Plaster walls of aerated concrete indoors

Construction of houses from silicate blocks - one of the most promising directions in the field of private construction.In particular, it has become very popular aerated concrete blocks, the production of which a part of the solution introduced special additives that causes excessive flatulence.As a result, aerated concrete has expressed an open pore structure, which causes it significant advantages over other materials for masonry walls.

premises However, such a structure of aerated concrete and brings a number of difficulties for finishing the walls erected.It needs a special approach, both on the sequence of work, and on the materials used.In addition, the plaster walls of aerated concrete indoors will depend on the planned their exterior trim.

What is the "moodiness" of AAC in matters of decoration, and some ways you can solve these problems - it is these issues the subject of this publication.

Features Aerated

Aerated concrete -one type porous honeycomb construction materials.

Apparently, sometime before-technology developers task was to create a light and fairly durable material, which could be used for thermal insulation of buildings.Approaches used different - as forced foaming raw concrete mass conventional aeration by mechanical agitation, and the introduction of the component composition of special additives coming into a certain reaction and cause at the same time actively gassing.

As a result, the output - the two materials are very similar to each other in appearance, but significantly different in structure of the porous structure, the physical and operational characteristics.

When forced foaming composition is obtained foam, air bubbles which are uniformly distributed throughout the volume are expressed closed structure - each of them is isolated and unconnected with the neighboring.The size of these pores are significantly larger than those of aerated concrete.

Other business - aerated.Foaming process by reactions of active additive leads to the fact that gas bubbles "break through" the mixture during solidification their way out, the open forming a finely porous structure.In fact, the concrete block is penetrated by numerous subtle channels.

Each of the materials has its own characteristics, certain advantages and disadvantages.But the foam now put aside, this is a topic for another article - we will talk specifically about aircrete.And entry is necessary in order to start construction, finisher, conceiving conduct independent work in their own home, yet did clear gradation between these materials - and in the process of laying and finishing at the technologies are very significant differences!

Aerated concrete blocks may have a different density.This predetermines their insulating qualities, mechanical strength and, therefore, the scope of the construction - from purely insulating functions to create multi-layer wall construction to the construction of internal walls and load-bearing walls of the building.For example - the characteristics of some of the most commonly used brands of concrete blocks are summarized in the table:

Mark aerated	D-350	D-400	D-500	D-600
The density of material, kg / m³	350	400	500	600
compressive strength, kgf / cm²	70 ÷ 100	100 ÷ 150	300	450
Thermal conductivity, W / m × ° C	0.08	0.11	0.13	0.15
Water vapor permeability mg / m × h × Pa	0.26	0.23	0.20	0.16
Frost, the number of cycles	not installed	15	30	35
Scope	wall insulation in multi-layer design.	wall insulation, laid unloaded openings, construction of interior partitions.	Construction of wall insulation in one-story building	Erection insulated walls in low-rise construction, including - as a basis for hanging ventilated facade.

What overall impression.Lightweight material, its strength increases with increasing density.It has good thermal insulation properties - even the densest of these brands of aerated concrete has a thermal conductivity of 0.15 W / m × ° C, which is comparable to natural wood, which is considered "warm" material.But aerated concrete porosity and structure of cells cause very high hygroscopic and vapor permeability.And here is the quality - it is the nuance which in itself greatly influences the specificity of walls, composed of concrete blocks.

What are these features?Unlike, say, from the brickwork, aerated concrete walls require mandatory exterior trim.

• Firstly, whatever is said about the fact that these homes and are without any coverage for years - hard to believe it.The high absorbency material will inevitably lead to its moisture and satiation just from the air and from the direct action of rainfall.A water-saturated porous structure is highly vulnerable to freezing - it leads to erosion, cracks, fracture.In addition, moist environment - almost ideal conditions for the development of mold and mildew.
• Secondly, the material, even the most dense, no high mechanical strength.Accented impact action ends with the appearance of chips, cracks, etc.
• Third, open porous structure is easily penetrated by air currents.According to the impressions of the owners who have lived the winter in unfinished house of aerated concrete - he clearly blown cold wind.
• And, fourthly, although high-quality units and feature a clear geometry, can not be called aesthetic unfinished wall.

Very often aerated concrete wall trim hinged facade systems - about the features of this approach will be mentioned below.Practice and plastering of external walls - with the use of decorative materials or followed by staining them with façade paints.Susceptibility to the aerated concrete finishing compositions, due to the nature of its structure, has a number of features, so the external plastering is usually carried out by using special compositions adapted precisely to such conditions.

