If the site has a high level of groundwater, then such conditions can harm garden plantings and foundations. As a result of this, a building can produce uneven draft, walls will change geometry, like doors, windows and roofs. Constant humidity at the base of the wall material can cause the formation of fungus, which leads to poor health of those living in the house.
The need for a drainage system
If you know that the groundwater in the area is too close to the surface, then you need to take care of the drainage system. It allows you to drain excess moisture around the perimeter of the site, while the health of your loved ones is preserved, and the plants in the garden, as well as the foundation of the house, do not suffer. In order to carry out the drainage system, it is necessary to become more familiar with the technology of work and ensure the slope of the pipe in accordance with sanitary norms and rules.
Pipe slope
Previously, plastic products for drainage systems were not produced. They were replaced with ceramic, asbestos-cement or steel pipes. For a complete drainage system, it was necessary to manually make holes. Such work could not be called easy, in addition, the holes were clogged with soil over time, which nullified all efforts to set up the system.
Today, various pipes in a large assortment are for sale. It is best to purchase corrugated made of plastic. They already have finished holes. In order not to become clogged with soil and silt, it is necessary to use low-density geotextiles, which are quite cheap.
However, it is important not only to choose the right materials, but also to ensure the slope of the drainage pipe. It should be directed to a place of water collection, for example, a well. The technology of laying the system provides for the installation of several drainage layers, they are located at the bottom of the trench and consist of sand and gravel. However, to begin with, the bottom and walls must be covered with geotextiles, only then sanding is carried out, and after that, from crushed stone.
What values should be followed
The slope should be maintained within 3 ° throughout one branch of the drainage system. Sometimes the installation diagram looks like a Christmas tree. At the same time, layering of perforated pipes according to the type of branches that extend from the tree trunk should be brought to the main drainage pipe.
Viewing wells are located 50 m from each other. They should be on the bends of the drainage system or a change in the slope of the pipes. It is important to remember that if the slope was not provided, then gravity water will not be able to drain into a storm sewer or drainage well.
If you will be engaged in the device of a closed system, the trench is located in the ground with a depression in the range from 70 to 150 cm. The width of the pit can be equal to 25-40 cm. The slope should be directed to a natural or artificial water intake. It is provided taking into account sanitary norms and rules.
For each running meter, the slope should be 3 cm, if you have to work in clay soil. When there are sandy soils on the territory, the slope is 3 cm per linear meter. The slope is provided by a gravel cushion on which the drains are located. The latter are corrugated perforated pipes. They turn into geotextiles, which will protect the system from soil and debris.
After laying the pipe, the slope must be checked again. To do this, you can use a conventional cord that stretches along the piping system. When carrying out work, SNiP are necessarily observed. The slope of the drainage pipe by 1 meter according to them is 3 cm.
SNiP
When designing, it is necessary to give preference to water drainage by gravity. Forced pumping requires additional justification. The use of vertical drainage and its water intake is provided for in the soil with high permeability. Open trenches and drainage channels are arranged in those cases when it is necessary to drain a large area. Their use is also possible to protect against flooding of terrestrial communications.
If you study SNiP, the slope of the drainage pipe by 1 meter should be approximately 3 cm. But as the material of the pipes, you can use not only the above options, but also reinforced concrete products, as well as pipes with a filter made of porous polymer concrete and ordinary concrete. In non-aggressive soils, reinforced concrete, concrete, as well as asbestos-cement pipes are used.
Having studied SNiP 2.06.15-85, you can understand that the depth of the drainage from the pipe filters is determined by the load. The size and number of water inlets on the surface of reinforced concrete, concrete and asbestos-cement products should be determined taking into account the culvert capacity and drainage rate.
What you need to know about the diameter of the drains
The minimum slope of the drainage pipe can be 0.5 cm per meter. The maximum value mentioned above. As for the diameter, the most common and recommended type of pipe is a corrugated single-layer product per 100 or 110 mm. Such a pipe is enough to drain water from a medium-sized house.
Providing a slope of the drainage pipe of 110 mm, you must take into account the depth of freezing of the soil, the level of groundwater and the relief of the site. Quite often, drains are located around the perimeter of the house. The lower the permeability of the soil, the greater the slope. This applies to clay soils.
