Lime plaster: technical characteristics of the material

Gusevsky Andrey Anatolyevich

Cement-lime plaster mix

Lime plasters have been used for quite some time. It is a beautiful elastic material that is best suited for indoor use. But with the addition of cement, it can also be used for exterior decoration.

Today we will tell you what the limestone composition is, what its types are and how to make lime stucco with your own hands in different ways. Also in the video in this article you can see a lot of additional useful information.

Types of calcareous compounds

Lime plaster composition can be with several types of additives. Which are reflected in the characteristics of the solution. Each of them changes the parameters. Let's figure out which cement-lime stucco mixture is suitable for.

Cement and lime plaster

Traditional lime-cement plaster in the composition includes cement and lime. In any case, sand is also added.

Plaster made only of cement (see Cement plaster: do it right), characterized by stability and rapid hardening. With the addition of lime and a decrease in the proportion of cement, the solution becomes less stable. Moreover, such a mixture stiffens longer.

Cement-lime plaster

So:

• Stucco consisting only of lime is rather weak and stiffens longer. However, an increase in its amount makes the solution more plastic than simplifies the work. The sand added to the plaster mixture should not exceed a proportion of 3-1 to the total proportion of the remaining components. Similarly to the operation of a cement mixture, grease mixtures made of cement and lime are forbidden to be applied to thin, loose places or oily coating on a thin base layer.
• Stucco mortarmade in proportion 3-1-1 (sand, lime, cement) is better suited for working with compacted material (concrete, low-porous clay bricks). If the plaster mix will cover the outside of the walls, it is better to reduce the proportion of lime and increase the proportion of cement. Such a mixture is better resistant to heavy rains. Thus, the composition of the mixture will look: 13/4: 1/4: 6 or 1: 4 + lime (10% by weight of cement) to improve ductility.
• External low-density surfaces with wide enough slots relative to each other (low-quality bricks, cinder blocks), must be covered with a solution not fatter than 1-1-6 (cement-lime-sand). Fatty stucco mortars made of cement with a small proportion of lime, or its complete absence - should not be used. For processing internal surfaces, the following mixtures are allowed: for primers 1-1-6 or 1-2-9, for the finishing layer - from lime 1-3 or 1-4, with the addition of 10% cement.

To prepare the mixture, you must adhere to a certain sequence of actions. First of all, lime and sand (pre-mixed) and water are mixed. You should add so much water to make a viscous dough. Cement is added last. The resulting stucco solution must be consumed no longer than within 45 minutes.

• On external objects, the shadow side is plastered first, in order to avoid getting the sun on the solution as long as possible.

When plastering, various defects may occur.

They arise for the following reasons:

• Cracks occur due to low-quality sand, strong smoothing of the plastering area. Also, the reason may be an insufficient pause between the coating of the primer and the coating or its very quick drying.
• Loose spots, peeling or sprinkling of the coating occurs due to moisture from inside the surface. Volumetric cracks, as a rule, arise due to settlement of the base of the building, changes in the volume of concrete. In some cases, the cause may also be insufficient exposure time of the cement-lime mixture, in which there is an excess of concrete.
• Swelling is due to local solar heating.
• Swelling and formation of small shells due to ingress of third-party additives.
• Soaking occurs due to the absorption by the soil of excess moisture from the finishing layer, with a strong leveling of the surface. Also, the cause may be overheating of the lining or its drying by a draft.
• Fading is due to salt crystals. This occurs if sea water was used in the preparation of the mixture, etc.

Attention: Lime-cement plaster for exterior decoration is done with a lot of cement. Then it is less affected by a humid environment.

Components and manufacturing process of lime mortar for plaster

The lime mixture consists of the following components:

• A mixture of sand and lime in a ratio of 4-1. To improve the adhesion of the solution to the surface, the use of PVA glue is allowed.
• A mixture of cement and lime in a ratio of 1-2. Thanks to the cement, the stability of the mixture increases and the time of solidification is reduced. Suitable for use in rooms with variable temperature and high humidity. To save money on creating a solution, you can add sand from the calculation: for one share of sand - three parts of a mixture of cement and lime.
• A mixture of gypsum and lime is prepared in a ratio of 1-3. It is characterized by quick drying and a high degree of adhesion. In most cases, it is used for decoration work. It can also be applied to wood materials.

Instructions for the preparation of lime mortar

First of all, in order to prepare a mortar based on lime, the following containers are needed:

• A metal container of sufficient volume in which the process of extinguishing lime will occur;
• Capacity for preparing the mixture itself;
• Capacity under water (bucket).

