Concrete pavement technology around the house. How to make a blind area with your own hands? Manufacturing instructions. Materials for coating the top layer

The blind area is a very important part of any structure. How to make a blind area around the foundation to protect the underground structures of the house? To do this, you need to correctly understand its purpose.

What is a blind area for?

blind area design

The blind area is a closed surface covering around the house. A strong protective belt protects the basement and foundation of the house from the penetration of natural precipitation (rain, melted snow) into the structure of underground structures. The protective belt around the building reduces the possible swelling of the soil from freezing. The blind area around the house should be made with a continuous tape.

Preparation of the base for the blind area

When the width of the protective coating is determined, the projection line of the edges of the roof is marked on the ground. 20 cm is added to the obtained distance from the walls of the building and the required width of the blind area is obtained. Usually the width of the coating is no more than 60 cm.

The resulting contour is fixed with pegs with string stretched over them.

By marking, they dig a trench 25-30 cm deep. To prevent the germination of plant roots, the soil in the trenches is treated with herbicides. Sand is poured at the bottom with a layer of 10 cm. Then the sand is poured with water and carefully rammed. If necessary, you can make an additional layer of rammed clay.

On a sand cushion, a layer of crushed stone or fine gravel is made.

The meaning and arrangement of expansion joints

The location of the expansion joints of the blind area

Expansion joints are made along the entire length of the blind area. These seams are extinguished internal stresses from uneven ground settlement.

Every 2-3 meters along the entire perimeter around the house, wooden slats 10-20 mm thick are installed on the edge. Reiki is laid with minimal slope 1.5 degrees from the wall outwards. The slope can also be made steeper. Their upper plane should correspond to the level of the surface of the blind area. wooden details treated with an antiseptic.

The expansion joint is performed with a width of 1.5 - 2 cm.

Particularly important is the installation of expansion joints at the corners of the building. Negative stresses are most strongly concentrated in these corners.

It should also be taken into account that when creating the surface layer, the laths of expansion joints will play the role of beacons. Beacons control the evenness of the surface and the correct slope of the coating.

Be sure to make the correct expansion joint at the junction of the blind area and walls. Such a seam is made while filling the formwork space with concrete or other material. Expansion seams cover bituminous mastic or cement mortar.

Formwork device

blind area formwork device

The formwork is made of planed boards 20 mm thick. In accordance with the marked markup, formwork is installed. The fixed boards with the help of spacers from the outside are installed taking into account the slope of the coating. The places where the blind area adjoins the wall of the house are beaten off with a dyed thread, marking the line of the upper surface of the coating.

The formwork is made in such a way that its outer side is at a distance of 50 - 100 mm from the edge of the underlying layer. This must be done to form the final bevel of the foundation railing after the formwork boards have been removed.

Waterproofing

Waterproofing is laid on a pillow in a trench. As a material for waterproofing, roofing material in two layers or a polymer film is used. The edge of the roofing material or film adjacent to the house is brought out just above the marked line of the blind area surface. The places where the waterproofing adjoins the walls are coated with hot bitumen. Roofing material laid in this way will form a deformation seam.

blind area covering device

There are several popular types of coatings:

concrete;
asphalt;
decorative ceramic tiles.

concrete pavement

Concrete pavement

The space enclosed by the formwork is poured with a concrete mixture with fine aggregate. The use of slag from the waste of metallurgical production will make it possible to obtain a coating High Quality. Before concreting, an additional polymer reinforcement mesh can be laid on the base.

Cement is rubbed on the wet surface of the screed. This process is called ironing. Ironing the surface strengthens the top layer of the screed and gives it an aesthetic appearance.

Asphalt pavement

The simplest and cheapest way to build a foundation fence is to lay asphalt in the formwork space. The production technology is the same as in the construction of roads. A manual roller is used for laying asphalt.

Laying decorative tiles

On the screed arrange the surface of decorative tiles. The blind area of the foundation from the tiles of different halftones laid around the house looks especially beautiful. Of course, this type of surface comes at a cost.

Blind area insulation

To protect the foundation of the house from swelling of the soil and its freezing, the blind area is insulated. Styrofoam slabs are laid on the bed waterproofing of the underlying layer of the base, mineral wool or another polymer material. Then proceed to the formation of the coating. Watch the video on how to build a blind area with your own hands.

For insulation of the enclosing structure, a material such as expanded clay is perfect. Expanded clay in its thermal insulation properties surpasses many Construction Materials. A properly selected layer thickness of it (no more than 10 cm) is quite sufficient to ensure effective thermal insulation.

Concealed drainage device

There is an expensive but effective method hidden drainage devices.

Pipes for hidden drainage

When the underlying layer is correctly made and installation is completed waterproofing material around the building, polymer pipes are laid on it around the entire perimeter of the house. In the locations of the drain holes of the drainpipes, receiving boxes are installed. A polymer box with an open top surface is designed to collect rainwater and drain it into a pipe. With special locks, all drainage fittings are manually connected into a single system. Rainwater from a hidden drainage system enters a pipe, which is discharged into a storm sewer. If it is not possible to connect the drainage system to the sewer, the pipe is connected to the water reservoir. A container dug into the ground acts as a water storage tank. Through the drainage holes, the water gradually drains into the ground at a fairly safe distance (8 - 10 meters) from the building.

All pipes must be laid at a slope that ensures that rainwater can drain freely from the system.

After installing the drainage, make a layer cement screed and carry out further work on the formation of the final surface of the enclosing structure.

The design of such a drainage system protects the surface of the fence from excessive rainwater. IN winter time you need to do regular cleaning of the blind area from snow.

With the correct fulfillment of all requirements for the construction of a blind area around the house, the foundation will be protected for many years.

A blind area is a protective path with a hard or bulk coating, arranged adjacent to the wall around the entire perimeter of the building. Its main purpose is to drain rain and melt water falling from the roof near the foundation and contributing to its premature destruction.

In addition, it is used as a convenient pedestrian passage and decorative design when landscaping the area adjacent to the house. The use of dense or bulk insulation when constructing a blind area allows you to protect the foundation from the effects of low temperatures and reduce heat loss through the building envelope.

A fairly simple device of such a protective coating simultaneously solves several important tasks related to protection and landscaping, without requiring large financial investments. At the same time, you can do it yourself, without inviting specialist builders for this.

The blind area around the house is made immediately after the completion of the exterior walls of the building, but before the start of the basement. This is due to the need to block the expansion joint between the wall and the track covering from rainwater due to the protruding surface of the base overhanging it.

For pile, deep columnar and screw foundations the presence of a blind area is not mandatory, but it is often made as an element of landscaping and as a convenient footpath.

blind area design

A protective coating must be made around the entire perimeter of the house, since it is necessary to ensure the protection of the entire foundation array. The basic requirements on how to properly make a blind area around the house with your own hands are set out in SNiP 2.02.01-83, which says that on normal soils its width should be at least 600 mm, and on subsidence - at least a meter. In general, the width of the covering should extend at least 200 mm beyond the protruding roof edge. Maximum Width not regulated.

General drawing of the blind area.

