How to prepare the mortar for plaster correctly
The rules for preparing the mortar for plaster can be quite different. It all depends on the environment and layer thickness. Materials for the preparation of stucco mortars are in retail and you can freely purchase them.
If you make the composition with your own hands, then its price will be much lower and this will significantly reduce costs for large volumes of work. Today we will talk about their types, composition and cooking rules. We will give instructions on the most used.
The content of the article
Mix for wall plaster - its composition and features
The requirements for plaster solutions are different, but they are divided into two main types:
| For exterior decoration | This type is used in the following situations:
|
| For interior surfaces | This plaster has the following features:
|
When choosing the material for this work, you need to take into account the following items:
- Stone and concrete facades, which are often subject to environmental influences, must be plastered with mortar on Portland cement or slag Portland cement.
- Facades of stone and concrete, which are not subject to the influence of the external environment, must be plastered with lime-cement mortar, with the addition of lime cement mortars.
- Plaster and plaster surfaces are plastered with lime mortar (see We prepare ourselves a mortar for lime plaster), in which clay or gypsum binder is added.
Attention: For plastering works inside the building, where the humidity is higher than 60%, the initial layer of plaster is made of cement-lime and ordinary cement mortars.
Cement mortar
It is most often used in construction work. But it should be said that sometimes this option will not be acceptable. So let's get to know him better.
The advantages of cement plaster
This version of the composition has many advantages and is most often used in construction:
| Low cost | Because of this, cement plaster is widespread and often used in construction work. |
| A wide selection of packaging by weight | Cement plaster may be prepared at home. Cement and sand just mix in the right proportions. You can purchase a packaged dry mixture from 1 to 30 kg. A prepared cement mortar is also ordered, which will be brought in a special mixer. |
| Easy to use | The cement mortar retains its elasticity for several hours. Thanks to these properties, plastered walls can be leveled even several hours after the mortar has been applied. By lightly wetting the plastered surface with water, you can rub it again if necessary. |
Cons of stucco made of cement
But here there are soybean flaws and they need to know:
| May crack after it dries completely | The main catch is that Portland cement and slag Portland cement are shrinkage materials. That is, the greater the thickness of the plaster layer, the higher the likelihood that the plaster will crack.
|
| Application | Cement-sand plaster is rather difficult to apply on a smooth concrete wall. This mainly relates to prefabricated houses and buildings made of reinforced concrete, as well as other buildings whose walls and floors are made of reinforced concrete using metal formwork. |
| Slow speed | Even a specialist with extensive experience in 8 hours working day will plaster no more than 7-10 m2 of the wall. |
| Hard work | Plastering works are hard physical work, however in the Soviet Union this occupation was mainly female, |
| Wet process | Plastering is wet and, one might even say, dirty construction work.
|
| Environmental friendliness | In the 90s of the last century, environmentalists began to actively promote the idea that cement brings very great harm to human health. In general, environmentalists have not come up with a worthy alternative to cement in modern construction. |
Lime mortar
This composition is most suitable for internal surfaces and is used quite often.
| pros |
|
| disadvantages |
|
How to choose a decorative wall plaster
The wall surface is leveled with stucco - video.The main use of decorative solutions is facade finishing work and interior decoration.
For the preparation of decorative solutions, such binders are used:
- Colored, white and plain Portland cement for facade work and interior decoration;
- Lime and gypsum for interior color finishes.
Granite of different fractions is used in the preparation of decorative mixtures.
To make the decorative solution more brilliant, up to 10% of crushed glass or 1% of mica is added to it. For coloring, you can apply light-resistant and alkali-resistant dyes, which are of natural and artificial origin - ultramarine, chromium oxide, red iron oxide, ocher and others.
Basics of preparing a plaster mortar
The plaster mix is made from sifted components, thoroughly mixed to a homogeneous mass. The mixture may contain one or more binders.
After the mixture is kneaded, a fat check should be done with a trowel:
- The fat mixture sticks quite strongly, lowering the fat content is possible by adding aggregate. Otherwise, throwing a plaster mortar of such a sotava will be difficult;
- A non-greasy mixture does not stick at all, you need to add astringent material to it.
Caution: In greasy mixtures, there is an excess of astringent and when the plaster layer dries, the surface begins to crack. Non-greasy mixtures make work difficult and have little strength. Mixtures with normal fat content are comfortable for work, they are distinguished as reliable and have a very long service life.
Basic recipes for stucco mixtures
As a finish, stucco mixtures in construction have been used for a very long time.
To prepare the mixture, containers with a depth of at least 15 cm are used:
- The volume capacity can be arbitrary. We mix cement with sand in the required proportions and the resulting dry mixture, pour into lime dough, previously diluted with water to a thick viscosity, and all this is thoroughly mixed.
- Before you spread the plaster mix, you need to clearly understand what layer it is used for. The next coat is applied step by step. Usually three layers of plaster are applied. Plaster for each layer is viscous. The consistency of the mixture is regulated by the volume of added liquid.
Here are the main ways to prepare some plaster mixes:
- Lime dough. Components: quicklime (one part), water (three parts). Production: pour lime with warm water, as soon as the chemical reaction proceeds, add more liquids and mix the resulting mixture. Close and leave for 24 hours. The next day you can work.
- Lime solution. Components: lime dough (1 hour), sand (1-5 hours, depending on how greasy the dough is). Production: we put sand and water in the dough, carefully mix the resulting solution, gradually add sand and add water to the required viscosity.
- Lime-clay mixture. Components: clay dough (1 hour), lime dough (0.4 hour), sand (3-6 hours, the strength of the solution directly depends on the amount of sand), water. Production: we dilute the clay with water to a liquid state, mix the resulting solution with lime, stir and gradually add sand to the desired viscosity.
- Gypsum-gypsum mixture. Components: lime solution (3-4 hours), gypsum (1 hour), water. Production: gypsum is added to the water and the dough is made of gypsum, the lime mixture is poured into it, mixed and produced.
- Cement mortar. Components: cement (1 hour), sand (2-3 hours), water. Production: sand and cement are placed in a container in layers and mixed until a homogeneous solution, we obtain the desired viscosity by adding water.
- Cement-lime mixture. Components: cement (1 hour), sand (3-5 hours), lime dough (1 hour), water.Production: dilute the dough from lime with water to a liquid mass, make a cement-sand mixture and mix it with milk of lime.
You will select the norms for preparing the mortar for plaster yourself. It should be noted that the leveling of the plaster in the final finish should be of high quality, that is, the composition should be plastic. So watch the video in this article and photo and choose the best option.