Tools are also needed:

• Shovel (if it is necessary to manufacture a large amount of the mixture);
• Small spatula for stirring and checking the density of the solution.

The first stage of preparation is the process of extinguishing lime: quicklime is placed in a container, the volume of which must exceed the volume of the material to be filled by 3 times. Then, lime is poured with water (1 to 2).

Attention: It must be remembered that during the extinguishing of lime, a large amount of heat is released (more than 100 C). As a result of this, measures must be taken to avoid chemical-thermal damage (burns).

• Without fail, when extinguishing lime, use protective glasses, a respirator (to protect the respiratory system), thick clothing and gloves (to cover unprotected skin). After the main stage of blanking, you need to wait a day. At this time, lime will reach the required state.
• Add the required amount of sand to the prepared container, and fill with water. Then, in accordance with the ratio, add lime and begin stirring the solution. To facilitate the procedure and get a high-quality mortar, it is better to use a drill with a special nozzle for plaster mortars.
• While mixing the solution, the liquid must be infused gradually, while simultaneously controlling the density of the mixture.In order for the solution to lie comfortably on the surface and adhere well to it, its density should be similar to the density of thick sour cream. It should not drain from the tool, but also not be a solid lump.

A solution of gypsum and lime

Such a solution is used when performing repair or decoration work. The gypsum-gypsum mixture is prepared in a small volume.

This is due to its rapid drying, which occurs within 10-15 minutes. Therefore, before preparing the mixture, prepare the area on which the mixture will be applied.

Photo gypsum-lime composition

• To create this mixture, lime sand can be used. Gypsum and lime are mixed in dry form to a state of homogeneous mass. Then, in ready-made dry solution, water is poured in small doses (with constant stirring). It is better to add water through all kinds of watering cans.
• For the mixture to be applied comfortably to the area, it is necessary that its density corresponds to the density of sour cream. The mixture should gradually drain from the tool. At the same time, a certain amount of solution on the instrument should still be delayed. The solution must be applied efficiently and as soon as possible. Correct the resulting flaws can not.

Plastering surfaces with lime mortar

The solution is applied to the area in stages.

All work is carried out using the following tools:

• Wide and narrow (10 cm) spatulas;
• Brush, roller or spray;
• Rule (tool for plastering);
• Scoop.

First of all, it is necessary to clean the treated area: to erase dust, to clean from dirt and paint, etc.

• Use a roller, brush or spray to moisten the wall with water. For good and high-quality adhesion of the mixture with the treated place, a primer can be used (see Primer walls and all for that matter);
• To repair the defective area, use a small spatula to apply the solution on a wide spatula. Apply the plaster vertically (bottom to top). Apply the same, sufficient amount of the solution, using undamaged areas like beacons. Level the solution until it forms a perfectly smooth plane.
• If it is necessary to apply plaster on the entire wall, beacons must be placed before the mixture is distributed (see Stucco beacon: types, purpose, installation) Like beacons, an appropriate sized beam of wood or metal profiles are used, which are used to assemble drywall.
• The beacons should be at a distance of 0.5 m from the corner, and be from each other at a distance slightly less than the length of the rule. The beacons are fixed by means of a mixture of gypsum, which must be applied to small sections of the wall. The resulting profile is checked vertically and horizontally for compliance with other beacons.
• After the gypsum mortar fixes the beacons, the process of applying the stucco mortar can begin. In order to simplify the work and improve the adhesion of the mixture to the wall, it is necessary to pour the solution on the wall in the required volume, and then distribute it in the vertical direction as a rule. At the same time, by smoothing, the excess solution should be transferred to those areas in which it is not enough.
• After completing work throughout the area, it is necessary to wait a while (until the solution is well set). A hard surface is felt at this time, however, when pressed, the plastered area is slightly deformed in the pressure area. The resulting small layer damage must be repaired with a spatula. If necessary, to facilitate the elimination of deficiencies, you can additionally spray the wall area with a spray.
• Next, you must extremely carefully remove the previously set beacons.This procedure is necessary to prevent the appearance of traces of rust or the destruction of the plaster, which may arise from the deformation of the tree. The irregularities that remained after the beacons were removed should be fixed with a spatula using the same mixture.
• The final stage of work is wall treatment finishing putty. It is carried out after final drying, in order to bring the surface to perfect condition.

Cement-lime plaster will be stronger from the composition with gypsum, which is more suitable for interior decoration. Any of the compositions can be done with your own hands, then the price will be much lower. And which solution to choose is up to you.