The hard coating must be laid on a dense base with a thickness of at least 15 cm. The slope of the blind area from the building is not less than 0.03%, with the lower edge exceeding the planning mark by more than 5 cm. Storm water must be discharged into storm sewers or flumes.

A well-made insulated blind area should consist of three main layers:

surface waterproof;
underlayment of gravel or a mixture of crushed stone and sand;
polystyrene foam insulation.

As an additional layer, geotextiles can be used, which will be a fairly reliable waterproofing against rising spring ground water and also prevent the possible germination of weeds.

Materials for coating the top layer

The materials used for the top layer when constructing a blind area are quite diverse and have their own distinctive features. The simplest and most inexpensive is ordinary clay. With its help, you can create a fairly reliable hydraulic lock. Such protection is often found in rural areas. However, modern developers have long abandoned such primitive materials and use more efficient technologies.

Options.

The most common option is how to make a blind area - a concrete pavement device. You can easily and quickly mount it yourself, without investing large financial resources. At the same time, concrete is characterized by high strength and durability, and also allows it to be covered with paving slabs in the future to improve appearance.

Finishing the blind area with paving slabs is made on a cement-sand mixture or mortar. Most often it is used to create a single color ensemble with the decoration of the building or its decorative elements. It is also easy to install and quite durable.

Paving stones can be laid on a compacted sand cushion. It has a beautiful appearance, but is more expensive than tiles and somewhat more difficult to install. When using paving stones, it is necessary to ensure high-quality sealing of the seams to completely seal the top layer.

Sectional diagram of a concrete pavement.

The blind area device made of natural stone looks very beautiful and will last without repair for many years. However high price material reduces the possibility of its wide application.

Asphalt is rarely used because of the unpleasant smell in hot weather. In addition, such homemade material does not differ in high strength, and buying a factory one costs a lot more expensive device concrete screed.

Saving on construction is a difficult stage, where the edge of quality / cost is important, so that in the future it will not go bankrupt for repairs, and at the same time, it is quite comfortable to feel comfortable during the operation of the structure.

The blind area should be built after the foundation, basement, walls, roof have already been finally built. Although, the blind area can be built at almost any stage of construction, after the walls have been laid. But the blind area after all stages of construction will cost the cheapest and least time-consuming, because in this case you save on calculations and errors, and the formwork can also be built from only three sides.

How to make a blind area?

A concrete blind area from 70 cm around the whole house will be the most simple option. For the construction of a high-quality blind area, it is necessary to take into account a number of rules:

The width of the blind area should be greater than the protruding part of the roof, as a rule, by at least 20 cm. This is done so that moisture dripping from the roof does not deform the land, which actively affects the quality of the foundation.
The blind area should be continuous, monolithic around the entire house. Only in this case, the foundation will be safely protected from moisture, which, however, does not exclude waterproofing in any case.
A wider blind area is also more functional with respect to moisture protection.
The slope of the blind area will optimally provide a tap at 1.5 degrees. You can do more slope, but remember that it is possible to slip on a steeper slope in winter. The slope is formed at the stage of the underlying layer, it is also possible at the stage of laying the coating.
The blind area, made in accordance with all the rules, determines the quality, economy and lack of repair for a long time, both the blind area and the basement.

The blind area is two structural layers

The underlying layer is an even compacted base for the coating. For him, materials such as clay, fine gravel, sand are used. The material of the underlying layer directly depends on the coating material used. Thickness up to 2 cm.
The coating must perform the task of complete waterproofness and resistance to the damaging effects of water. Use clay, concrete, asphalt, small cobblestone. Layer thickness up to 10 cm.

These layers are necessary for any blind area.

It is necessary to markup for future blind area

In our case, the width of the blind area is 100 cm. The soil along the entire perimeter of the house must be removed to a depth of 20-25cm. As a rule, the soil is removed here at the very beginning of the construction of the house. Dig should be under the entire width of the blind area of 1m. The calculation is also carried out from the material with which the blind area is laid. With respect to the blind area of concrete, a depth of 20-25 cm is needed, with respect to other materials - a different depth.

Some developers recommend immediately after digging a trench around the house, level the floor and walls, and then immediately cover them with herbicides. So that the roots of the plants do not then grow and do not damage the blind area. This is your own choice.

The formwork is made from boards. As a rule, boards 2 cm thick are used for this.

On the soil that we have compacted, a layer of clay a few centimeters should be laid. Then, it is necessary to level the layer and compact it.

A layer of sand is laid with a thickness of 10 cm. It also seals very well. To make compaction easier for yourself, dampen the sand with water. But not abundantly, so that the water does not reach the clay.

Then, there is a layer of rubble in 5-10cm.

In order to strengthen the blind area - reinforce it with fiberglass reinforcement with gaps at the joints of 10 cm. Reinforcement makes it possible to achieve stability of concrete not only in compression, but also in tension. Land displacement occurs frequently, so reinforcement is required in any case.

At the junction of the blind area with the walls of the basement, a seam must be made. It's called compensation. Also, this seam is called deformation or temperature. This seam will protect the basement and blind area from soil subsidence and further destruction. In this case, the blind area will go down, but when moving, it will not damage the base, since all the mechanical impact will fall on the seam. The width of such a seam is up to 1.5 cm. It should be made from a mixture of fine gravel and sand, bitumen, mastic, or two layers of roofing material. Someone even uses a tourniquet made of polyethylene foam. The diameter of such a bundle is a quarter larger than the width of the seam. Thus, the jute fits very tightly into the gap for the seam.

Features when placing the tourniquet - it must go into the gap completely, and leave some space on top. Those. there should be a depth free from everything on top, which is equal to half the width of the seam. A piece of plywood will allow you to carry out this process faster.

In our case, a simple sealant was used.

Filling the blind area should be done every 2 meters across the expansion joint. They keep the blind area from breaks in winter period. Wooden slats placed on edge are perfect for this purpose. The surface of the rails should be flush with the surface of the blind area. The slope of the blind area should also be taken into account, and therefore, place the slats either under the slope, or make the slats pre-oblique on the edge, to match the slope. In order to protect wooden inserts from decay, they should be treated with bituminous mastic.

Expansion joints should also be installed in the corners of the house. Those. at the corners of the blind area.

Concrete, in addition to pouring, should also be compacted and leveled. Reiki will help you navigate the height of the concrete pour. It remains to wait until it completely hardens.

Ironing gives the greatest strength to the formwork. Ironing, performed by the wet method, will help the blind area to achieve the greatest water resistance.

The last stage - we cover the concrete surface with a fabric material, gradually, as it dries, wetting the fabric with water. This will help keep the concrete from drying out until it has completely hardened. If you have to lay the blind area during the rainy season, then you can do without moisture.

After 2 weeks, the blind area will be ready.

Concrete pavement repair

With the correct laying of the foundation, basement and blind area of the house, for many years you will not have any problems. But what if they appeared? For example, the blind area is cracked? Yes, even significantly.

Small cracks will be enough to fill the stakes concrete mix in a ratio of 1:1.

cracks over large sizes it is necessary to cut down to the entire depth of their formation, clean the recess from dust, dirt and other debris, and fill it with liquid mastic (2/3 bitumen, BND-90\130, 10% crushed slag and 15% asbestos material). Then sprinkle the filled cracks with any sand.

