Plastering walls with your own hands on clay: step by step instructions

How to prepare a mortar for plastering walls from cement and sand

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Components used

A common solution includes fillers, a variety of binders, and water. Depending on the components used, there are lime, cement, clay and combined lime-clay, lime-cement mixtures. Let's take a closer look at each of the components used.

• The most common filler contained in the plaster is sand. He, in turn, is river, quartz, ravine, mountain and sea. The highest quality of them is considered to be river quartz sand. Plaster mixes usually use sand with medium grains. Coarse-grained material is less commonly used. The fillers must always be clean, free from dirt and dirt. The screening method depends on the type of work. So, with a small amount of work, a mesh sieve is usually used, in other cases an inclined sieve.
• One of the components of the plaster is lime. Today, gray, white, slaked, carbide, ground, quicklime are distinguished. Each of them is distinguished by its strength, poor water resistance and poor moisture resistance.
• A filler such as cement is much stronger than lime. Its complete hardening lasts up to four weeks. In addition, it is resistant to moisture and various weather conditions. The cement slurry can withstand strong overloads.
• As for gypsum, it has low strength, hardens quickly, does not tolerate moisture well and has poor resistance to the external environment. Gypsum should not be mixed with cement. Typically this filler is used for small plastering jobs. It is sometimes added to lime for quick setting.
• Another popular plaster filler is clay, which, when mixed with water, produces a viscous dough. In its raw form, it is very plastic, therefore it can take any shape that remains even after drying. The clay becomes very hard after firing.

Types of clay solutions for stoves and fireplaces

When laying the stove, depending on the temperature regime of the zone being built, several types of mortar are used:

• 1200-1300 С - clay-fireclay and cement-fireclay;
• 1100 С - clay-sand mixture;
• 450-500 С - lime-sand;
• 220-250 С - cement-lime;
• range of atmospheric temperatures (furnace foundation) - cement-sand mixture.

Of the listed masonry mortars, clay or chamotte made from it are included in three mixtures: clay-sand, clay-chamotte and cement-chamotte).

Consider these important components of masonry kiln mixes.

Clay mortar for masonry ovens proportions, materials and preparation procedure

What material is the progenitor of cement and concrete mixtures? Every stove-maker knows the answer - clay. Until now, it is an indispensable material for masonry. The use of clay mortar when laying bricks and fireplaces is due to several factors:

• Chamotte clay with natural kiln firing acquires the properties of a brick. That gives high rates of coupling of the entire structure.
• High thermal stability. After being treated with fire, the clay actually turns into a ceramic stone. It is able to withstand high thermal loads without significant damage.

However, in order to achieve the above, when preparing the solution, it is necessary to follow a number of rules and recommendations.

Clay types

First you need to decide on the method of obtaining clay.For residents of the private sector, you can get it yourself. The depth of the clay layers is low up to 1 m. But at the same time, its composition should be taken into account - not every consistency is suitable for the solution.

In addition to this method, you can purchase prepackaged fireclay clay already prepared by the factory.

The main indicator for clay is its fat content. For laying stoves (for example, a Russian stove), it is necessary to use medium fat clay. If this indicator is exceeded, then during firing irregularities will appear and the structure of the layer will be disturbed. A mortar made of oily clay is convenient for masonry - it has good adhesion rates and fits snugly on the brick surface. However, its use is not recommended anyway.

Training

The so-called "skinny" clay has a dense structure and it is necessary to apply certain physical efforts to create a high-quality homogeneous masonry.

The fat content can be balanced by the sand content. To determine the proportion, you can conduct a small experiment:

• Divide a small amount of clay into 5 parts. One of them does not mix with sand, and the rest are 1/4, 1/2, 1 and 1.5 parts, respectively.
• Knead each of them separately to a plastic state, make flat rounded blanks.
• After final drying, the quality of the mortar can be determined. If there is too much sand, the workpiece will crumble. If it is not enough, then the surface will be covered with cracks. It is optimal if the composition of the workpiece remains homogeneous and does not become covered with cracks.

After that, it is necessary to carry out the process of cleaning the clay from foreign impurities. For this, a sieve with a mesh size of 3 * 3 mm is used. In addition to this method, you can rinse the clay. For this, the container is installed at an angle of 4-8 degrees. Dirty clay is loaded into the upper part, and water into the lower part. Using a small spatula, wash the clay with water until a homogeneous solution is obtained in the lower part. The resulting solution is poured into a separate container.

