Water poses a threat to construction sites, eroding soil near and negatively affecting the structure of their materials. So that the most open structures of the house are not subjected to such influences, it is necessary to provide special engineering structures. A comprehensive solution for this kind of protection can be a blind area around the house and drainage on a sand and gravel base.
What is blind area?
This is a technological coating, which is usually arranged after the completion of major construction activities. The blind area is recommended to be performed together with adjacent structures (garage, building facade) or landscape structures - it acts as a kind of floor frame for an architectural object, providing stable drainage. Its main function is to protect the soil near the walls, plinth and foundation. But if in the old days this coating performed exclusively the task of external waterproofingon a certain area of the ground, today it is also a full-fledged floor basis for movement. For example, a car may well drive along the concrete pavement near the garage. However, not every solid platform can be considered as a blind area. Its fundamental difference, from the point of view of the structural device, is the insulating function. To ensure it, the coating is based on a substrate with a monolithic structure that prevents or reduces the possibility of water passing into the soil.
Materials for blind area
The following materials may be used in the device of this coating:
- Concrete tiles. It is used most often as a durable and versatile material in terms of texture and size. The blind area can be laid out from rectangular, square and round elements 5-10 cm thick and 10-30 cm long. Concrete tiles are resistant to frost, physical stress and are organically combined with sand embedding in the seams.
- Stone tiles. Stone derivatives have much more design advantages, since in any design this material will win with a natural noble texture. Particularly good in this regard is granite pavers for blind areas, but it is produced only in the form of a cube or parallelepiped. In terms of wear resistance, this is the most durable solution.
- Paving slabs. In this segment, there are practically no restrictions on design, textures and release form. Moreover, you can find material for a soft blind area around the house.on a polymer basis with a rubber crumb. It is from the point of view of waterproofing the soil that this is the best solution.
- Rubble. A variant of combining the principles of blind area and drainage. Around the target object, crushed stone is backfilled onto a layer of geotextile. Also, pebbles, gravel or expanded clay fractions from 8 to 30 mm can be used in this capacity.
Design of the drainage system
In the classical view, drainage is a network of pipelines designed to collect and drain wastewater. Today, this principle of rainwater protection is combined with local filtration through a sand-drainage cushion. The main components of such systems include water collection points, channels for its movement and places of accumulation. Both the blind area around the house and the drainage provide for the function of providing isolation, however, the second option not only embodies a kind of barrier, but also provides targeted drainage to a specific area or collection point. This is made possible by pipelines. Another thing is that such systems are much more technically complex and, in principle, can only be organized on a site with a flat terrain.
Drainage materials
Pipes are the main structural element of the drainage system. They can be made of metal or ceramic, but the most practical will be the use of polypropylene or polyvinyl chloride (PVC) products. Moreover, the pipes must be perforated for water infiltration without earth particles and debris. The best solution would be to buycorrugated plastic perforated pipes, which also include a geotextile sheath or coconut filter. It is also recommended to use plastic in the form of geofiber as an insulating substrate. Any solid bulk material in combination with sand is used as a backfill. According to engineers, proper drainage around the house is carried out by sprinkling pipes with layers of gravel with a fraction of 5-30 mm. On this surface, layers of soil are further laid and rammed.
Applied Equipment
Power units and, in principle, machinery with mechanisms are not recommended as part of drainage systems. It is desirable that the channels operate in full autonomy mode, steadily diverting accumulated water. But if we are talking about areas with difficult terrain, where it is impossible to organize natural drainage, then you will have to use special pumps. These are drainage pumping units placed directly at the places where wastewater is collected. You should think in advance about the place where the water will be directed both from covering the blind area around the house and from the drainage on the site. There may be several such collection points on a large site. Wells are arranged in them, into which the pump is immersed. Pipes extend from the equipment nozzles, transporting water already under pressure.
Preparing the soil for the blind area
The device of a durable coating for a floor drain is possible only on a rigid, reliable base. That is, on dense soil, which is rammed around the entire perimeter of the walls. The humus layer is completely removed by 10-15 cm. It cannot be left either because of the depreciation of the blind area, and because of the ability of the root system to retain moisture. On the cleared area, you can lay out a layer of the same rubble or expanded clay. But how to make a blind area with your own hands around the house so that it matches the planning level in height? At each stage of the device during ramming, the height will change, but a win-win option would be to keep a small margin of 2-3 cm. If necessary, it can always be leveled with more intense compaction. On average, the calculation is made from the fact that the layer of vegetation to be removed will be approximately 15 cm, the coating itself will take 6 cm, and the preparatory base with sand will be about 4-5 cm.
Instructions for arranging the blind area
When the vegetation layer is removed and the soil under it is compacted, you can start work on covering the blind area:
- The target area is being marked with subsequent delimitation by curbs - the opposite side relative to the walls.
- The initial backfill is made with crushed stone or gravel 5-6 cm thick. This layer must also be compacted.
- If you plan to install a soft blind area around the house, then under it it is desirable to organize a reinforcing cage to stiffen the supporting base.
- An insulator is laid - geotextile with sand sprinkling. However, it should not be made monolithic. It is recommended to leave expansion joints after 2-2.5 m.
- Requireda slope of 1.5-2% is maintained, that is, for every 50 cm, a bevel is made towards the curb by about 1 cm.
- The coating material in the form of tiles or paving stones is laid out on a sandy base.
- The resulting gaps are rubbed with special moisture-resistant solutions for tile joints.
Step-by-step instructions for installing drainage around the house
Configurations and options for organizing this drainage system may vary, but in the standard version it is implemented as follows:
- A circular trench with a depth of about 40-50 cm is being dug around the perimeter of the house. Contours also depart from it with a direction towards one point of collection or redistribution of wastewater.
- Points of potentially greatest accumulation of water are marked, after which deeper pits are organized in them - up to 100 cm, depending on the volume of expected drains.
- At the bottom of the trench, a sand and gravel cushion up to 20 cm high is laid along all lines. Again, expanded clay, crushed stone, and broken brick with pebbles can be used to fill it. The main thing is that the fraction is not less than 4 mm and not more than 30 mm.
- Waterproofing material is laid on the surface of the completed filter base.
- Perforated pipes are being laid. Mounting is carried out by segments that run without refraction in a straight line. Joints are made with fittings at the turning points.
- Sprinkling again with sand and gravel 5-10 cm thick.
- Trenches are covered with excavated soil, which is compacted.
Organization of drains for drains
Even at the stage of designing and drawing up a drainage scheme, you should consider the place of the final collection of wastewater. It is on him that the drainage network will be guided by the slope and direction of pumping from the pumping equipment. Both the blind area and the drainage around the house can act as sources for one drive, and the correct organization of wells for local collection of wastewater will allow natural drainage. The simplest solution is to dump water into a nearby body of water. One branch pipe is supplied to it, with which channels from different water collection points on the site are connected at the reception point. If this is not possible, then you can install a septic tank with biological treatment. It will ensure thorough filtration of the accumulated water, which can later be used for irrigation in the same area.
Conclusion
It is possible to solve the problem of soil erosion under the building without special equipment and structures. It is enough to use simple plumbing fixtures and bulk building materials. A typical concrete blind area is completely carried out according to the type of a conventional screed with the inclusion of a waterproofing agent. However, in order to increase the efficiency of the drainage on the site, it is still recommended to organize an integrated drainage system, which will eliminate the possibility of flooding the territory of the household during heavy rains. Moreover, as the example of using a septic tank shows, rainfall can be collected not just in order to protect foundations, but for subsequent use inwatering activities without harm to plants.