If the destruction of the blind area turned out to be even more significant, then it should be fully restored, with the help of a fresh portion of concrete and a couple of simple manipulations. The surface must be cleaned of dirt and primed. For the latter, a cement mortar is suitable. Lay the fresh mixture and level it. Then, it is necessary to prevent the fresh concrete mixture from drying out until it is completely cured. Those. stably moisten it, at the slightest drying, and cover with a film of polyethylene.

Repair of the blind area is best done in the spring or autumn. Need cool weather. During the summer period - you should choose the morning as the most prosperous time for work. Because due to high temperatures the concrete will expand and the cracks will shrink. In winter, concrete work is not possible.

Do not forget that the brand of concrete also affects the strength level of the blind area. It is easy to find a 500 brand of cement on sale, which we then divide into the desired proportions. With the highest density of 500 marks, the blind area will turn out to be very strong, and it will really last for decades. If only because it is the 500 grade of cement that is used for the construction of large bridges and tall buildings over 30 floors.

Video instruction for the construction of the blind area

The blind area is a strip of some kind of external coating around the entire perimeter of the house, which is adjacent to the foundation or basement and is under a slope that performs the function of water drainage. Any owner of a private house wants his house to stand for as long as possible., did not require repair and, accordingly, additional investments of money. plays a key role here preservation of the foundation from external climatic influences. One of these important elements is to create a foundation around the house to protect the foundation from the penetration of surface water, the so-called .

In addition to its main function, it simultaneously serves as an element of the external improvement of the house, and also serves as a decorative path. The blind area must be approached with all responsibility, and in no case should you neglect such an important step in creating reliable protection for your home.

the main task

It performs several functions but the main one is still - protective. She creates the so-called hydro-barrier. With the help of it, melt and rain water are diverted away from the foundation of the house. This, in turn, excludes damage to the foundation due to frost. The fact is that water, freezing in the winter season, increases in volume.

This creates a large lateral load on the foundation and, as a result, a skew is obtained, which ultimately can lead to significant damage to the house. So, making a blind area around the house is an elementary necessity in order to avoid many problems as a result. Of course, it is done around the entire perimeter of the house, otherwise it makes no sense to do it at all.

Its main purpose is to drain water from the foundation.

The next and most important factor is warming function. If you put a heater under it, it, in turn, will prevent the foundation from freezing, which will ultimately affect the reduction in the cost of heating the house. Again, if it is insulated, it creates a layer of unfrozen soil next to the foundation, which provides uniform lateral pressure.

Further, one can say that it also performs a protective function. It prevents the growth of grass and plants close to the foundation, thereby preventing excessive moisture in the foundation. And finally she is purely practical, since it performs the role of the footpath and at the same time gives the house finished aesthetic look.

Device principle

No matter what it will be general device blind areas around the house, it consists of a protective coating and an underlying layer. Her device is not complicated. A trench breaks out close to the foundation around the entire perimeter of the house. Next, an expansion joint is made between the foundation and the future blind area. The next step is laying a waterproofing coating in the trench, followed by backfilling and compacting layers of sand and gravel. The final step is the device of the outer coating.

At its core, the blind area is divided into 3 types. The first type includes tough, consisting either of either asphalt, or cement - bulk with subsequent ironing of the surface. The next type are semi-rigid: they are a multilayer pillow with subsequent flooring paving slabs, cobblestone, porcelain stoneware, etc. And the last to go soft: they are poured from crushed stone on a multilayer pillow.

Based on these considerations, it may contain a different structure of layers of sand or gravel, as well as different kinds coatings. But regardless, there are some elements that should always be present.

The blind area should have a slope from the house.
An expansion joint must be present between the foundation and the protective coating, it is also called a deformation joint.

Underlayment

The blind area device technology implies the creation of an underlying layer.

Its main task is to create a compacted and even base for further laying the top coat.

The underlying layer is layered cake. Crushed stone, sand and clay can be used as it, gravel or native soil can also be used. Ultimately, the choice also depends on the applied topcoat.

Crushed stone and sand lay down as a rule on normally draining soils. To do this, sand is first poured, followed by pouring with water and tamping. Next comes a layer of rubble, which is also compacted.

If, on your site, prevail loam or clay, then in this case you can go in two ways. First is to use native soil. In the second variant if you still lay gravel and sand, then there will always be water near the house.

The fact is that the density of clay is higher than the density of the underlying layer of gravel and sand and, accordingly, water will accumulate under the blind area. Exists the only and effective way How to solve this problem. Around the perimeter of the bedding fit The disadvantage of such a device will be an increase in the number of works and material costs. But still, it must be admitted that, compared with repairing or replacing the foundation, these are not the costs to save on them.

Width, thickness and slope

The width of the blind area is determined based on the type of soil on the site and the removal of roof overhangs. There is such a thing as subsidence. So, on subsiding soils, the width is usually greater than on normal soil. According to the rules, normal ground the optimal width is at least 80 cm. But in any case, it should be 20 cm more. roofing material towards bearing walls. If subsiding soil is present, then it should be at least 60 cm. from roof overhang. The main point here is to protect the foundation of the house as reliably as possible from destructive impact moisture.

It should also be noted that in the end choice width depends and from the purely practical side of things. For example, you will only walk along it, or you plan to drive a car to the porch of the house. Or maybe you want to arrange a gazebo or terrace. The thickness or height must be at least 7 cm., the optimal is 10–15 cm. Here you need to take into account that it should rise above the ground by at least 5 cm. By the way, for the car zone you need to choose the most durable outer coating, in other respects this also applies to the pedestrian zone too.

In order not to delve into percentages and degrees, tilt angle is usually 1.5 - 2 s m. per linear meter. This is enough to fulfill its main function of diverting water from the house. Of course, you can make the slope of the blind area even more, but this is fraught with the fact that the water, picking up speed, will destroy the outer edge. In addition, it becomes uncomfortable to walk on it, especially in winter, when there is ice.

And yet, in order to guarantee complete drainage of water and ensure a completely “dry mode”, it will be necessary to make a blind area about 3 meters wide, which is not always possible. In this case, the so-called "stormwater" or drainage will help.

Expansion seam

It is also called deformation. This is a gap between the wall and the blind area, as well as transverse seams from the wall of the house with a step width of 2 - 3 meters, depending on its width.

His direct appointment is to compensate for shifts from the effects of frost, thereby preventing the destruction of the wall and cladding.

Based on practical experience, it has been proven that if we neglect this element, then all the previous work on the blind area will go to the "smart" since it will begin to collapse after the first winter season.

It is made thick 1 - 2 cm. and filled with sand, or a heat-resistant sealant that can withstand temperature fluctuations - 100 + 100 degrees or polystyrene foam. At the same time, a warm seam is formed, by laying roofing material to vertical surface walls (there may be several layers), or a sheet of insulation.

First of all, it must meet the following necessary requirements:

wear resistance.
Frost resistance.
Resistant to leakage and destruction from water.