When the required amount of material has been received, you can start making the solution.

Preparation of the solution

Before starting work, the clay must be soaked. To do this, a small layer of clay is poured into a large container, which is filled with water above the solution level. Then the next layer is applied and the procedure is repeated. After a day, the solution is mixed until smooth.

How to properly prepare plaster mortar

A solution for plastering various stories consists of three components:

1. The main element of the solution.
2. Binder
3. liquid.

The main rule is to choose the perfect combination of all the elements of the solution. The plaster should not be too thin or too thick.

Now many ready-made plaster mixes are sold, in which all components are ideally selected, as well as additional elements are added. The manufacturer must attach detailed instructions for the use of the mixture and its preparation.

You just have to pour the dry mixture into a container for preparing the solution, then add the required amount of water specified by the manufacturer and mix the solution thoroughly. In the process of mixing the solution, you can use a special mixer that does its job quite well. The solution mixed with a mixer will be homogeneous.

You can prepare a solution with your own hands. To do this, you need to select the composition that is most suitable for carrying out repair work, combine all the components in the specified proportions, add water and mix everything thoroughly.

Specifications

The composition of such a solution necessarily includes cement, sand, slaked lime and water.

It is worth paying attention to the fact that it is necessary to add slaked lime.Otherwise, the quenching reaction will begin in the solution itself when water is added, and bubbles, forming already inside the solution, will lead to cracking of the plastered surface.

This process of bubble formation will lead to a deterioration in the quality of the solution and to brittleness after it dries.

Building mixtures, their composition and properties are regulated by various GOSTs. This is necessary for the standardization and regulation of building codes. GOST 28013-98 is the main regulatory legal act governing the technical requirements for mortars and materials included in the composition.

This standard also includes the characteristics of quality indicators, acceptance rules and conditions for the transportation of ready-made solutions. It contains the qualitative and quantitative characteristics of masonry mortars, materials for plastering and for interior work, used in various operating conditions.

Clay-sand mortar

Sold in hardware stores or prepared by hand. When it is possible to extract clay, the mixture is practically free. A mortar of clay with sand is the main one, since it is used for laying almost the entire furnace. An exception is a chimney with a foundation, since the moisture resistance of the resulting mixture is rather low.

Sand and clay kiln mortar works well with fired clay bricks. It has average strength, is resistant to fire, and, most importantly, does not allow gases to penetrate into the substance. Another advantage is its recyclability. The solution has no expiration date. It can be diluted with water and reused.

Clay

The basis of the kiln solution, which, in case of independent "extraction", requires the correct determination of fat content. Routine wetting and kneading in the hand is not enough. A more thorough check needs to be done. It can be done in different ways, but kneading 2-3 liters of clay with a jar with plain water is considered among the simplest and most accessible.

When the resulting mass almost completely adheres to the paddle, it means that the clay has a high fat content and needs to be artificially depleted by adding sand. If the clay remains small clots on the tool, it is ideal for the mortar and does not require any "rework". This stage can be continued by direct kneading of the masonry mixture, but the clay must first be cleaned. This also applies to sand, which must be washed.

Clay preparation

Correctly selected clay should be pre-cleaned, which will significantly improve the quality of the material. It is enough to sift the dry material through a sieve with meshes of 2-3 mm. Further, it is subjected to soaking, laying in layers of 15-20 cm, poured on top with water, and then after a day it is mixed, with the addition of a small amount of liquid. When another 24 hours have elapsed, the completely swollen mixture is thoroughly stirred again. It is this clay that is used for further preparation of the oven solution.

Sand cleaning

Purchased bulk material is usually sold washed, but it often requires additional preparation. The presence of any extraneous inclusions reduces the quality of the masonry mortar, and, therefore, affects the quality of the seams being performed, which should not be allowed. It is enough to sift the sand purchased in the store through a fine sieve with cells from 1 to 1.5 mm, and the sand obtained on its own will require additional rinsing under a high pressure of water. On an industrial scale, sand is purified from organic components by heating to high temperatures, at which the bulk material dries perfectly.At home, this can be done, but only when a special installation is made on their own, which is inappropriate for laying out one structure.

