The blind area around the house - we do it ourselves in compliance with SNiPs and other requirements. The depth of the foundation and the insulated blind area How to insulate the blind area on a shallow foundation

A properly insulated blind area is a structure consisting of several layers: waterproofing material, insulation, drainage. Insulation of the blind area prevents the destruction of the foundation and walls of the house, washing out of the soil, and when building a building on heaving soils, it helps to avoid the damaging effects of soil freezing.

Blind area insulation scheme

In order to properly insulate the blind area with your own hands, you need to know the device and follow the order of the layers of the “pie”.

1. The bottom layer is geotextile. This is the layer that forms the entire structure.
2. The next layer of 10-15 cm is sand.
3. A layer of insulation is placed on top of the sand embankment.
4. The next layer is again sand 15 cm.
5. More geotextiles.
6. A layer of small gravel.
7. Decorative tiles (or other material).

What is the insulation of the blind area around the house for?

Insulation of the blind area is necessary in order to protect it from premature destruction due to heaving of the soil in winter.

This event has other important functions:

• Reducing the cost of heating the house;
• Reducing the shifts of the blind area in relation to the basement of the building.
• Improving the water resistance of the blind area;
• The ability to reduce the depth of the foundation.

On heaving soils, to determine the magnitude of the foundation, the freezing depth is of decisive importance, even if the technical requirements allow for less deepening.

And vice versa: on low-heaving soils, the depth of laying the foundation does not depend on the amount of soil freezing in depth. The depth of its occurrence is dictated by the design features of the house.

Features of warming the blind area with your own hands

Insulating the blind area of ​​the shallow foundation of the house, you can not take into account the freezing of the soil. Thus, even with spending on the installation of an insulated blind area, the savings will be very significant.

Warming is a costly undertaking, but unreasonable savings can lead to the futility of all efforts. The work will make sense only with parallel insulation of the blind area, basement and foundation with your own hands.

The width of the insulation of the blind area must be at least the amount of soil freezing.

Insulation of the basement and blind area with expanded polystyrene (foam plates)

The best option would be to insulate the blind area with extruded polystyrene foam. Penoplex insulation is produced in places where it is impossible to use other heaters. For example, in excessively humid.

In addition, it has other advantages:

• high compressive strength;
• zero water absorption and vapor permeability;
• durability;
• ease;
• frost resistance;
• weak combustibility;
• environmental friendliness.

For do-it-yourself foam insulation, you need to use 50 mm sheets in two layers or 100 mm sheets in one layer. The joints of polystyrene foam sheets will be protected by high-density polyethylene. To do this, it is laid on top of a layer of expanded polystyrene plates.

PPU insulation

Polyurethane foam can be applied to any complex surface and therefore it is used almost everywhere in housing construction.

Positive properties of PPU:

• Has low thermal conductivity;
• Biologically resistant;
• Resistant to decomposition;
• Used at both low and high temperatures;
• Requires 2-3 hours to complete all work;
• Resistant to ignition;
• Has low water absorption;
• The application layer has integrity, without gaps.

The disadvantage is the toxicity of one of the constituents of the material, which requires protective measures when spraying the agent.

Expanded clay insulation

This is one of the most common materials for do-it-yourself insulation of different parts of the house. It is efficient and fireproof. Differs in size of granules (from 2 to 40 mm): gravel, crushed stone and sand. Expanded clay sand is used as a filler for concrete solutions. Expanded clay gravel is more frost-resistant and water-resistant than sand and crushed stone. It is used mainly for do-it-yourself insulation of basements, garages, as well as basements and blind areas.

Insulation of the blind area with expanded clay does not require high costs and special knowledge. A layer of clay and waterproofing is laid in the excavated recess for the blind area, sand and drone on top, as a protection against subsidence. Then expanded clay and again a layer of dronite and sand. Top crushed stone for the design of the territory.

Expanded clay is absolutely harmless and well protects the foundation from moisture penetration. Plus, it's very cheap.

An important stage of warming is the drainage device. The groundwater level in wet areas is about 1 meter. When wet, expanded clay loses most of its thermal insulation properties, because of this, water should be drained from the house.
At a distance from the base of the house, they dig a trench, put geotextiles, a layer of rubble and pipes in it. Drainage pipes are covered with a layer of rubble, the edges of geotextiles and covered with sand.

Do-it-yourself blind area device

Insulated blind area is important for arranging houses on wet heaving soils. Moisture-saturated soil with the onset of severe frosts can begin to shift, rise and destroy the foundation. With warming, the reverse process begins - the soil settles, which also negatively affects the foundation of the building.