There are several types of external coatings:

Concrete coating: is rightfully considered one of the most reliable and durable.
Asphalt concrete: also very reliable, the only negative is that it will require special equipment to lay it.
Paving stones, paving slabs: Today, in order to make a blind area at home, there is a huge selection of paving stones and paving slabs on the market. These types of blind areas have a wide variety of shapes and colors, so you can safely choose to your taste and style. Only an indispensable condition is also the thickness of the material, it must be at least 6 cm in order to withstand the harsh operating conditions. There are also other types of coatings. We already briefly mentioned them, or rather types, at the beginning of the article.

Conclusion

To make a blind area around the house, even, in principle, is not difficult. The technology is extremely simple and unpretentious. The main thing here is to comply with the necessary rules and regulations. The point here is also in a slightly different aspect.

If you still have a question whether to do in principle or not to do a much-needed procedure, then the answer here should be unambiguous and positive. Otherwise, later, very unpleasant “surprises” associated with the foundation, and the house too, may await you. As the saying goes, "Forewarned is forearmed."

In contact with

A blind area is a single continuous covering encircling a house or other building around the perimeter. The arrangement of the blind area is one of the final stages of construction, i.e. it is done after the construction of the building. If the developer has planned to finish the basement with plaster, tile, brick or other material, the blind area is built after the completion of the said event.

Helpful advice! With the implementation of all tasks related to the arrangement of the blind area, it is necessary to cope before the arrival of cold weather.

For the manufacture of the structure in question, a variety of materials can be used: paving stones, asphalt, tiles, etc. The most widespread among private developers was the blind area made of concrete. This material is characterized by a long service life, high performance and relatively affordable cost.

Blind area around the house
The blind area is concrete

Stone pavement
Brick pavement

Many owners are not fully aware of the importance of the blind area, considering it exclusively decorative element landscape. Along with this, such a coating performs a number of significant practical functions. After reviewing the information below, you will find out why a blind area is needed, what materials can be used to equip it, and how to make such a coating on your own.

As noted, the decorative function of the blind area is one of the main, but far from the only one. You can find information about the purpose of the design in question in the following table.

Table. blind area functions

Functions	Explanations
decorative	The blind area makes the general view of the building more attractive, solid, thoughtful and complete.
Protective	A properly equipped blind area is a reliable barrier to melt water. This structural element does not allow moisture to contact the supporting structure of the house, due to which the risk of destruction of the foundation will be significantly reduced. The design is arranged so that sewage and other waters are immediately discharged into the sewer system or other suitable place, for which the required surface slope is set.
Thermal insulation	At this point, few people pay attention, and in vain. The presence of a properly equipped blind area contributes to a significant decrease in the degree of freezing of the soil and, as a result, the foundation, and with it the entire structure.
Soil heaving prevention	As noted, the presence of a blind area can reduce the degree of soil freezing. Along with this, swelling of the soil will also be significantly reduced. Thanks to this, good protection of the foundation of the building from shifts in the ground will be provided, which will eliminate the risk of violating the integrity of the supporting structure and deteriorating its characteristics as a whole.

Design features and requirements for the blind area

The design of the blind area includes 2 main layers. The first one is underlayment. His main function comes down to creating a dense reliable foundation for the overlying layer. The underlying layer can be made with or without a slope. For the manufacture of this ball of construction, it is allowed to use crushed stone, gravel, sand. The recommended thickness of the underlying layer is about 2 cm.

Sometimes the soil around the building is additionally treated with special chemicals- herbicides. The use of such eliminates the growth of plant roots and grass in the future, thereby minimizing the risk of violating the integrity of the supporting structure of the house.

The top layer is a coating that provides a decorative function and protection of the foundation from water. Thickness - up to 100 mm. For the manufacture of the upper ball, asphalt, paving stones, concrete and other materials are used.

In addition to the above, the blind area includes other important layers. The structural features of the structure can be found in the following image.

In order for the blind area to fully cope with the tasks mentioned earlier, in the process of its arrangement it is necessary to ensure compliance with a number of important requirements.

Firstly, the width of the blind area should exceed that of the roof overhang. When arranging a site on sandy soil, it is recommended to make its width 25-30 cm larger than the cornice (the total width, in this case, should be more than 60 cm). In most cases, the total width of the blind area does not exceed 80 cm, but when working on heaving type soils, the mentioned indicator increases to an average of 100 cm.
Blind areas: a - clay gravel; b - concrete; c - asphalt; g - cobblestone; 1 - compacted crushed stone 20 mm; 2 - clay; 3 - cement screed 15 mm; 5 - concrete preparation 100 mm; 5 - asphalt 15-20 mm; 6 - crushed stone 10 mm; 7 - cobblestone; 8 - sand preparation 50 mm
Secondly, the blind area must be done with a slope in the direction of the site. specific meaning the slope is selected taking into account the characteristics of the finish coating. For example, in the case of a concrete blind area, a 3-10 degree slope from the walls is made. The minimum allowable slope value, regardless of the material used, should be 1.5 degrees.
Thirdly, the blind area should be continuous, encircling the structure around the entire perimeter. It is strongly not recommended to make gaps - the overall quality of the structure will decrease significantly.
Fourthly, the blind area cannot be associated with the foundation - these systems are characterized by varying degrees of settlement. In view of this, a minimum expansion joint of 1-1.2 cm must be maintained between the supporting structure and the surrounding surface. It can be filled with bitumen, sealed with sealant, filled with geotextiles and similar materials, or covered with sand.

Varieties of blind areas and their purpose

Depending on the material of manufacture, design features, service life and a number of other indicators, all existing types of blind areas can be classified into 3 main groups. Information about them is presented in the table.

Table. Types of blind area

Group of blind areas	Description
	This group includes monolithic concrete structures, asphalt blind areas, as well as coatings equipped with a bulk method (used cement mortar) on gravel, followed by ironing the fill. A monolithic structure, ceteris paribus, will serve no less than the building encircled by it. A significant disadvantage of such a system is the high cost and complexity of the arrangement. This is also true for asphalt: the use of tar, which is a binding element, is financially expedient only when performing large-scale road asphalting works. Important! If it is planned to insulate the blind area, a rigid system is the only possible option- it is pointless to insulate soft and semi-rigid coatings. Additional disadvantages of hard blind areas include their low decorative performance - a concrete or asphalt site can hardly be called very beautiful.
	The functions of the underlying layer here are performed by a multi-layer pillow, the top - paving slabs or paving stones. In addition to tiles and paving stones (the most popular options) can be used reinforced concrete slabs, cobblestone, stoneware, etc. Self-leveling coatings are relatively easy to install, they require much less labor and financial investment compared to monolithic systems, but are not suitable for use on heaving type soils.
	A multi-layer pillow is set up, a layer of gravel is poured on top. They are the least financially costly and labor intensive. The disadvantage of soft blind area is the low service life, averaging up to 7 years. Along with this, such a design can be used without any fear in any climatic regions, without paying attention to the type of soil. Yes, and it is not difficult to disassemble a failed soft blind area in order to repair or replace it. Practice shows that it is advisable to use a soft blind area only as a temporary solution if there are problems with finances, time or labor resources - it is unlikely that you will like to do the same thing every 5-7 years.

