Even the strongest foundation of a house without reliable protection will lose its strength under the influence of environmental factors. Therefore, the waterproof strip around it is an important element of the structure, and the exterior without the blind area looks like unfinished.
The device has its own technical subtleties and nuances. You will learn about them from our article. We will also talk about the best options for arranging the system. And possessing theoretical knowledge on how to make a blind area around the house, and following the step-by-step instructions, you can do this job yourself.
Why do you need a blind area?
The blind area performs many functions. The main one is to protect the base of the house and the soil around it from moisture. Therefore, the soil does not freeze, does not swell, the foundation geometry is not disturbed.
It is inappropriate to set up the blind area only if there is a pile-screw foundation.
In all other cases, it is necessary, since water entering this zone creates serious problems:
- Vertical buoyancy. The presence of water at the base of the foundation and under it entails wetting of the soil. If the foundation is laid shallow, the soil will freeze, and the heaving forces will squeeze the structure. If their distribution is uneven, cracks will appear.
- Tangent swell. When there is a swelling of soil, which is in contact with the side walls of the laid foundation foundation. The load is quite large - it can reach 6 tons per 1 m² of wall construction. The presence of a well-made blind area minimizes the likelihood of problems.
- Penetration of water into the rooms of the basement. This occurs not only with poor waterproofing. In conditions where humidity goes off scale, even with good protection, leaks can occur.
The blind area may be far from the last element of landscape design. If it goes well with the decoration of the basement and walls, the house blends in seamlessly with the landscape.
The blind area fully performs its functions only in conjunction with other elements. By itself, it will not become a protective structure, but only in combination with a waterproofing base and a drainage system
A foundation without a protective structure can destroy not only moisture, but also the roots of trees. A better way to protect the base from all kinds of adverse factors than the construction of the blind area has not yet been invented.
Existing system variations
To choose the best option for the blind area, you need to know what types of it exist. The design of any blind area includes 2 base layers - nested and covering.
The first is a dense base of sand, gravel, fines, gravel under the upper layer. The second is a barrier to the penetration of moisture into the soil under the blind area and the foundation.
Blind area of any type will perform its functions. The difference is only in the duration of full functioning.
Option # 1 - clay ebb system
This is the easiest and cheapest way to protect the bottom of the house from moisture. But also rather capricious - at specialized forums it is full of reviews that “the neighbor made a blind area from clay and covered it with tiles, but after a year it completely distorted it”.
Clay in itself with a certain degree of purity is a good natural waterproofing agent. With proper installation, it will completely protect the house from ground and atmospheric waters in the form of precipitation. But keep in mind that at subzero temperatures it expands.
If we compare the blind area with other types of clay, it turns out that it has many advantages. The main one is resistance to significant temperature differences, since the clay layer has ductility and extreme cushioning capabilities.
Other coatings when freezing, without having similar properties, give cracks. To make such a blind area, it is not necessary to be a specialist. It is important to make the right “cake”, and not just fill the entire trench with clay, ordering 10 cars of this material.
The arrangement technology is as follows:
- They dig a trench up to 0.3 m deep. The optimal width is 0.8 m.
- Arrange a "pillow", towering 10 cm above the bottom, using sand and gravel. Tamping her.
- A waterproofing is placed between the foundation and the clay blind area.
- Clay with a slope of more than 5⁰ from the foundation is laid with a layer of about 15 cm to drain the water.
To prevent the leaching of particles from the clay layer, its top is made out of pebbles, coarse gravel or stone. Clay is better to use quarry, because it has sufficient purity. Especially harmonious looks such a simple design in combination with the wooden walls of the house.
If a clay tape is exposed to direct water for a long period, the material will still be washed out a little. This is its main drawback.
Option # 2 - concrete paving device
To protect the foundation, a concrete blind area is most often chosen.
This solution has a number of undeniable advantages:
- high mechanical strength;
- resistance to the harmful effects of water;
- long service life;
- simple styling technology;
- ample opportunities for decoration.
The disadvantages of this material are no less significant than the advantages. They include fragility. For the design, the heaving forces are heterogeneous in magnitude. Cracks appear due to this. Reinforcing solves the problem, but such a design is much more expensive.
The scale of the blind area depends on the type of soil and the width of the overhang of the eaves of the roof, beyond which it must necessarily protrude by 25 centimeters. Optimum dimensions - 60 - 100 cm
Periodically, the blind area of concrete needs to be repaired. If dismantling is required, the work will be very time consuming.
An amateur builder for the device of the blind area with his own hands is better to use the step-by-step instruction below:
- Perimeter trench. The initial stage of constructing a concrete blind area is to surround the structure with a trench along the perimeter. Its bottom should be below the surface of the final coating by 35 cm. In turn, the final flooring must be raised above the adjacent soil by an average of 7 cm.
- Groove. For effective water drainage, the edge of the structure is formed with a groove (“tooth”) of approximately 0.2 x 0.2 m. The slope is performed in the direction of the natural drain.
