Among the huge mass of building materials used for the construction of buildings or a private house, foam blocks stand out. They compete successfully with the traditionally used concrete and brick, having a lot of positive characteristics. Foam-block walls guarantee high thermal protection of the room, do not interfere with the release of excess moisture, and form a comfortable local climate.
These positive properties are explained by the cellular structure of foamed concrete.. Nevertheless, the presence of pores makes foamed concrete sensitive to absorption, which reduces the performance properties of the building material. You can create reliable protection of the surface of the foam blocks indoors and on the front side of the building if you plaster the foam blocks.
Do I need to plaster?
The foam block is a representative of cellular concrete. It is warm, lightweight and has excellent sound insulation properties. Moreover, standard dimensions make it possible to erect structures that are perfectly even in geometry. As a result, some believe that finishing foam blocks is not needed.. However, there are a number of factors why such work needs to be done..
Since foam concrete carries cells, moisture can get into them. This leads to an increase in the mass of the entire structure and an unnecessary load on the foundation..
Walls and base can crack.
Foam blocks without adequate protection will collapse.
The durability of the building is lost.
If you find the time, money and effort to plaster the building, you can achieve its protection from temperature surges and adverse street factors, such as wind, precipitation, ultraviolet radiation..
And the plaster itself will additionally serve as heat and sound insulation, as well as decor, decorating the facade.
What is used?
Before starting finishing activities, you need to prepare the necessary tools and buy building materials in the proper amount..
For plastering, you will need the following tools:
drill mixer, which will simplify mixing of the finishing mixture to the desired density;
spatulas with different widths of the working part, which are designed for applying plaster composition;
one and a half meter building rule used for uniform distribution of the mixture;
plumb line and building level, used to control the quality of finishing work;
paint roller and wide brushes used to apply primer to the surface of foam blocks.
You will also need a chisel, a metal brush and a sharpened knife to adjust the size of the blocks and level their surfaces. Do not forget to prepare a container with a large capacity for plaster mortar, and hardware for fixing the mesh for reinforcement.
Under any conditions, for the finishing of foamed concrete, specialized plaster mixtures with a high degree of adhesion are required. They are sold in special construction outlets. When buying a dry mix, pay attention to the recommendations of the manufacturer indicated on the package..
The compositions used for aerated concrete plaster differ from the traditionally used mixtures in increased adhesion and have high strength.. Trading networks offer ready-made mixtures used for:
For cellular materials, it is better to choose the following types of dry compositions.
Mixtures in which finely dispersed perlite filler is present, hydrated lime and gypsum. The use of this material makes it possible, at low cost, to putty inside walls that are operated at normal humidity levels..
Finishing materials with high water resistance. They are practiced in rooms with high levels of humidity, where it is problematic to use gypsum compounds..
Compositions with polymer additives. They can provide high hardness and flatness without finishing.
Professional builders trust the following compounds:
acrylic plasters based on synthetic resins with increased elasticity and high vapor permeability;
mineral mixtures made on the basis of cement with the introduction of specialized additives – these plasters are distinguished by their special strength;
silicate compositions based on an aqueous solution of potassium silicates, providing the necessary working properties;
cement-lime plasters, which, in the presence of specialized components, provide the necessary level of adhesion.
When purchasing mixtures for covering walls from foam blocks, be sure to consult with the seller, or discuss this issue with a specialist. This will make it possible to eliminate unexpected costs and frustrations associated with peeling and subsequent cracking of the plaster..
Here are the basic rules for the implementation of internal plaster, which must be followed.
Indoor plastering must be carried out at least 30 days after the walls have been built. This requirement is due to the fact that foam block walls are capable of significant shrinkage, due to which an immediately applied layer of plaster can simply collapse.
The plaster should not be applied at temperatures close to zero. Ideal temperature limits for DIY work – from +5 to + 30 ° C.
On the eve of the work, it is required to carefully prepare the surface – to clean the walls from any dirt and, if necessary, remove oil stains.
When the technology involves the application of more than one layer of plaster, the next layer can be applied only after the last layer is completely dry..
It is required to prime both the foam blocks themselves and the surface of the plaster outside.
Foam concrete plaster consists of several stages.
