Waterproofing violations - what this can lead to
Underground waterproofing is a whole complex of various measures aimed at ensuring reliable protection of concrete and reinforced concrete structures from the negative impact of thawed and groundwater.
Unfortunately, this process is aggravated by poor ventilation, lack of natural light and other factors. In the list of the main problems caused by waterproofing violations, one can single out:
- corrosion of all fittings;
- weakening bearing capacity constructions;
- interruptions in the operation of underground communications;
- breakage of power cables;
- dissatisfaction of tenants (up to filing a lawsuit);
- increase in the cost of repairs, finishing works and restoration of waterproofing.
Types of waterproofing
Protection from water is provided during the construction works... This is due to the availability of free access to the outer walls of all underground structures (up to the moment of filling them with soil). An equally important condition for creating effective waterproofing of basements, parking lots and underground garages is the presence of a drainage system.
In order to prevent the destruction of reinforced concrete structures under the influence of water, the following types of waterproofing are used:
Primary - involves the use of concrete mixtures or special compounds characterized by a high level of moisture and frost resistance. The main task of waterproofing is to ensure the stability of the entire structure against external negative influences.
Secondary - includes the application of a protective layer to the surface of the structure, the use of "liquid rubber" and PVC membranes, as well as penetrating waterproofing. This is done to prevent the penetration of moisture into the basement and protect the structure from the aggressive effects of groundwater (they contain a large number of salts and acids). However, for the restoration or repair of underground waterproofing, it is recommended to use a more effective injection waterproofing.
Injection waterproofing of the underground part of the building has many advantages, among which there is no need for earthworks, which, accordingly, saves money (including the use of earthmoving equipment).
Services "GidroStroy" for waterproofing underground structures
Provision and restoration of waterproofing by injection
Depending on the operational characteristics and hydrogeological conditions of the object, the specialists of the company "GidroStroy" develop the most optimal ways of carrying out and restoring waterproofing. The list of services provided includes:
- fracture injection using packers;
- low pressure injection;
- injection of joints in concrete;
- reinforcing injection;
- injection over large areas.
We would like to emphasize that the company "GidroStroy" has in its arsenal all the necessary equipment. This ensures that the waterproofing of the underground part of the building will be performed in compliance with all technological features of the facility.
Waterproofing of underground structures
In most cases, underground structures are affected by high-pressure groundwater. These include the following objects:
- metro stations;
- autotunnels;
- bunkers;
- underground reservoirs;
- mines.
Unfortunately, access from the outside to such structures is absent or extremely difficult. It also becomes necessary to carry out waterproofing work in conditions of constant water supply. Injection waterproofing technologies used by GidroStroy specialists can cope with such problems. The applied injection method allows you to effectively deal with groundwater (even in the case of a continuous gushing flow). In particular, polyurethane foam is used, which, in contact with water, increases in volume. After that, the polymerization component is injected, which on long years blocks the path of moisture. No less attention is paid to the sealing of joints, interfaces and seams.
Waterproofing the underground part of the building
If, in the process of restoring waterproofing of underground structures, an average or low pressure of groundwater is observed, resins with long time grasping.
Ancient buildings are often located on brick foundations... However, over time, not only in the rubble or brick fold, cracks and voids form - a similar process occurs in concrete.
Highly qualified specialists of the GidroStroy company will quickly restore the waterproofing, reinforce the filling of voids and increase the bearing capacity of the underground part of the facility.
Employees of GidroStroy are real masters of their craft. Their knowledge and experience is sufficient to select the most effective waterproofing technology. This, as well as the use of modern materials, provides maximum protection for reinforced concrete structures, rubble and brickwork, and therefore your property.
Preparatory work
Depending on the waterproofing technology used, preparatory work is carried out, during which specialists determine the locations of the packers. In the future, it is through them that synthetic waterproofing material will be injected, which can be read about in the section "Injection waterproofing".
If it was decided to use a different type of waterproofing (for example, penetrating or “ liquid rubber»), The preparation of the treated surface can play an important role in achieving the maximum level of protection against water. Composition preparatory work includes providing:
- strength;
- high bearing capacity;
- dryness;
- roughness, without which the adhesion of the composition to concrete is impossible;
- cleanliness (no old coating, grease and other contaminants), etc.