- Clay castle. At the bottom of the moat, a clay castle is built with a height of about 110 mm, using greasy clay for this.
- Crushed stone layer. A crushed stone layer is arranged - 55 mm, and after it a sandy layer - about 10 cm. The difference between the height of the finished underlying layer and the future level of coverage is within 4.5 - 6 cm.
- Geotextile. To prevent mixing of the materials of the underlying formation, they are separated by geotextiles. A geocomposite drainage mat is placed between the compacted soil and the substrate.
- Reinforcement. So that the finished blind area does not crack, reinforcement is performed using a metal bar or steel mesh. The diameter of the rods is from 0.8 cm, the cell is inclusive up to 20 cm.
- Formwork + concrete. A formwork is installed under the side of the ditch, adjusting its height according to the final level of the structure. After they perform the laying of the concrete mixture.
In the presence of heavily-soiled soils, it is better to insulate the blind area.
To preserve the recess made along the edge of the trench, the thickness of the bed should be the same both in length and in width
As a heater, plate extruded polystyrene foam is used. Lay the insulation on top of a centimeter layer of sand, then add sand to a height of about 5.5 cm.
For the formwork device, two boards 2 x 10 cm are knocked down. After 0.5 - 0.6 m, connecting jumpers are installed. At intervals of 1.5 m, stakes are driven around the trench. Formwork is screwed to them. Its upper edge should be at the level of the finish coating. From the outside, to strengthen the boards, they are propped up with soil.
They must be removed as soon as the solution sets a little. Subsequently, these grooves have to be filled with damping material. More on this process is a little lower. If you do not plan to remove it, then you need to treat the boards with an antiseptic composition and wrap it with roofing material.
An important nuance - the blind area cannot be rigidly connected with the base of the house. Therefore, upon completion of the arrangement, temperature seams are made to minimize deformation of the canvas. They are made with a distance of 1.5 to 2 m. Extruded polystyrene foam, bituminous mastic or damper tape are used for their device.
An articulation with the foundation can also be created using rods that reinforced the blind area. This will not allow the gap to increase. Any clutch material needs to be masked. To do this, use borders, finishing elements, slopes.
In private homes for the installation of the temperature seam often use boards of 1.5 - 2 cm. They are impregnated with resin and set with a rib, then close the seam
Thus, using the expansion joint, the effects of uneven shrinkage of such structures as the base of the house and the monolithic blind area are smoothed out. If this nuance is not taken into account, structures can prematurely collapse.
The next caveat - fresh concrete should be protected from atmospheric influences, so they cover the blind area, using sheets of chipboard or plywood for this.
The top layer of concrete to give it a special strength is covered with primers or enamels, liquid glass, cement milk, sometimes natural stone or tile. A particularly popular way is ironing. Its essence lies in the use of dry cement or milk based on it.
Option # 3 - blind area from paving slabs
While concrete blind area refers to rigid structures, paving slabs are a semi-rigid system.
Structurally, the blind area is similar to a multi-layer cake and consists of the following elements:
- priming;
- clay - 30 cm;
- crushed stone - 18 cm;
- geotextiles;
- cement-sand mixture - 6 cm;
- sidewalk tile.
Such a semi-rigid system has many advantages: maintainability, relatively small financial investments, and subject to technology, the service life is quite long.
For heaving soils, this option is unacceptable, since they often violate the integrity of the coating.
Instead of paving slabs, cobblestones, porcelain tiles or reinforced concrete slabs can be used as a finishing coating. There is a wide variety of paving tiles. They have different texture, color
Tiles are released smooth and grooved in a wide range of colors - from orange to black. At any time of the year one of the defective elements can be replaced.
Option # 4 - features of soft design
A rigid and semi-rigid blind area often merges with the tracks and is a continuation of the basement decoration. Soft design is another. She continues, adjacent to the building, a front garden or a flower bed.
To perform work on the device, you need to purchase the following materials:
- waterproofing in the form of roofing material, PVC membrane, polyethylene;
- filter layer type geotextile;
- crushed stone of the middle fraction;
- pipe for drainage.
Geotextiles not only separate fractions, but also distributes loading forces. The lowest layer is well-compacted soil. The preparation layer, laid out with coarse gravel, stabilizes the surface.
This happens due to the fact that the stones are wedged in contact with each other and the load is distributed evenly. The subsidence of the coating is not observed. The drainage slope is also formed by the rubble layer.
If the house is on the foundation of the tape type, a soft blind area, like any other, is arranged around the perimeter.
The soft blind area not only protects the foundation, but also serves as a decoration for the exterior of the house. You can plant lawn grass or ornamental shrubs on it.
When the house is based on stilts, a 0.4 m hydrobarrier is placed under it.
There are no particular difficulties in creating this type of construction, provided that you carefully figured out how to make a solid blind area around the house and there are no unclear moments for you.
