Light plaster mixes.
Some manufacturers offer so-called light plaster mixtures, which, although they have an order of magnitude worse thermal insulation characteristics than heat-saving plasters, are excellent for plastering weak bases, on the surface of which it is not possible to lay heavy and durable plaster.
This type of plaster is ideal for old walls with low bearing capacity, and for walls made of fairly fragile building materials.
The coefficient of thermal conductivity of light plaster mixtures is in the range from 0.25 to 0.32 W / (m * K). Light plaster mixtures can be applied to the wall both manually and by machine. They are best not used for plastering basement and foundation walls, building plinths. Lightweight plaster is recommended for exterior walls built from cellular concrete blocks.
The main features of light plasters are:
• the ability to hide small defects and uneven walls, as it should be applied to the walls in a thick layer,
• it has twice the thermal conductivity than heat-saving plaster,
• has a high degree of vapor permeability,
• has a high covering power (35% higher than conventional traditional plasters),
• excellent for application on weak substrates such as old plaster,
• has greater resistance, compared to other types of plasters, to the appearance of shrinkage cracks,
• light and easy to work (easier to apply than heat-saving plaster mixes),
• has a lower resistance, in comparison with traditional plasters, to mechanical damage.
Due to the fact that heat-saving and light plasters do not look very aesthetically attractive on the facade, they can be covered with decorative or thin-layer plaster.
Particular attention should be paid to the fact that some manufacturers (both domestic and foreign) offer a wide range of gypsum-lime and gypsum heat-saving and light plasters that can be used exclusively indoors (they are not intended for outdoor use).
Carefully read the recommendations for the use of these plasters, printed on the packaging by the manufacturer.
Sanitizing plasters. This type of plaster is a kind of cement-lime plaster modified with special additives that give the structure a high porosity. Basically, sanitizing plasters are recommended for use when performing repairs in houses that have damp walls. This type of plaster should be used from the outside (front) side of the wall, but in case of moisture penetration through the walls into the basement, then also from the inside. A distinctive feature of sanitizing plaster mixtures is a very high level of vapor permeability, which ensures excellent evaporation of moisture from the wall surface, which in turn contributes to their drying.
In addition, such plaster can effectively retain salts, which in turn reduces the risk of efflorescence (white salt deposits) appearing on the surface of the wall being dried. Sanitizing plaster should be applied in a layer of 1 to 4 cm, while on average its consumption can be from 10 to 16 kg/m2/cm. Currently, several types of sanitizing plaster mixtures are widely represented on the construction chemistry market:
• leveling – should be used when plastering walls with slight irregularities, as a spray,
• two-layer (finishing and lining) – with such a complex solution, the lining layer is able to effectively accumulate salts, and the finishing (sanitizing layer) – to prevent these salts from appearing on the surface of the plaster layer, • single-layer – this type of plaster, due to its structure with high porosity, is ensure effective accumulation of salts and at the same time ensure the evaporation of moisture from the wall to the outside, while not allowing them to crystallize on the surface of the plaster layer,
• absorbent – are special removable sanitizing plasters, which are designed for application on walls with high humidity (very wet).
This type of plaster must be applied to the walls so that they absorb all the salt present in the wall structure. Moisture through a layer of such plaster can evaporate freely, while bringing efflorescence to the surface of the plaster. After the process of the appearance of salts on the surface of the plaster layer is completely completed, it is necessary to knock this layer of plaster off the wall and apply a layer of any traditional plaster on this surface.
Given the high cost of sanitizing plasters, it is advisable to apply it only in those places that are largely exposed to moisture or places that are directly adjacent to them. This type of plaster is perfectly combined with cement-lime plasters, with which the rest of the wall surface can be plastered. One of the best options is to cover such a wall with a refinishing putty with microfiber reinforcement, so that the façade will have a uniform structure in terms of strength and absorption. This feature is important in the subsequent painting of the facade, since the paint on such a surface is able to form a fairly uniform coating. When renovating walls, it is also recommended to use special binder repair plaster mixtures, which are able to provide an absolute barrier to water vapor and water. With the help of such plasters, it is possible to perform effective waterproofing of vertical surfaces of basement and foundation walls.
We pay special attention to the fact that it is recommended to use astringent repair plaster no higher than the basement level, since its layer will not allow moisture to evaporate from the surface of wetted walls. Drying speed of plasters. How quickly the plaster dries determines whether it is ready for subsequent painting or finishing.
Direct executors of finishing works should know that:
• one centimeter of cement-lime and cement plaster dries within 7-14 days,
• one centimeter of light plaster layer thickness — within 7-10 days.
• one centimeter of heat-saving plaster for 5-7 days.
It should be taken into account that thin-walled plasters can be painted 12-48 hours after they are applied to the wall, other types of plaster have different drying times, which are usually indicated by the manufacturer on the packaging. During the drying process, special attention must be paid to ensure that the walls do not get very hot in the sun. For the same reason, artificial methods that speed up the drying process should not be used, as this may adversely affect the quality of the plastered surface, shrinkage cracks may appear on the surface of the plaster layer. The beauty and attractiveness of the facade. Along with all types of facade plasters currently on the market, only a thin-layer type of plaster has a beautiful, colored or textured surface.