Turning to the company "HydroStroy", you get a reliable underground waterproofing, completed in the shortest possible time in compliance with all established international norms and requirements.
Literature
Construction production technology. Textbook for universities / L. D. Akimova, N. G. Ammosov, G. M. Badin et al. Ed. G.M.Badyina, A.V. Meshcheninova. 4th ed., Rev. and add. - L .: Stroyizdat, Leningrad. department, 1987, 606 p.
Protection of underground structures and buried premises of industrial enterprises from underground waters is carried out using the following types of waterproofing:
Painting (bituminous, bitumen-polymer, polymer);
Plastering (cold asphalt, hot asphalt, cement);
Oleechny (roll, sheet);
Facing (made of steel or polyethylene sheets);
As a waterproofing, non-waterproof concrete can be used, which is obtained from ordinary concrete by introducing special substances into its composition in liquid, pasty or powder form.
Waterproofing is used in cases where it has operational and economic advantages in comparison with other measures (drainage, bitumization, cementation, silicification, etc.).
The impact of water on a structure can be of three types:
Filtration or leaking water;
Soil or ground moisture;
Underground water.
Filtration ox arises from rain and melt water, as well as accidental runoff. Once in the ground, it fills the pores between individual soil particles and, under the influence of its own weight, sinks into deeper layers.
Soil moisture is water that is held in the soil by adhesive or capillary forces. Soil moisture is always present in the soil, regardless of groundwater or seepage water.
Groundwater is determined by the level of groundwater depending on the terrain and the position of the water-resistant layer.
Unlike groundwater, infiltrating water and ground moisture do not exert hydrostatic pressure on the structure, if the constructive solution ensures the unhindered flow of water without the formation of stagnant zones.
Soil moisture, being under reduced pressure, can penetrate into the structure, rising upward under the influence of capillary forces opposite to the direction of gravity.
The purpose of waterproofing is as follows:
Protection of the internal volume of underground structures from the penetration of capillary, ground or surface water into it through the enclosing structures.
Protection of enclosing structures from corrosion.
All kinds waterproofing works can be combined into several main groups:
a) external anti-pressure waterproofing;
b) internal anti-pressure waterproofing;
c) waterproofing water collectors;
d) roof-shaped waterproofing to protect against surface or seepage waters;
e) waterproofing against groundwater protection.
1-vertical waterproofing;
2-horizontal waterproofing;
3-floor waterproofing.
Figure 1.1 - Types of waterproofing
The choice of the type of waterproofing depends on the following factors:
The value of the hydrostatic head of water;
The permissible indoor air humidity;
Crack resistance of insulated structures;
The aggressiveness of the environment.
When choosing the type of waterproofing, it is also necessary to take into account the mechanical effect on the waterproofing, temperature effects, the conditions of work, the scarcity and cost of materials, as well as the seismicity of the construction area.
Depending on the hydrostatic head, the range of application for different types of waterproofing
determined according to table 1.1.
Table 1.1
Waterproofing of structures must be provided above the maximum groundwater level by at least 0.5 m.
Above the maximum water table, structures must be insulated from capillary moisture.
Bituminous-polymer compositions:
bitumen-latex emulsions;
bitumen-naprit mastics;
bitumen and rubber compounds.
Polymer:
from synthetic resins;
from paints and varnishes.
It should be borne in mind that the capillary rise of water in the sands is 0.03-1.1 m; sandy loam - 1.1-2.0 m.; loam-2.0-6.5m .; clays up to 12m.
Waterproofing works should be carried out in accordance with the requirements of the SNiP chapter 3.04.01-87, and if necessary, the project should indicate additional requirements for the method and sequence of work, due to a specific waterproofing project.
The type of waterproofing is chosen depending on the operating conditions, technical and economic indicators, the main of which are:
The required moisture regime of the insulated rooms and the degree of permissible moisture of the enclosing and supporting structures;
Crack resistance of protected structures;
The height of the capillary inflow of water depending on the density of the soil;
The value of the hydrostatic pressure;
Mechanical effects on waterproofing (compression by the mass of upstream structures, backfill soils, exposure to temporary loads, settlement of backfill soil, foundation, base);
The action of aggressive environments;
Temperature effects (maximum permissible operating temperature of waterproofing, minimum ambient temperature;
Natural influences (solar radiation, ice, waves, precipitation, biological pests, etc.);
Seismicity of the construction area;
Special properties of soils and foundations;
Features of the operating mode (exposure to acids, alkalis, oil products, corrosive liquids and gases, etc.);
Work conditions (the possibility of mechanizing the population for insulated structures, the possibility of carrying out work in winter);
Cost of materials, production of work and operation of facilities;
Reliability and durability during operation;
Environmental Safety.