The main purpose of insulation is to prevent these processes. If the layering scheme and the main stages of work are known, then even a beginner can do the insulation. Penoplex insulation is easy to use and effectively protects the lower elements of the building from the cold.

The work process includes the following steps:

1. Arrangement of a place for subsequent manipulations. The place is cleared, the roots are removed, the upper ball of earth with vegetation is removed to the depth of the layers of insulation. It is necessary to correctly calculate this value, it depends on the thermal characteristics. All vegetation is carefully removed, since in the future it will destroy the blind area and the structure itself with its root system.
2. Crushed stone is laid on the cleared place as a drainage layer. It is necessary to calculate its layer by subtracting the thickness of the facing tile and sand cushion from the height of the turf layer.
3. The dug recess is enclosed around the perimeter with formwork. Protection against moisture penetration should be made of clay, which is distributed over the ditch and compacted with a layer of 25 cm.
4. The next layer of sand is poured, to ensure shrinkage it is poured with water.
5. Extruded polystyrene foam is laid on a layer of sand.
6. Paving slabs or other material is placed on top of the polystyrene.

To work on arranging the insulation of the blind area with your own hands, you need to carefully prepare and decide on the choice of heat-insulating material. The possibility of using any particular material is decided individually in each particular case. If everything is done qualitatively and correctly from a technological point of view, then the result of the work will please for many years.

Blind area rules regulated by a number of regulatory documents, each of which contains many requirements. Therefore, it makes no sense to look for SNiP on the blind area as the only norms: if you want to do everything in compliance with the requirements, then you will have to comply with all of them. At one time, I collected a fairly large number of excerpts from the requirements for installing a blind area for suing the customer's service, because its representatives grossly violated the rules for compiling estimate documentation, reflecting both incorrect and non-existent values ​​in it. Let's analyze everything in sequence.

General requirements for bases (according to SNiP 2.02.01 83)

By SNiP 2.02.01 83, which is often defined as SNiP on the blind area, only the general moments of the construction of the foundations of buildings and structures are regulated, including deformation calculations, the impact of groundwater and other similar things. Accordingly, SNiP 2.02.01 83 can be followed for general calculations and fulfillment of the basic requirements for soils, etc. However, this document does not define specific values, and therefore it is not possible to recommend it as the only one.

General requirements for the improvement of territories (according to SNiP III-10-75)

“The blind areas along the perimeter of buildings should be tightly adjacent to the basement of the building. The slope of the blind area must be at least 1% and not more than 10%.

In places inaccessible to the operation of mechanisms, the base under the blind areas can be compacted manually until the imprints from the impacts of the rammer disappear and the movement of the compacted material stops.

The outer edge of the blind area within the straight sections should not have horizontal and vertical curvature of more than 10 mm. Concrete pavement for frost resistance must meet the requirements for road concrete "

According to the paragraph above, the requirements for concrete must satisfy "GOST 9128-97 *. Mixes asphalt concrete road, airfield and asphalt concrete. Specifications” and “GOST 7473-94. Concrete mixes. Specifications".

Requirements of technical supervision services (manuals on SNiP)

Let's study another regulatory document, which is called "Schemes for operational quality control of construction, repair, construction and installation works." Documents of this type are used by technical supervision services as instructions for performing inspections of facilities and quality control of work:

1. Technical requirements: according to SNiP 3.04.01-87 tab. 20, SNiP III-10-75 p. 3.26

2. Tolerances: coating slope from the specified - 0.2% of the width of the blind area; the surface of the asphalt or concrete pavement from the plane when checking with a two-meter rail - 5 mm; surfaces of crushed stone preparation from the plane when checking with a two-meter rail - 15 mm; blind area coating thickness from the design - -5% - + 10%. The blind areas around the perimeter of the building should be tightly adjacent to the basement. the slope of the blind area from the building must be at least 1% and not more than 10%.

The width of the blind area should be: for clay soils - at least 100 cm; with sandy soils - at least 70 cm.

3. Not allowed in the concrete monolithic blind area, the presence of cracks, shells and depressions.

For the preparation of the base (evenness, quality of compaction) under the blind area, an act of examination of hidden works should be drawn up. I'll add a note here: if the representative of technical supervision refuses to sign the acts, suspend work, and demand from the official either signing or a written justified refusal. Before the customer, blame everything on technical supervision - they are required to sign your acts or refuse with justification. Do not believe the words, because if you (or you) are sued for arbitration, then permission to pour concrete without acts, only in words, will not be evidence. Refusal to sign acts (oral) write down on a dictophone. Demand your own and send everyone - if you are set up, then it will be you who will pay, and not the customer, and even more so, not technical supervision. Get it right. Let's continue.

