Facing natural stone.

By Admin | Building Materials
30 May 2016


OPERATION FACING

oblitsovkak of natural stone Operational factors related to the temperature, humidity, dust, air, precipitation as rain, snow, shock effects, etc.All of them have an impact on the safety of operation during its operation.Production factors, such as the compliance of the quality of work performed with regulatory requirements, are formed in the course of performance of facing works, and appear during operation facing.Structural factors are associated with the selection of stone and design decisions facing.

External facing during operation, first of all, experiencing temperature effects that cause stress.They may be the result of deformation of plates facing.They appear as a change in temperature during the day and during the seasons.On the outer facing of stone are strongly influenced by precipitation as rain, hail, snow, and wind, moisture penetrates the lining both outside and inside, light and mechanical effects.Exposure to wind load, which is itself the effect of the liner does not have, it may be signific
ant in the case of increasing precipitation, as rain water by the wind can penetrate the lining and cause the displacement of the freezing plates.

In the operation of buildings moisture caused by functional processes in buildings continuously migrate through the wall to the outer surface.In winter, the contact cement-sand mortar with the stone there is a difference in temperature and the conditions for its condensation.The resulting water, freezing may cause delamination, and in some cases, deformation of the lining plates.Significant damage to the lining is applied to the chemical effects of air pollution, contaminated by industrial emissions, transportation, power plants, etc., Especially in cases where the gases dissolved in the moisture penetrating the lining.For example, facing the objects of natural stone soft rock over time exposed to degradation caused by airborne industrial cities sulphurous gases generated in conjunction with atmospheric moisture sulfuric acid.As a result of this acid on marble, limestone slabs calcium carbonate is transformed into gypsum, unstable air moisture.

Moreover, the liner acts migrans moisture containing solutions of salts, which it receives from the cement-sand mortar masonry, especially when applied winter working procedures.Between the elevated temperature of the outside air in a relatively loose rocks type dolomite, limestone moisture is movable relatively freely.And if on the outer surface of the facade give the equilibrium conditions between capillary suction, and the rate of evaporation, the water evaporates, leaving the salt stains on the facade of the so-called "blooming" stone, which degrades the quality decorative facings.In the case of dry areas or relatively high outdoor temperature balance between evaporation and suction can not occur on the outer surface of the liner plates, and a little deeper.In this there is a danger of internal crystallization of salts with the emergence of large internal stresses, resulting in the liner may exfoliate.

of natural stone more resistant to the effects of physical and chemical effects of the granites.Granite cladding can collapse due to the fact that in a part of rock crystals of different chemical composition and colors possess unequal thermal expansion and cleavage planes of crystals may form cracks increases with time.They fall into the moisture during freezing is even more destruction of the rock, which is particularly dangerous for the coarse-grained granite.On the southern facade of the building, where the daily fluctuations of the temperature of the greatest degree of cracking is higher than in the northern.

combined effect of solid, liquid and gaseous contaminants in the air, combined with its high humidity and significant variations in temperature accelerates the process of destruction.This process can be accelerated by the use of substandard building materials, products and structures, non-compliance in the production process technology and the established norms of others. Facing is an integral part of the building as a whole, so it is necessary to take into account the impact of her weight of overlying layers lining deformations walling and cladding layer.In accordance with the instructions for the design and manufacture of outdoor works of natural stone facing work, as a rule, should begin no sooner than 6 months after the full completion of brickwork on the entire height of the walls.However, these terms are not met, and almost at the beginning of tiling the walls retained a large amount of moisture, and the building is not stabilized sludge.This can lead to significant shrinkage and residual deformations which occur irregularly over time.In the first two months, they reach about 55-60%, and to six months their size is between 80 and 90%.

a result of shrinkage and deformation of sedimentary movement walling in the case of a rigid connection with the wall cladding may create conditions which in some cases can lead to the destruction of the layer of stone finishes as the wall takes unusual for her load.