The most common type of waterproofing today is pasting. According to experts, glued waterproofing accounts for 90-95% of the market. The most in demand are domestically produced bitumen-polymer surfacing materials, mainly low- or medium-modified. Imported rolled materials also find their consumers, who primarily focuses not on the cost of materials, but on their quality. Although their market share is small - no more than 4-5%. Several dozen domestic manufacturers work in the segment of glued waterproofing.
A somewhat different situation in the penetrating waterproofing market. This market segment is dominated by imported products. However, penetrating waterproofing is also produced in Ukraine. Experts point out the outstripping growth rates of demand for these materials in comparison with other rather popular positions of dry building mixtures.
There is a sharp increase in demand not only for penetrating waterproofing, but also for its other types. This is due to an increase in the volume of work on the reconstruction of industrial, infrastructure and residential facilities, as well as underground construction. An equally important factor is an increase in the level of groundwater in large cities due to the compaction of buildings.
The foundations of low-rise buildings are primarily protected from the direct impact of rain and melt water by installing a blind area along the perimeter of the outer walls.
Any soil contains capillary moisture, which penetrates into the foundations and rises to the interface with the walls. To prevent the access of capillary moisture to the walls, horizontal waterproofing is arranged at the border of their contact with the foundations. In this case, the minimum distance from the surface of the blind area to the waterproofing should be 150 mm.
Horizontal waterproofing is made from a layer of cement-sand mortar (1: 2 composition with the addition of water repellents) or polymers (latexes, vinyl acetate, polyurethane emulsions, polyurethane emulsions or synthetic resins) 20-30 mm thick, one or two layers of roll waterproofing materials, etc. Ground floor floors located on the ground must also have horizontal waterproofing. At the same time, on the side surface of the wall in contact with the ground floor, a coating waterproofing is performed from the level horizontal waterproofing to the top of the floor preparation.
When installing gluing or coating waterproofing, the insulated surfaces must be primed, for example, with a primer compound "Primer bitumen concentrate", diluted with gasoline to the required consistency (1: 1.5-1: 2). When gluing the material to steel structures, Technomast bitumen-polymer mastic can be used as a primer.
With a high groundwater level (GWL), the structural elements of the underground part of a low-rise building end up in the water. If the water is aggressive towards the materials of the foundations, then these elements must be made of special materials that are resistant to its effects.
The waterproofing design of buildings with basements depends on the water table.
If the calculated groundwater level is below the basement floor, both horizontal and vertical insulation from capillary moisture are arranged. Horizontal insulation is located in two levels: at the level of preparation under the floors under all external and internal walls and basement pillars, and at least 150 mm above the blind area or sidewalk in the external walls. The vertical insulation layer is arranged along the outer walls of the basement from the side where they are in contact with the ground, in the form of a continuous strip between the horizontal insulation layers. The composition of the insulating layer is selected depending on the moisture content of the soil. With low-moisture soils, the outer surface of the basement walls is covered with one layer of coating waterproofing, with wet soils - in two or more layers.
Instead of coating, impregnating waterproofing can be performed, which is often more reliable and economically viable.
If the calculated groundwater level is above the basement floor, provide for isolation from pressure water using waterproof concrete, or performing it in the form of a waterproof shell of pasting, plaster or membrane insulation covering the basement floor and its outer walls up to 500 mm above the calculated ground level water. Above this mark, insulation is arranged only from capillary moisture.
To protect the glued vertical waterproofing from destruction, a protective structure is required.
Particular attention should be paid to the protection of the lower waterproofing layers from pressure water, which is achieved by the constructive solution of the floor and foundations.
The glued waterproofing is laid on the base prepared from concrete class. 7.5 mm thick. If membrane waterproofing is used, it is laid on the base over a layer of geotextile (for example, Tura SF40).
In the last two cases, it is imperative to check the probability of a low-rise building "surfacing" under the pressure of groundwater.