Although the insulation quality of aerated concrete and high enough, they may not be sufficient for the particular climatic conditions of the region - then you need to provide additional insulation.It also can be its own characteristics associated with high vapor permeability of the material.

dependence plastering the inside of the exterior decoration of the facade technology

would seem - the theme of the article plaster aerated concrete walls on the inside, so why focus on the exterior?A sense of this considerable - on the type of planned external decoration, the presence and type of insulation layer will directly depend approach to the interior.And the reason for that - again all the same high vapor permeability of aerated concrete.

fact that during the life of people living in the building, continuously released very substantial amount of water vapor in the air.Even a person capable of breathing during all hours in the atmosphere to add about 100 grams of water in the vapor state.Add to this the washing and drying clothes, cooking and boiling water, taking a shower or bath, wet cleaning - a very considerable amount of turns.It is clear that the moisture leaves the ventilation flows, but in winter, when windows and doors are mostly closed, the vapor pressure in rooms higher than the street, and the moisture is looking for a way through the building design, and above all - through the outer wall.

would seem that the water vapor permeability of aerated concrete plays a positive role only.It is - true, if the wall design is organized by the "right", that is, couples do not meet on its way any formidable obstacles.A "correct structure" means that the vapor permeability of the material the wall ( μ ) should increase in the direction of the street.To be able to visualize the picture, look at the diagrams:

• It - "naked" aerated concrete wall.Due to its high vapor permeability of moisture is virtually unimpeded moves toward saturation vapor low pressure, and the wall is, in principle, dry.However, as already mentioned, without external finishes such walls will never leave.

• second example - outside facade is decorated with brickwork "to unravel", but leaving a gap and ventilated air holes to ensure free air circulation.In fact, the picture is almost unchanged - a pair of pass freely through this barrier.Inside the aerated concrete wall, you can finish the plaster, water vapor transmission rate that is comparable to or slightly lower than that of the aerated concrete.In fact, this definition fits most plasters or coatings for interior applications, such as gypsum-based.

Equally this case refers to the external plastering walls with special structures, calculated specifically for aerated concrete - their high vapor permeability provides natural moisture balance.

• As already mentioned, sometimes even aerated concrete walls require additional insulation.If applied thermal insulation material with high water vapor permeability, such as mineral wool, while the facade created an opportunity for ventilation, even here the picture remains the same - the moisture is provided access to the outdoors.Although, ideally, aerated concrete wall and to elevate to its insulating qualities to fully satisfy the needs of the job in the insulation for a particular region, and it is best to completely abandon the additional insulation.But, alas, this is not always and everywhere possible.

Quite different is the situation, if the exterior finish is made of materials that have a vapor permeability lower than the aerated concrete (and it is - almost all types of finishing, except plasters mentioned above), and a system of ventilationthe gap is not provided.Even worse, if the external wall insulation is made of materials, very little or absolutely impermeable couple - foam or extruded polystyrene.In these cases, the penetration of moisture to the outside, or very difficult, or completely eliminated, and the wall begins to accumulate, which leads eventually to the formation of condensation in the design thickness.But this, in turn, entails a lot of negative consequences.

clear that such situations should be avoided whenever possible, advance planning for the "right" wall construction.But what if, for whatever reason can not be?Login one - to carry out interior finishing materials such vapor permeability which is significantly lower than that of aerated concrete.In a word, it is necessary to provide a barrier which prevents the active penetration of water vapor from the air space in the wall material.Here is more suitable impregnation hydrophobic surface composition, dense sand-cement plaster, wall decoration vapor tight vinyl wallpaper or special paints.However, in this case, many times, the role of high-quality ventilation of premises - to excessive moisture does not condense on the surface of the walls, in the corners of the window slopes and on the glass.

How to get rid of excess moisture in the apartment?

Unsatisfactory humidity balance is always manifests itself, especially in winter, abundant condensation on the window panes and angles and damp.If you noticed that windows plastic windows constantly misted - action must be taken.To learn how to do it - in a special publication of our portal.

And another important feature.Very often, the owners of houses constructed seek as soon as possible to give his possessions "decent" appearance, hurrying with exterior trim.This is - a very serious mistake.

• Firstly, seemingly so strong and smooth aerated concrete wall will necessarily shrink.To start any kind of decoration was not after waiting at least 6 ÷ 7 months after construction - completely pointless.Even with the highest quality materials and skilled work is required to mesh cracks appear.

• And secondly, in the homes of aerated concrete interior must precede external.The reason is the same - water vapor permeability of the material.Internal plastering inevitably associated with priming and other "wet" work, and moisture should definitely give time for the free release into the atmosphere.Only after the wall of humidity after the interior decoration is stabilized to normal values, you are ready to finish the facade.Otherwise, moisture will be "conserved" in the wall, which will necessarily lead to destructive processes.

Like what plastered aerated concrete wall inside the premises

can say at once that, in principle, the technique of aerated concrete plastering walls to a greater extent repeats the most conventional techniques such finishes.The problem, rather, it is the specifics of the wall material, which require compliance with certain nuances.In short, everything depends, probably, to the question "what" rather than in "how".

Technique plastering of the walls inside

Calling technology such decoration simple and accessible - is quite difficult.However, "no gods pots", and work-out in a small area, filled his hand, analyzing the mistakes, all the landlord be able to cope with such a task.To help him - a special publication from our website about plastering walls .

But on the materials for the work should walk more.

• open porous structure of AAC will not be limited only to Shpatlevanie walls - a thin layer just will not stay on such a surface.Therefore, even if the wall is lined with high accuracy and does not require any adjustments to its plane - without plaster is still not enough.And aerated concrete wall will have to "throw" a layer of not less than 5 mm.
• Such a layer is subject to cracking and shattering (impact adhesion especially highly porous structure), if it does not enhance the reinforcing mesh.If other wall materials use reinforcing mesh is desirable, it is the case with gas concretes, this condition should be considered as mandatory.Grid best - fiberglass, resistant to an alkaline environment, so that it eventually disappeared simply not in the thick mass of hardened plaster.