50 mm), do not drain from vertical walls and keep their shape well. Their use significantly reduces the repair time, construction skills are not required for work. Reviews testify in favor of gypsum in terms of cost savings, thanks to its minimum flow. Yielding in strength and moisture resistance to cement-sand compositions, they win in decorativeness and ease of application. But you can definitely choose which one is needed: gypsum or cement plaster, only when taking into account all external factors.

Characteristics and properties

An important parameter is the consumption of material, cement mixtures are cheaper, but they are also required in a larger volume. When leveling significant surface deviations, it is desirable to calculate the thickness of the layer, in some cases it is more expedient to choose drywall. In particular, gypsum plasters are not suitable for creating layers over 50 mm (they are applied in several stages and dry for a long time), and cement plasters, in addition to complex and time-consuming pouring, will make the wall heavier. To determine which mixture is better, all working properties and operating conditions should be taken into account. The main parameters of binders are given below.

Summing up, it can be noted that cement mixture plasters are more suitable for outdoor work and interior cladding with high humidity, and gypsum - for interior decoration. But we should not forget about exceptions: in the market building materials There are many compositions with modifying additives. They can accelerate the drying time of cement mortars and enhance their plasticity, insulating properties and decorative effect.

In turn, dry gypsum mixes are on sale for preparing walls in the bathroom (for example, Rotband), with their help, repairs in the sanitary zone are carried out in a matter of days. It is not worth giving unambiguous preference to any one material; before purchasing, carefully study its characteristics and conditions of use.

Plaster is used to level walls. In this case, the question often arises: which mixture is better to choose - cement or gypsum? Plastering walls is a costly process, both in terms of labor and money. Therefore, the desire of any owner is understandable to choose a material that will create a reliable grip with the base, will not crack, will not fall off, and will last for many years. It is quite difficult to unambiguously answer the question of which plaster is better - gypsum or cement - to cover the walls. Each mixture has its own advantages, disadvantages, features.

Plaster is used for work outside and inside the house. Its task is to eliminate defects in the base, to level it. In addition, it creates protective layer, which prevents the penetration of moisture, the spread of fire, heat loss. The main task with which the plaster must cope is to prepare the wall for further finishing.

When choosing a mixture, it is necessary to take into account its purpose and composition. By appointment, plaster is ordinary and decorative. Ordinary mixtures are used for interior or exterior work, they can also be universal, special. Decorative compositions allow you to create a relief, structural or Venetian coating. Mixes of different composition are offered for sale. The most popular are gypsum and cement plaster. To better understand which one to choose, you need to understand their main characteristics.

Features of the gypsum mixture

The basis of gypsum plaster is gypsum with different fillers, helping to reduce consumption, and plasticizers that improve adhesion to the surface. A gypsum-based solution is used to level surfaces, preparing them for subsequent finishing. It is not used in wet rooms. Depending on the size of the filler, fine, medium, coarse-grained mixtures are distinguished. To obtain thin layer, use a fine-grained composition. To equalize large differences, eliminate large defects, a coarse-grained mixture is required.

Gypsum plaster is usually used for interior work. For outdoor it is better to take cement. Although there are gypsum compositions that, by adding additional components to them, perfectly cope with the influence of negative factors. However, they will cost more than cement.

The solution can be applied in a sufficiently thick layer, while it does not crack when dried. Therefore, it can be used to eliminate even large defects and damage. Advantages of gypsum plaster:

• Environmental friendliness. It does not contain harmful components, is not aggressive, is absolutely harmless.
• Vapor permeability. Due to the porosity, gypsum regulates the humidity in the room: it absorbs excess moisture, and releases moisture if necessary.
• Creates sound and heat insulating layer. This is especially true in panel houses.
• Effectively removes roughness.
• Plastic and easy to apply.

It is not recommended to use gypsum plaster in rooms without heating. It is convenient when working hard-to-reach places because it dries quickly. In addition, if the layer is perfectly even, then it can not be puttied.

If you decide to use gypsum mixture, then it is necessary to take into account its inherent disadvantages:

• it sets quickly, so it is impossible to prepare a lot of solution at once;
• with a large layer thickness, it can shrink;
• badly "lays down" on metal;
• how better quality, the higher the price.