The choice of the type of waterproofing depending on the groundwater level (below or above the basement floor) is not confirmed by practice. As a rule, the groundwater level rises with an increase in building density, during drainage works in adjacent areas, when installed near artificial reservoirs, when the channel of local rivers changes, etc. Therefore, in cases where the forecast of a possible change in the level of groundwater is difficult, it is necessary to immediately arrange high-quality waterproofing, which will both withstand the high pressure of groundwater and will not collapse with possible deformations of the soil.
With a high level of groundwater, the construction of prefabricated foundations (basement walls) is impractical, since water seeps through the seams of prefabricated elements. In this case, the underground part of the building must be made in a monolithic version of waterproofing concrete.
For the waterproofing of existing and planned monolithic and prefabricated concrete and reinforced concrete structures of all categories of crack resistance of brick masonry of grade not lower than M100, materials of the Penetron system are used.
In order to eliminate and prevent capillary filtration, vertical and horizontal concrete surfaces are treated twice with a solution of Penetron material. The layers are applied by brush or by spraying with a mortar pump. The first layer is applied to damp concrete, and the second is applied to a fresh, but already set first layer. Cracks, joints, seams, abutments, communication entries are insulated with Penekrit material. A section is made with a section of 25x25 mm, then it is filled with a Penecrite solution. After that, the surface is moistened and treated with Penetron solution in two layers.
For waterproofing structures made of brick or stone, they are plastered with a cement-sand mortar of at least 150 grade and treated 2 times with a solution of Penetron material. Plastering is carried out on a masonry mesh (mesh size 50x50 or 100x100) firmly fixed to the surface with a gap of at least 15 mm. The thickness of the plaster layer must be at least 40 mm.
Figure: 6.26. Internal insulation on a brick wall
Department of SD site consults and carries out work on moisture protection, incl. underground structures using the technology of cold seamless waterproofing with liquid rubber.
Most damage to underground structures is caused by moisture. Where it is humid, concrete leaches out, wood rots, steel corrodes, varnishes dissolve, paints peel off, wallpaper falls off. If the water contains harmful substances (and in modern realities this is exactly the case in cities and in rural areas), then the destructive effect of water increases. This is already aggressive water.
Waterproofing of underground structures is a set of measures, as a result of which contact of structures with moisture, which appears in a finely distributed form in building materials or soil.
By the way, the quality of waterproofing of underground structures also affects thermal insulation. It should be remembered that water conducts heat 25 times better than air, so the thermal insulation of wet building structures will be significantly reduced. In other words, if water entered the basement in the fall, then in winter it will be colder in such a basement than in the one that remained dry.
The need for underground waterproofing
Water and moisture can enter the structure, both from the outside and from the inside. But in relation to underground waterproofing, we are talking about moisture protection from the outside.
Outside water flows from both the top and bottom. The water on top is precipitation and melt water. It comes in the form of surface water "verkhovodka" and water from splashes. Water from below is percolating water, water in soil layers, water accumulating in soil lenses, as well as ground water. And all this has a negative impact if the waterproofing of underground structures has not been performed.
Consider what kind of underground structures, from what water, in what cases they can be damaged. The table below shows what problems underground waterproofing prevents.
| View building structure // Water type | In what situations | What damage | |
| Walls in contact with the ground and basement floor slabs above the water table. // Capillary water, bound water, seepage water. | Strongly permeable soil | Ground moisture and non-collecting seepage water | |
| Little permeable soil | With drainage | ||
| No drainage | Accumulating leaking water | ||
| Walls in contact with the ground, floor slabs and slabs below the water table. // Groundwater. | Any kind of soil, buildings and construction methods | Pressurized water outside | |
For clarity, what kind of water and what parts of underground structures is affected, below is a figure that explains the need for a device underground waterproofing.
Impact of water on underground structures
The figure explains the need for underground waterproofing, without which the structure will not stand for a long time. Moreover, it can be seen from the figure that water affects underground structures both from below and from the side. Especially about the "bottom", many forget or do not think.
The building is affected not only by groundwater, but also by seeping water, and accumulating and bound water in the soil layers. Moreover, the impact on the walls of the foundation, again, is possible not only from the side, from the side of the walls, but also from below, from the base of the walls.
The highest water table should be below the base of the foundation. This condition must be met in order to minimize the impact of groundwater on the underground part of the building. The distance between the foot of the foundation and the upper level of groundwater should not be less than 0.3 m.