4. Requirements for the quality of the materials used: GOST 9128-97*. Mixes asphalt concrete road, airfield and asphalt concrete. Specifications; GOST 7473-94. Concrete mixes. Specifications.

Concrete mixtures should be characterized by the following indicators: strength class; workability; type and quantity of raw materials (binders, fillers, additives); size of fillers.

By agreement with the design organization exercising architectural supervision, samples of the concrete mixture at the place of their laying in a monolithic structure are allowed. The workability of the concrete mixture is determined for each batch no later than 20 minutes after the delivery of the mixture to the place of installation.

Concrete mixtures at the place of laying are taken by volume. Ready-made concrete mixtures must be delivered to the consumer by concrete mixer trucks, concrete trucks. By agreement between the manufacturer and the consumer, it is allowed to deliver concrete mixtures by dump trucks and by cars in bunkers (buckets).

Asphalt concrete mixtures are characterized by the following indicators: the nature of the mixture depending on its temperature; density of asphalt concrete; the largest size of the filler mixture. The temperature of hot mixtures when they are discharged from the mixer must be at least 140°C.

Quality control of asphalt concrete mixtures is carried out at asphalt concrete plants during their manufacture, as well as during laying. To control the quality of the mixture, one sample from each batch is taken and tested. Each batch of the mixture upon delivery to the consumer must be accompanied by a quality document. I'll add one more note: documents should not be for the entire batch of concrete or asphalt, but for each mixer (dump truck). demand certificates for each flight– they are obliged to provide them. Send back poor-quality material, because you can be issued a certificate for a batch of 100 cubes, and of these, only 25 cubes will more or less correspond to this certificate. Let's continue.

Work instructions: according to SNiP III-10-75 p. 3.26

The base for the asphalt concrete pavement should be compacted with crushed stone or gravel with a particle size of 40-60 mm and pressed into the ground with a roller or rammer. The blind area of ​​monolithic concrete should be arranged on a sandy base, compacted to a density coefficient of at least 0.98.

Asphalt concrete blind areas should be arranged from a prefabricated hot mix with a temperature of at least 120 ° C during its laying. The concrete used for the blind area must correspond to road concrete in terms of frost resistance and the grade must be at least M200.

Asphalt-concrete mixes are allowed to be laid only in dry weather. The bases under coverings have to be cleared of dirt. The air temperature during the laying of asphalt concrete pavements from hot mixes should not be lower than +5°C in spring and summer, and not lower than +10°C in autumn. To remove moisture from downpipes, special concrete or asphalt concrete trays with a slope of at least 15% should be made.

In general, here is such a quote. Pay attention to the lines: “samples of the concrete mix at the place of their laying in a monolithic structure are allowed not to select, but to evaluate the strength of concrete according to the control data of the manufacturer of the concrete mix". In practice, this usually means that you have to cast a few cubes of concrete and send them to the factory laboratory (without giving it to technical supervision). Each concrete plant has its own laboratory in which samples will be tested and certificates will be issued, which will need to be presented to the technical supervision or to the customer (if you work directly with him). Cubes during casting must be well tamped, otherwise they may fall apart. I made molds for casting like this: I went to the garbage dump near the supermarket, rummaged through it, found about five fruit boxes and a piece of plywood. From all this, I built homemade forms with cells, like this:

These pieces must be placed on a hard surface (GKL, for example), pour concrete into them and compact it well. Then the molds must be broken and samples removed from them (in the photo below, some of the samples turned out to be of not very good quality). From each mixer it is necessary to prepare 3-4 cubes with a side of 15 cm, it is better to wrap the finished products in a rag before transportation. It is strictly necessary to take samples not earlier than they gain primary strength (at least 7 days). In practice, laboratories sometimes pick them up in a day or two, as soon as they are ready. If you work directly with the customer, be sure to include laboratory testing of concrete and the production of samples for them in the estimate. On a government order, you will have to make samples even if this is not reflected in the estimate.

This is about "instructions". As you can see, SNiP 2.02.01 83 is not mentioned in them at all, which confirms the comments I made above that this item can be considered only general, indicative, and some information can be used for calculations.

