After completing the construction of any house, it is necessary to make a blind area. Let's look at how to fill a blind area and look at the methods for constructing it. A lot of methodological recommendations are devoted to this topic, which can be read by anyone who decides to start arranging a blind area.
Our conversation today is dedicated to one of the most common types - pouring concrete blind area.
How to fill a blind area with your own hands?
We begin work by preparing a trench that will be located along the perimeter of the entire foundation of the building. Excavation of soil is carried out based on the length of the overhang of the roof eaves with an indentation of 20-30 cm, however, it should be taken into account that the width of the blind area should not be less than 60 cm if it is built on normal soil, at least 100 cm on subsidence soil.
At the next stage of arranging the blind area, you need to start laying the underlying layer. For this, clay is used, the cushion from it should be 10-15 cm. If the ground on the site is heaving, then to absorb heaving forces, it is worth laying another, additional layer of sand 6-8 cm thick on top of the clay. In this case, each of the layers should be compacted .
The last layer is crushed stone or gravel. IN in this case this material will act as drainage in case moisture gets under the blind area if poured incorrectly.
To give greater strength, it is necessary to reinforce our structure. For this, a mesh with a cell of 100x100 mm or 150x150 mm is used.
The final stage of constructing a blind area is pouring concrete in a layer of at least 10 cm. This is the most important and crucial moment; when pouring, you need to remember some nuances.
Rules for pouring a blind area
1. Under no circumstances you should not make a blind area of a monolithic structure. Even if all the work on insulating the blind area is carried out according to all the rules, under the influence of temperature changes, the soil under it may heave. Which sooner or later will lead to cracking of the blind area. In order to avoid this, in the places where it joins the foundation, it is recommended to make a horizontal damper or expansion joint, the width of which will be 1-2 cm. It is made of damper tape or polyurethane sealant. Ordinary 10-20 mm boards are also suitable as a material for transverse seams. They are placed on edge, and before that they are coated with bitumen. The waterproofing layer, if the foundation is waterproofed, is brought out to the outer edge of the blind area.
2. In addition the blind area should be reinforced, this will provide it with a longer service life. Before pouring the blind area, a frame of connected reinforcement rods or metal grid cells measuring 10x10 cm. Metal carcass laid in sections formed after laying transverse seams at an equal distance from the edges of the blind area. In addition, the frame needs to be raised above the pillow, for which fragments of brick and other available material are used.
3. Upon completion of filling, still not dried concrete must be reinforced, that is, sprinkle it with a 3-5 mm layer of dry cement and rub it in with a trowel. This will give the blind area additional strength and moisture resistance.
4. Do not allow the solution to dry out quickly, for this, the blind area is covered with damp burlap or rags, which must be periodically moistened with water. Gradual drying of the cement will give it greater strength.
Concrete blind area- an important element of the house. Often this design seems insignificant, but if you look at the issue, it is very important. It is necessary to follow the technology and choose the right type of design. How to properly fill the blind area around the house yourself is described below.
What is it for?
Concrete blind area is a mandatory event. Its device performs a very important function - protecting the foundation. This element around the house removes rain and melt moisture from the perimeter of the basement walls, thereby reducing the load on the drainage system and vertical waterproofing.
Before making a blind area with your own hands, you should decide on its width. For execution given function its protrusion of the blind area around the house is taken equal to one meter. This value allows you to reliably protect the basement walls. In some cases, it is allowed to reduce the width, but only if absolutely necessary (for example, tight conditions on the site). The minimum value is 80 cm. It is important to take into account the protrusion of the roof eaves. Its projection onto the ground surface should be at least 20 cm less than the protrusion of the concrete protection.
The main role of the blind area is to protect the foundation from water
In addition to waterproofing, the blind area takes on several more functions:
- completion of the architectural appearance of the house;
- arrangement of a pedestrian zone around the building (the blind area plays the role of a pedestrian path).
The blind area can be used as a path only for low-rise individual buildings, subject to timely removal of ice from the eaves and snow from the roof. It is important to remember safety precautions in winter period, since when driving close to the cornice there is a danger of snow and ice falling on a person.
To perform the main function - water drainage, the blind area must be made with a slope. The height decreases away from the walls of the house.
The installation of a blind area around the building requires a slope of at least 0.015.
This value means that for every horizontal meter there is a vertical change of 1.5 cm. Before pouring the blind area, you should calculate its height near the walls of the house.
Blind area design and materials
The concrete blind area is designed quite simply. Even a non-professional can do the pouring of the blind area around an individual house. The device requires the preparation of the following materials:
- The bedding that needs to be done before pouring the solution with your own hands. You can make bedding from various materials. The design allows the use of medium or coarse sand, sand-gravel mixture, crushed stone or gravel of a not very large fraction. Can't fill cement mortar on fine sand. Such a base can shrink, which will lead to the concrete for the blind area cracking. It is best to make a pillow from two types of material. The first layer must be done in order to compact the base soil and level it. For this, gravel or crushed stone is used. The second layer should be made of sand.
- To increase strength, pouring the blind area involves reinforcement. You can reinforce the element around the house with your own hands using reinforcement mesh. It is recommended to make meshes from reinforcement with a diameter of 6-8 mm, depending on the characteristics of the base soil. The design of the blind area assumes mesh cell sizes of 30x30 or 50x50 mm.
- Before pouring, it is necessary to make formwork. Do wooden boards along the perimeter of the blind area it is necessary to ensure that the concrete solution does not spread. To make the formwork you will need wooden boards. The width is selected depending on the thickness of the blind area. To hold the solution, it is enough to purchase material with a thickness of 22-25 mm.
- The main material for production is concrete mortar. The most important thing here is to choose the right brand of mixture. The strength class of concrete should be at least B15 (old marking M200).
You can use a solution of higher grades, but this is not profitable from an economic point of view. To make a durable building element, you also need to think about frost resistance. The frost resistance grade of concrete for the blind area must be at least F50. It is best to choose the F100 brand; such a solution will provide better resistance of the element to temperature changes. When preparing concrete, it is important to maintain the proportions of its components.
Composition of concrete for blind area
To do quality work with your own hands, you will need to choose the right concrete mixture. There are two ways to obtain a filling solution:
- purchase at the factory and transportation by concrete mixer;
- self-cooking.
It is better to opt for the second option. This is due to the following factors:
- buy ready mixture always more expensive than making it yourself;
- required for blind area a small amount of concrete, and factories sell it in fairly large volumes;
- no need for transportation costs.
When making a mixture, a home craftsman must only correctly select its components and maintain the proportions. The composition of concrete for the blind area is as follows:
- cement (it is better to use PC400);
- sand (the best option is medium, fine is allowed);
- coarse aggregate (crushed stone or gravel);
- water.
The proportions of each of these components are set depending on what grade of concrete needs to be obtained. For concrete grade B15 (optimal for blind areas), the proportions should be made as follows:
- cement -1 part;
- sand – 2.8 parts;
- coarse aggregate - 4.8 parts.
These proportions from 10 liters of cement make it possible to obtain 54 liters of concrete mixture. For every 6 parts of water by weight there should be 10 parts of cement.
If you need to create a material of a different brand and there is no opportunity to familiarize yourself with the information more carefully, you should remember that in general the proportions look approximately like this: 1: 3: 4 (cement: sand: crushed stone, respectively).
Work order
The DIY device involves performing actions in the following sequence:
- first you need to mark the blind area on the ground;
- digging a trench around the perimeter of the building to the depth of the blind area (depending on the thickness of the layers of bedding and concrete);
- compacting the base;
- installation of formwork panels and fastening them together;
- styling bulk materials(sand, crushed stone) with compaction;
- laying reinforcing mesh;
- installation of boards that will play a role expansion joints, preventing concrete from cracking in winter) in increments of 2 meters;
- laying concrete and its compaction, leveling;
- ironing of the surface;
- waiting for time to gain strength, caring for concrete.