Clay plaster composition and recipe

There are many compositions of clay plaster, but there is no universal recipe, the quality of the composition depends on the components. And the main one is clay for plastering walls, it is divided into 2 types: light and oily, the latter is the most suitable.

To check the quality, roll a ball of small diameter out of clay, put it on a flat surface and flatten it. If the edges remain intact, then the material is suitable for plaster, cracks have begun - the composition is of little use. Another test is to roll a flagellum with a length of 200-300 mm, with a section of 10-20 mm and gently bend it, the edges of a high-quality material do not crack.

Material features

It would seem that clay as a building material turned out to be in the distant past in the past, but with the development of ecological construction in recent years, they began to actively use it again. The fact is that finely ground clay is a good astringent and preserving agent.

If you dilute it with water and add a filler to the solution, for example, plant fibers or sawdust, it is possible to take a good and environmentally friendly thermal insulation material. For example, such a mixture is usually used to fill hollow slag and expanded clay concrete blocks, or as an insulating plaster.

In addition, gypsum, lime or, in addition, cement is added to the mixture from time to time, which makes it possible to make the clay concrete more durable. This allows it to be used as a load-bearing material in the construction of eco-friendly houses.

The bulk density of the material depends on the ratio of ingredients. The optimal indicator is considered - 550-600 kg per cubic meter.

There is a conclusion that such material lends itself to decay, and is fire hazardous, since it contains straw or sawdust. But this is just guesswork, since the cut of plant stems and sawdust in a clay liquid solution swell and are well enveloped with clay, which not only reliably binds them, but also preserves them.

As for the fire hazard, the aggregate begins to smolder only when exposed to an open fire, for example, a gas flame, within a few minutes. As a result, the fire safety of the material is also higher than that of some more classical materials that are used in construction work.

Benefits

The growing popularity of the material is explained by its following advantages:

• Promote the formation of a human-friendly microclimate... Clay is capable of absorbing and releasing moisture more rapidly and significantly more than classic building materials. Moreover, this does not affect the strength of the material.
• Accumulates heat... Thanks to this property, the material can create comfortable conditions in housing, in addition, in conditions of huge daily temperature drops.
• Reusability, for this you need the material in water.
• Ideal for DIY home construction... The material does not require the use of construction equipment and expensive equipment. The technology of working with it is also available to inexperienced builders.
• Clay protects wood and other organic materials from decay... If you treat wooden walls with it, then neither fungus nor insects will hit them.
• Clay clears the airabsorbing pollutants.
• Low material cost... That is why building with the use of clay turns out to be not only environmentally friendly, but also economical.

Binder materials: cement, lime, clay

One of the main components of some finishing materials are the so-called binders, which are generally divided into two large groups: aqueous and non-aqueous. The first group, in turn, is divided into mineral and organic.

The mineral includes cement, lime and water glass.

Organic adhesives include a variety of vegetable, animal and synthetic adhesives.

Cement

It gives the concrete high strength. Thanks to him, the concrete sets quickly and is less in the formwork. Typically, cement is made from substances such as alumina or calcium silicate, which are thoroughly ground and fired before sintering.

As a result of firing, cement clinker is obtained, which is well ground. The quality of the cement depends on the fineness of grinding and the composition of raw materials.

Cement is used for the preparation of mortars, concrete mixtures, for the manufacture of concrete and reinforced concrete products. Cements are divided according to composition, strength during hardening, hardening speed, etc.

Cement has the ability to set well not only in air, but also in water, so it must be stored in a dry place.

Most often used in construction are Portland cement (silicate cement), Portland slag cement (Portland cement with slag added to it) and alumina cement, which is obtained from alumina and lime fused at a temperature of 1400 ° C.

The resulting mass is crushed into pieces, which, in turn, are ground into powder in tube mills. Grade strength (alumina cement is produced in grades 400, 500, 600) cement is gaining in 3 days.

Portland cement is a gray-green powder. It is obtained by firing clay and chalk at a temperature of 1500 ° C. After that, cement clinker (this is the name of the resulting mass) is ground in special mills, while adding various active and inactive (inert) additives to it: slag, gypsum, quartz sand.

If the cement is dissolved with water, then after a short time it hardens, turning into a solid substance like a stone. Portland cement is available in grades 400, 500, 600 and 700.