From TSN of Moscow

“4.11.4 To ensure surface drainage from buildings and structures along their perimeter, it is necessary to provide for a blind area with reliable waterproofing in accordance with SNiP III-10. The slope of the blind area should be taken at least 10 ‰ from the building. The width of the blind area for buildings and structures is recommended to be 0.8-1.2 m, in difficult geological conditions (soils with karsts) - 1.5-3 m. »

This is how the requirements for the blind areas of buildings are regulated by the “Norms and Rules for Designing Integrated Improvement on the Territory of the City of Moscow MGSN 1.02-02 TSN 30-307-2002”. Surprisingly, I carefully tried to find a similar document for St. Petersburg, but I could not find it. However, appealing to the fact that in this case the requirements set forth in the document are not caused by special climatic and other conditions, as well as construction conditions and / or features of the operation of buildings and structures in a particular region, these figures and recommendations can also be applied to the territory Petersburg.

Requirements for buildings under construction according to 384-FZ

Article 25. Requirements for ensuring protection against moisture

1. In the design documentation of the building and structures, design solutions must be provided that provide:

1) drainage from the outer surfaces of the enclosing building structures, including the roof, and from the underground building structures of the building and structure;

2) water resistance of the roof, external walls, ceilings, as well as walls of underground floors and floors on the ground;

3) preventing the formation of condensate on the inner surface of the enclosing building structures, with the exception of the translucent parts of windows and stained-glass windows.

2. If it is established in the design assignment, the design documentation must also provide for measures to prevent flooding of premises and building structures in case of accidents on water supply systems.

As you can see, unlike TSN and SNiP, 384-FZ only outlines the requirements for waterproofing, being not a regulatory document, but a guiding one. Accordingly, paragraph 2 of Article 25 refers to the provision of watertightness of "walls of underground floors and floors on the ground", which includes both waterproofing of foundations and the installation of a blind area that protects these foundations.

Requirements for the thickness of the blind area

As I believe, the thickness of the layers (pillows) of sand, crushed stone and other similar things should, in theory, be calculated according to the materials of SNiP, Part II, section B “Floors. Design standards. II-B.8-71.” Usually, however, the thickness of the sand layer is taken at least 10 and up to 15 cm, crushed stone - at least 6 and up to 9., and concrete - from 7 to 12 cm (all in a solid body, i.e., a compacted layer ). The standard average thickness of a reinforced concrete blind area for residential and public buildings (in practice) is 10 cm, and for asphalt concrete - 5 cm. I have not found direct indications of the minimum blind area thickness anywhere.

However, according to par. 3.1 and 3.128. "Guidelines for the design of concrete and reinforced concrete structures from heavy concrete without prestressing", the thickness of monolithic slabs must be assigned and accepted not less than 40 mm. This is not a normative document, but a recommendation. If we consider the blind area as a monolithic structure (like a beam slab), then, therefore, these recommendations apply to it too.

This concludes the basic requirements for the construction of reinforced concrete and other blind areas. As you can see, they include not only SNiP, but also TSN norms, as well as all sorts of other notes, calculations, and recommendations set out in guiding and recommending documents. Accordingly, if this is a government order, any additional requirements may also be set out. Naturally, in this case, the additional wishes of the customer should not contradict the established norms and rules, so you need to be careful before taking any contract. It must be said that concrete work on public procurement is notable for its low cost and draconian nit-picking, since concrete, as a general building material, has an abyss of all sorts of permits, certificates and other bureaucracy.

Every builder wants to build an economical and at the same time reliable foundation. But often one desire is not enough. The type and design of foundations largely depend on the properties of the soil under the future building.

In one of the previous topics, we looked at how a classic strip foundation works. In this article, we will consider a monolithic reinforced concrete shallow-depth strip foundation.

Shallow strip foundations are the most economical when building light frame and wooden houses or houses made of gas and foam concrete. They allow to reduce the consumption of concrete by 2-3 times and significantly reduce labor costs compared to conventional strip bases.

In order to understand how it works, you need to figure out why the foundations are buried to the depth of freezing.

If during the construction of the house a basement or basement is not provided, then such a recess does not allow the forces of frost heaving to push the building out. In order for these forces to arise, two conditions are necessary, these are water and sub-zero temperatures. Everyone knows from a school physics course that water expands when it freezes, so when it happens in the thickness of the earth, it simply pushes everything that is above it up.

Therefore, traditionally, strip foundations are laid to the freezing depth, where the temperature does not drop below zero, respectively, the water does not freeze and there are no forces capable of pushing the foundation out.

Based on this, in order to make a shallow foundation, you need to reduce the freezing depth or remove water from under the foundation.

This is done by insulating the foundation and soil around the house, and installing a drainage system. This allows you to reduce the depth of laying by 2-4 times, depending on climatic conditions.

