In order to protect the foundation of the house from the effects of groundwater and external factors, it is necessary to arrange a concrete blind area. It is located around the house. This approach provides complete protection against moisture, which no other material can handle. This design protects not only the foundation, but also the base of the building. In addition to the barrier, the blind area performs another important function - it organizes movement along the surface. In addition, using this site, you can give the house a finished look.
Blind area requirements
Before you make a blind area around the house of concrete, you should familiarize yourself with the sanitary standards and rules 2.02.01-83. According to them, the blind area should have such a width that is 200 mm more compared to the overhang of the roofing material. If the building has a drain, its parameters must also be taken into account. These same rules and regulations govern the width, which is also affected by the type of soil. The optimal width can be considered 1 m. This parameter provides freedom of movement and serves as a path.
It is also important to remember that the foundation must be protected along the perimeter. The blind area should encircle the building. The exception is only the place where the concrete porch is located. Before you begin, you must also consider the depth of the structure. This parameter should not be more than 1/2 of the depth of soil freezing.
The thickness of the blind area is equal to the limit of 70 to 100 mm. If it is planned to increase the load during operation, for example, the impact of a car, then the mentioned parameter can be increased to 150 mm. One important indicator is bias. It is regulated by sanitary norms and rules III-10-75 and is equal to the limit of 10 to 100 mm per meter of width, which is 1-10%.
The slope of the blind area should be directed in the opposite direction from the base of the building. The requirements for this parameter depend on the amount of precipitation in your area and the type of soil. In practice, the slope is equal to the limit of 20 to 30 mm per 1 m, which is approximately equal to 2-3%. If you make this value larger, then when icing along the blind area it will be difficult to move.
It is important to remember the presence of a border. This element in this case is decorative, and the decision to install it is made taking into account the preferences of the owner of the house and the budget for the work. If next to the blind area there are bushes that are root aggressors, or trees that have a powerful root system, then it is best to resort to installing a limiter.
Before starting work, it is important to take into account the height of the base. Minimum is 500 mm. This is true for a hard blind area. If we are talking about its soft variety, then the height of the base should be 300 mm minimum. The described construction refers to a rigid variety. From the ground level, the blind area should be raised by 50 mm. This recommendation is because the fluid should not linger on the edge and form puddles. If this happens at low temperatures, it will cause freezing of water, which will contribute to the destruction of the structure.
Blind Fabrication: Material Preparation
The brand is an indicator of the quality of concrete. From this value in the range from 100 to 1000 depends on what characteristics the design will have. The mentioned figures indicate the cement content in the solution. The class of the mixture can range from B3.5 to B8 and indicates strength. For example, a class B15 solution indicates that a pressure of 15 MPa can be applied to the fill cube. This is true for designs with dimensions equal to 15 x 15 x 15 cm.
You may also be interested in the question of what kind of concrete is needed for the blind area. Usually, cement grade M200 is taken for this, which corresponds to class B15. Concrete parameters depend on its brand. They are determined by the components. For the device of the lower layer you will need sand, which will form the basis of the pillow. It can be career or river. The main condition is that the material does not contain large impurities that could damage the geotextile.
For the blind area, it is better to use crushed stone fractions in the range from 10 to 20 mm. It could be gravel. To install a hydraulic lock, you will need geotextiles or clay. This layer is absent in the pillow, because concrete copes well with water diversion. For ironing, you need to use cement.
Solution composition
The arrangement of the blind area around the house made of concrete can be carried out using a ready-made solution, otherwise it will have to be prepared on its own. The brand of concrete will be determined by the brand of cement and its specific gravity. For the blind area, it is better to use cement grade M400. Cement should be fresh, so you should not buy it in advance, because after a month of storage the material will lose 5% of its properties. If you use fresh high-grade cement, this will save on mortar and get good concrete.
To prepare the solution, you need to prepare sifted sand, pre-washed and freed from impurities. In order for the volume of water to remain unchanged, the material must be dried. As for crushed stone, crushed stone is preferable to fine pebbles. If there is a need to give concrete the quality of frost resistance, then additional substances should be used, it can be liquid glass. Among the tools should be highlighted:
- container for kneading or concrete mixer;
- bucket;
- a shovel;
- measured capacity for water;
- vibrating plate or ramming log.
Solution preparation
The manufacturing technology of the blind area around the house from concrete provides for the preparation of the mixture on its own. It is recommended to shut the composition in separate portions, which is true if you plan to do the packing yourself. The order in which the ingredients are served matters.
For mixing, pour cement and pour water. The rest are added to these components: first a small portion of sand is poured, and then crushed stone or gravel. It is recommended to maintain an interval of 5 minutes between the supply of components, this will improve mixing of the mixture.
Base preparation, marking and hydraulic lock device
Before you make the area around the house of concrete, you must prepare the foundation. To do this, remove the topsoil, remove stones and roots. Under the substrate, the activity should be eliminated by the use of herbicides. Given the moment that the blind area exceeds the edge of the roof slope by 200 mm, a plumb line should be used to mark the boundaries of the structure. For marking, it is necessary to pull a rope over the pegs hammered in the corners. In order to avoid sagging, it is necessary to install intermediate stakes, the distance between which will be 6 m.
In order to determine the slope of the blind area, it is necessary to install additional beacons on the base (pull the rope). Mounting is carried out through each meter. Then you can go to the hydraulic lock device. To do this, a 150 mm layer of oily clay is laid, which can be replaced with geotextiles.