Group of blind areas

Description

This group includes monolithic concrete structures, asphalt blind areas, as well as coatings equipped with a bulk method (used cement mortar) on gravel, followed by ironing the fill.

A monolithic structure, ceteris paribus, will serve no less than the building encircled by it. A significant disadvantage of such a system is the high cost and complexity of the arrangement. This is also true for asphalt: the use of tar, which is a binding element, is financially expedient only when performing large-scale road asphalting works.

Important! If it is planned to insulate the blind area, a rigid system is the only possible option- it is pointless to insulate soft and semi-rigid coatings.

Additional disadvantages of hard blind areas include their low decorative performance - a concrete or asphalt site can hardly be called very beautiful.

The functions of the underlying layer here are performed by a multi-layer pillow, the top - paving slabs or paving stones. In addition to tiles and paving stones (the most popular options) can be used reinforced concrete slabs, cobblestone, stoneware, etc.

Self-leveling coatings are relatively easy to install, they require much less labor and financial investment compared to monolithic systems, but are not suitable for use on heaving type soils.

A multi-layer pillow is set up, a layer of gravel is poured on top.

They are the least financially costly and labor intensive. The disadvantage of soft blind area is the low service life, averaging up to 7 years. Along with this, such a design can be used without any fear in any climatic regions, without paying attention to the type of soil. Yes, and it is not difficult to disassemble a failed soft blind area in order to repair or replace it.

Practice shows that it is advisable to use a soft blind area only as a temporary solution if there are problems with finances, time or labor resources - it is unlikely that you will like to do the same thing every 5-7 years.

The most optimal type of coatings in terms of cost, quality and appearance are semi-rigid blind areas. They serve up to 20-30 years, are suitable for use in almost all climatic zones, with the exception of permafrost, are characterized by high maintainability and require relatively little resources for their arrangement.

An additional advantage of semi-rigid blind area is an attractive appearance. For example, having made a paving slab covering, the owner gets at his disposal a very beautiful platform that is no different from traditional garden paths. At the same time, semi-rigid blind areas are equipped in the same order - only the material of the finishing coating differs (usually it is paving stones or paving slabs).

Prices for paving slabs

paving slabs

The underlying layer (pillow) is made in the same order, regardless of the type of blind area chosen (the only exception is a monolithic concrete system, related issues will be considered separately).

As you can see in the image, the pillow consists of soil, clay and sand. In the case of a soft gravel blind area, a layer of crushed stone is poured on top. If a semi-rigid blind area is being built, a layer of gravel and an additional layer of sand are poured over the pillow shown in the image, after which tiles / paving stones are laid. In the case of pouring a hard site, a sand and gravel pad is equipped, sand and gravel are poured, insulation is laid, reinforcement is performed and a number of other activities are carried out prior to pouring the concrete mix, which will be discussed separately in the corresponding section of the manual.

Sand cushion under the blind area
Rubble pillow

The arrangement of the pillow is described in the table.

Table. Do-it-yourself blind area pillow

Stage of work	Description
	A trench is dug along the perimeter of the future blind area. Depth is determined by the type of soil. The minimum recommended indicator is 15-20 cm. When working on heaving soils, the depth should be increased to at least 30 cm. For greater convenience, you can pre-make the markup, based on the recommendations from the article on arranging the foundation, or go the simplest way: Drive metal rods or wooden pegs into the ground in the corners of the future blind area; Drive in intermediate pegs; Pull a mooring cord (or other similar rope) between the landmarks and dig in accordance with the prepared markings. At the same stage, you can set the previously mentioned gap between the foundation and the blind area, using any of the listed materials for this, for example, it is very convenient to work with damper tape and polyurethane sealant. Depending on the chosen type of blind area, at the same stage, you can set the required slope of the structure. To do this, it is enough to simply dig a trench to different depths at the points of inclination. The bottom of the trench is carefully compacted. To do this, you can use an ordinary log: take it in vertical position, lift up, lower with effort down, and continue until all the earth is rammed.
	Vertically evenly drive intermediate pegs into the ground, if this was not done at the marking stage. At the same time, they will act as formwork supports. Bars with a cross section of 2-3 (up to 5) cm will do - it no longer makes sense. Install supports in half-meter increments. The principle is shown in the image. Armed with a level, mark the height of the formwork on the pegs. You will nail the boards according to the marks.
	Boards with a thickness of 3-4 cm are suitable for the construction of formwork. Select the height of the elements in accordance with the parameters of the blind area. For greater convenience, you can pre-mark the boards with the height of the future layers that make up the pillow. You can tighten the corners of the structure along the outside with corners. To fasten the elements, it is preferable to use bolts - such fasteners are easier to dismantle. Bolts with a diameter of up to 1 cm will be enough. Important! If you do not plan to dismantle the formwork in the future, pre-treat its wooden components with an antiseptic and wrap it with roofing material or other insulating material- unprotected wood will soon begin to rot, which is not in the best way will affect the quality of the blind area. Note one. The image shows reinforcement. We are not paying attention to it yet. Note two. The image shows a variant with inclined supports. If you wish, you can give preference to this method - this moment does not matter in principle. In general, you can do without such supports, ensuring the stability of the boards with the help of installed with reverse side bricks/blocks. Important! The temperature seam is made not only at the junction of the blind area with the walls of the house, but also across the equipped structure. Failure to comply with this recommendation will lead to extremely unfavorable consequences: as a result of heaving of the soil with temperature differences, the blind area will crack over time. Transverse seams are arranged on average with a 2-meter gap. To ensure the required clearances, install boards up to 2 cm thick in the indicated increments, as shown in the image. Important! All wooden structural elements must be impregnated with an antiseptic before use. If a blind area is planned that does not involve pouring concrete, you can easily do without formwork - it's just more convenient with it.
	Pour a 10-15 cm (depending on the initial depth of the pit) layer of sand into the trench. If possible, use fine river sand. This layer of the pillow will take on the functions of waterproofing. The backfill is carefully compacted. You can use the same method as for tamping the soil. Spill the sand with water for better compaction. Important! A thickness of 10-15 cm should be obtained after tamping, and not the initial filling of the material. Crushed stone is covered with a 5-10 cm layer, again, depending on the initial depth of the trench. It is best to use sand of different fractions so that the number of voids in the backfill is minimal. Instead of crushed stone, you can fill in gravel or brick battle. This layer of the cushion will ensure the removal of moisture that has penetrated through the sand from the overlying structures. Important note! If the venue construction works there is a high location of groundwater, be sure to lay geotextiles between the sand and gravel layers for additional waterproofing. Make small (in the conditions under consideration, 5-10 cm is enough) overlaps on the formwork walls. Do not forget to maintain the specified slope of the surface (if provided) when filling sand and gravel.

The pillow is ready. Further order actions is determined by the features of the type of blind area chosen by the developer. We suggest that you familiarize yourself with the instructions for arranging the most common options for the design in question.

Soft crushed stone blind area

In fact, the pillow described above can be considered as a soft blind area made of gravel. To broaden your horizons, we suggest that you familiarize yourself with an alternative arrangement for such a design using additional waterproofing material.