Shallow foundation device

A shallow foundation is identical in design to a conventional strip foundation. The difference is the depth of laying, horizontal thermal insulation and drainage system.

First, let's start with the general device, and then we will consider in detail the most important points.

1. We dig a trench 50-70 cm deep and level the bottom. It is desirable to make it more horizontal, but you should not be particularly zealous.

2. We spread geotextiles to prevent silting of drainage pipes.

3. We fall asleep a sand cushion of 20-30 cm and compact it. If the earth is pure sand, then there is no point in such a pillow; you don't have to do it.

4. We lay waterproofing from bitumen-polymer roll material on the bottom of the trench and build the formwork.

5. We make a reinforcing cage and pour concrete.

6. The next stage is the vertical waterproofing of the walls of the shallow foundation using bituminous mastics or various roll materials.

7. We make vertical insulation of the foundation with the help of polystyrene foam plates.

8. We lay drainage pipes. It should be noted that if the groundwater level is deep enough, more than 2 m, then the drainage system can be omitted.

9. We fill the sinuses with sand or a sand-gravel mixture.

10. We make horizontal soil insulation around the foundation tape and the blind area.

We have listed the main stages, now we will consider in more detail the most important points.

The width and height of the shallow foundation

The width of the foundation depends on the bearing capacity of the soil and the weight of the structure. How to calculate the width depending on the properties of the soil, we wrote in the topic "Calculation of the load on the foundation".

After the required width is calculated, it is necessary to determine the height of the tape.

You can pour concrete to ground level, and then lay out about 50 cm more with well-burned red brick. But it’s better to immediately build the formwork 50 cm above the zero level and fill everything with concrete with reinforcement.

Foundation reinforcement

This is one of the most important stages in which a shallow foundation forms a monolithic rigid frame and acquires increased strength.

When calculating the number of bars, it is necessary to calculate the cross-sectional area of ​​\u200b\u200bthe foundation and multiply by 0.1%. A value will be obtained that will show the total cross-sectional area of ​​\u200b\u200ball the bars. The following is an example of a calculation.

It is also necessary to take into account that, according to the rules, the distance between the longitudinal reinforcement bars should be no more than 40 cm. The distance from the concrete wall to the reinforcement should be 30-50 mm.

The most suitable reinforcement has a diameter of 10, 12, 14 mm.

Example: We decided to make a shallow strip foundation with a strip width of 400 mm and a height of 800 mm. Sectional area 400x800 \u003d 320000 mm 2. Multiplying by 0.1%, we get the total cross-sectional area of ​​\u200b\u200ball the rods 320 mm 2.

Now we calculate the cross-sectional area of ​​\u200b\u200bone bar. In general, this is done according to the formula S=πd 2 /4. We get: S 10 \u003d 78.5 mm 2, S 12 \u003d 113 mm 2, S 14 \u003d 153.9 mm 2.

Dividing 320 mm2 by the cross-sectional area of ​​​​one rod, we get n 10 \u003d 4 pcs, n 12 \u003d 3 pcs, n 14 \u003d 2 pcs. According to the rules, if the tape width is more than 15 cm, then the installation of one bar in one row is prohibited. Under such conditions fittings d=10mm are suitable. You need to place it 2 pieces on top and 2 on the bottom.

You also need to tie the reinforcement together. This is done using rods with a diameter of 6-8 mm and knitting wire. The longitudinal bars are connected to the transverse ones every 20 cm, and the rows are interconnected every 60 cm.

Thickness and amount of insulation for the foundation

Insulation is mandatory when constructing shallow foundations on heaving soils. It is laid under the blind area in order to reduce the depth of soil freezing.

As a heater, it is best to use extruded polystyrene foam boards. To prevent soaking of the plates, it is better to wrap them with special membrane films that prevent the penetration of moisture into the thickness of the insulation.

To select the required amount of insulation for shallow foundation, you need to know the climatic features in the area, the level of groundwater, the thickness of the snow cover in winter, the properties of the soil under the building, the thickness of the foundation, whether the house will be heated permanently or temporarily, etc.

As you can see, there are many factors to consider. Therefore, horizontal insulation is generally laid to a width equal to the depth of soil freezing, and the thickness of the insulation is taken with a margin of 10-15 cm.

Vertical thermal insulation is made 5-10 cm thick. It should protrude at least 50 cm above ground level.

Installation of a blind area

One of the important design features of a shallow foundation is the blind area. It drains water that forms when snow melts or during rains away from the base, and for shallow foundations it is an additional insulation.

It is done as follows: the upper fertile layer of soil is removed, insulation is laid, a masonry mesh with a cell of 10x10cm is installed and poured with concrete.