The soil around the building can be different in structure, and therefore in drainage properties. So, under the top layer of the soil there is a layer through which water quickly seeps. This is, for example, sand, which has good drainage properties and excellent water permeability. But then there is a change in soil layers and the soil already weakly passes water. For example, these are clay soils. Accordingly, the water already percolates more slowly, therefore, water accumulates in the soil layers, and moisture appears bound in the soil. And all these waters affect the foundation. Moreover, these are "flowers", real "berries" will be in winter, if it turns out that the poorly permeable soil is within the depth of freezing.
This "nuisance" comes as an additional "bonus" to the destruction of underground walls due to the ingress of water into them and due to the forces of frost heaving. About why the soil "moves" when freezing and how the water in the capillaries of concrete destroys the cement stone, you can read in the article on.
Water accumulating underground and seeping water occurs when the outer walls of the underground part of the building are buried more than 3 m below ground level. In this case, the soil on the site and the backfill soil are soil that is poorly permeable to water, i.e. clayey. Under such conditions, a drainage device is required, either wall or trench throughout the entire area.
Types of waterproofing of underground structures
To protect against water, it is necessary to waterproof underground structures. The following figure clearly shows what and how and from what water should be protected in the underground part of the building.
The figure shows various underground waterproofing, which is convenient and reliable to perform with liquid rubber, if.
Outdoor and interior walls the first floor must be protected from below from rising capillary moisture. For this, horizontal waterproofing of the walls is performed.
If the underground part of the building is built in poorly permeable soil, then a drainage device is required to drain the seeping water.
For example, the figure shows a horizontal basement waterproofing, on top of which is a leveling screed. Those. a waterproofing layer between the basement floor and the foundation slab. This is possible for relatively small buildings, without a layer " lean concrete"under the slab. For example, it is now becoming fashionable to use profiled membranes instead of lean concrete.
If the lifting structure is massive and deep, then it is "quieter" to make the base of the slab from "lean concrete". And then put the waterproofing between the base foundation slab and the stove itself. In this case, basement floor waterproofing is no longer required.
In any case, if you correctly perform the horizontal waterproofing of the basement floor or the base of the foundation slab and bring it out, beyond the line of the walls, then the problem of horizontal waterproofing of the basement walls will be solved. Why?
Because in this case, the subsequent vertical waterproofing of the foundation is hermetically joined with the horizontal waterproofing, forming a seamless rubber "bag", inside which is an underground structure. This is the best and most reliable underground waterproofing. You can read about why liquid rubber guarantees the tightness of the joint between vertical and horizontal waterproofing for an underground structure on the page.
This section of the site is dedicated to underground waterproofing... If you are interested, for example, in how liquid rubber is used for the roof, then go to the section.
For all issues of waterproofing underground structures, if you need advice or perform underground waterproofing, please contact the SD Department website.
In order for the foundation to serve for a long time and, moreover, to protect the basement, the basement and the house from dampness, it first of all requires protection itself - from ground, rain and melt water. Moreover, not only the underground part of the foundation needs protection, but also the aboveground one - the basement. Waterproofing must not only resist the flow of water during spring melting snow or heavy rains, but also - just as important! - protect the walls of the foundation from capillary moisture, prevent water absorption by its surfaces.
Waterproofing is usually performed in both planes - vertical and horizontal.
There are three types of waterproofing, corresponding to the types of water exposure:
§ unpressurized
§ anti-pressure
§ anti-capillary
Non-pressure waterproofing of basements is carried out against the temporary effect of moisture in atmospheric precipitation, seasonal top water and in drained floors, ceilings.
Anti-pressure - to protect enclosing structures (floors, walls, foundations) from hydrostatic groundwater backwater.
Anti-capillary - for waterproofing walls and floors of buildings in the zone of capillary rise of ground moisture.
According to the device method, waterproofing is distinguished:
Pasting (made of rolled materials, for example, glass-proof, waterproof, roofing material, izol, brizol),
Coating (hot bitumen, hot bitumen mastics, solvent-thinned bitumen),
Hard (cement or asphalt plaster in several coats on hot or cold bituminous mastics, well-fired clay brick),
· Shell (metal).