Pre-dig a trench and fill in a layer of sand, leveling it and setting the required slope, as in the above instructions, then follow the steps below.

Table. Soft blind area

Stage of work	Description
	A layer of waterproofing material is laid on top of the sand. Many developers use roofing material, but we recommend giving preference to rubimast - it costs a little more, but it lasts much longer. In this example, a formwork 80 cm wide is set up. The width of the rubimast roll is 100 cm. In order not to cut the material, simply bend its excess and glue it to the wall using molten bitumen or another suitable composition.
	A 10 cm layer of a mixture is poured over the waterproofing material, including an equal amount of sand and gravel / crushed stone. The backfill is carefully compacted and leveled in compliance with the specified slope.
	On top of the sand and gravel backfill, you can pour an additional 3-5 cm (or to the top) layer of gravel and compact it well - so the blind area will definitely not sag while walking on it.

Temporary soft gravel blind area is ready. If desired, you can hide the formwork boards with decorative borders.

Prices for crushed stone

Basic information

As noted, the technology for arranging the blind area with a finish coating in the form of paving stones and tiles remains the same. The choice of a particular material is up to the owner, but there are a few important considerations.

So, the use of paving stones is permissible only if the foundation has previously been waterproofed. Among the shortcomings of paving stones, one can only note a relatively high cost.

Tile is one of the most popular materials widely used in arranging the blind area. This option has a number of significant advantages:

tiles are much cheaper than concrete in the amount necessary to fill the site;
the material is presented in a huge range of size variations, colors and shapes, which allows you to get exactly the finish option that the owner wants to see it;
tiles can be laid on their own, spending relatively little time on this - you definitely won’t have to wait 3-4 weeks until the concrete hardens.

Prices for paving stones

paving stones

What tile to use?

When choosing a tile for the blind area, follow the tips below.

Council the first. To perform the work in question, tiles made using the vibrocompression method are best suited. By purchasing such material, you significantly reduce the risk of acquiring a fake for yourself, because. the manufacture of this finish in artisanal conditions is impossible - for the production of tiles of this group, serious expensive industrial equipment is used.

Vibrocast tiles (the second popular variety) are relatively easy to make in an ordinary garage. It costs less, but the actual quality of such products usually remains a mystery.

Tip two. Pre-prepare a plan for the future arrangement of tiles on paper or in a special computer program - so you can choose the pattern you like best and make it easier for yourself to continue the work. If you wish, you can use one of the ready-made options presented in the images.

Tip three. Choose tiles for paving the blind area that will go well with other paths and other areas with similar finishes located on the site.

Paving technology

You have already made a pillow for the blind area. Further work is performed in the sequence shown in the table.

Table. Do-it-yourself tile blind area

Stage of work	Description
	As you can see on one of the above images, blind area cushion with paving tiles has an additional top layer in the form of sand backfill. Pour 8-10 cm of sand over gravel. Recommendations in leveling and material rammers are similar previously equipped layer.
	Proceed to paving the blind area. Tiles lay from any convenient angle. Move away from you. Place elements according to the principle brickwork, i.e. with offset seams in adjacent rows. You can choose a specific styling option from the previously proposed illustrations or come up with your own.
	A rubber mallet is used to ensure a snug fit of the tile / paving stone to the base. Working with the tool is carried out in the following order: The tile is laid; A wooden plank is placed on top of it; The performer gently taps on the plank, trying hard enough, but gently, to press the tile with a mallet through the mentioned gasket. Each tile is laid in this sequence.
	Using a spirit level, check the evenness of the tiles in relation to each other and the ratio of the rows. Sprinkle sand under the sagging trim elements, precipitate the protruding parts of the tile with a mallet, following the above guide, while maintaining the desired slope of the blind area. Pave the entire site in accordance with the above sequence. If you need to cut tiles, do it with a grinder.

Important note! Many developers insist that a layer of cement screed be poured before laying paving stones / tiles. We advise you to lay the finish directly on the compacted sand - in this case, more efficient water drainage through the gaps between the tiles down will be ensured. In the case of the arrangement of cement pouring, the permeability of the system will decrease, and this threatens the appearance of ice in the cold season and all the attendant troubles.

If, due to any circumstances, a blind area without the use of a cement screed is not possible, after filling the sand layer, do the following:

prepare a mixture of 1 share of cement (from M400), 3 shares of sand (sifted, fine-grained, river) and clean water in an amount sufficient to obtain a homogeneous plastic solution of medium density;
spread the solution over the surface of the site to be equipped using a trowel or any other the right tool, then level it with a mop or a long straight rail (rule). The final thickness of the cement layer should be 30-40 mm.

After waiting for the cement to dry, proceed to laying the tiles. It is most convenient to use glue designed specifically for fixing the considered finishing materials. Check the manufacturer's instructions for the preparation and proper use of the adhesive - for different compositions, these points may differ.

Some developers even accept a cement-filled structure without subsequent finishing as a finished blind area.

This option is possible, but its appearance does not satisfy everyone. If desired, special coloring pigments can be added to the cement composition - the surface will take on a more attractive appearance.

Concrete pavement

An option for owners who are accustomed to doing everything thoroughly and for a long time. Having once spent a relatively significant amount on the arrangement of a concrete blind area, you will have at your disposal a durable, reliable and most durable structure.

We will talk about the procedure for arranging an insulated reinforced concrete blind area. The presence of a heat-insulating layer will have a beneficial effect on a number of key operational and technical characteristics of the foundation, basement and the entire structure as a whole. If you wish, you can exclude the steps that affect the installation of insulation from the manual and use the same instructions, but it is strongly not recommended to refuse thermal insulation.

Insulated blind area made of concrete - photo of layers
Concrete pavement - scheme

Ideally, the width of the insulated blind area should correspond to or exceed the depth of soil freezing. In practice, a device of a similar design, firstly, will require very large financial investments, and secondly, it will take away the usable area of \u200b\u200bthe site. In view of this, developers adhere to the "golden mean", which is 700-900 mm.

Before starting work, you need to choose a suitable thermal insulation material. In order for the choice to be as objective and correct as possible, it is necessary to take into account a number of significant points.

Firstly, this is the ratio of the cost of insulation and its characteristics.
Secondly, the operating conditions (in the ground, outdoors, i.e. the material should not rot).
Thirdly, the climate at the location of the building.

Taking into account the above criteria, the most optimal material for insulating the blind area is foam. Extruded polystyrene foam performs even better, but it costs more. For most regions of the Russian Federation, a 5-centimeter layer of insulation is sufficient. In particularly cold areas, this figure can be increased to 10 cm. In this case, it is better to equip the insulation in 2 layers.

The composition of the pillow for the concrete blind area remains similar to the previous designs, but the sequence of actions undergoes certain changes.

First of all, you need to understand the nuances of lateral insulation of the structure. If the impossibility of subsequent dismantling of the wooden formwork does not bother you (for example, the subsequent decoration of visible structural elements with special borders or other suitable elements is planned), you can simply glue the insulation boards to pre-assembled boards using a binder composition designed specifically for polystyrene foam materials.