It is also necessary to provide temperature seams. To do this, every 6 m, a vertical wooden insert from a board 10 mm thick is mounted in the blind area.

To achieve a greater effect, grass is sown around the house and shrubs are planted, due to which the snow cover in these places accumulates and is not blown out. This contributes to even greater warming of the shallow foundation.

There is an article on our website that discusses in detail the construction of an insulated blind area for various types of foundation. In it you will find answers to the questions “How to insulate the blind area?”, “What brand of concrete to choose?”, “How wide should it be?”. (link)

Video on the topic "Shallow Foundation":

A shallow strip foundation is erected in soils that are least prone to frost heaving.

And yet, its insulation from the outside is an obligatory stage of construction in order to avoid heat loss from the room and prevent possible freezing of the soil by the base of the support.

Technique

When protecting against heat loss for a support with a shallow depth, insulation is performed on the outer surface of a shallow strip foundation vertically and horizontally at its base. Most often, for this kind of construction, a heater is used - extruded polystyrene foam. Penoplex practically does not transmit heat, has high strength, moisture resistance and fire resistance.

The technology for carrying out work on the insulation of a shallow strip foundation consists of several stages:

1. Waterproofing. The side part of the base and the plinth is coated with bitumen 2 times or pasted over a hot layer of polymer bituminous mastic with roofing felt or PVC membrane.
2. Covering the waterproofing layer on top with geotextile.
3. The device of a sand and gravel base in a trench, the thickness of which is equal to the thickness of the pillow under the support itself. In this case, the sand and gravel layer should have a slope from the walls of the house.

1. Pouring concrete screed with a thickness of 3-5 cm and coating with polymeric bituminous mastic for waterproofing.
2. Pasting a shallow strip foundation with extruded polystyrene foam plates 5 cm thick. Special glue is applied along the perimeter and diagonals of the insulation panel, then pressed tightly to the side surface of the foundation structure. Between themselves, the plates are connected with tongue-and-groove ends. To prevent the appearance of cold bridges, the seams and gaps are filled with mounting foam.

1. Laying foam on a concrete screed in a trench. See photos of thermal insulation on the website
2. Arrangement of a vapor barrier layer along a heater located on a horizontal and vertical plane, from a profiled membrane or a dense polyethylene film. Cloths of vapor barrier material are overlapped. The seams and edges are glued with a special adhesive tape.
3. Installation of a drainage system. Corrugated drainage pipes are mounted along the perimeter of the shallow-depth tape structure 30 - 50 cm below the bottom of the tape to drain ground and melt water. The drainage pipe is laid on a gravel base.
4. Backfilling the trench with sand with layer-by-layer compaction.
5. The device of a concrete blind area around the house.

Watch a video on this topic:

Insulation of a shallow foundation, made in accordance with building codes and regulations, will prevent its destruction from the action of frost heaving forces and groundwater and significantly reduce heat loss from the room.

The blind area is a simple, but at the same time extremely important element for every home. Therefore, in the process of arranging it, it is necessary to follow some rules. To help in this matter, further we will consider how to make a blind area from different materials in compliance with all norms and requirements.

Blind area - what is the secret of the longevity of the house?

First of all, let's figure out what function the blind area performs in general, and whether it is possible to do without it. So, this element of the building, in fact, is a cornice laid on the ground and adjacent to the basement. Visually, it resembles an ordinary path, which is made with a slight slope from the house. Due to this slope, the blind area diverts water from the foundation.

As you know, "a drop wears away a stone." Therefore, the blind area laid around the house significantly increases the life of the foundation, and hence the entire house. Actually, this is its main task. In addition, it is capable of performing additional functions:

• heat-insulating - this allows you to neutralize the negative impact of heaving of the soil on the foundation;
• decorative - with a blind area, the house has a complete and attractive appearance;
• stabilizing - stabilizes the gas regime of the soil around the house, in other words, prevents oxygen from reaching the soil near the foundation. Due to this, plants do not germinate.

In addition, the blind area can serve as a path, as most often happens. From the foregoing, it is easy to conclude that theoretically the house can be operated without a blind area, but this will greatly affect its durability, and not for the better.

What you need to know about the device - soft or hard option?

In order for the blind area to effectively solve the tasks assigned to it, it is necessary to follow the basic rules for its arrangement. First of all, you need to properly deepen the structure. The fact is that most of it is in the ground, and not on the surface, as many beginners think. The level of deepening of the blind area should not exceed ½ of the design level of soil freezing. This allows the blind area to "play" with the ground, but at the same time not lose touch with the foundation.