To create a horizontal layer of waterproofing, roll materials are laid under the base of the foundation and in the places of its articulation with the walls of the house. On the surface of the basement, leveled with mortar, or in its thickness (10-15 cm above the blind area), waterproofing is laid from two layers of roofing tar (or from any new waterproofing material) on glue mastic or from a layer of cement.
In basement buildings, the first layer of horizontal waterproofing is placed between the foundation and the basement, the second is 10-15 cm below the ceiling within the basement wall and 15-20 cm above the blind area.
Basement waterproofing or basement floors of old buildings should be combined with bioflora and salt removal measures.
Protection against capillary ground moisture of the walls of buildings is mandatory even when groundwater is below the basement.
Vertical waterproofing is arranged to protect the basement walls from getting wet with water. The type of waterproofing, materials for its device are chosen depending on the moisture content of the soil, on the level and pressure of groundwater, and their aggressiveness.
With a high location of the groundwater horizon (above the basement floor), special measures may be required to strengthen the construction of foundations and waterproofing, up to the construction of sealed metal shells. At the same time, measures are taken to lower the groundwater level (GWL) - drainage, etc. Events.
If the groundwater level is below the floor mark of the felling and does not rise above it (Fig. 28a), but moisture can penetrate into the basement through the capillaries, then the floor and wall plaster are made of tiles or cement-sand mortar with iron, and from the outside the foundations are covered with waterproofing mastic. In this case, the building sediments that develop after the flooring and plastering of the walls in the basement can damage them. However, due to the relatively low penetration of moisture through individual cracks, this has little effect on the moisture regime of the basements. In addition, such cracks can easily be repaired from the basement side.
If the water table is or can rise above the basement floor mark, it is necessary to perform continuous waterproofing under the floor and along the walls above its maximum position mark. Such waterproofing is subjected to hydrostatic pressure directed towards the insulated area. To keep the waterproofing in the given design position it is pressed by a special structure capable of taking the indicated pressure.
If the groundwater level rises above the basement floor by no more than 0.5 m (Fig. 28b), then to keep it in the design position, either a low brickwork outside or a surcharge concrete layer inside the room is sufficient. In other cases, special bending structures are required. Depending on the nature of this structure, external and internal waterproofing is distinguished.
Below, in Fig. 28 and 29, various cases of waterproofing basements are shown (Fig. 28 - waterproofing from the outside of the basement wall; Fig. 29 - from the inside).
Fig. 28 External waterproofing of foundations
Fig. 29 Internal waterproofing of the foundation
External waterproofing is arranged before the construction of the foundation, internal - after. External waterproofing is more reliable, since it has fewer bends (fractures) compared to the internal one, during the construction of which it is necessary to make bends in all rooms in the places where the floor joins the walls, the walls turn and in the doorways of the basements. The weak point of the internal waterproofing is the reentry corner, where two angled walls meet the floors.
One of the ways to isolate the underground parts of a building or structure from surface water (atmospheric precipitation) is to install a blind area outside the building with a slope of 1-2%.
Today there are many new modern materials for waterproofing. For example, geotextiles (Fig. 30), liquid glass, etc. Liquid glass - unlike bitumen - does not lose its properties over time. However, the cost of the foundation increases dramatically. But if you are building on damp ground, then perhaps this particular option may be preferable for you. It is better to save the foundation once and for all once and for all than to regularly save the whole house.
Fig. 30 Outdoor device variant vertical waterproofing foundation using new generation materials
But there are even more effective methods for protecting foundations. For example, the penetrating waterproofing method. Special compounds are applied to the wet surface of the foundation. Getting into microcracks and pores filled with moisture, these substances crystallize and clog them. Moreover, with the formation of new cracks, the process spontaneously resumes. This miraculous effect continues as long as free active substances remain in the treated surface. protective compounds... We can say that with their help, the foundation for a long time acquires the ability to heal itself.
Today there are many new modern ways waterproofing foundations. For example, injection, diffusion or surface impregnation. When injected, "crystallization barrier" materials can be used. Among polymer-cement waterproofing materials, an important place is occupied by the so-called "flexible cement membranes". Noteworthy is the use of waterproofing mats containing sodium bentonite clay, which are laid along the outer perimeter of the insulated surface as a “wall in the ground”.