Along with this, an alternative option is available: slate sheets are wrapped in plastic wrap and deepened into the ground along the blind area. If such a design remains in sight after the event in question, it will be much easier to disguise it than wooden elements. This system looks like this.

Improvised formwork with heat-insulating material installed along the entire length of the blind area. Bricks can be used as supports or building blocks by placing them on the ground from the back of the formwork. Will be shown in the following photos.

The foam plastic will already stand quite confidently on a pre-compacted base, while it will be supported by the materials that are poured further. For greater confidence, you can bury the plates in the ground for a couple of centimeters or glue the insulation to the slate. It is not worth using mechanical fasteners - each hole in the slate leads to a decrease in its strength, and in the foam - to the formation of cold bridges.

From the insulation, in this case, you can make a damper layer between the basement of the house and the blind area. With the help of a separating layer, you can ensure that the slope of the formwork is maintained: for this, it (the damper) must have a greater height in relation to the opposite wall.

After installing the side heat-insulating plates, make the pillow discussed earlier. Its composition will be the same as when arranging the blind area with subsequent paving with paving slabs.

Table. Do-it-yourself concrete pavement

Stage of work	Description
	In this case, it was decided to use a two-layer thermal insulation of conventional foam and extruded polystyrene foam. First, a layer of foam is equipped. The plates are stacked as tightly as possible to each other. Bricks are used for temporary fixation. Having laid out the entire area with insulation, blow out the existing gaps mounting foam. Let it dry, cut off the excess with a sharp knife and proceed with laying the second insulating layer. Plates of extruded polystyrene foam in most cases are equipped with end grooves, the presence of which eliminates the possibility of gaps between the elements laid next to each other. Important! Heat-insulating layers are laid with bandaging of seams, i.e. the joints of the top row must be offset relative to the joints of the bottom row. If you need to trim the plates, you can use an ordinary sharp knife for this.
	For reinforcement, you can buy a ready-made mesh or make it yourself from reinforcement with a diameter of 8-10 mm. The bars are assembled into a grid with cells of 150x150 mm and fastened at the intersections with a knitting wire (cheaper) or special clamps (faster and easier). The grid must be laid indented from the base. To ensure it, special clamps-props are used. In the absence of a sufficient budget, you can get by with stones, broken bricks, etc. In this case, it will not work to provide a 5-centimeter indent, as when pouring the foundation, because. this will lead to an inappropriate increase in the height of the blind area. Try to maintain at least a 5-10 mm gap.
	Concrete is prepared according to a standard recipe: a share of cement of a grade not lower than M400 is mixed with 3 shares of sifted sand and 4-5 shares of gravel or crushed stone. Water is added in such an amount that a plastic homogeneous mass of normal density is obtained at the output. The pouring of the finished solution is carried out in the same way as the cement-sand mixture, i.e. the composition is laid out on top of the base and leveled with a mop or other suitable device, for example, the rule is a long straight slat. The function of the beacons in this case will be taken over by the side walls of the formwork. After pouring, pierce the concrete with a reinforcing bar in several places to release excess air, seal the resulting depressions with mortar, sprinkle the surface with a thin layer of dry cement and leave the structure to gain strength. According to GOST, this takes 28 days. To protect the structure from precipitation, cover it with plastic wrap. Periodically (every 1-2 days) lift the film, spill the concrete with a little water and cover it back - thanks to this, the maximum amount of cement will react, which will ensure a higher final quality of the concrete structure.

Stage of work

Description

In this case, it was decided to use a two-layer thermal insulation of conventional foam and extruded polystyrene foam. First, a layer of foam is equipped. The plates are stacked as tightly as possible to each other. Bricks are used for temporary fixation. Having laid out the entire area with insulation, blow out the existing gaps mounting foam. Let it dry, cut off the excess with a sharp knife and proceed with laying the second insulating layer.

Plates of extruded polystyrene foam in most cases are equipped with end grooves, the presence of which eliminates the possibility of gaps between the elements laid next to each other.

Important! Heat-insulating layers are laid with bandaging of seams, i.e. the joints of the top row must be offset relative to the joints of the bottom row. If you need to trim the plates, you can use an ordinary sharp knife for this.

For reinforcement, you can buy a ready-made mesh or make it yourself from reinforcement with a diameter of 8-10 mm. The bars are assembled into a grid with cells of 150x150 mm and fastened at the intersections with a knitting wire (cheaper) or special clamps (faster and easier).

The grid must be laid indented from the base. To ensure it, special clamps-props are used. In the absence of a sufficient budget, you can get by with stones, broken bricks, etc. In this case, it will not work to provide a 5-centimeter indent, as when pouring the foundation, because. this will lead to an inappropriate increase in the height of the blind area. Try to maintain at least a 5-10 mm gap.

Concrete is prepared according to a standard recipe: a share of cement of a grade not lower than M400 is mixed with 3 shares of sifted sand and 4-5 shares of gravel or crushed stone. Water is added in such an amount that a plastic homogeneous mass of normal density is obtained at the output.

The pouring of the finished solution is carried out in the same way as the cement-sand mixture, i.e. the composition is laid out on top of the base and leveled with a mop or other suitable device, for example, the rule is a long straight slat. The function of the beacons in this case will be taken over by the side walls of the formwork.

After pouring, pierce the concrete with a reinforcing bar in several places to release excess air, seal the resulting depressions with mortar, sprinkle the surface with a thin layer of dry cement and leave the structure to gain strength. According to GOST, this takes 28 days.

To protect the structure from precipitation, cover it with plastic wrap. Periodically (every 1-2 days) lift the film, spill the concrete with a little water and cover it back - thanks to this, the maximum amount of cement will react, which will ensure a higher final quality of the concrete structure.

Helpful advice! Before pouring the concrete mixture, cover the parts of the insulation protruding above the ground with a fiberglass mesh. To fasten it with foam, ordinary PVA glue is suitable. The presence of a mesh will protect the insulation from possible damage.

In this case, it was decided to abandon the intermediate transverse damper partitions from the boards (described earlier). The structure is insulated in 2 layers and on the sides, which is why the thermal insulation simultaneously takes on the function of dampers, and it is better not to break the reinforcement - the strength will decrease.

concrete mix prices

concrete mix

Drainage Issues

To ensure the effective removal of atmospheric precipitation, the blind area is equipped with a drainage system. The design is elementary in its execution:

an asbestos-cement pipe with a diameter of 10 cm or more is cut lengthwise into 2 parts. A grinder is suitable for cutting;
the resulting halves of the pipe are laid along the perimeter of the blind area close to it;
in the corners of the blind area at the junction of the pipes mentioned above, integral drainage systems are placed. The same asbestos-cement pipes will do. To accommodate them, trenches are dug. Choose the dimensions of the pit so that at least 5 cm of free space remains on the sides and top of the pipe. At the bottom of the trench, first fill in a 5-centimeter layer of sand and tamp. The pipes themselves are wrapped in geotextiles and diverted towards the structure for collection Wastewater. The specific option depends on the individual characteristics of the arrangement of the site.

The described drainage looks like this:

To improve the appearance of the concrete blind area, it can be tiled or decorated with other material of the owner's choice.

Successful work!