An important advantage of the gypsum mixture is the cost-effectiveness of use. Compared to cement, it will take 1.5 times less for the same area.

Features of the cement mixture

in residential, utility rooms, for internal and facade works often used cement plaster. The binder is cement, the strength of which is determined by the brand. Sand is used as a filler. The quality of the solution largely depends on it. Sand is considered good if it contains dusty, silty, clay impurities. Therefore, river or quarry sand is usually used.

Its size affects finished plaster. If the particles are large, it will be difficult to obtain a smooth surface, it will take a long time to grind it. On the contrary, too small particles lead to the fact that the cement plaster cracks after drying.

The ratio of sand and cement is affected by the required strength of the solution and the brand of cement. Usually it is 1 to 3 or 4. Polymers help improve the plasticity of the solution. Increases vapor permeability slaked lime. Cement plaster has the following advantages:

• affordable cost;
• you can purchase a dry mix, and it’s also easy to cook it yourself;
• suitable for work inside and outside the building;
• differs in high adhesion;
• creates a durable coating;
• tolerates humidity and temperature fluctuations.

Cement mixture dries much longer than gypsum. Therefore, it is possible to eliminate small defects on the surface. In addition, this property allows you to dilute a lot of the solution at once, reducing the preparation time. Cons of cement mortar:

• The application process is very laborious and long. The classical technology provides for the implementation of 3 layers: spray, soil and grout. It also takes time for them to dry.
• The cement mixture does not fit well on plastic, wood.
• Because of high density cement creates an additional load on the base. It must be calculated to take into account before plastering.

Gypsum or cement: what to give preference?

It is difficult to say unequivocally which plaster is better. The choice of mixture depends on the characteristics of the room, the tasks that will be solved with its help. To align the walls in a living room, when preparing them for wallpapering, painting, creating a relief pattern, it is better to use a gypsum composition. To restore the walls in the kitchen, in the bathroom, if necessary, strengthen and level them, it is recommended to take a cement mortar. Such a surface will be resistant to any influences, durable, reliable.

Regardless of which mixture is used, in order to obtain a quality plaster layer certain factors must be taken into account. First of all, the weather affects the plaster. Plastering should be carried out at positive temperatures, normal humidity. From draft and strong wind drying is accelerated. These factors increase the unevenness of moisture removal, as a result of which the surface cracks.

Cause Bad quality often becomes a heterogeneity of the mixture. Often this happens due to inaccurate proportions during self-mixing. A large difference in thickness can lead to cracking: a thin layer dries faster. To improve adhesion and protect walls from fungus, obligatory step primer must be applied before plastering.

Good plaster lasts for decades. Now gypsum mixtures have replaced cement finishing coatings. But not all plasterers refuse the usual materials. Let's look at the strengths and weak sides gypsum and cement mixtures and figure out which plaster is better.

Features of cement-based plaster mixture

The word "plaster" comes from the Italian term stuccatura, which denoted the finishing materials familiar to the Romans (lime, alabaster, gypsum). Modern plaster refers to hardened mortar for leveling walls. It is unambiguous to say which solution is better and which is worse. Composition optimal coverage depends on many factors.

Plaster solutions have been used for thousands of years to decorate houses, apartments, building facades. The demanded finishing material has evolved along with humanity. In recent decades, when building and repairing houses, builders have mainly used cement coatings.

The mixture consists of cement (main component), sand (filler), plasticizers. As the latter, limestone, gypsum, or combinations thereof are used. Solutions are distinguished by the proportions of the components and depending on the surfaces to be finished. Cement-based coatings cover the walls outside, inside buildings. Moreover, in the latter case, the premises may be unheated and with high humidity.

TO strengths cement finishing mortars include:

• universality;
• plasticity lasts for several hours - you can immediately prepare a large volume, spending it as needed;
• strength of the finishing layer;
• affordable price.

However, cement plaster is far from ideal. Masters note the following shortcomings:

• the mixture does not fit well on the concrete base:
• the layer dries for about 14 days, which reduces the rate finishing works;
• high humidity when working with the mixture - for the crystallization of cement particles, the surface to be trimmed must be sprayed with water;
• the main component cement gives the finished surface an unsightly gray color;
• at the final stage, finishing puttying is mandatory;
• when working, a suspension of sand, cement, which enters the respiratory tract, rises into the air.