Based on the object (under construction or undergoing major repairs), the list of works at the preparatory stage varies. In the latter case, it is required to remove the previous coating, repair the detected chips, cracks, cover up the cavities formed in the seams of the brickwork, treat the areas of contamination (until completely remove corrosion, oil stains, foci of mold and mildew), dust off.
Plastering in a new building is carried out exclusively after dust removal.
The next step is priming the surface. This operation is fundamental and guarantees:
decrease in the level of moisture absorption of foam concrete;
the adhesion to the applied plaster is significantly improved.
The primer is applied in several layers (at least 2). Each subsequent one fits only after the previous one has completely dried out. The time during which this is done is indicated by the manufacturer on the container..
Installation of beacons
When the walls do not come out very even, and it is necessary to apply a layer exceeding a thickness of 7 millimeters, the installation of plaster beacons is required. Taking into account the professionalism of the plasterer, they can be installed by means of mechanical fixation (then the beacon will remain in the body of the plaster layer), or on an auxiliary solution (it can be removed after the applied layer has dried). During installation, the level is applied. The ideal pitch of the beacons is 1.0-1.3 meters. These components create conditions for more accurate surface removal in 2 planes.
First of all, the extreme beacons are exposed. After that, a nylon harness is stretched between them, along which the rest are installed.
Installation of plaster mesh
The mesh can be polymeric or steel. The first is the most preferable because it is not susceptible to rust. It is fixed to the wall with dowels. Laying is done after the first layer of plaster has been created. The mesh is recessed into it, not reaching the surface of the foam blocks, and is overlapped by 50 millimeters.
The entire area of the mesh should be covered with plaster mortar, which is leveled and “lined” with a spatula and a comb.
There are two plastering technologies. In the first version, the material is applied in a thick layer (some brands allow a thickness of up to 30 millimeters). In the second – in several layers.
Each layer has its own mixing. Before the start of the measures, the surfaces of the walls are moistened from the spray. Upon completion of this, the application process itself is carried out..
Spray applied – the first layer of plaster. A half-liquid mortar is poured onto the wall with a trowel (layer thickness up to 5 millimeters) without further leveling and traced with a spatula to enhance adhesion to the primer.
Second layer – base (ground). Has a normal viscosity, smoothed by the beacon rule.
Trowel (cover) – third layer. As a rule, its thickness is no more than 2 millimeters. A more fluid mixture is practiced. It is applied over a slightly dried base layer and immediately smoothed out.
After the outer layer of plaster stops sticking to the hands, it is necessary to grout. For this, a grater is used.. The first pass is carried out in a circular motion parallel to the plane of the wall, with slight pressure.
Then two times the grout is carried out “overclocking” (the first time – the passage vertically, and the second – horizontally).
This is required when plastering for wallpaper or painting is performed..
Next, we will consider the technology of plastering walls made of aerated concrete from the front side of the structure.
The procedure for facade plastering is similar to the technology for finishing walls made of cellular composites from the inside. Plastering walls from the outside of a building is often carried out with a cement-sand composition containing specialized ingredients that increase moisture resistance.
The facade plastering procedure includes the following points:
cleaning the surface of the facade walls of the structure;
hydrophobization of a porous surface;
reinforcement of walls with plaster mesh;
preliminary and final finishing.
Design plays an important role in the modern world and makes a good impression.
Actually, for this reason, it is very important to choose the right finishing material for the facade, which will carry both a protective and aesthetic function.. Competently selected plaster will become a kind of face or, in other words, a business card of a private house, high-rise building or a public building. Facade decorative plaster “bark beetle” makes it possible to obtain the desired effect and has been practiced for more than one year for cladding external walls of structures.
It is not difficult to give the plastered surface of the building facade the required appearance by painting or by means of spraying technology.
Mechanized plastering of the foam block
The manual plastering technology described above takes quite a lot of time and effort. In this regard, it is advisable to use mechanized plastering, especially for buildings with an impressive wall area..
The undoubted advantages of this technology include:
reduction in the number of hired workers;
reduction of the period of work;
saving building materials;
increase in productivity and quality of work.
The machine itself prepares the mixture and applies it. Due to this, per shift, plaster is applied up to 45 m2 (with manual method up to 7 m2).
For the correct plastering of the foam block wall, it is very important to follow the above instructions and the advice of the manufacturers of the compounds..
In addition, it is advisable to purchase building materials and tools in large chain retail outlets, since quite a lot of low-quality counterfeits are sold in the markets..