PROTECTION trim piece from the harmful effects during operation

In operation, facing the impact of precipitation, erosion, dust, alternate wetting and drying, freezing and thawing, sudden changes in temperature significantly reduces the service life and reduce fine quality.The main reason for the destruction of the lining is a physical-chemical effect of water in the presence of which is particularly strong influence of other destructive factors, such as freezing temperatures, sulphurous gases, etc.One way to protect the cladding from destruction is to protect against possible penetration of moisture.To this end take constructive measures and, if necessary, and use a variety of chemical coatings.

Constructive solutions must provide the device required for water drainage slopes, correct joints and junctions cladding elements, various types of coatings, sealing joints.The use of materials with a polished surface texture, excluding the stagnation of water, contributes to greater safety linings.

so-called "chemical" activities include impregnation of porous stone with special structures that seal the surface and protect it from moisture.In order to protect the facade against atmospheric precipitation using tools such as the reinforcement and water-repellency, reducing removal of salts and the formation of efflorescence on the surface of the facade.

reinforcement increases the density and weather in limestone and dolomite containing calcium oxide.Produced by coating its surface facing aqueous solutions of salts of fluorosilicic acid.This ensures the formation of calcium fluoride, silica hydrate and other insoluble compounds, which seal the outer layer material, which in turn reduces the water absorption and frost resistance and increases durability of natural stone facings without changing their outer appearance and color.Stone materials containing no calcium compounds are not amenable reinforcement.To do this, they first need to impregnate calcium chloride.Reinforcement is carried out in dry weather at temperatures below 5 ° C. The solution of magnesium silicofluoride applied to the surface two or three times.Consumption of the solution is 150-200 g per 1 m2 cover plate.

Hydrophobization produce to make the surface of facades water repellent and to reduce dust façades and prevent the formation of efflorescence.To use hydrophobic 5-7% aqueous solution alyumometilsilikata AMSR-3 features good hydrophobicity.It can be applied manually or mechanized manner.Is used for this purpose and conventional alkilsilikonaty and poliorganosilozanovuyu resin.Resin also hardens the surface layer.Their concentration is 3-5%, the number of layers - two or three, flow rate - 100 g per 1 m for each application.

reinforcement and hydrophobization of facing - and slabs of natural stone can be produced and on the back side to protect them from moisture coming through the thick walls of the building.However, in all cases, to the inner surface of the lining does not accumulate moisture and to prevent dampness gradual peeling of the outer wall and the exterior cladding, fill joints between tiles is recommended such solutions that would enable the wall to "breathe" and does not interfere with the continuous evaporation of moisturefacade surface.

On the Application of protective coatings from experts and architects there is no consensus, because the water-repellent coatings lose their water repellency after 3 years, and repeatedly renewed them unrealistic.By increasing the water resistance of these coatings are deprived stone "breath", and in the absence of convection condensation occurs on the inner surface, which has a negative effect on the structure of the stone.As a result, many architects are not supporters of the stone slabs covering protective structures.The answer to the question of whether the device protective coating on the surface of the stone can be given only after testing the stone facings with different coatings in a continuous operation.

effective way is a solid device and the back of the sinuses between the facing slabs and masonry walls.This design solution eliminates the contact transfer of moisture through the thickness of the wall lining and contributes to the safety of decoration.Experience in various countries confirms this view.For example, in Hungary cover of stone slabs fixed to the wall, leaving an air layer thickness of 2-3 cm. The air gap is left up stone slabs, ensures the removal of vapor, about diffuse through the wall, but only if the top and bottom there are holesor slots through which can enter or leave the air.In Finland veneer set ensuring the ventilation layer, and between the boards are left unfilled gap of up to two cm, which creates a play of light and shadow.Stone slabs hang on the wall with fasteners made of non-ferrous metals, steel or stainless steel.This solution creates interesting shape and at the same time ensures effective removal of vapor passing through the wall.

major defects in the finishing of natural stone surfaces

Natural stone - vysokodekorativny and durable building material, and the appearance of defects in the wall before the expiration of their service life - an unacceptable phenomenon.Errors in the selection of the stone significantly reduces the aesthetic quality of the lining, degrade its appearance.More serious are the violations that lead to the displacement of elements of facing and loss of individual plates.

defects in the lining of natural stone are the result of mistakes made in the design stage - about 60%;poor quality materials - about 10%;deviations from the projects of works - about 20%;poor maintenance of the building as a whole and in particular stone cladding and al. reasons - almost 10%.

