Plaster walls of aerated concrete indoors
The construction of houses made of 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 composition of the solution are special additives which causes excessive gassing. The result is expressed aerated open porous structure, which causes its significant advantages over other materials for masonry walls.
Plaster walls of aerated concrete indoors
However, such a structure of aerated concrete and brings a number of challenges for finishing the walls erected. It needs a special approach, both on the sequence of work, and on the materials used. Furthermore, plaster of aerated concrete walls indoors will depend on planned their exterior finish.
What is the "capriciousness" of aerated concrete in matters of decoration, and some ways you can solve these problems - that these issues the subject of this publication.
Features of AAC
Aerated concrete - a type of porous, honeycomb construction materials.
Apparently, once the front-technology developers task was to create a light and fairly durable material, which could be used for thermal insulation of buildings. Different approaches have been used - as forced foaming raw concrete mass ordinary mechanical stirring aeration and the introduction of the component composition specific additives, entering a specific reaction and thus causing flatulence active.
As a result, at the output - the two materials are very similar to each other in appearance, but significantly different in structure of the porous structure, physical and performance characteristics.
for comparison &# 8212; porous foam structure of aerated and
When forced foaming foam composition is obtained, in which air bubbles are uniformly distributed throughout the volume, have a closed structure expressed by - each of them is isolated and unconnected to neighboring. For its size, these pores are significantly larger than those of aerated concrete.
Other business - aerated. The process of foaming due to the reaction of active additive leads to the fact that gas bubbles "break through" during solidification of a mixture its way outwards, forming a finely porous open structure. In fact, the concrete block is permeated with numerous thin channels.
Each of the materials has its own characteristics, certain advantages and disadvantages. But the foam now put aside, it is a topic for another article - we will talk specifically about aircrete. And such entry is necessary for the novice builder, finisher, conceiving conduct independent work in their own home, yet make a clear gradation between these materials - and in the process of laying and in finishing technologies used are very substantial differences!
Aerated concrete blocks may have a different density. It determines their insulating qualities, mechanical strength and, therefore, the scope of the construction - from a purely insulating functions to create multi-layer wall construction to the construction of internal partitions and load bearing walls of the building. For example - the characteristics of several of the most commonly used grades of concrete blocks are summarized in the table below:
|Material Density, 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|
|Permeability mg / m × h × Pa||0.26||0.23||0.20||0.16|
|Frost resistance, the number of cycles||not installed||15||thirty||35|
|Application area||Wall insulation in the multilayer structure.||wall insulation, laid unloaded openings, construction of interior partitions.||Erection of wall insulation in a one-story building||The construction of insulated walls in low-rise construction, including - as the basis for attaching a ventilated facade.|
What is the general impression. Lightweight material, its strength increases with increasing density. Has a good thermal insulation characteristics - even the most dense of said marks aerated has thermal conductivity of 0.15 W / m × ° C, which is comparable to natural wood, which is considered "warm" pictures. But the aerated concrete porosity and structure of cells cause very high hygroscopic and vapor permeability. And here is the quality - it is the detail that 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 satiety and moisture out of thin air, and from direct precipitation. A water-saturated porous structure is highly vulnerable to freezing - which leads to erosion, cracking, breakage. In addition, moist environment - almost ideal conditions for the development of mold and mildew.
- Secondly, the material, even the most dense, are not characterized by high mechanical strength. Accentuated impact action ends with the appearance of chips, cracks, etc.
- Third, open porous structure is easily penetrated by air currents. On 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 Suspended facade systems - about the features of this approach will be mentioned below. Practice and plastering of the outer walls - with decorative materials or followed by staining them façade paints. Susceptibility aerated to finishing compositions, due to the nature of its structure, it has a number of features, so external plastering is usually carried out using special formulations adapted precisely to such conditions.