Compared to binders such as clay and lime, cement sets much faster.

Setting occurs already after 35–40 minutes, and the final setting - no later than 12 hours, depending on the brand of cement. You can speed up the hardening process by adding warm water to the cement.

Conversely, the use of cold water postpones the setting of the diluted cement for some time.

The brand of cement depends on the fineness of grinding. In the event that the brand of cement is unknown or there are some doubts, you can roughly determine it by the density of the cement. It decreases with long-term storage: in 6 months - by 25%, in 1 year - by 40%, in 2 years - by 50%.

Portland cement

It is a hydraulic binder, a product of fine grinding of clinker with the addition of gypsum (from 3 to 5%), which regulates the setting time of the cement. By composition, Portland cement is distinguished without additives, with mineral additives, slag Portland cement, etc.

The beginning of the setting of Portland cement at a water temperature in a solution of 20 ° C should occur no earlier than 45 minutes after the preparation of the solution and end no later than 10 hours.

If water with a temperature of more than 40 ° C is used in the preparation of the mortar, the setting may occur too quickly.

The strength of Portland cement is characterized by grades 400, 500, 550 and 600. In order to bring Russian standards closer to European ones, the cement is divided into classes: 22.5; 32.5; 42.5; 55.5 MPa.

Fast hardening portland cement

It is a Portland cement with mineral additives, characterized by increased strength. It reaches more than half of the planned strength after 3 days of hardening.

Fast-setting cement is available in grades 400 and 500.

Extra fast hardening high strength Portland cement

They are used in the production of prefabricated reinforced concrete structures and during winter concrete work. Grades 600 are produced.

Portland white cement

They are produced in two types - white Portland cement and white Portland cement with mineral additives.According to the degree of whiteness, white cements are divided into 3 grades (in descending order). The beginning of the setting of white Portland cement should occur no earlier than 45 minutes, the end - no later than 12 hours after the preparation of the solution.

Colored Portland cement

It comes in red, yellow, green, blue, brown and black. It is used for the manufacture of colored concrete and mortars, finishing mixtures and cement paints.

Grades 300, 400 and 500 are produced.

Slag Portland cement

It contains blast-furnace slag and natural gypsum, added to regulate the setting time of the solution.

Available in grades 300, 400 and 500.

Fast-hardening slag Portland cement

Differs in increased strength after 3 days of hardening.

Grades 400 are produced.

Gypsum-alumina cement

It is obtained by mixing high-alumina slags and natural gypsum. The beginning of the setting of gypsum-alumina cement should occur no earlier than 10 minutes, the end - no later than 4 hours after the preparation of the solution.

Lime

This material is mainly used when working with stone and for preparing a plaster mixture. There are three types of lime: hydraulic, high-hydraulic, air. They differ in the method of hardening. Air lime hardens in air. Its main drawback is water resistance.

Hydraulic is capable of hardening in air and in water, its hardening process is faster than that of air, and its strength is much higher. Highly hydraulic lime is characterized by high strength and hardening speed.

When buying lime, you need to pay attention to the presence of instructions for the preparation and storage of the solution.

Lime is quenched by processing quicklime lump with water. Depending on the amount of water required for slaking, hydrated lime (fluff), lime dough and milk of lime are obtained.

Powdered hydrated lime is obtained when the volume of water is 60–70%. As a result of slaking, the volume of lime increases 2-3 times. Slaked lime is a white powder consisting of the smallest particles of calcium oxide hydrate with a density of 400 kg / m3 (loose) to 500-700 kg / m3 (compacted).

To obtain a lime dough, when quenching water, take 3-4 times more than lime. The volume of the resulting dough is 2-3 times larger than the volume of lime taken for its preparation.

Lime paste is a white plastic mass with a density of up to 1400 kg / m3.

Lime, which has been extinguished well, having increased in volume by at least 3 times, is called fat, and if it has increased in volume by less than 2.5 times, it is called lean.

According to the ability to harden, it is divided into hydraulic and air. In the first case, lime hardens both in water and in air, and in the second, as the name implies, only in air.