It is important to ensure a distance between the blind area and the wall of approximately 2 cm. This gap will allow structures with different weights to settle independently of each other and prevent the appearance of cracks.
Concrete gains full strength in 28 days at an average daily temperature of +20 degrees Celsius. If the air temperature is lower, it will take longer. The formwork can be removed after reaching 70% strength.
Caring for concrete involves periodically wetting it. To prevent moisture evaporation, the blind area after pouring is covered with film or burlap. These measures will prevent the appearance of cracks during hardening.
An additional measure could be insulating the element. For this, extruded polystyrene foam is used, which is placed under a layer of concrete on a bedding. Insulation is relevant when the depth of the foundation base is higher than the freezing depth.
The blind area of a house compared to its foundation has an incomparably lower cost. Do good blind area much easier than building a foundation. But all of the above does not mean that attention to this important detail it should also be much less, which, alas, often happens. The blind area may seem like a small cog compared to the entire structure of the house, but the “health” and long life of the entire structure greatly depend on it.
In the article we are going to look in detail at how to make a blind area around the house, and how to do it correctly, and we will also look at different options and indicate in which cases it is advisable to use them. We will consider the recommended building materials that should be used to create a good blind area for the house.
A blind area is usually called a strip of waterproof covering that encircles the entire perimeter of the house. Most often, we are accustomed to seeing blind areas made of concrete or asphalt, however, everything is not limited to these two materials. The main task of the classic blind area is to prevent atmospheric water from entering the foundation structure and the soils located near it. Why is this being done?
- Firstly, water that gets to the structure of the foundation base can saturate the soil near it and, if it is shallow, this can lead to freezing and the appearance of heaving forces. The so-called heaving soils, which include clayey and loamy soils, are especially dangerous. The forces of frost heaving are simply enormous, they are trying to squeeze the house out of the ground. If they are distributed unevenly across the foundation, this can lead to cracks and even destruction of the house.
- Secondly, the forces of frost heaving act not only on the sole, but also on the side structures of the foundation. In construction science, such forces are called tangential heaving. According to experts, 1 m² of wall can carry a load of 5-7 tons. Not every structure can withstand this. The blind area is designed to minimize the ingress of water from above.
- Thirdly, waterlogged soil with poor waterproofing of the foundation can cause water to enter the basement premises. Even good waterproofing does not always save you from leaks or high humidity. Everyone knows the proverb: “Water will always find a hole.” And here the blind area also plays its role, reducing the moisture content of the soil adjacent to the foundation.
- And finally, a poorly made blind area will provoke its own destruction, which will have a bad effect on its protective and decorative qualities.
Creating a high-quality blind area for a house is part of a set of measures for waterproofing the foundation and its drainage - wall or ring. By itself, it is “not a warrior in the field” and will be able to fulfill its main protective purpose only together with other elements. Why do you need a blind area at home?
- As noted earlier, the blind area prevents the penetration of atmospheric water to the foundation of the building. Water that gets onto the blind area must drain from it and enter the surface drainage system.
- The blind area, provided it is insulated, prevents the freezing of the soil underneath it and therefore reduces or eliminates the occurrence of frost heaving forces. This function works best in conjunction with foundation insulation. In northern European countries, insulation of foundations and blind areas has long been mandatory measures in the construction of houses.
- The blind area can serve as a sidewalk along which people move.
- The blind area performs a decorative function. thanks to it, any house in combination with the decoration of the walls and basement has a harmonious and complete look. We can say that the blind area is one of important elements landscape design.
Almost all houses and buildings require a blind area. For strip, slab, monolithic strip foundations, it is simply necessary. If the house is built on a pile or, then the blind area will serve only a decorative function.
What types of blind areas are there?
Let's consider what types of blind areas exist so that there is an “opportunity” to try one or another option to suit your conditions and choose the most suitable one.
Clay blind areas
This type of blind area has roots in the distant past. It was this material that our distant ancestors used to protect the foundation of their house from moisture. And, despite the fact that this method of creating a blind area may seem archaic, which is high time to be sent “to the dustbin of history,” it may well be used on modern buildings. Everyone knows the properties of clay - its plasticity, fire resistance and most importantly - water resistance. This material is the best natural waterproofing material. Almost all underground sources of artesian water are located between clay layers. Another useful property clay – it is impossible for any plants to grow on it. Of course, if the clay has a certain degree of purity.
This blind area is very easy to make. The fertile layer of soil is removed to a given width and depth, and then clay is poured and compacted. It is better to use clean quarry clay. The profile of the blind area is given a slope in the direction from the wall to its edge, and then the clay is reinforced with gravel or crushed stone, which must be pressed into its layer. An interesting composite coating is formed. Clay provides reliable waterproofing and plasticity, and crushed stone or gravel provides the necessary rigidity of the blind area and prevents erosion by water. A clay blind area together with crushed stone or gravel looks good and can even become an element of home decor, especially a wooden one. The clay blind area will never crack and can be easily repaired. It can serve for decades. Surely many have come across unpaved roads in clay soils ah, which are fortified with stones. They have served for a long time and will continue to serve for a long time. Even trucks in rainy weather do not trample the ruts on such roads.
A significant limitation to the widespread use of clay blind areas is their main drawback - with direct, prolonged and strong exposure to water, the clay will still be gradually washed out. Therefore, in most cases, more modern materials are used.
Concrete blind areas
This type of blind area is the most common. And this is absolutely not in vain. one of the most common materials and blind areas made from it have a number of advantages:
- Properly prepared and laid concrete has high mechanical strength
- Concrete is not afraid of exposure to water and practically does not allow it to pass through, and treated with various hydrophobic coatings becomes an ideal waterproofing barrier.
- Concrete blind areas have a long service life - at least 25 years, provided that technology is followed.
- Concrete blind areas can be made independently; this does not require the services of special construction equipment.
- Concrete blind areas can be decorated with pebbles, gravel, and various natural stones.
Concrete blind areas, however, are not without drawbacks:
- Along with high mechanical strength, concrete blind areas are fragile. When heaving forces of different magnitudes occur in different areas of the blind area, cracks may appear. This problem is solved by reinforcement, which makes the blind area significantly more expensive.
- Bare concrete has an unpresentable appearance, beautiful house In a harmonious natural landscape, a concrete blind area will only spoil it.
- The concrete blind area is very difficult to dismantle; it is difficult to local repairs, the need for which sooner or later arises.
The thickness of the concrete blind area in its thinnest part should be at least 5 cm, but given that it is constantly under the influence of natural forces, it is better to make it at least 7 cm. Naturally, the concrete blind area is given a slope of 3-10° in the direction from walls to its edge. The width should be at least 20-30 cm greater than the overhang of the roof eaves, but in no case less than 60 cm.
The blind area should encircle the entire perimeter of the house and not have a rigid connection with the walls. The fact is that during seasonal soil movements, the structure of the house and the blind area will behave differently and the presence of a rigid connection will lead to the appearance of cracks. Besides, different materials have different coefficients of thermal expansion. That's why they do the so-called expansion or expansion joint , which, on the one hand, provides the necessary seal to prevent water penetration, and on the other hand, allows mutual movements of the house and the blind area. Expansion joints have been made from tarred boards since ancient times, but now various types can be used synthetic materials. Very often, expansion joints are made from roofing felt or polyethylene foam folded in half. There are also special damper tapes for screeds or heated floors, which can also be used for an expansion joint between the blind area and the base of the house.
Expansion joints must also be installed in the concrete blind area. They are made in the corners, and then every 1.5-2.5 meters. Oiled or tarred edged boards 20 mm thick, strips of laminated plywood or OSB are used as seams. When pouring a blind area, they serve as beacons for leveling it and later, after setting, they can be removed and filled with polyurethane-based sealants or left in place.