Mistakes made at the design stage, cause the most numerous, not only in quantity, but also on the severity of the defects of the lining.What is this error?This is the wrong choice of types of stone from the conditions of his work in the design, inadequate structural study of the decisions facing, defects in structures that protect the stone surface.Wrong choice of stone.Stone selected for facing any structural element must exactly match the specified conditions of use.Therefore, do not put the device in the plinths, steps, walls, terraces, etc.the use of such rocks as limestone and dolomite.Moisture from snow and surface water from adjacent pavings and sidewalks leading to constant wetting plates, which, combined with freezing causes the destruction of not only themselves, but also the material of the walls in places facing violations.Moreover, in these zones lining experiences maximum physico-chemical effects of salts, oils, exhaust gases, gasoline, transportation, cleaning equipment, etc.In humid climates the use of plates with an increased number of cavities (shell rock, travertine, tuff) leads to stagnation of moisture, dirt accumulation that affects the appearance of the walls and contributes to premature failure of the plates.When selecting types of stone for facing horizontal surfaces also sometimes make mistakes.If, for example, limestone and dolomite area designed exterior stairs, terraces, stylobates, etc., in this case, precipitation and melting snow moisture will contribute to the destruction of the lining plates and the intensity of their bundle.There are cases when the average density of the stone, such as limestone, used for horizontal surfaces (stairs, platforms) with heavy traffic of people (in various administrative buildings, markets, schools, etc.), which causes premature wear their izfor enhanced abrasion.

For the interior of the building mistakes in the choice of stone is not so dangerous.However, they lead to tangible losses violate functional processes in buildings.For example, the marble steps in department stores due to increased abrasion material fail after 5 years, after which they require complete replacement.Sometimes the area immediately adjacent to the floor, using polished stone texture (dolomite, shell rock, travertine, limestone), which causes a loss of MDF and decorative qualities due to moisture and dirt during cleaning.Construction of stone cladding in modern architecture is simpler than in the old buildings and structures, so the errors associated with the combinations in the lining of various types of stone, are relatively rare.Sometimes still allow direct contact of a granite stone plinth cordon with dolomite-field wall that is due to a systematic inflow of moisture wetting the walls and to the deterioration of its appearance.The same result occurs when opiranii plates lining the walls of limestone and dolomite in the granite slabs sites stylobates.In order to avoid such defects, it is necessary to strictly observe the requirements for the selection of types of stone in the design of it in those or other structures;provides for mandatory device only stone plinths made of granite and marble;avoid facades where possible leak of moisture, direct contact between the elements of the stones of different hardness.

case of insufficient elaboration of constructive decisions facing mistakes are quite numerous.They are linked to shortcomings in the selection of the thickness and size of the stone, configurations, architectural details, errors in the design of joints, support elements, mounting units, waterproofing and slopes.Thus, when the device caps most often occur disadvantages such as under the height of the cap;height plinths in projects often reduced to 140-250 mm, it should be at least 350-360 mm and the main facade, with contiguity to the driveways and sidewalks, to be increased to 1200 mm;Incorrect type socket;use of small length and height of plates, which leads to an increased number of joints in the region of the cap;poor-quality solution seams;no bevel on the top of the cap and a simple projection bias on Cordon stone (for composite basement);erroneous division of profile articles to the elements and a few others.

errors in the design of the walls with natural stone finishes can cause the fall of the plates from a great height.

errors in the design of structures facing walls can be caused by factors such as under-slab thickness of fronts, resulting in drowning protective shelves between the hook fasteners and the face plate and insufficient adhesion with a solution to reduce the reliability of the product installation.

defects in devices reinforcement.One of the most used in practice, and is the most efficient scheme reinforcement device in which the lining plate attached to the rods by means of hook.