The film should not tear, for this, a 100 mm layer of sand is poured onto the bottom of the trench. One more layer of sand is poured over the film. Sand needs to be leveled, moistened and condensed. If you decide to work with a clay hydraulic lock, then the sand layer should be one. When laying the film, it is necessary to avoid its tension, it should move freely with the soil.
If you wondered how to make a blind area around the house, then you should remember that it is better to put a good drainage near the hydraulic lock. For this, a trench is excavated, the depth and width of which are 100 mm and 200 mm, respectively. Crushed stone is poured at the bottom, then a pipe is laid, which must be wrapped with geotextile. This will increase the rate of water drainage. Many neglect this stage of work, but in practice it results in the fact that water goes under the foundation, and when it freezes, it increases the pressure on it.
Backfill of rubble and sand. Warming blind areas and reinforcement
If before you, like many home masters, the question arose about how to make a blind area around the house, then you should know that gravel is poured at the next stage. The thickness of this layer should vary from 50 to 100 mm. Gravel must be decomposed and compacted. To do this, you can use a special lattice, which is used in landscape design.
In the sand, you need to make a recess under the pipes and storm water inlets, after which you can proceed to the insulation of the blind areas. Foam or polystyrene foam should be placed on compacted sand that falls asleep at the bottom of the trench. A hard insulation is suitable for the blind area, but it is afraid of point loads, so it is necessary to place it on a sand cushion.
Cold bridges can be removed by laying the insulation in 2 layers. The insulated blind area must be organized. For this, a reinforcing mesh with square cells is used, the side of which is 50 or 100 mm. Reinforcing frame is connected. The mesh netting should not be used for this, as it is too flexible. If you do not need an insulated blind area, then the reinforcing mesh can be located on the rubble. This will contribute to a better distribution of the concrete mix.
Formwork Installation and Filling
Formwork may consist of plywood or boards. It is reinforced by stakes that are installed externally. During installation, one should not forget that the formwork is removable. To create expansion joints, it is necessary to install wooden slats on the rib, which are treated with an antiseptic. The distance between the seams should be 2 m.
The seams should be located diagonally in the place where the formwork turns at the corners. The expansion joint has one important purpose, which is expressed in compensating for the thermal expansion of the material during operation. Filling the blind areas should be with the removal of air pockets. If the mixture evenly fills the entire space, then you will be able to get a solid structure.
When pouring, it is important to exclude hollows and tubercles, their presence will contribute to stagnation of water. If it is not possible to make the entire blind area at one time, then you can fill in only part of it, and then resume work. Filling the blind areas should be accompanied by bayonet. To do this, concrete is punctured, which will contribute to filling the entire space.
Varieties of blind areas without concrete
In construction, the blind area is divided into three varieties:
- monolithic;
- classic
- from asphalt or stones.
A classic blind area usually has a width of 80 cm and is built around the perimeter of the house. Clay can act as the basis of such a design. A trench is dug around the perimeter of the house, where moist clay is poured and densely compacted. After drying, you can get a dense mass, which will provide the proper level of protection of the foundation from moisture.
On top of the clay layer, crushed stone of the middle fraction can be poured and compacted well. Considering the types of blind areas around the house without concrete, you should get acquainted with the stone structure, which is arranged with stones and cobbles. In this case, the trench has a depth of 30 cm. Gravel is laid at the bottom, it needs to be compacted, and then clay should be poured, which must also be tamped. Insulating materials in the form of roofing material must be laid below the top layer to provide protection from moisture. Then you can proceed with the construction of a decorative layer using stones.
Alternative blind areas: tile structure
If you want to make a blind area, then you can perform it from the tile. It is important to pay attention at the same time to the limb of waterproofing gravel. Its purpose is to prevent the first layer of sand from spreading. The total power of the pillow should be 30 cm. However, this parameter is relevant only for the blind area that will lie in the humus.
If its layer is thinner, then the drained layers should not go deep into dense soil. The clay layer should make a limit of 15 to 20 cm. The thickness of the crushed stone layer is equal to the three values of the first sand layer. As for the slopes, they should decrease from the bottom up. Clay preparation will have a slope ranging from 8 to 12 cm per meter. The bottom layer of gravel has a slope of up to 7 cm per meter. The upper layer of crushed stone will have a slope of up to 4 cm per meter. The top of the pillow under the tile will be horizontal.
Cost of work
If the question arose before you about how to make a blind area around the house made of concrete, and you, evaluating your capabilities, decided that it was better to entrust this matter to specialists, then you should ask about the cost of the work. The construction price per square meter is 2,170 rubles. It includes 10 cm of concrete, the same thickness of sand preparation and reinforcing mesh. Admittedly, the price per meter of the blind area around the house may seem quite impressive, which is especially true if the building has a large area. Therefore, it may be worthwhile to study the technology first.
Finally
Without a blind area, the foundation and basement of a building can quickly become unusable. After completing all the work, you can do the ironing of the structure. These manipulations are carried out on freshly poured concrete, which is sprinkled with a layer of cement and subsequently rubbed. If you still think about the question of how to make a blind area around the house from concrete, you should know that there is also a wet method of ironing, which is carried out 14 days after the completion of pouring, when the solution dries. To do this, walk along the surface of the structure with a cement-sand mortar.