Blind areas made of asphalt and asphalt concrete
Such blind areas are also quite widespread, but mostly not in housing construction, and in industrial or commercial facilities. Asphalt is more plastic than concrete, and the likelihood of cracks appearing on it is negligible. Asphalt blind areas are less material-intensive, since 3-4 cm is enough to create a durable and water-resistant coating. They are quite durable and can last for decades.
However, asphalt blind areas have been widely used only in the construction of non-residential buildings. When heated sun rays asphalt can soften and the hydrocarbons that make up the bitumen, which is the binder for this type of coating, begin to evaporate from it. In addition, laying asphalt requires the use of special road equipment.
Blind areas made of paving stones or paving slabs
This type of blind area will be most preferable if the house is planned to fit harmoniously into the surrounding landscape. Cozy and beautiful garden with paths made of paving stones, a plinth finished with natural stone or its imitation will be in perfect harmony with blind areas made of paving stones or paving slabs. Natural stone can also be included in the same category, since from the point of view of technology for preparing the base and laying it there are no big differences. Natural stone, however, requires a highly qualified craftsman.
What are the advantages of blind areas made of paving stones or paving slabs?
- As noted earlier, this is an attractive appearance.
- Properly laid high-quality paving stones or paving slabs have a long service life. According to the manufacturers, at least 20 years.
- High-quality paving stones have good frost resistance.
- Coatings made of paving stones or paving slabs made by vibropressing (namely, these are recommended for blind areas or paths) are not as slippery in wet weather or in the cold season as concrete, asphalt or made from vibrating tiles.
Vibropressed paving stones are an excellent material for blind areas
- Each paving stone is laid separately on the base, so this type of coating is not prone to cracking.
- Coatings made from paving stones or paving slabs are distinguished by their environmental friendliness.
- A blind area made of paving stones can also serve as a path along which people can walk.
- High strength and wear resistance.
- Blind areas made of paving stones can be repaired locally; complete dismantling is not required.
- or you can lay paving slabs yourself. This does not require the use of special construction equipment.
The main disadvantage of blind areas made of paving stones is its relatively high cost compared to “classic” concrete ones. There is a good way out of this situation - if the blind area will only be walked on, then it can be paved with paving slabs, which are both thinner and cheaper than paving stones. Areas and paths that will be subject to increased loads can already be paved with paving stones that harmonize with the blind area. Most manufacturers of vibropressed paving slabs or paving stones offer products of different thicknesses. Once laid, it is no longer possible to distinguish where the stones are thicker and where they are thinner. The construction of a blind area made of paving stones or paving slabs is shown in the figure.
Paving stones or paving slabs also have one important feature, which can appear as in in good shape, and vice versa. Such coatings are laid on a sandy base and have gaps between adjacent elements. When water gets onto the paving area, most of it will be received by storm water inlets, taking into account the required slope, and flow down the gutters and surface into the water intake trays of the surface drainage system. But some part will still be able to seep between the paving stone elements into the underlying layers. Now let's look at how this feature can manifest itself in good and bad ways.
- Let's talk about the good stuff first. If water seeps through the seams, then such a coating will be dry and puddles will not stagnate on it. Of course, this is very useful for paths where the surface is horizontal, but the blind area has a slope and most of it will still flow into the water intake trays. But some of it will still end up in the underlying preparation.
- Now about the not very good possible manifestations. Let's say the house is built on heavy clay soils and the blind area of paving stones or paving slabs is made correctly. Underneath it there are both crushed stone and sand layers that can accept a certain amount of water. When the snow melts, a situation may arise when the water completely saturates both sand and crushed stone and there is simply nowhere for it to go, since on one side there is a foundation wall with good waterproofing, and on the bottom and sides there are heavy clay soils. If a thaw is replaced by severe frosts, which often happens in the climatic zones of Russia, then the water in the crushed stone and sand layer will freeze and accordingly expand in volume. The blind area can collapse in such conditions very quickly. Even after one season of use.
On thematic forums dedicated to construction, a lot of questions are raised about paving stones and paving slabs in general and blind areas made from them in particular. Developers are sometimes simply perplexed because a good and impeccably laid paving area begins to swell after the first winter. And this most often happens due to the fact that when the snow melts, crushed stone and sand become saturated with water, which simply has nowhere to go due to the clay soils around. This problem can be solved very simply, but not free:
- The first solution to the problem is drainage. In the case of blind areas, this is high-quality wall-mounted deep drainage, as well as surface point and linear drainage. You can read more about drainage on our portal. Preference should be given to drainage with a wall-mounted relief geomembrane. Then water, having got into the gravel and sand, will not linger in them, but will flow down, where it will be “picked up” and removed by the drainage system.
- The second solution to the problem is insulating the foundation. This measure will avoid freezing of the soil in the area of the foundation and blind area. Materials and technology are described in our portal.
The blind area around the house, in addition to vibro-pressed concrete paving stones, can also be made from more expensive natural materials.
- It may be a natural “wild” stone, which owes its name to its irregular shape.
- Natural chipped, split-sawn or full-sawn granite paving stones are also used as the top layer of the blind area. This is a very worthy option, but the cost is very immodest.
- A blind area made of clinker paving stones in combination with finishing the base with clinker tiles not only looks rich, but also has a very long service life. This option is no less modest than a blind area made of granite paving stones.
We will look in detail at how to make a blind area from paving stones or paving slabs in one of the following sections of our article.
Soft blind areas
It may seem that there is some kind of catch hidden in the name itself. We are subconsciously accustomed to perceiving the blind area as tough and reliable design, and the word “soft” seems inappropriate. However, this is far from the case. Such blind areas have been used for a very long time and successfully. For many decades, soft blind areas have served without repair, and in climate zones where they are exposed to water, snow, severe frosts and heat in different seasons.
Some types of soft blind areas are also called Finnish, thanks to the country where they are widespread. It is difficult to convict the inhabitants of Finland of stupidity and impracticality; they live in harsher climatic conditions than most regions of Russia, and build a lot of good and comfortable houses for living. It is not for nothing that Finnish builders are considered one of the best in the world. It is possible that it makes sense for us to learn some experience from the Finns.
As noted earlier, the blind area must solve two main problems. The first is to prevent water from entering the foundation structure and the soil near it, and the second is to preserve the integrity of the blind area itself in order to maintain its presentable appearance and solve the first problem. That is, the integrity of the blind area is one of the main tasks and a person is forced to constantly fight for this through reinforcement, creation of expansion joints, drainage and other measures. The wise Finns decided to stop fighting and make the area soft. One of the options for implementing this approach is shown in the figure.
The main thing in the construction of soft blind areas is a very interesting approach - you don’t need to worry too much about the integrity, solidity and waterproofness of the structure of the top decorative layer, but it is better to focus on how to remove water that has already penetrated through it. That is, the “most interesting”, those elements that have a protective function, in these types of blind areas are out of sight. If water penetrates through upper layer, then it’s better not to interfere with it - let it seep into your health and the sooner the better. But then the water is already “waiting” for the drainage pipe, which also “gladly” accepts it and carries it away from the foundation into the wells.
The permeable layer on which the blind area and the drainage pipe are located are securely cut off from other soils by some means waterproofing material. It can be roofing felt or other materials, for example, PVC films for swimming pools.
The best results for waterproofing are provided by so-called PVP membranes (profiled waterproof polyethylene). They are made of high-density polyethylene (HPDE), which is completely inert to all substances that may be found in the soil. According to official documents - test reports, the service life of the PVP membrane declared by the manufacturers is at least 60 years, but in reality it will be longer if installed correctly. This means that you won’t have to do waterproofing again during your entire long and happy life. In principle, the durability of the membrane is approximately equal to the average lifespan of a house.