Another important point is the additional waterproofing of the blind area. For these purposes, a waterproofing material is laid on the bottom of the trench, which is placed on the foundation. A pillow is laid on top of the waterproofing, consisting of several layers of sand and gravel. To avoid the migration of bulk materials, the layers of the cushion are reinforced with geotextiles. It must be said that the multilayer foundation device is a relatively new solution that significantly reduces the cost and simplifies the construction of the structure.

A cover is laid on top of the pillow. Depending on the type of the latter, blind areas are divided into three types:

• rigid - imply a monolithic concrete, asphalt or cement-filled coating;
• semi-rigid - these include blind areas paved with paving slabs or other piece materials;
• soft (loose) - made of crushed stone, gravel, pebbles or other bulk material that is poured over the pillow.

I must say that the choice of type of coverage depends not only on landscape design and your preferences, but also some other factors. For example, a cement-filled coating is not suitable for heaving soils, since after the first winter it will crack and become unusable. If you need to insulate the blind area, then it is advisable to use a hard coating.

Preparing the pillow - dig trenches and fall asleep "pie"

Regardless of which coating you use, the blind area begins with the preparation of the pillow, and it is always performed in the same way. First of all, you need to decide on its width. According to SNiP 2.02.01-83, the blind area, and, consequently, the pillow, must extend beyond the roof overhang by at least 200 mm, at the same time, its width must be at least 700 mm.

Then, having decided on the width, you need to mark up the perimeter of the house. A trench is dug according to the marking, i.e. it must correspond to the width of the blind area. As we said above, the depth of the trench is half the level of soil freezing. A layer of clay 15–20 centimeters thick is laid at the bottom of the resulting ditch - this is an additional water seal. The clay must be carefully compacted and leveled, while ensuring a slope of about 8-12 cm per meter. Then the trench is covered with a waterproofing material, for example, you can use a polypropylene film or even several layers of roofing material. The main thing is that the waterproofing should be wrapped on the foundation by 10 centimeters, as well as on the trench wall to the level of rubble.

To fix the edge, you can attach a rail or corner over it.

Then the waterproofing is covered with a layer of sand at least 3 cm thick. The sand must also be leveled. Geotextiles are laid on the sand and wrapped around the trench wall. Then a layer of crushed stone with a thickness of about 9-10 cm is filled up and carefully rammed. In this case, a slope of 5-7 cm per meter is formed. On this pillow, one might say, completed. Further actions depend on the material that will be used as a cover for the blind area. The only thing, if you do not plan to carry out stormwater drainage along the perimeter of the blind area, you need to make drainage around it.

To arrange drainage, it is necessary to dig a ditch below the level of the pillow by 30 centimeters. The bottom of the ditch should be covered with geotextile, the edges of the canvas should be left with a margin of 35 cm. Then a layer of crushed stone is filled up and drainage pipes are laid. From above, the pipes are also covered with a layer of crushed stone and wrapped with the free ends of the geotextile. The finished drainage sewer should be brought to a retained well or connected to a storm sewer, if, of course, there is one.

We lay FEMku - a simple and beautiful option

To begin with, let's consider how to make a blind area with paving slabs with your own hands, since this is one of the most common options. Work should begin with laying geotextile over crushed stone with a twist on the trench wall. Next, install the border along the edge of the blind area. To do this, dig a groove along the width of the curb and fill it with cement mortar. The border can be placed directly on the fresh mortar so that it is slightly concreted.

In order for the curb to be even, stretch the cord along the edge of the blind area and align the curb sections along it.

Then the geotextile is covered with a layer of sand with a thickness of at least 6 mm. Sand must be rammed, and it is desirable to spill it with water, which will allow it to be compacted better. I must say that in the case of using paving slabs, the function of water drainage completely falls on the waterproofing film. Therefore, the slope of the upper layer of sand can be omitted. The process of laying FEM tiles is standard - you simply lay the tiles on the sand and align them relative to each other, as well as in a horizontal plane.

Here, in fact, are all the nuances of performing such a blind area. I must say that according to this scheme, it is made not only from paving slabs, but also from paving stones. The only thing, the latter, unlike tiles, needs to be buried a little in the sand.

We make a blind area from bulk materials - one or two and you're done

It is even easier to make a blind area from rubble. In fact, it is performed in the same way as the pillow. But the crushed stone layer should be thicker, i.e. its thickness should be equal to the thickness of the crushed stone layer of the pillow, plus the thickness of the sand layer, plus the thickness of the coating layer. The result is about 20 centimeters. The surface of the crushed stone is leveled in a horizontal plane. As for the slope, there is also no point in making it for a crushed stone blind area.