Optimal results are obtained by finishing compositions, specially designed for the aerated concrete
Although the insulation quality aerated and high enough, they may not be sufficient for the particular climatic conditions of the region - then you need to provide additional insulation. There may also be the features associated with high water vapor permeability material.
Dependence plastering technology inside of the exterior decoration of the facade
It 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 - the type of planned external finishes, presence and type of insulation layer approach will depend directly to the inner. And the reason for that - again, all the same high water vapor permeability of aerated concrete.
The fact is that during the life of people living in the house permanently allocated a very significant amount of water vapor in the air. Even just breathing person is capable of just over an hour to add to the atmosphere of about 100 g 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 some of the moisture leaves the ventilation flow, but in winter, when windows and doors for the most part closed, the saturated 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 .
It would seem that the water vapor permeability of aerated concrete here only plays a positive role. It is - true, if the wall design is organized by the "right", that is, couples do not meet on your way any stumbling blocks. A "proper design" 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, Refer to the diagram:
Across &# 171; naked&# 187; Aerated concrete wall of the steam passes virtually Smooth Function
- This - "naked" aerated concrete wall. Due to the high moisture vapor permeability is practically unhindered moves toward the saturated vapor reduced pressure, and the wall is, in principle, dry. However, as already mentioned, without external finishes such walls will never leave.
Ventilated facade &# 8212; water vapor permeability of the wall is not broken
- The 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 which is comparable to or slightly lower than that of the aerated concrete. In fact, this definition fits most plasters or coatings for interior applications, for example, gypsum-based.
Equally, this case applies to the external plastering walls with special structures, calculated specifically for aerated concrete - their high vapor permeability provides natural moisture balance.
For thermal insulation is best to use a thermal insulation material with high water vapor permeability, covered with ventilated facade
- As already mentioned, sometimes even aerated concrete wall requires 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, 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.
And such external finish becomes a barrier to vapor. adequate measures should be taken in the decoration inside
Quite different is the situation, if the exterior finish is made from materials that have a vapor permeability lower than the aerated concrete (and this - almost all types of finishing, except plasters mentioned above), and the system of the ventilation 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 column structure. But this, in turn, entails a lot of negative consequences.
It is clear that such situations should be avoided whenever possible, advance planning "right" wall construction. But what if, for whatever reason can not be? Login one - to carry out interior finishing such materials, water vapor permeability of which is significantly lower than that of the aerated concrete. In short, it is necessary to provide a barrier which prevents the active penetration of water vapor from the air space in the wall material. There are 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?
Inadequate moisture balance always shows itself, especially in winter, abundant condensation on the window panes and angles and damp. If you notice that glazed plastic windows constantly misted - action must be taken. To learn how to do it - in a special publication of our portal.
Said quantity of materials need to be purchased, and then you can move on to practical work:
|That everything worked out really high quality, the wall must be prepared to work. |
To begin, it should be inspected - perhaps the masons left shortcomings, which are better addressed.
|For example, here such gaps should not leave - this can subsequently affect the quality of the plaster layer.|
|Slots or chipped possible to fill in the repair mortar and align to the overall surface of the wall. |
It is best to use this special glue for concrete blocks - it will require not so much.
|After drying patches repair surface is superfluous obmesti rigid plastic brush, the dust boa or fragments of dried-solution.|
|The next step - a mandatory priming surface of the deep penetration of the composition. |
Middle primer consumption is estimated at about 150 ÷ 180 g / m², but for the primary coating composition is diluted with water in a ratio of 1: 1.
|The primer is applied in any convenient manner, trying to minimize the unnecessary losses. |
It is possible to use a roller and brush.
Many artists prefer to use composition spraying, for example, by conventional garden sprayers or if there is, compressor plants.
You can also use an old vacuum cleaner working "blow-out".