PVP membranes have irregularities on their surface in the form of truncated cones, 8 mm high. Thanks to these protrusions, water easily collects on the surface and flows off under the influence of gravity. Therefore, the membrane in a soft blind area is always laid at a slope in the direction drainage pipe. For laying in the ground, it is better to use a composite geomembrane consisting of two bonded layers. The first layer is the PVP membrane itself, and the second is a geotextile fabric that freely allows water to pass through and does not allow the surrounding soil to fill the entire space between the relief protrusions.
For waterproofing a blind area, a profiled geomembrane bonded with geotextile is best suited
Soft blind areas may have different finishing layers, that is, those that are visible from the outside.
- The blind area can be filled with crushed stone or gravel, which will give it a natural natural look. Such blind areas will always be in harmony with the surrounding landscape.
- Colored decorative or gravel is currently widely used. With their help, you can realize the most daring design ideas. These blind areas, and other landscape elements, look very good.
- Outer layer soft blind area can generally be made from fertile soil on which to plant a lawn. It will seem that there is no blind area, although we already know that the main thing is underground. Houses made of logs or standing in the middle of emerald green lawns look simply amazing.
Soft blind areas are increasingly used in individual housing construction in Russia. And this is quite justified, because their advantages are obvious:
- The soft blind area is not afraid of seasonal soil movements, which have always been, are and will be in any, even impeccable structure. After freezing and thawing, and, accordingly, movement, the blind area returns to its place. Accordingly, there is no need to equip expansion joints.
- The soft blind area does not have to be made on a slope, since water drainage occurs under it. This allows them to be used as a pedestrian area. Even a blind area with a top layer of lawn can be a pedestrian zone if it is well drained and reinforced, for example, with geogrids.
Lawn reinforced with geogrid
- The soft blind area is easy to repair in case of local damage, and also easy to completely dismantle.
- The soft blind area has an attractive appearance that is in harmony with nature. The use of colored decorative crushed stone or gravel allows you to create unique compositions. And also on such a blind area you can plant various plants: lawn grass or various flowers and small shrubs. For this, however, special measures will have to be taken.
- A soft blind area is cheaper than concrete or paving stones, and the process of creating it is less labor-intensive.
The disadvantages of soft blind areas include:
- When constructing a soft blind area Special attention should be paid to the preparation of the base, waterproofing the foundation and the drainage system. If a concrete blind area is guaranteed to “throw” water away from the foundation across its width even with a poor drainage system, then a soft one under the same conditions may not be able to cope with the incoming water.
- Crushed stone or gravel covering of a soft blind area is more difficult to clean from dust and debris than concrete or paving stones.
- Various weeds can grow through the gravel and will require periodic removal.
- Lawn blind areas also require constant maintenance.
In some sources, blind areas made of paving stones or paving slabs are classified as soft, arguing for this choice by the fact that such structures do not have a rigid base. We deliberately do not do this for two reasons:
- A blind area made of or paving slabs can hardly be called soft even by tactile sensations.
- Very often, to increase the reliability of a blind area made of paving stones or paving slabs, it is made on a concrete base, on which a thin (5-7 cm) layer of cement-sand mixture is poured. Clinker tiles or paving stones are laid only on a concrete base using special adhesive mixtures. Such blind areas simply cannot be called soft anymore.
In order to avoid unnecessary disputes about whether a particular type of structure belongs to soft or hard, in this article we consider blind areas made of paving stones or paving slabs in a separate category. It will be much easier this way.
Is it necessary to insulate the blind area?
In the recent past, some 20-30 years ago, such issues did not arise at all during the construction of houses in our country. The foundation could be insulated with expanded clay poured into the sinuses, but the blind area was not separately insulated at all. The foundation was always laid below the soil freezing level. And this was one of the few measures to protect the foundation from seasonal ground movements on heaving soils. However, construction science and technology did not stand still; new materials appeared along with them. As a result, in global construction practice they came to one conclusion in order to reduce Negative influence forces of frost heaving on the foundation, especially on heaving soils - it must be insulated. In addition, this makes it possible to reduce the depth of the foundation base in the ground, which significantly reduces its costs. And if the foundation itself is insulated, then the blind area must also be insulated. Only this way and no other way! Here are the main reasons why it is necessary to insulate the foundation and blind areas.
- If the house has a heated basement, then insulation of the foundation and blind area is mandatory. This, firstly, will reduce heat loss, and secondly, it will prevent soil freezing, which will reduce heaving forces. With a properly calculated foundation and its insulation, soil freezing can be avoided.
- If the house has a shallow foundation, then insulation of both the foundation and the blind area is mandatory. Shallow-depth systems, which are now gaining popularity slab foundations type USHP (insulated Swedish plate) must be insulated on all sides, including from below.
- Insulating the blind area still makes sense so that melt water that gets into the crushed stone and sand layers of the substrate does not freeze when the temperature drops, but calmly goes into the drainage pipes.
Insulation of the blind area does not need to be done only in two cases:
- When a house is built on pile foundation. But then, in principle, no blind area is needed.
- When the house has a submerged uninsulated foundation and does not have a basement floor. In this case, insulating the blind area is simply a pointless burying of insulation in the ground.
Completely different materials are offered as insulation, but in order to save readers from the agony of choice, we offer only the best in terms of price and quality ratio. This is extruded (extruded) polystyrene foam - EPS. Why is it recommended to use this particular material?
- Firstly, EPS has low thermal conductivity (0.029-0.032 W/(m*K°), which in principle explains its use as insulation.
- Secondly, XPS has a high mechanical strength. Compressive strength with deformation of no more than 10% is no less than 0.25-0.5 N/mm². That's quite a lot. The foundations of houses are built on this insulation.
- Thirdly, EPS has low density. One cubic meter of this material has a mass of 38 to 45 kg.
- Fourthly, EPPS has extremely low water absorption (no more than 0.2-0.4%) and vapor permeability (0.013 Mg/(m*h*Pa)), which is very useful when located in the ground.
- Fifthly, EPS is very easy to process and install. A minimum set of tools is required.
- Sixth, EPS is durable. Its service life in the ground is at least 30-50 years.
- Seventh, EPS in normal conditions operation does not emit any harmful substances, does not harm either living beings or nature.
- And finally, XPS has a reasonable cost. The presence on the market of a large number of this insulation from different manufacturers plays into the hands of us, the consumers.
The world's most popular insulation material is extruded polystyrene foam.
The thickness of the insulation of the blind area is calculated, but in no case should it be less than 5 cm.
As an example, we will consider in detail the processes of creating three types of blind areas: reinforced concrete, paving stones and soft ones.
DIY concrete blind area
Let's consider the process of creating a concrete insulated blind area around the house. At the end of this section, a calculator will be offered that, based on the perimeter of the house, its configuration and the size of the blind area, will help calculate the volume of concrete required for laying.