All other types of plaster are far from attractive and require high skill when laying them or additional finishing with a layer of decorative plaster. This applies to a greater extent to light and traditional plasters, much less often to heat-saving ones. In order for ordinary traditional plaster compositions on the facade to look not quite corny, they need to be given an original decorative texture. For these purposes, simple construction tools can be used: spatulas, trowels, brushes, trowels, boards with nails hammered into them, or ordinary brooms. With the help of such simple tools, it is possible to simulate a setting, but not yet completely hardened, plastered wall surface.
In this way, you can get a different original texture, for example, formed by a trowel, drawn, grooved, speckled, scraped, etc. In addition, using a special stamp or template, you can imitate rusts, seams or other masonry effects. Please note that in order to perform such surface decoration, it is necessary that the plaster layer has at least a thickness of 1-1.5 cm. Machine plaster mixtures are best suited for this purpose, since they set much more slowly than those that designed for manual application. It is allowed to leave the plastered facade of the house without finishing, but this will not benefit its appearance. As an exception, only finishing with white or ready-made tinted plaster mixture can become. Therefore, it is worth at least covering such a facade with a layer of facade paint. In addition, such plaster on the facade can be covered with a layer of thin-layer decorative plaster: silicone, mineral, silicate or acrylic.
In addition, the range of thin-layer decorative plaster includes a huge variety of colors and textures (mosaic, lamb, bark beetle) that will help you give the facade of the house beauty and originality. Basic rules for applying plaster mixture to the wall. The process of plastering the surface of the wall is not such a simple process. At first glance, this is a process that does not require special theoretical knowledge, but its quality implementation requires a certain skill, patience, diligence and practical experience. If you do not have an urgent need, then it is best to entrust the plastering of the outer surface of the facade of the house to a team of professionals, since a beautiful and neat facade is, first of all, the face of its owner, his calling card. In any case, every developer must know and understand the rules and principles of plastering walls. One of the main rules is that you can start plastering work no earlier than 2-3 months after the completion of the walls.
Plastering of reinforced concrete and concrete bases can be started no earlier than 8-9 weeks after their concreting. It is necessary to carry out external plastering work only after the plastering of the internal walls of the premises has been completed. Before starting external plastering work, it is necessary to complete the entire complex of works on the construction of the house box, close up the holes in the walls, insert doors and window blocks, and complete the wiring of all engineering systems inside the walls. Before performing plastering work, special attention must be paid to the quality of the wall surface: it must not have defects, be thoroughly cleaned of peeling fragments of old plaster and paint. External plaster is recommended to be applied to the walls at an outdoor temperature of +50C to +250C, with a humidity of not more than 70%. It is very important to choose the right time for this type of work: you must be completely sure that there will be no heavy rainfall or frost. If you are not completely sure that the facade work will be completely completed at “plus” temperatures, then it is best to play it safe and use special plaster solutions in the robot, designed for application to the wall in the winter
When performing these works in the heat, it is recommended to protect the plastered walls from direct sunlight, and the cement-lime and cement plaster masses must be additionally moistened during the drying and setting processes. If you allow rapid drying and setting of the plaster layer on the facade, then shrinkage cracks may appear on its surface. It is necessary to plan facade works in such a way that they are carried out without long breaks or downtime. Breaks are allowed only in case of complete completion of the entire plane of the wall or a separate facade. Similarly, the base for the plaster layer should be prepared, and before starting to apply the plaster, it should be carefully checked for stability and strength.
Defects and damages existing on the base must be repaired with putty, the composition of which must be combined with the type of plaster used. If the prepared wall base has increased absorption, then it is best to prime it so that it does not absorb moisture from the freshly applied plaster layer. If this is not done, then there is a high probability that, in the process of rapid drying, the plaster may crack in places or even peel off. When performing work using cement-lime and cement plaster, you can save a little – before applying it, moisten the wall with plain water. For all other plaster compositions, it is recommended to use special primers. The application of the first layer (spray) of cement-lime or cement plaster can be done without much effort, as it is only the basis for the subsequent layer, which must be done more carefully. If the facade of the house has a fairly even surface, then a solution of cement-lime and cement plaster can be applied in just two layers. It is especially necessary to remember that plaster solutions with greater strength should never be applied to plaster with less strength. The same applies to the foundation. Lime and light plasters are considered to be the weakest in strength, heat-saving, sanitizing and cement-lime plasters are considered more durable, and cement plasters are the most durable.
We hope that the information presented by us about the properties and features of the use of various types of plaster has become not only interesting, but also useful for you. The right choice of facade plaster will help you not only give the house an attractive look, but also effectively protect the wall material from adverse atmospheric effects, provide it with additional reliability and durability.