The main problem with cement coatings– cracked finishing layer. In addition, as it dries, the composition will shrink, which will lead to irregularities. By the way, for this reason, it is not used for drying rooms. optional equipment(heaters, hair dryers, heat guns).

Thus, the cement finishing mortar is suitable for walls in technical rooms, facade works, in apartments with draft and.

Advantages and disadvantages of gypsum coatings

Despite all the advantages of cement mortar, with interior decoration gypsum plaster confidently competes with him. As the name suggests, the main component of the mixture is gypsum powder, made from a natural mineral. During the production process after a long heat treatment this powder is crushed. As a result, the finer the fraction (grain size), the better the treated surface.

In addition to gypsum, the composition of the solution includes natural or synthetic fillers, polymer additives. For leveling walls, the shape and size of the grains are of no small importance. In addition, fillers reduce the cost of the mixture and increase the strength of the finishing layer. And the polymer ingredients increase the adhesion of the solution, make it more elastic.

Based specifications finishing coating, its advantages can be distinguished:

• High adhesion - the solution falls on any base;
• Leveling ability - the surface finished with gypsum coating is immediately ready for painting, whitewashing, wallpapering;
• The consumption of this mixture is lower than that of cement. True, for this you need to follow the rules and technology of work;
• Solid thickness of the finishing layer - sometimes it reaches 6 cm;
• It is easy to work with the mixture - it fits well on the surface, leveled, smoothed;
• The surface treated with such plaster acquires additional sound and heat insulation qualities.

Despite all their positive traits, gypsum coating is not used everywhere. There are reasons for this:

• Price. Gypsum mixture costs 1.5–2 times more than cement;
• Strength. The surface plastered with gypsum coating does not withstand mechanical damage;
• The solution quickly seizes, therefore, in order to avoid overspending, it will have to be prepared in small batches;
• The need to use additional materials. For example, when processing a concrete surface, it is necessary to use primer solutions, and plastering metal surfaces without a waterproofing layer is unacceptable. In addition, for this decorative coating tiling is not recommended. On contact adhesive composition from finishing material ettringite is formed - a mineral that destroys gypsum.

The main disadvantage of such a mixture is the undesirability of using it for surface treatment outside the house.

Among plaster finishing coatings distinguish three types. The first is a fine-grained solution, it includes carefully ground sand. Such material is recommended to be applied in layers of 0.5–0.8 cm thick. For leveling, apply a second layer. The main area of ​​​​application is the decoration of ceilings.

Medium-grained gypsum mortar is the most popular and, as a result, widespread. It is the main competitor of cement-based mortars. Allowable thickness 5 cm.

Coarse-grained gypsum plaster is used to hide significant surface defects. As a rule, broken slopes are repaired with its help, facades are updated. By the way, in the latter case, the selected mixture must be checked for resistance to water. Sometimes, despite the claims of manufacturers, it is better to play it safe and apply a protective layer.

Work with gypsum and cement plaster - a comparative analysis

The main factor determining which plaster is better and which is worse is the characteristics declared by the manufacturer. But along with them, secondary factors must be taken into account - ease of use, the need to use additional materials.

At first glance, the advantages of gypsum coatings are obvious - they are elastic, stick to any surface, and are easy to set. And the faster the layer hardens, the faster the work moves. But with insufficient skill, the prepared batch of plaster will dry out. It cannot be reused. In other words, the price of a mistake is an additional cost, and the cost of gypsum plaster is not affordable.

Cement plaster mortar dries for at least two hours, which allows you to cover in one go large areas. However, the adhesion of such a composition is lower and in some cases (ceiling, corners) the surface will have to be reinforced plaster mesh. On the one hand, this entails additional labor costs, on the other hand, the strength of such plaster is many times higher.

As you can see, the answer to the question of which plaster to choose will be ambiguous. For outdoor work the best option becomes cement plaster. But gypsum mortar is a great option for working inside the apartment (with the exception of the kitchen, bathroom,). In rooms with high humidity, you will have to cover the finished surface with varnish.