Lime is obtained by calcining limestone in shaft furnaces. After firing, quicklime is obtained - boiling lime, or lump. To slake lime, it is poured with water at the rate of 35 liters of water per 10 kg of lime. In the process of slaking lime begins to "boil", crumbling into small pieces, after which it noticeably increases in volume. By the time of extinguishing, there are quick-extinguishing (about 8 minutes), medium-extinguishing (about 25 minutes) and slow-extinguishing (more than 30 minutes) lime.

Slaked lime is called fluff. In order for all lime particles to be extinguished, it must be kept for about 2-3 weeks under a closed lid.

After the specified period, a finely dispersed mass with a water content of not more than 50% remains.

Air lime is quicklime and slaked (hydrated). Lime without additives is divided into 3 grades (1st, 2nd, 3rd), lime with additives - into two (1st, 2nd). Hydrated powdered lime (fluff), with and without additives, is of two grades (1st, 2nd).

The area of ​​application of air lime is the preparation of lime-sand and mixed mortars, which are used in masonry and when plastering surfaces, as well as for whitewashing and in the production of silicate products.

Hydraulic lime is either weak hydraulic or strong hydraulic. It is used for the preparation of masonry and plaster mortars, as well as low-grade concretes intended for hardening both in air and in conditions of high humidity.

Lime-containing hydraulic substances

They are subdivided into lime-slag with the addition of granular slags, lime-pozzolanic with the addition of sedimentary or volcanic active rocks, lime-ash with the addition of ashes of certain types of fuel. Lime-containing substances are involved in the preparation of low grades of concrete and mortars, which are used in underground structures.

Lime-containing hydraulic substances are produced in grades 50, 100, 150, 200.

Gypsum binders

It is obtained by firing and grinding from sedimentary rock, which includes gypsum dihydrate. Gypsum binders have the ability to quickly set and harden. Depending on the temperature of the heat treatment of raw materials, two groups of gypsum binders are distinguished: low-fired (molding construction and high-strength gypsum) and high-fired (anhydrite cement, extrich gypsum).

In terms of compressive strength, there are 12 grades of gypsum binders - from low-strength G-2 to high-strength G-25. According to the setting time, they are divided into fast-hardening (A), normal-hardening (B) and low-hardening (C).

According to the degree of grinding, gypsum binders are also divided into three groups: I, II, III.

Grades from G-2 to G-7 (groups A, B, C and I, II, III) are used for the manufacture of various gypsum building products. Grades from G-2 to G-7 (groups A, B and II, III) are used for the manufacture of thin-walled building products and decorative parts. Grades from G-2 to G-25 (B, V and II, III) are used in plastering work, for sealing joints and for special purposes.

To increase the strength and accelerate the setting time, gypsum binders are added to lime-sand mortars. They also impart greater smoothness and whiteness to the plaster layer, they are used as the main substance in mastics.

Clay

Clay is oily, bold (medium fat) and lean (loam). This division is due to the degree of sand content in the clay.

Clay is used as a binder in the manufacture of oven and plaster mortars, added to cement mortars intended for laying structures in conditions of normal air humidity.

Dense clay that does not contain impurities is an excellent material for construction. Bricks are made from it.

If clay will be used in the construction of a house, its quality can be checked as follows. To do this, put 1 kg of material in a bucket and pour 4 liters of water into it, mix everything well and leave for 24 hours. Thanks to the water, the clay will become soft, and the sand will separate from the loam. Then the contents of the bucket are thoroughly mixed again and the water with the silty loam contained in it is drained so that only clay and sand are at the bottom of the bucket. Clay and sand are weighed and their mass is subtracted from 1 kg - this way you can find out how much loam was in the material under study.

The quality of the clay depends on its plasticity and can be tested by touch. Oily clay resembles a bar of moist soap or a slice of lard. The quality of the clay can be determined in another way. Having made a flagellum 15 cm long and 2 cm thick from clay, you need to pull it at both ends at the same time.

Skinny clay does not stretch well, and uneven edges form at the site of the flagellum rupture. The flagellum of plastic clay, smoothly stretching, gradually becomes thinner and eventually breaks, forming sharp teeth at the site of the break.

The color of the clay depends on what impurities are included in the composition of the clay.Clay with an admixture of iron oxide and manganese oxide is colored red, yellow and brown, and black - with organic impurities.

Silty loam can be added to clay concrete to increase its strength and ability to maintain its shape after drying.

• Drywall, aggregates and stone finishing materials
• Mortars: the choice of brand and composition of the mortar