Video - Do-it-yourself blind area

The blind area around the house no longer performs a decorative function, it protects the soil near the foundation from getting wet and uneven softening. The blind area device has its own tricks and technical requirements, which we will share with readers in our today's review.

Timing and soil preparation

Work on the construction of a concrete blind area should be carried out as early as possible. From the moment the foundation has assumed more than a third of the design load, it already needs protection from soaking. Therefore, a house with lined walls is not recommended to be left for the winter without a blind area. Heaving forces are able to do their "dirty" work even in one season. You can schedule work for almost any time of the year, but taking into account weather conditions, observing the technology of working with concrete.

The first stage is digging a trench along the outer perimeter. The bottom should be located 30-35 cm below the final level of coverage, and it, in turn, should be 50-80 mm higher than the adjacent fertile soil.

The width of the blind area cannot be less than the cornice and gable overhang above it and cannot be less than 60 cm. In the general case, it is defined as 50% of the depth of the foundation. For basement buildings on soils of the first type of subsidence, the width of the blind area can reach two meters.

The general scheme of the concrete blind area: 1 - parent soil; 2 - formwork; 3 - concrete blind area; 4 - clay castle; 5 - gravel preparation; 6 - sand preparation; 7 - damper tape; 8 - fittings

When the trench is open, an clay castle is formed at the bottom with greasy clay 10-12 cm thick. Above, make two layers of incompressible and non-porous materials: first crushed stone with a layer of 50-60 mm, then up to 100 mm of sand. Along the outer edge of the trench, be sure to dig the so-called "tooth" - a groove of about 20x20 cm.

The level of the finished sub-base layer should be 45-60 mm below the planned level of coverage. It should be borne in mind that the thickness of the layers of sand and gravel must be constant at each point of the trench, so that the recess under the “tooth” after the backfilling device is preserved.

To prevent mixing of the layers of the underlying layer, separate them from each other with a geotextile sheet, and separate the substrate itself from the compacted soil with a drainage geocomposite. On strongly heaving and, sometimes, medium heaving soils, insulation of the blind area may be required. It can be done with slabs of extruded polystyrene foam, which are laid on top of a thin (10-15 mm) backfill with sand over a layer of crushed stone, and then another layer of 50-60 mm of dry sand is poured.

Formwork, reinforcement

The device is considered correct. storm sewer for the purpose of diverting atmospheric precipitation and perched water into the drainage system. Water from the blind area is collected in a tray at the edge, from where it is discharged into a drainage trench. If a system of hidden channels is provided for these purposes, they are arranged at the stage of preparing the underlying layer. During the preparation of the reinforcing layer, all the necessary elements of the drainage system should be prudently laid.

The formwork under the blind area has the simplest device. It is only necessary to knock down a pair of 20x100 mm boards into shields in parallel, connecting them with jumpers after 50-60 cm. The formwork is installed under the side of the trench, the height of the upper edge is adjusted according to the final level of coverage. For ease of alignment, with an interval of 150 cm, wooden stakes are hammered on the outside of the shields, to which the formwork is screwed with self-tapping screws. After that, from the outside, the shields are supported by a dump of soil from the adjacent territory.

The most important point in the device of the blind area is that it should not be monolithically connected with the basement of the building. Best Schema the removal of external water, including those flowing down the wall, is observed when two layers of concrete are separated by a material with sufficiently high ductility, provided that the plinth finish is put on the blind area from above, preventing water from seeping through the separating layer. If the plinth will not be finished with hinged sheathing, its lining should begin with an EPPS damper strip that compensates for the “floating” of the concrete slab.

The easiest way to achieve such a device scheme is to paste over the bottom of the base with a strip of polyurethane foam about 20 mm thick. The separator sits on the adhesive mastic, as it is mounted, the upper edge is aligned with the cord, setting the slope of the coating towards the adjacent soil at least 3:100. However, the separating material can be cut along a common line after the adhesive has dried, but the principle remains the same: the formwork and the separating layer serve as beacons for leveling the concrete mixture.

Reinforcement of the blind area is carried out with a steel mesh with a rod thickness of 8 mm and a cell size of up to 200 mm inclusive. The reinforcement is laid in one row and placed on remote supports that regulate the protective layers of reinforced concrete at least 45 mm above and below and about 60 mm on the sides.

Preparation of concrete mix

The blind area is allowed to be cast with concrete prepared on site, but the requirements for the quality of the mixture are quite high.

The desired concrete strength class is B25 or higher. The feedstock should be measured by volume so as not to take additional corrections for the moisture content of sand or gravel. In total, 20 liters of sand and 35 liters of crushed stone or large granite screenings are added for 10 liters of cement grade 500 for the preparation of concrete.

To ensure the homogeneity of the mixture, cement milk is first prepared in a concrete mixer with the addition of half the calculated amount of water and sand. After 2-3 minutes of kneading, you can add the rest of the filler and sprinkle the mixture with water as needed. The final consistency of the concrete is a loose mix with a low moisture to cement ratio, with all stones being evenly wetted.

The cycle of continuous mixing of one portion should take at least 15 minutes. To entrain air and provide additional plasticity, one tablespoon of liquid is added to the water. detergent on a bucket. As a result, concrete has a frost resistance class of at least F200 and water absorption resistance of at least W6. Reinforce if necessary desired properties modifier additives.

Optimal concrete consistency for pouring formwork

Filling, leveling, ironing

The blind area should be poured from the most remote part, gradually moving closer to the place of concrete preparation. The formwork is filled with the mixture almost to the top, after which the concrete is bayoneted or vibrated.

The need for transverse separation of the blind area with expansion joints is determined by the operating conditions. For the shaded sides of the building, this is not necessary, but under the open sun, the blind area should be poured, dividing the mixture with strips of polystyrene foam every two widths.

When leveling, it is convenient to move straight through the liquid mixture in rubber boots. Armed with a rail-rule, check the degree of filling of the formwork and the depth of immersion of the tray box in concrete. If necessary, upset the formwork with gentle hammer blows, but do not overdo it: it will be much more difficult to raise the edge higher.

When both beacons and the edges of the tray are brought to the same level, add a small amount of the mixture and stretch it with a rail. It is not necessary to smooth the surface, it is enough to ensure its flatness and correct slope, to remove depressions in which water can collect.

After leveling, a board is laid flat on the edge of the formwork and the tray, on which a small oppression is set for 10-12 hours of preliminary setting of the mixture. For the next 7-10 days, the blind area will need to be sprayed once a day with water from a hose and then covered with a film.

Two weeks after pouring, the formwork can be broken up and wet ironed. For him, a mixture of sand and cement is prepared in equal proportions, instead of water, three parts of milk of lime and one part of liquid glass are added to the solution. The finished mixture should have a consistency slightly thicker than cream.

Before ironing, the blind area must be well moistened and wiped with a metal brush, breaking the structure of the crust formed on the surface, then sweep and rinse again. After preliminary drying, the ironing mixture is poured over the surface from the plinth outward, and then leveled with a wide spatula in the longitudinal direction. The iron layer must be at least 1.5-2 mm, the time for the mixture to solidify is at least 3 days with periodic surface moistening.