Let’s say right away that the number of options for implementing a concrete blind area using various materials and technologies is endless. It is simply impossible to describe them all not only in one article, but even in a multi-volume publication. We will describe one of many, but one that has been implemented on a large number of objects and has been successfully operating for quite a long time to say that such a design is justified. For ease of perception, let us present the main stages of the process of creating a concrete blind area in the form of a table.
| Image | Process description |
|---|---|
 | Work should be carried out only in the warm season. First, the blind area is marked. It should be no less than 20-30 cm wide than the overhang of the roof eaves. The smallest height is 7 cm, slope 3-10°. First, the outer edge of the blind area is marked using a cord stretched level between stakes driven into the ground. If curb stones and drainage trays for a surface drainage system are installed, their width is also taken into account, since the soil must be developed for them as well. The horizontalness of the cord is checked with a spirit level or laser level. |
 | The upper level of the blind area junction is marked on the plinth wall. To do this, marks are made in one place on comfortable height(1-1.5 m), and then they are transferred to other places using laser level or spirit level. Next, using a plumb line and a tape measure, the horizontal is transferred down. The junction line can be drawn with a pencil or marker, but it is most convenient to “beat it off” with a paint cord. |
 | On the marked base, soil is removed to a depth of at least 30 cm. The main thing is to remove the entire fertile layer and “get” to a solid, reliable foundation on which the blind area will lie. If necessary, the soil is removed to greater depths. It is imperative to get rid of the roots of all plants and to prevent their growth in the future, you can treat the soil with herbicides. The profile of the bottom of the trench is given a slope towards the outer edge of the blind area. |
 | An underlying layer of quarry “fat” clay can be poured onto the bottom of the trench, which is then compacted. This layer is also given a slope. If the site has clay or loamy soils, then they can only do so by compacting the bottom of the trench. |
 | Formwork made of edged boards, which are secured using wooden pegs or pieces of reinforcement driven into the ground. The upper edge of the formwork is aligned along the previously tensioned cord and checked with a level. |
 | The bottom of the trench is lined with a non-woven geotextile thermally bonded fabric with a density of at least 150 g/m², which must completely cover the bottom and have at least 30 cm of overlap with the plinth wall and the edge of the trench. Geotextiles are needed to separate dissimilar soils. |
 | Layers of coarse construction sand at least 20 cm thick are poured onto the geotextile layer. The sand is leveled with a rake, spilled with water and compacted for the first time. It is preferable to use a mechanized tamping method using a vibrating plate. |
 | In hard-to-reach places where a vibrating plate cannot pass, a manual tamper is used. After the first tamping, pour into in the right places sand and compact it again. The process of pouring water and compacting is continued until there is a smooth and dense sand base on which there are practically no traces left when walking. |
 | If elements of the surface drainage system are installed - rainwater inlets and sewer discharge pipes from them, then holes and trenches are dug for them in the already compacted sand. In this case, it is necessary to take into account the level of the future blind area - the rainwater inlet must be installed at its level, taking into account the slope. It must be installed on a concrete solution with a layer of at least 5 cm. Sewer pipes must also be laid with a slope of at least 2 cm per 1 linear meter of pipe. |
 | Trenches with pipes and installation pits for rainwater inlets are sprinkled with sand, which is then compacted. In places where sewer pipes pass and near storm water inlets, this can only be done carefully and manually. |
 | 5 cm thick EPS insulation is laid on a layer of compacted sand. If the upper part of the base has not been insulated, then this can be done simultaneously with the blind area. Insulation boards are laid on a compacted sand base. They can be easily trimmed if necessary construction knife. The slabs must lie tightly on the base. If necessary, when laying them, sand is added in the right places. |
 | After installation, the seams between the slabs are filled with polyurethane foam. |
 | An expansion joint is formed at the junction of the blind area and the base. This can be done by doubling roofing felt, polyethylene foam, and special self-adhesive tape for heated floor seams and glued to the wall. The seam should protrude beyond the upper edge of the future blind area by 5-10 cm. If the blind area is adjacent to polystyrene foam insulating the base, then it will be necessary to additional materials No. |
 | A metal reinforcing mesh made of wire with a diameter of 4 mm and a cell size of 100*100 mm is laid on the insulation layer. The mesh is trimmed in the right places. The edge of the mesh should be 5 cm from the end of the blind area. If it is necessary to lay more than one mesh, then an overlap is made by one cell, and then the meshes are fastened with knitting wire. |
 | The reinforcing mesh should be located in the concrete layer in its lower part at a distance of 3-4 cm from the insulation. To install the mesh on required height It is best to use special reinforcement clamps, which have different heights and are designed for different surfaces. For installation reinforcing mesh It is better to use clamps for loose surfaces. Before laying concrete, all parts of the surface drainage system are covered plastic film. |
 | Beacons are made from edged boards 20 mm thick, strips of OSB boards or thin laminated plywood, which will simultaneously serve as expansion (compensation) joints in the blind area. Segments are cut from them the right size, which are attached at one end to the base at the previously designated level, and at the other to the formwork. The upper edge of the beacons should coincide with the surface of the future blind area, and the lower edge should be tightly pressed against the insulation slabs. Beacons are placed in the corners, as well as every 1.5-2.5 m along the entire length of the blind area. A distance of 2 m is considered optimal. |
 | To fill the blind area, use concrete grade M250-M300, but not lower. Read more about the recipe and preparation of concrete of the desired grade in the right quantity can be read on our portal. The volume required for the blind area can be calculated in the calculator at the end of this chapter. |
 | To improve the properties of concrete when preparing it, it is recommended to use plasticizers, as well as add polypropylene or basalt fiber. |
 | It is better to mix concrete using a concrete mixer or mixer - such mixtures are of better quality than those mixed by hand. |
 | Concrete is laid gradually, in sections between the beacons. The concrete is first laid on the surface, then spread with a trowel or shovel, and then leveled with an aluminum rule along the beacons. After laying in one area between the beacons, they move on to another. |
 | 1-2 hours after installation, it is necessary to iron the blind area. To do this, pour through a sieve onto the upper surface of the concrete. thin layer dry cement - approximately 2 mm. Then hand grater Dry cement made from polyurethane is rubbed into the surface of the blind area. Walking on the blind area is possible only after 48 hours. |
 | For high-quality maturation of concrete, it is necessary to moisten its surface daily with water, and then cover it with plastic film or a damp thick cloth. This operation should be done within 10-14 days. |
 | After the concrete has completely hardened - after 28 days, the formwork is dismantled. The blind area is ready. |
In the future, the blind area can be equipped with curb stones, made along the edges storm sewer– install drainage trays and sand traps. How to do this is described in detail in an article on this topic on our portal.
Video: Construction of a concrete blind area
Calculator for calculating the required volume of concrete for a blind area
We provide readers of our portal with the opportunity to independently calculate the volume of concrete required for the blind area. The initial data for the calculation are geometric dimensions blind area: its height at the wall, height at the end, width. And also for calculations you need to know the perimeter of the house: the sum of the lengths of all its sides. This calculator calculates the volume only for houses with a rectangular configuration; if there are any roundings in the foundation, then this calculator cannot be used or it will be possible to calculate the volume only on straight sections.
The calculations also take into account the configuration of the house, namely how many external or internal corners. If you need to calculate the volume of concrete for any straight section, then you must indicate that the number of external and internal corners is zero.
A reliable, time-tested method of protecting the foundation from exposure surface waters– installation of a concrete blind area around the house. The undoubted advantage of a concrete blind area is its low cost and ease of manufacture.
100% protection from moisture, which is provided by a concrete blind area with a complete coating, cannot be guaranteed by any material (without arranging a multi-tiered “pie”). The condition of the foundation directly affects the position of the entire structure. Therefore, the foundation needs major protection.
This is precisely the main task of the blind area - protecting the foundation and base of the house. In addition to the barrier, it performs several other functions. For example, it allows you to organize more convenient movement along the blind area and gives the building a finished appearance.
Let's take a step-by-step look at how to properly make a blind area around a concrete house with your own hands. We propose to divide all the stages of arrangement into theoretical and applied.
- In the first part, we will look at what you need to know and prepare before getting started.
- In the second - how to prepare the bed and properly pour the concrete blind area.
Requirements for the blind area and rules for its construction
- width of concrete blind area, according to SNiP 2.02.01-83 should be 200 mm. more than overhang roofing material. If there is a drain, its parameters are also taken into account. The same SNiP regulates the width depending on the type of soil. The traditional (optimal) width of the blind area can be considered 1 meter. This width provides freedom of movement and acts as a path around the house;
- length. Since the foundation needs protection along the entire perimeter of the house, it is logical that the blind area should also completely surround the building. The only exception may be the installation site of a concrete porch;
- depth or level of penetration of the blind area should not exceed half of the calculated depth of soil freezing characteristic of a particular region. This parameter can be viewed in the table or you can request information from the architecture department at the location of the object.