The labor costs here are not as large as with a concrete structure and the cost is less. The main thing is to observe the sequence.
To ensure a stable level of the bottom of the ditch, mark a rectangular area using a water level or level.
When marking around the perimeter of the house, starting from the wall, lay equal distances and mark the points with stakes. It is better to drive in pieces of reinforcement to a depth of 0.3 m. Such beacons will definitely not move when excavation works are carried out.
Next, they remove the soil, forming a recess located 43 cm below the centimeter with respect to the lowest point. A groove is made along the perimeter of the trench to a width of 4 cm. Its depth is 2.5 cm. Elements of a storm system are placed in it. The edges of the trench need not be strengthened.
Ram the soil at the bottom of the trench with fine gravel. Greasy clay is moistened, poured to the bottom and kneaded, distributed with a layer of 0.2 m, setting a slope of 5: 100. A channel channel for storm water is formed from clay.
A groove is made along the perimeter of the trench to a width of 4 cm and a depth of 2.5 cm. Elements of a storm system are placed in it. The edges of the trench do not need to be strengthened
Be sure to let the preparatory layer dry. To prevent cracks, the surface is periodically sprayed. A layer of crushed stone is placed on clay with a fraction of about 18 mm in height of 11 cm, forming a slope.
In order to finally level the surface slope, the optimum value of which is 3: 100, a layer of fine-grained material is poured - 8 cm. Sand, screenings or expanded clay chips are used in its quality. The latter serves as a heater.
When laying, mixing sand and clay should not be allowed. This is explained by the fact that when the sand is saturated with water, it will “draw” the second component into the ground
Further, layer by layer, they begin to arrange a “pie”. As they are laid, each layer is rammed, watered with water.
After tamping, the sand surface is leveled and the geomembrane is laid out. At the same time, this material covers the bottom of the tray. Storm sewer pipes are also wrapped in geotextiles and laid. Then collectors are mounted.
A layer of geocomposite is applied to the membrane. Due to this, water will not accumulate in the embankment, but will drain into the canal. Thus, the question is solved, how to make effective ebbs around the house with your own hands without special costs.
The geocomposite is followed by a four-centimeter leveling layer consisting of sand and gravel.
The waterproofing layer in the construction of the soft blind area plays a special role. He needs quality material. It can be a frost-resistant plastic film, roofing material or a profiled membrane
Geotextiles are placed on it, and behind it is the topcoat. With crushed granite, the structure is completely leveled. If you lower the whole cake below the zero mark by 150 mm, you can pour a layer of fertile soil and plant a lawn right next to the house.
The decision to make a soft blind area is ideal when the groundwater is close, but in a situation where there is drainage around the house
Stormwater discharge from the blind area
The minimum slope is 2% of the width of the finished structure. So, with a coating width of 60 cm, a slope of 1.2 cm is needed.
The photo shows how, through a specially created groove, water flows into the drainage. The deviation from the building in the outer edge of the blind area is made by tamping each layer
When deciding what to independently make both a blind area for the house, and the ebbs, one must proceed from the characteristics of the soil on the site.
To divert fluid from the surface of the blind area, gutters are needed in the form of gutters. They are produced specifically for the sidewalk, and they are designed for directional water drainage. At the same time, neither the soil nor the foundation is wet.
Since the slope, formed earlier around the perimeter, is directed away from the building, gutters are placed along the edge of the blind area so that they fit snugly against the blind area. The drains themselves can be plastic, metal, concrete, or you can just saw an asbestos-cement pipe.
If the house is on a slope, and even standing on clay, a drainage pipe is needed. It is placed, retreating from the wall of the house about 1.3 m, at the location of the edge of the geotextile or slightly lower.
The pipe from below and from the outside should be covered by a membrane and geotextiles. Through the perforation, water will enter the pipe, then it will go to a predetermined place.
For drains, you also need to provide a bias towards the sewer, septic tank or drainage pit. This whole system must be airtight. To do this, the joints are sealed, and an end cap is placed at the end.
Gutters will be able to fulfill their functions subject to proper calculation and selection. Here it is necessary to take into account the degree of contamination of the liquid, throughput, material blind area
Ways to drain the liquid provide in advance. If it is a septic tank, one of the gutters is directed in its direction. The same thing is done when water is drained into the central sewer.
Video tutorial on the correct installation of the blind area:
An independent device of the blind area may not be the most difficult task, but it is far from simple. There are many options, but you need to choose the best way.
To make a blind area correctly, our step-by-step instruction will help. Adhering to it, you will avoid many mistakes and improve the operational properties of your building.
Choose the best way to create a blind area around your house, but doubt the correctness of the option you like? Ask for advice from other visitors to our site and from our experts - together we will help you choose the best type of blind area.
Or maybe you used one of the above instructions for building the blind area and now want to share the results of your efforts? Add unique photos in the comments section - your work will become an inspiration to other home craftsmen.