I can unequivocally answer this question, it is impossible to add gypsum to the cement mortar, even in small quantities. Although they say that in the production of cement into clinker, this is an intermediate product, they add a small amount of gypsum one or two percent, but I'm not strong in chemistry, I don't know. But I have extensive experience in plastering with cement-sand mortar with the addition of gypsum.

I even had to work for such unscrupulous foremen who, apart from this "ominous mixture", did not work with anything else. Why is this needed? The speed of work increases five to ten times, and as you know, the faster you hand over the object, the faster you get the money. And do not think that only small private traders are guilty of this.

The plaster layer made with a cement-gypsum mixture after a while, one to five days, depending on the base, begins to become covered with a web of very small cracks, they can be seen if the surface is well primed with a primer. You can putty and forget only if the base is made of red brick, and plastering work were carried out indoors. But in most cases, gypsum is added to cement when plastering. concrete bases, on red brick, plaster sets quite quickly even without gypsum.

The favorite excuse of such plasterers, if the cement-gypsum plaster layer is rubbed from above with a solution without gypsum or puttyed with facade putty, then everything will be in order. This is a pure lie, checked more than once, does not help.

Each layer of cement-sand plaster, on concrete wall, it will set from 5 to 10 hours, and there may be several such layers. The addition of gypsum allows the job to be completed in one go, the plaster will be hard (but not dry) in 5 to 10 minutes. Such plaster will not last long, indoors up to 5 years, on the street it will not survive the first winter. If under such plaster was stuffed metal grid it will begin to rust very quickly 3 - 6 months. outdoors and indoors for several years (depending on humidity), and traces of rust will constantly appear on the surface.

Before 50 - 80 years, there was a practice, when plastering the ceiling, upper slope etc. add gypsum to the cement-sand mortar, at that time it was the only solution, even in the educational literature of that time you can find a recipe for this plaster mortar. Currently, to increase the plasticity of the mortar, plasticizers and a number of other additives are used to improve the adhesion of the mortar, and gypsum is added to the composition of the cement-sand plaster mixture only in order to save money.

It is very difficult (long) to plaster the ceiling or the upper slope with cement-sand plaster, in such situations I add to cement-sand mortar tile adhesive (1 to 5 or 8). This facilitates the work of the plasterer and saves on plaster mixtures, but at the same time does not lower the quality of work.

The quality of the plaster finish depends not only on the professionalism of the master, but also on the chosen mixture. On the shelves of hardware stores there is a great variety of plasters of different composition - here are solutions that have been “tested for centuries”, and modern materials. Plaster differs not only in price, but also in purpose, properties, and advantages. Let's figure out what this material is generally used for and how its main varieties differ.

Purpose and main types of plaster

Regardless of the variety, plaster mixtures can perform the following functions:

• surface leveling;
• increase in noise and heat insulation performance of the structure;
• sealing seams;
• creation of fire protection.

There are a lot of options for classifying plaster, but most often the composition of the mixture is taken as the basis. Accordingly, there are types such as plaster, clay, lime, cement plaster, etc. The most popular are mixtures based on gypsum and cement, so we will talk about them in more detail.

Features of cement plaster

Over the years, the composition of cement plaster has undergone significant changes. Previously, the mixture was obtained by kneading cement with sand or lime, but gradually many modifications to this traditional composition appeared. New cement mortars have properties such as plasticity, low water absorption, improved adhesion and others.

Cement plaster can be applied to brick, concrete, aerated concrete, etc. Before starting work, the base is prepared: cleaned of dirt and dust, primed.

Cement plaster is used for both exterior and interior work:

• wall alignment;
• decoration of rooms with high humidity (kitchen, bathroom);
• decoration of unheated premises or entrances;
• preparation of surfaces that require an increase in frost resistance.

Advantages of cement plaster

Cement plaster has many advantages, due to which it does not lose popularity among builders even now, in the presence of many similar materials.

• High strength. According to this parameter, cement plaster is the undisputed leader. In cases where it is necessary to give the surface maximum strength and reliability, experienced craftsmen always choose mixtures of cement - this makes it much less likely to carry out overhaul premises.
• good adhesion. Cement plaster does not require the use additional funds to increase adhesion to the base. In this case, the applied solution will retain its integrity for a long time.
• Moisture resistance. This property allows the use of cement plaster when finishing rooms in which there is a permanently humid microclimate. This is due to the fact that the solution has a dense structure - it eliminates absorption, thereby perfectly protecting the base.
• Affordable cost. As noted earlier, the composition of cement plaster includes fairly cheap and affordable components.