The ability of a concrete blind area to move with the soil gives it its functions. Otherwise, its role will be reduced to draining water, which is not enough to protect the foundation.
Note. The depth of freezing is affected by the presence of communications in the ground.
- concrete blind area thickness. The minimum thickness of the surface layer is 70-100 mm. If increased operational load is planned, for example, car movement, the thickness can reach up to 150 mm;
- slope of the blind area. SNiP III-10-75 recommends what the slope should be - from 10 to 100 mm per 1 meter of width (i.e. 1-10%). The angle of inclination is directed in the direction opposite to the foundation of the house. Slope requirements depend on regional rainfall levels and soil type. In practice, the slope is taken to be 20-30 mm per 1 m (2-3 degrees). If you do more, then in case of icing, it will be difficult to move along such a blind area;
- border. In the case of a blind area, the border is a decorative element and the decision to install it is made based on the preferences of the home owner and his financial capabilities. However, if bushes are planted in the immediate vicinity of the blind area - “root aggressors” (raspberries, blackberries) or trees that have a powerful superficial root system (poplar, sycamore), then installing a limiter is mandatory;
- plinth height. The standards establish a minimum plinth height of 500 mm for a hard type blind area and a minimum of 300 mm for a soft type. Let us remind you that the blind area around a concrete house is of the rigid type;
- height of the blind area from ground level. It is desirable that the blind area be 50 mm higher above the ground level. This recommendation is due to the fact that water should not accumulate on the edge of the blind area and turn into puddles. In winter, this is fraught with freezing and, accordingly, destruction of the structure.
- concrete blind area design has a specific device diagram, which is shown in the drawing below.
Armed with the above data, you can proceed directly to the installation of a concrete foundation blind area.
How to make a concrete blind area around a house
Preparation of material:
- concrete for blind area. Grade is an indicator of the quality of concrete; its value ranges from 100 to 1000. It indicates the proportion of cement content in concrete. The concrete class ranges from B3.5 to B8 and indicates the strength of concrete. Thus, class B 15 indicates that a concrete cube measuring 15x15x15 cm is capable of withstanding a pressure of 15 MPa.
What brand of concrete is needed for the blind area? To prepare the solution, use cement grade M 200 (class B15).
The parameters (properties) of concrete depending on the brand are shown in the table.
- sand. Which one do you need? For the bottom layer of the pillow, river or quarry sand. The main thing is that it does not contain large impurities that can damage geotextiles;
- crushed stone (gravel). Crushed stone of fraction 10-20 is suitable for the blind area;
- clay or geotexil for hydraulic locking. In practice, this layer is absent in the base cushion, because concrete drains water well;
- cement for ironing.
Composition of concrete mortar for blind area
If it is not possible to use ready-made concrete, you can mix it yourself. To do this you need to prepare:
- cement for blind area. You should know that the grade of concrete is determined by the grade of cement and its specific gravity as a percentage of the components of the solution. For the blind area, cement M400 Portland cement is used. The cement must be fresh; with each month of storage it loses 5% of its properties. It’s easy to check the freshness; just squeeze a little cement in your fist; if it shrinks into a lump, its shelf life is running out; if it crumbles freely, you can work with it;
Note. What cement is best for blind areas? Naturally fresh and of high quality. This will save on cement consumption and prepare a good concrete solution.
- sand. To prepare concrete, you need to take concrete that has been sifted and washed to remove impurities and soil;
- crushed stone It is advisable to use crushed stone of a fraction of 5-10 mm. At the same time, crushed stone is better than, for example, small pebbles;
- water. Should be at room temperature;
- additives. They are needed to give concrete frost-resistant properties. Often used as a supplement liquid glass.
The tools you will need are a concrete mixer or a mixing container, a shovel, a bucket (it’s better to take a plastic one, it’s easier to clean), a measuring container (for water), a hand-tamping log or a vibrating plate.
Preparation of concrete mortar for blind area
In practice, the solution for the blind area is prepared in portions, after all preparatory work. We will provide a ready-made recipe for cement mortar and how to mix it correctly.
The composition of the concrete solution includes: cement, crushed stone, sand, water and various additives, increasing its strength. The durability and strength of the blind area depends on the ratio (proportions) of these components.
Note. Components are measured by weight only.
Proportions of solution for blind area
Note. 1 cubic meter of sand is on average equal to 1600 kg, 1 cubic meter of crushed stone is on average equal to 1500 kg.
Depending on the brand of concrete, the proportions will differ. SNiP 82-02-95 regulates the composition of the mixture for producing concrete of a certain grade.
The concrete mixture is very demanding on the amount of water supplied. Its excess reduces the strength of concrete, because removes cement flour to the top layer of the solution. This leads to the fact that the strength is distributed unevenly. In practice, it is calculated that water should be approximately half the amount of cement. More accurate data is contained in the table (water-cement ratio (W/C) for concrete).
The order in which the components are added to the solution also matters. Cement is first poured into a mixing container or concrete mixer and water is added. By mixing, the so-called cement laitance is obtained. Next, the remaining components are added to it. First, sand is poured in small portions, and then crushed stone (gravel).
Note. Professionals advise maintaining an interval of 5 minutes. between feeding components. This way the mixture mixes better.
Technology for constructing a blind area made of concrete with insulation
Step-by-step instruction:
Preparing the base for the blind area. To do this, the top layer of soil is removed, all roots, stones, etc. are removed. Using a blanket herbicide will eliminate activity under the substrate. For example, the drugs Agrokiller or Tornado.
Advice. Considering that the blind area must exceed the edge of the roof slope by 200 mm, it is recommended to use a plumb line to accurately mark the boundary of the blind area.
Marking. To do this, we pull the rope onto the stakes hammered in the corners. To avoid sagging of the rope, you need to install intermediate stakes (at a distance of 5-6 m from each other).
Advice. How to determine the required angle of inclination of the blind area? Craftsmen install additional beacons (stretch a rope) on the base of the house. Fastening is done every 1-1.5 meters.
Hydraulic lock device. To do this, lay fatty clay in a layer of 100-150 mm or cover the bottom with geotextiles (roofing felt, PVC film, advertising banner, etc.). Please note that to prevent the film from tearing, it is better to pour a layer of sand of 50-100 mm at the bottom of the trench. A layer of sand of the same thickness is also poured on top of the film. The sand is leveled, moistened and compacted. In the case of a clay hydraulic lock, there is only one sand layer. When laying the film, you should avoid tension. It must be able to move freely with the ground.
Note. Experts advise making high-quality drainage near the hydraulic lock. To do this, you need to dig a trench 100 mm deep and 200 mm wide and fill it with crushed stone or lay a drainage pipe in it, wrap it with geotextile and fill it with crushed stone. This will increase the rate of water drainage.
It is worth noting that many people ignore this stage of work. In practice, this attitude results in the fact that the water passing through the expansion joint goes directly under the foundation, and when it freezes, it leads to an increase in pressure on it.
Backfilling of crushed stone. The layer thickness varies from 50 to 100 mm. The gravel is leveled and compacted. Since crushed stone is difficult to compact, some recommend using a special grid for laying it, which is used in landscape design for the construction of gravel paths. We note right away that this will increase the cost of the blind area without much need.
Backfilling with sand.
Laying communication pipes. To do this, make a depression in the sand for pipes and storm drains.
Insulation of the blind area. Expanded polystyrene or penoplex is laid on the compacted sand with which crushed stone and communications are covered. Only hard insulation is suitable for the blind area, but it is afraid of point loads, so it must be laid on a sand cushion.