As you can see, the process of arranging a soft blind area is quite quick and simple. However, it has several drawbacks - it is fragility and not very presentable appearance. True, if the landscape design is designed in the appropriate style, then pebbles or even ordinary rubble around the building can look quite good.

Approximately the blind area is also performed with the upper cement-filling layer. The difference lies in the fact that the crushed stone layer should be a few centimeters smaller, since the screed will take this thickness. To fill the solution, a formwork is necessarily installed along the edge of the blind area. As a rule, it is made of boards, plywood or OSB. The most important thing is to fix it qualitatively so that the formwork does not move during the pouring of the mortar. To do this, you can use spacers and racks.

On the side of the foundation, before pouring, a sealant is necessarily laid, which is responsible for the installation of a thermal seam and its sealing. Most often, for these purposes, a conventional polyethylene foam damper tape is used. A cement-sand mortar of the M200 brand with a thickness of about 3 cm is poured on top of the rubble. When the mortar begins to set, it is ironed, i.e. a thin layer of cement is poured on top and rubbed with a small amount. Thanks to this operation, the blind area will become smoother and more durable.

After rubbing dry cement, it is advisable to cover the surface of the blind area with a dark film, since ironing ripens better without light. So that the blind area does not crack during the drying process, for the first few days it must be sprinkled with water every day.

Concrete blind area - we create for a long time

The most durable and durable is the concrete blind area. The process of its manufacture begins with the preparation of a sand cushion, as before laying paving slabs. Then the formwork is installed around the perimeter in the same way as in the previous case. Before laying the reinforcement, it is advisable to install expansion joints from wooden planks with a thickness of about 15 mm. Compensators should be located perpendicular to the blind area, i.e. between foundation and formwork. The distance between compensators should not exceed 2.5-3 meters.

Since the planks will remain in the thickness of the concrete, they must first be treated with a protective antiseptic and bituminous mastic. Thanks to this, they will last more than a dozen years. When installing compensators, try to align their ends in the same plane with a slope of 10 cm per meter. As a result, the slats will additionally serve as guides.

After the formwork is installed, a damper tape is laid along the wall, and reinforcement is performed with a reinforcing mesh. Its optimal dimensions are 100x100x4 mm. Keep in mind that the mesh should not lie on the pillow, so special racks or small stones must be placed under it. Otherwise, the grid will not perform its functions. After that, concrete work begins. First of all, you need to prepare a solution of the following ingredients:

• cement grade not lower than M400 - 280 kg;
• crushed stone - 1400 kg;
• sand - 840 kg;
• water 180–200 l.

Let me remind you that cement is mixed with sand first, then water and filler are added. The solution will turn out very dry, but don't let that bother you. This consistency is necessary so that the concrete can hold the required slope angle. Filling is carried out section by section. In the process of performing this procedure, do not forget to ram the concrete. It is best to use special equipment for these purposes, but if it is not available, you can also use a piece of reinforcement. During ramming, try not to move the reinforcement mesh, as this will reduce the strength of the concrete.

After pouring the blind area, the expansion joints can be smeared with construction sealant to eliminate the possibility of moisture penetrating into them. After setting the solution, it is desirable to carry out ironing according to the scheme described above. Do not forget that for the first few days the surface of the concrete blind area must be moistened with water.

A few words about thermal insulation - why is the soil warm?

Insulation of the blind area may be needed in the following cases:

• the house has a heated underground room (ground floor or basement) - in this case, insulation will reduce heat loss;
• the house is built on heaving soil - insulation will prevent the soil from freezing;
• several times per season, the freezing depth may exceed the design value according to SNiP, i.e. the soil freezes to the very foundation of the foundation.

As mentioned above, it is better to perform insulation under a concrete blind area - this will achieve the greatest effect. As for the choice of insulation, the best solution is extruded polystyrene foam. This material is not afraid of moisture, is able to withstand heavy mechanical loads and is very durable. Its only disadvantage is its high cost.

You can, of course, use ordinary high-density polystyrene foam (styrofoam) as well. However, it is desirable to waterproof it. As for the process of insulation itself, everything is quite simple - the slabs are laid on a sand cushion, and then a concrete blind area is performed according to the standard scheme. The main thing is to properly lay the insulation in order to prevent the appearance of cold bridges. Therefore, for thermal insulation of joints, it is desirable to use ordinary polyurethane foam.

Here, perhaps, are all the main points of arranging the blind area. Given all these nuances and subtleties, you can reliably protect the foundation from moisture.