Disadvantages of cement plaster

Cement-based mortars are not ideal - we have identified four main drawbacks that do not allow us to call this material universal.

• Cement plaster is not compatible with plastic, painted and wooden substrates.
• The large weight of the solution creates a serious load on the walls, so before applying it is necessary to accurately determine the thickness of the layer - for this, special calculations are carried out.
• The application process itself is laborious, as it takes place in several stages.
• In order for the surface to be ready for painting, the plastered walls need to be additionally putty - this increases the time for finishing as a whole.
• Many cement mixtures harden for a long time - about 3-4 weeks.

However, the last drawback today is already a thing of the past. Major manufacturers building materials modify cement mixtures with the help of various plasticizers - this allows the mortar to harden within a week.

Features of gypsum plaster

A solution of gypsum plaster is made from a dry mixture, which includes not only gypsum powder, but also various plasticizers. To obtain the desired pasty consistency, the mixture is diluted with water.

Gypsum plaster is applied manually or machine method. As a rule, a perfectly flat surface can be obtained even when applying only one layer of mortar.

Gypsum plaster is chosen when necessary:

• carry out interior decoration;
• prepare surfaces for painting (wallpapering).

For exterior finish this mixture is not suitable, as well as for use in rooms with high humidity.

Advantages of gypsum plaster

Gypsum plaster has almost twice as many advantages as cement plaster. Let's take a look at why she's so good.

• Ecological cleanliness. Gypsum mixtures do not contain components hazardous to human health. Their use in residential areas optimizes the microclimate, since gypsum plaster is not as dense as cement plaster, and therefore does not interfere with natural air exchange.
• No shrinkage. This suggests that the plaster will not crack during the hardening process - one of important conditions getting a flat surface.
• Small specific gravity . This characteristic hides several advantages at once. First, light weight reduces the load on bearing walls, which contributes to the long-term preservation of their integrity. Secondly, it allows you to reduce the consumption of the mixture.
• Plastic. When applied gypsum compositions there is no need to use a reinforcing mesh - the mixture is already viscous enough to stick to the surface without dripping or deforming. In some cases, you can apply plaster in several layers, without fear of any consequences.
• Vapor permeability. As noted above, gypsum mixtures are loose, porous. This not only improves the microclimate, but also prevents the formation of fungus and mold on the walls.
• Excellent sound and heat insulation. Gypsum plaster contributes to the preservation of heat in the room - the walls covered with it are never icy. In addition, the walls transmit much less noise.
• High finishing speed. Three days is the normal curing period for gypsum plaster. Only in exceptional cases, this period can be extended up to seven days (for example, if the mixture was applied in several layers).

The use of gypsum plaster can significantly reduce the time of finishing work - in comparison with cement mixture, labor costs and material consumption are reduced by at least two times.

Disadvantages of gypsum plaster

All the disadvantages of this material are rather conditional and usually do not bring significant inconvenience. We have identified two shortcomings.

• As already mentioned, gypsum plaster is used only for finishing. interior spaces, since this mixture does not tolerate excessive moisture.
• The cost of gypsum mixtures is higher than cement mixtures by about 1.5-2 times.

As a rule, these shortcomings do not play decisive role when choosing plaster, since the advantages fully pay off two small minuses.

Output

At first glance, it may seem that gypsum plaster is of higher quality - it is easy to apply, allows moisture to pass through, does not disturb the microclimate, and allows you to quickly complete the finish. However, this does not make gypsum mixtures universal, which means that you need to choose plaster based on the purpose.

Cement mortar is suitable if facade, basement or bathroom finishing is required. It should also be preferred if it is necessary to ensure maximum surface strength, and perfect smoothness “for painting” is not needed. Also keep in mind that cement plaster is more difficult to apply - it will be almost impossible to cope without the appropriate experience.

It is better to choose a gypsum mixture if decoration of the living quarters is necessary, and if you plan to carry out the work on your own. Gypsum plaster is easy to apply and is well suited for pre-finishing.