Advice. Cold bridges can be eliminated by laying insulation in two offset layers.
Reinforcement of concrete blind area. This is done by laying reinforcement mesh with cells of 50x50 or 100x100 mm or by knitting a reinforcement cage.
Advice. Chain-link mesh is not suitable for reinforcement - it is too flexible.
If insulation is not intended, the reinforcing mesh is laid directly on the crushed stone to a height of 20-30 mm. Which will contribute to better distribution of concrete.
Formwork installation. Boards or plywood are installed strictly according to level. To level out the pushing force of concrete, the formwork is reinforced with stakes that are installed on its outer side. During installation, do not forget that the formwork is removable, which means that all seams will be visible after its dismantling. In this case, the blind area will have an ugly appearance. Therefore, when installing boards, you need to ensure that internal seams were invisible.
Construction of expansion joints. To do this, we install wooden slats and boards (on edge), which are pre-treated with an antiseptic or tarred. The recommended distance between the expansion joints of the blind area is 2-2.5 meters. Expansion joints must be made diagonally in the place where the formwork turns (at the corners). The purpose of the expansion joint is to compensate for the thermal expansion of concrete during operation. They are installed level, taking into account the angle of inclination of the formwork, because When pouring concrete, they are guided by them. An alternative to wood can be Guerlain butyl rubber tapes (10 RUR/m) or a hydro-swelling elastic cord, for example, Penebar Rapid SW45 A/B.
How to seal the seams in the blind area?
According to reviews, those who ignored the formation of expansion joints had cracks after the first winter. Many people believe that wood swells and allows moisture to pass through. You can seal the resulting cracks with special sealants, such as TEKTOR 103 mastic (225 rubles/piece), ISOSEAL P-40 (280 rubles/piece).
Pouring a concrete blind area. When pouring concrete, you need to ensure that no air pockets are formed and that the cement mixture evenly fills the entire space. It is important that no bumps or depressions appear when pouring. Their presence will lead to stagnation of water in these places. If it is not possible to do the entire blind area at one time, part of it is poured, and then work is resumed.
Advice. When pouring a blind area, you can use a technique for uniform distribution of concrete - bayoneting. To do this, the concrete is “pierced” with a rod, and the solution fills the entire space.
How to properly pour a concrete blind area around a house - video
Protection of concrete blind area from destruction
Many people are interested in how to cover the concrete blind area around the house. After all, after pouring the solution, the blind area must be protected from heaving, deformation, destruction, and exposure to moisture, rain, and snow. Let's consider how and what is the best way to do this.
Ways to protect the foundation blind area:
Ironing of concrete blind area around the house
How to iron a blind area with your own hands?
- Dry ironing method - freshly poured concrete is sprinkled with a layer of cement (2 mm) followed by grouting. Dry cement binds to the concrete mortar and increases its ability to withstand the effects of water.
- Wet ironing method - 12-14 days after pouring (when the concrete has dried), you need to walk over the surface of the blind area with a cement-sand mortar (1:1) with the addition of lime paste (10% of the volume of the mixture).
Coating the blind area with a primer
Primers are suitable for this deep penetration, such as AURA Unigrund KRAFT (90 rubles). Primer solutions are used when additional finishing is planned. For example, tiling or painting. If this is not in the plans, it is better to use a water repellent, for example, Eskaro Aquastop Waterproof W (1200 rubles) or GKZh-11 (195 rubles/5 l). Concrete hardeners such as Monopol 1 (1,600 rubles/5 kg), Monolit-20M (1,200 rubles/10 l), Protexil (3,600 rubles/20 l) or Ashford Formula ($120/10 l) are gaining popularity.
Protecting the blind area with liquid glass
A solution of liquid glass and cement is a more budget option protective composition(primer, water repellent), providing a similar result. A solution with liquid glass is prepared from a mixture of cement, water and liquid glass in a proportion (ratio) of 1:1:1.
Covering the blind area with a layer of enamel
The enamel must meet certain parameters for frost resistance, vapor permeability, moisture resistance, and environmental friendliness. Has proven itself to be excellent polyurethane enamel ELAKOR-PU (220 rub/kg).
Covering the blind area with tiles and stones
Lay tiles (ceramic, clinker, paving), pebbles or natural stone on top of the concrete blind area. In this case, concrete acts as a binding solution.
- It is advisable to install a storm drain near the blind area, which will drain the flowing water and prevent siltation of the area;
- To ensure uniform drying of the poured concrete, the blind area is covered with film. Thus, evaporated moisture will be retained on its surface. Since it is difficult to cover a wide blind area with film, it can be periodically moistened. The time until complete hardening with a blind area thickness of 100 mm is 1.5-2 weeks;
- After the concrete has completely dried, the blind area is removed. You should be careful here, because... Removing the blind area can lead to damage to the edges of the blind area.
This order of work and taking into account all these nuances guarantees the long-term full functioning of the concrete blind area.
Do-it-yourself concrete blind area around the house repair
The most common problems include:
The appearance of cracks in the blind area
How to repair cracks in the blind area?
Elimination depends on the depth of the damage (cracks, crevices, concrete breaks):
- no more than 1 mm. Self-healing is used. Such a crack is not dangerous and is usually rubbed away by friction during walking;
- no more than 3 mm. Involves the use of “cement dough”. Shallow cracks can be sealed (filled) with a liquid cement solution (1 part cement to 1 part water);
- 3-30 mm. Such cracks are considered large. To eliminate them, you can use a special sealant such as the above-mentioned TEKTOR 103, ISOSEAL P-40. You can seal the crack with freshly prepared concrete mortar. However, before this the crack needs to be widened. In cross section it should resemble a cone. Apply primer over the entire area of the crack. Any will do, for example, Ceresit ST-17 (450-500 rubles/10 l). Next, the solution is poured. You can use the so-called hydroseal, a special cement-based solution that hardens in 15 minutes. An example is Lugato 5-Minuten Mortel putty (410 RUR 5 kg)
- crack depth exceeding half the thickness of the blind area, this is already a cracking of concrete and refers to significant damage. It can only be eliminated by expansion followed by pouring new concrete.
Delamination of the surface of the blind area over the entire area
In the language of masters, this process is called concrete dusting or delamination (delamination). The reason for this phenomenon may be several factors. For example, uneven hardening of concrete happens if you pour concrete mortar onto a cold surface (observed when working in early spring) or make the blind area thicker. Increased air content in the concrete mixture. Excess of crushed stone parts in the concrete composition.
What to do if the concrete blind area crumbles?
If the process is just beginning, then the surface should be covered with “cement paste” or a composition that contains liquid glass (proportions: cement, water and liquid glass - 1: 1: 1).
If the damage has reached significant proportions, then radical measures must be taken:
- determine the boundaries of the damage to prevent its spread;
- cut out part of the concrete;
- cover the edges of the blind area with a primer;
- apply a new layer of solution;
- cover with film until completely dry.
If you start it, you will have to completely dismantle the blind area and fill in a new one. The measures described above will help extend the life of the blind area and save on alterations and reconstruction.
The cost of installing a concrete blind area without material
And the last thing that interests everyone who wants to order the construction of a blind area is the prices for a concrete blind area. If you entrust the work to craftsmen, then the estimate must contain the costs of the work, which are presented in the table (approximate data as of the end of 2015)
| Service - work on the blind area of a private house | Doing the work yourself | The cost of a master’s work per sq. m. |
| Material price | We do not take into account, because the cost will be the same | |
| Removing the old blind area (dismantling) | 0 | 65 |
| Marking and excavation (depth 600 mm) | 0 | 300 |
| Hydraulic lock made of clay | 0 | 100 |
| Laying film or geotextile | 0 | 40 |
| Backfilling the sand layer + tamping (5 mm.) | 0 | 80 |
| Formation of crushed stone layer (100 mm) | 0 | 80 |
| Installation of a storm drain | 0 | 250 |
| Pipe laying (per m.p.) | 0 | 50 |
| Construction of a concrete blind area (ready-made concrete) | 0 | 300 |
| Construction of a concrete blind area (mixing concrete) | 0 | 650 |
| Total | Saving | About 1200-1400 rubles |
Please note that it is unlikely that you will be able to negotiate a significant discount here. After all, this price does not take into account the cost of materials. For a complete picture, we recommend that you familiarize yourself with the cost of materials for the production of a concrete blind area per 1 m.