Before late XIX For centuries, waterproofing of buried premises was carried out in the form of a "clay castle" - a layer of crumpled and densely compacted clay 26.7-30.5 cm thick. It was arranged under the floor and around underground walls and foundations of buildings. "Clay castle" protected foundations, walls or glued insulation from direct contact with groundwater (including aggressive) and thereby increased the service life of the underground part of the structure. Clay castles were replaced by products in the form of bentonite clay. Bentonites are highly dispersed rocks with a montmorillonite content of at least 60%. On the domestic market there are Nabento insulating mats (Akzo Nobel concern), as well as Bentomat panels and Voltex mats (Cetco firm). AT source material bentonite is in the form of granules enclosed in a geotextile, aero-textile, polyethylene or polypropylene shell, in a shell made of biodegradable cardboard. In working condition (after contact with water), bentonite, while remaining in a closed volume, swells and turns into a gel state, which has very low water permeability, but sufficient vapor permeability.Currently, bentonite derivatives are added to other waterproofing materials, such as thermoplastic and rubber-bitumen. Materials are produced and used in the following forms: powder, which is applied by spraying; boards on a cardboard base; rolls on various bases, bentonite and rubber sheets; fabric mats. Of all waterproofing materials bentonite, as well as cement, are the least toxic and cause minimal damage to the environment. Waterproofing membrane based on clay has the ability to self-healing cracks. But for this it is necessary that the material adheres tightly to the concrete. Clay is extremely sensitive to weather conditions and should be protected during application. If it rains or the water table rises and the material is moistened before backfilling, hydration is carried out ahead of time and the waterproofing capacity disappears, since the increase in volume has occurred in an open space. Bentonite coatings should not be applied in areas where there is a free flow of groundwater, since in this case they will be washed out. - see what is not written and add from here
? Insulation of foundations
The desire for comfort and the high cost of electricity makes modern builders think about the need for thermal insulation of house foundations. According to existing estimates, heat losses through foundations account for a significant share of the total energy load on heating and air conditioning of a building - more than 20%. In many countries, foundation insulation is a mandatory procedure regulated by state regulations. It is expected that this tendency will be duly spread in Russia. Nowadays, many homeowners with basements insulate them to obtain additional living space. In this case, they usually insulate the basement walls around the perimeter.
Thermal insulation in direct contact with soil is subjected to harsh operating conditions, including prolonged exposure to water, high soil moisture, and repeated exposure to freeze-thaw cycles. These natural factors can drastically reduce the effectiveness of thermal insulation. Therefore, thermal insulation in contact with the soil must be inert to the effects of soil and water, and thermal insulation characteristics should not decrease when exposed to them. Rigid extruded polystyrene foam (XPS) rigid boards are used to insulate the walls and floors of underground structures. XPS material has very low thermal conductivity, which remains stable for many years. The material is waterproof, therefore, invulnerable to prolonged contact with soil moisture. In this case, the thermal conductivity of the material does not increase in the presence of moisture, because XPS material has a closed cell system. It is resistant to common acids contained in the soil, does not support the growth of mold and mildew, does not corrode and decay. All these qualities make XPS boards a material suitable for long-term underground use.
Freezing has little effect on thermal insulation material XPS that stays dry, or rather, does not absorb moisture from the environment. On the other hand, moisture-absorbing insulation cannot perform its function properly. This is an important factor when choosing thermal insulation for locations where freeze-thaw cycles are common. Independent research demonstrates that only XPS can be used for thermal insulation of underground objects in humid environments with multiple freeze-thaw cycles.
There are four ways to insulate basement walls (basement floors): insulation from the inside, outside, between walls or on both sides at the same time.
From the point of view of building physics, the most logical placement of thermal insulation is outside. A layer of thermal insulation, placed on the outside of the wall and outside in relation to the waterproofing, keeps the basement walls at a constant (almost room) temperature. The walls act as a thermal reservoir, smoothing out possible temperature fluctuations in the interior. At the same time, thermal insulation does not interfere with the natural diffusion of water vapor from the interior of the underground structure to the outside and excludes the conditions for the formation of condensation on the inner surface.
Another advantage of external thermal insulation is the simultaneous protection of the walls of the underground part from the direct impact of frost heaving forces. Frost heaving is an increase in the volume of water-saturated soil during its freezing, which occurs due to the freezing of moisture in the soil and the formation of ice lenses.