For reference
Some sections of the flexible pipe should not sag, because otherwise, water will stagnate in these zones. What slope the drainage pipe should have, you now know. However, it is important to know also about the features of the technology. For example, when cornering, the pipe is usually laid in a straight semicircle. Bends close to the right angle should be avoided, as they may impede the flow of water.
Pipe installation: preparatory work
Before you start laying the pipe, you need to draw up a site plan and create a project. The latter will determine the location, depth and length of the trench, and also allow you to understand in what places should be located viewing and drainage wells. It is important to take into account at this stage, according to which technology water will be discharged, it can be a capacity for collecting water or storm sewers.
If the slope of the drainage pipe is known to you, then in the project you must indicate the level of groundwater occurrence, as well as the type of soil on the site and the freezing line of the soil. Before laying drainage pipes, it is necessary to prepare a trench. It should be 50 cm wider than the pipe diameter. If the freezing line is small enough, then the worker can fit in such a trench. With an impressive depth of freezing, it will be more convenient to dig a hole when the space allows you to turn around there with a shovel. The main thing at the same time is to observe the bias from the house to the drainage wells or the place of water collection.
Methodology
The slope of the drainage pipe must be provided at the excavation stage. Next, you need to prepare a pillow of sand and gravel, laying it at the bottom of the trench. However, to begin with, the bottom and walls must be covered with a geotissue, then sand is added, the next layer will be crushed stone. A perforated pipe is laid on it, which is filled in the reverse order - crushed stone, sand, geo-fabric and the selected soil. Manholes will be needed to clean the clogs and to monitor the water level in the system. If water drainage during the installation of the drainage system is provided for in an open reservoir or storm sewer, then check valves must be provided at the ends of the pipes.
How to avoid mistakes
Even if the slope of the drainage pipe has been observed correctly, the system can work intermittently. Sometimes this leads to a violation of technology or work sequence. If at first you poured rubble, and then sand, then the result may be a clogging of the holes in the pipe. If the dumping was not done at all, then this can also lead to problems.
If you did not provide a slope, then water can not drain by gravity into a storm sewer or a well. Even if the work was carried out correctly, and the drainage system works flawlessly, it must be remembered that such a device requires periodic maintenance and inspection. These manipulations consist in measuring the water level in the wells, cleaning the system of accumulated dirt and debris. After installing the drainage pipes, the system must be inspected four times a year.
Specialist recommendations
When carrying out excavation work, it must be remembered that the ditch should expand on top. To prevent freezing of the system at low temperatures, it is necessary to lay pipes below the freezing line of the soil. For the correct operation of the system, it is not enough to ensure the correct slope of the drain pipe. It will also be necessary to make a blind area from the foundation to the drainage under a slight slope. This will allow rainwater to enter the catchment.
After 15 cm of sand is poured into the ditch, crushed stone is laid on top, its layer will be approximately 20 cm. Pipes are laid on the base, which can be wrapped in a building non-woven. It has good water permeability. When the slope of the pipe between the septic tank and the drainage well was arranged, you need to think about what material to use as a filter. It may also be coconut fiber. For loam and sandy loam, non-woven or needle-punched textiles are usually used , which serves as a filter. On sandy soils, fiberglass will be an excellent option.
You should not be afraid to increase the cost of work by laying biomaterial between the layers of crushed stone and sand. This will eliminate siltation and make system maintenance less necessary. In addition, this approach helps to extend the operating time.
Installation of drainage pipes is necessarily accompanied by trimming of products. To do this, use a mounting knife. Parts are interconnected by special couplings. To increase the strength, you can use a welding machine.
Conclusion
Drainage is used today in agricultural technology and construction. Using a special system of canals, wells and drainage wells, as well as pipes and other devices, it is possible to drain excess water from the surface of the soil and underground space. It is important not only to choose the right materials, but also to ensure the slope of the drainage pipes. In general, such a system is needed if an elevated level of groundwater is noted in the territory. But if the building is being built with a basement, then you can’t do without a drainage system at all.