Conclusion
Agree, it’s a good incentive to make a concrete blind area with your own hands. Moreover, from the given instructions it is clear that this work does not require special tools, any special materials, only the desire to protect the foundation of the house with a reliable barrier.
Construction of the house has been completed, but the owners still have a lot of trouble ahead, primarily aimed at ensuring the safety of their new home. Building construction, no matter how durable they may seem at first glance, without proper protection they can suffer significantly from the effects of frost, snow, rain, and winds. This effect on the foundation is especially dangerous, because its deformation or partial destruction can negatively affect the strength of the entire structure of the house. As protective agent It is recommended to build a blind area around the house - it is intended to protect the foundation from the destructive effects of precipitation.
What is the blind area of a private house
The blind area of a private house is a strip of dense material, for example concrete or asphalt, which is adjacent to the foundation, protecting it from moisture. When laying the blind area, the slope angle recommended by building regulations must be observed, which allows melt or rainwater to flow freely; usually it is in the range of 10 to 15 degrees.
The recommended width of the blind area of a private house is from 0.8 to 1.2 - 1.5 m, it is located along the entire perimeter of the structure. It is difficult to overestimate the importance of the blind area for houses with ground floor or basement: it not only significantly increases the strength of the foundation, but also helps create an additional insulating layer that creates a thermal cushion.
In addition to its protective functions, the blind area around the house helps to give the structure a more aesthetically pleasing and complete appearance. Practical owners resort to constructing blind areas not only around a residential building, but also around all kinds of technical and service premises, brick fences built on the estate.
Types of blind area
In construction, it is customary to divide blind areas into three types:
- made from asphalt or stones
- classical
- monolithic.
Classic blind area usually has a width of 80 cm, is built along the entire perimeter of the structure, its slope is about 10 degrees. However, the width of the blind area should be chosen taking into account the protrusion of the roof of the house; at least 20 cm should be added to it. The width may also depend on the type of soil in the area where the house is located: the easier the soil is compressed, the wider the blind area should be made. If there is a basement in the house, it is recommended to insulate the blind area using heat insulating material.
It should be noted that the blind area, no matter what material it is made of, will be subject to destructive effects if the drainage from the roof is not done correctly or is missing.
Clay can be used as the basis for a classic blind area. The procedure for performing the work is as follows: a shallow (about 10 cm) trench is dug around the perimeter of the house, wet clay is poured into it and compacted tightly. After drying, the clay forms a dense mass that can provide the proper level of protection from moisture.
The boundaries of the blind area are curbs; they should be dug into the ground up to half the height.
On top of the clay layer, crushed stone of the middle fraction is poured and compacted tightly. The last layer is concrete or cement mortar, reinforced or monolithic; a composition of asphalt and artificial filler is often used. Using asphalt concrete, popular in urban housing construction, in a private home may not be practical: laying it requires the use of professional equipment and compliance with operating standards. In addition, laying asphalt concrete should be carried out at a material temperature of about +120 degrees and an air temperature of at least +5 degrees.
For styling stone blind area you will have to stock up on enough cobblestones and stones. In this case, the trench should have a depth of about 30 cm. Gravel is laid at the bottom of the trench, compacted, then clay is poured in and compacted. To provide protection from moisture, a layer of insulating material - roofing felt - is laid below and above the clay layer. Next, they begin to construct the decorative layer: selected stones are laid on the cement mortar.
Most quality option experts believe monolithic type blind area. A monolithic blind area at home can be done with your own hands if the owners are familiar with the technology for performing such work. In addition, it will require serious financial expenses. In order to fill the trench, only clean sand is used, it is compacted and poured with a layer of concrete 6 to 8 cm thick. The concrete must have good quality and be resistant to freezing. The structure must be strengthened with reinforcement laid on the base before pouring concrete.
We should also not forget about the need to create an expansion joint in the monolithic structure. For this purpose, carefully selected and treated resin and by special means board. Preference should be given to boards with a thickness of more than 15 mm. Temperature seam will prevent cracking of the monolithic coating, increase its resistance to mechanical loads with sudden changes.
How to properly make a blind area at home with your own hands
Now let’s look in detail at how to make a blind area at home using hand-made reinforced slabs. Making them is not very difficult. To create the slabs, you will need to make a formwork measuring 60x60 cm. It is recommended to make it on two slabs located next to each other. The height of the slab is 3 cm. The formwork boots are assembled in such a way that after hardening sand-cement mortar they were easy to take apart.
For increase quality characteristics It is recommended to reinforce the slabs; for a 3 cm thick slab it is very important to provide additional rigidity. Any mesh with a cell size larger than 8x8 cm can be used as a reinforcing component. Cells that are too large will lead to a decrease in the strength and rigidity of the finished product. Any metal products can be used as a reinforcing component, for example, cable or wire, but must be cleared of insulation.
After making the formwork, you can begin making the slabs. The base of the formwork will need to be covered with polyethylene. The film should be carefully leveled. Next, the formwork is filled 2/3 in height with a solution prepared from 3 parts sand and 1 part cement, the prepared reinforcing mesh is laid, and the rest of the solution is added until the desired height is obtained.
To improve the setting process, the surface of the tiles is covered with burlap. The formwork can be removed after 3-4 days. Slabs made in this way can be used even if the drainage is not properly organized. Plates laid on a prepared base will last a long period; moreover, their service life can be extended by periodically rotating the slab 90 degrees.
In addition, self-made slabs will help improve the area around the house and make it more decorative look: If desired, you can add dyes of different shades to the solution - the slabs will turn out colored.
Blind area made of paving stones and paving slabs
Today construction market is saturated with all kinds of paving slabs and paving stones, their price is quite affordable, so often instead handmade slabs for blind areas resort to purchasing ready-made finishes. Industrially manufactured slabs have their advantages:
- they are very easy to install,
- if necessary, damaged fragments can be easily replaced with new ones,
- These tiles are resistant to high loads, exposure to moisture and low temperatures.
It is quite possible to construct a blind area at home with your own hands. In order for the blind area to last for a long time, you will need to properly prepare its base. A trench about 40-50 cm deep is dug around the house, a layer of drainage is laid in it: gravel, crushed stone, coarse sand with a thickness of 25 to 35 cm. The recommended slope of the paving slab blind area is from 5 to 10%, this is done at the installation stage drainage system. The minimum slope value is 1.5%, i.e. about 8 mm for every about.5 m of blind area.
A gap of a couple of centimeters should be left between the foundation and the blind area, otherwise at subzero temperatures the tiles, expanding, will create additional pressure on the foundation, which is extremely undesirable. The gap can be filled with sand or polystyrene and closed with several layers of roofing felt.
After the drainage layer, a layer of reinforced concrete is constructed, the dry mixture is poured, leveled and compacted, and tiles are laid on it. An attractive factor in the use of paving slabs can be considered the variety of their shape, size, and wide range of colors.
When choosing optimal option When making a blind area around the house, you should definitely take into account not only the financial side of the issue and external attractiveness finishing material In order for the blind area to serve for a long time, first of all, it will be necessary to take into account the peculiarities of the soil structure on the site, its geographical location, quality drainage system roofs of the house.