In the case of external insulation, there is a need for mechanical protection of the thermal insulation itself during the construction period, this task is successfully solved with the help of insulation with high compressive strength, as well as with the help of modern profiled membranes, which in the structure of the foundation wall play the role of mechanical protection and a wall drainage layer ... Another problem is the formation of "cold bridges" through the layer of facing bricks. According to some estimates, the heat loss in this case can be so significant that it can negate the effectiveness of the thermal insulation layer.
Figure: 2. "Cold bridges" through facing bricks reduce the effectiveness of thermal insulation
Figure: 1. a) thermal insulation from the inside: the most economical method, which is used most often. Has the greatest moisture problems; b) thermal insulation outside: the most attractive location in terms of building physics. There are practical problems with "cold bridges"; c) insulation in the middle of the wall: the most expensive and most difficult method to implement, reducing moisture problems; d) thermal insulation on both sides: has similar problems with thermal insulation on the outside. Additional costs for the device of the inner layer.
These factors may force one to look for alternative approaches to thermal insulation of underground structures, first of all - to thermal insulation on the inside of the wall. Unfortunately, this method has a significant drawback: in the cold season, the outer walls of the underground structure are in the zone of negative temperatures.
It is known that when protecting a structure from diffusion of water vapor (from indoor spaces outward through the walls), one of the activities involves the location of dense materials in multilayer walls, always closer to the inner surface, and more porous materials closer to the outer. This requirement is not met when performing insulation from inside the room. Thermal insulation installed from the inside and covered with a vapor barrier film from the interior side prevents the natural diffusion of moisture from the interior and promotes the formation of condensation. This usually causes mold, odor, and corrosion problems. Thus, it turns out that if the walls of an underground structure are designed and arranged in such a way that they have the ability to release excess moisture into the interior (regardless of which side the thermal insulation is placed on), then it is necessary to abandon the vapor barrier film in the interior. However, rejection of the vapor barrier film from the interior side also does not solve the problem: water vapor will migrate outward, creating conditions for moisture condensation on the inner surface of the wall, mold and other problems.
Since most interior insulation materials are breathable, they allow air to pass from the interior to the outer walls. When insulating from the inside, the structures of the walls of underground structures will be cold in winter (reinforced concrete in direct contact with cold soil), and the contact of warm air with a cold outer wall will cause condensation to form between the insulation and the wall. Therefore, for thermal insulation of the walls of underground structures, a material with minimal water absorption and vapor permeability should be used, which would prevent the contact of indoor air with the cold surfaces of an underground structure.
The higher the vapor permeability of the materials of the walls of the underground part of the building, the more intensive the drying process of the inner surface of the wall and, therefore, the less risk of accumulation of excessive moisture. However, in the cold Russian climate and / or in buildings with high relative humidity In the cold season, the upper part of the wall of an underground structure can become so cold that vapor-permeable thermal insulation will allow a significant amount of moisture from outside to penetrate into the room. In such a situation, semi-permeable vapor barrier films or an additional layer of external thermal insulation can be used.
When insulating walls from the inside, the most energy-saving option is a combination of extruded polystyrene foam and a layer of fibrous thermal insulation (mineral wool or fiberglass), which is laid along wooden frame... In this case, the vapor barrier film is not mounted over the fibrous thermal insulation. The structure is then sheathed with plasterboard and prepared for subsequent finishing.
Figure: 3. Variant of combined insulation from the inside
Floors underground structures heat insulated, most often, with rigid plates of extruded polystyrene. Most often, the floor is insulated under the slab. Floor insulation under the slab is necessary if there are heated floors in the basement. In addition, this type of floor insulation creates additional comfort and protects against the damaging effects of moisture, including protection against moisture condensation in summer.
On top of the insulation boards, it is necessary to lay a reinforced polyethylene film, which will act as a vapor barrier. Shouldn't be satisfied sand pillow between the vapor barrier and the concrete slab. A layer of sand placed between the slab and the film can be saturated with moisture, which subsequently cannot evaporate into the soil due to the presence of a vapor barrier. In this case, moisture evaporation can only take place upward through the plate. This usually leads to destruction flooring in the interior.
The Heck system provides for thermal insulation of underground and basement parts of buildings with special fiber panels, reinforced and covered with sealing sludge. Due to temperature gradients and steam partial pressures, the moisture flow is directed from the inside, that is, the wall “dries out” without the formation of condensation on the inner surface. - add logical to the written
rice…. insulation of the foundation using electric cables