The second primer layer is applied only after the complete drying of the first.
|When dried and primed wall ceased after such treatment actively draw the water, can be diluted tile adhesive. |
Everything is done according to the instructions to the specific composition to a uniform consistency in the likeness "of thick cream."
|While preparing the adhesive, the assistant may be cut into strips masking plaster grid - the height of the room. |
The grid is better to buy a width of about 1000 ÷ 1200 mm - so it is more convenient to work with.
|Ready glue begin sketching on the wall in the band, a little more than the width of the reinforcement stacks. |
The amount of glue calculated so that it sufficed for the formation of the layer on the wall is about 5 mm.
|Outline extends upward across a target band ...|
|... and it ends up near the ceiling.|
|Adjustment severed fiberglass wall strip stacks pritaplivayut a deposited layer on top ...|
|... and slightly flattened bottom is fixed in a solution - it is securely held.|
|Now hand trowel is taken to the height of teeth 5 - 6 mm. Starting from the top of the wall, the ceiling, with a spatula in an effort mesh vtaplivaetsya adhesive layer. |
It must be completely "drowned" in the solution, and practically "reach the bottom" that is, the wall surface.
Excess adhesive, respectively, are pressed outwardly therethrough.
|So it treated the entire surface, without gaps. |
Initially, the movement direction of the spatula can be chaotic - the main thing, to drown the reinforcement layer ...
|... but gradually the movement direction is horizontal. |
Such a "combing" the wall must cause her glue horizontal grooves.
|All the strips are oriented in one direction.|
|After processing one section, for example, to the middle of the wall, moving lower - and repeated.|
|Such an operation with good effort on trowel provides excellent contact with the surface of the adhesive mass of gas concrete wall.|
In addition to this, the adhesive layer has excellent reinforcement. In the picture - formed deep grooves in the adhesive layer.
|On the edge of the area to be treated can be made smooth wall strip - it will nahlostyvatsya regular fiberglass fabric. |
The width of the overlap should be at least 100 mm.
Work continues in the same manner, from band to band wall. As a result, the entire surface should be covered with a layer of glue with horizontal grooves.
|Why is this done? |
Such a layer provides excellent connection with the wall, and the further act as a "mediator" - it is possible to throw any absolutely, without exception, plaster, and the strength of such a coating will be provided.
Moreover, horizontal stripes will not let plaster solutions to crawl - is extremely facilitate the work. A solution of the area of contact with the base thus increases almost tripled.
|To further plaster works can move after complete solidification of the adhesive base layer. |
There is a caveat - tile adhesives typically contain special components for the retention of water, and the dry type of coverage can sometimes be misleading. Actually, the layer is still damp and plastered thereon is inconvenient.
Check the possibility of the resumption of work by simply splashing water on the wall - it must be absorbed and not run down.
If the image of a wet spot - glue is completely frozen, and the wall is ready to "accept" the plaster.
|Then - all the usual wall plastering technology. To begin with exposed profiles beacons.|
|Preparing plaster. |
As already mentioned, after such preparation is quite suitable even the most inexpensive cement-sand mortar (1: 4 or even 1: 5 cement M400).
The only thing - it is advisable to add a plasticizing ingredient in it. This may be part of a factory, but some painters, plasterers successfully apply the usual kitchen cleanser concentrate the rate of 100 g per 100 kg of solution.
|The solution is obtained with good ductility and excellent ties into the wall, which still contribute even and horizontal furrows prior layer.|
|Continued spraying (outline) in the strip between the two beacons.|
|Leveling plaster thrown over the rule of the solution.|
|Gradually, the wall becomes conceived evenness, in accordance with the beacon system.|
|Leveling plaster layer over ...|
|... and check shows that the gaps between the wall and there is no rule.|
|As a result, aerated concrete wall plastering coating sturdy received within, which lends itself to any kind of further decorative finishes.|
Perhaps someone this approach seems too costly and time consuming. Nothing like this - the method is simple and available to perform even the novice master, and the quality of the coating will then be up to par. But the total cost - just not comparable, when compared with the use of special compounds for plastering aerated concrete walls.