Drainage system drainage system

The qualitative arrangement of a courtyard of a private house or country plot is impossible without a drainage system, especially if they are located in places where the amount of precipitation is above average or ground water approaches close to the surface. Extra moisture is not only puddles and permanent mud, but also a serious danger to the foundation of buildings.

In this article we will talk about what constitutes a device for drainage systems for a suburban area or a courtyard of a private house. In addition, we will consider what types of drainage structures are and how much it will cost to equip your site with such a system.

What is the drainage system

Drainage (drainage) system - a complex of aboveground or underground channels, designed to drain excess moisture. In other words, it is an artificially created watercourse, through which water located on the surface of the ground or inside it, is withdrawn beyond a certain area. There are only three main tasks for drainage:

• Reduction to the design value of the groundwater table;
• Collection and removal of melt water;
• Collection and drainage of water, resulting from prolonged precipitation of precipitation.

So does drainage

If you live in a warm region, where snow is a rarity, rains are 2-3 times a year, and groundwater is located at a depth of more than 50 meters, the installation of drainage systems is of no use to you. But if your house or dacha is located in the middle latitudes, where the winters are snowy, and spring and autumn are rain, you can not do without them. And the point here is not only that excessive moisture creates certain inconveniences and does not influence the plants growing on the plot in the best way. Water, penetrating into the crevices of the foundation of the house, can freeze, expanding them and thereby destroying the foundation of the structure. Groundwater, approaching the bottom of the basement, can contribute to the subsidence of the ground beneath it, and this leads to the appearance of cracks on the walls of buildings.

According to the requirements of the Guidelines for the Design and Installation of Drainage (2000), the installation of drainage systems is mandatory:

• For used buried structures located below the calculated level of groundwater, as well as when the floor level of the basement above it is less than 5 meters;
• Used buried structures in clayey and loamy soils, regardless of the availability and level of groundwater;
• Technical underground (basement) premises in clay and loamy soils, when they are buried more than 1.5 meters, regardless of the availability and level of groundwater;
• All buildings and premises located in the areas of capillary moistening, if they are used in severe humid and temperature conditions.

Based on which the calculation of the drainage system is made

The installation of drainage systems and storm sewage is carried out on the basis of data:

• On soil characteristics and soil structure;
• Average amount of water falling in the form of precipitation;
• The level of the location of groundwaters depending on the season.

Such information can be obtained by contacting the department (department) of the region's land resources (district).

Types of drainage systems

The arrangement of drainage and drainage systems involves the use of three types of their structures:

• Open;
• Closed;
• Zasypnoy.

Each of the structures under certain conditions can effectively cope with the removal of excess moisture.

Outdoor drainage

The installation of open drainage systems is the simplest and most widespread type of drainage of a site. The main element of this drainage is open channels (ditches) dug along the perimeter of the site. Usually they have a width of 0.5 m and are excavated to a depth of 0.6-0.7 m. The edges of the ditch are cut at an angle of 30 degrees so that water can easily enter it.

Wastewater collected in the surface discharge circuit, from it enter the gutter, which takes them out of the site into a specially designed drainage basin or into the central storm sewer.

The walls of each channel are strengthened with the help of bricks or concrete. Instead of these classical materials, special modern devices can be used - trays made of the same concrete or plastic. To ensure that the channel does not fall branches, leaves, stones, sometimes on top it is covered by a suitable size grating.

It is worth noting that such a drainage system, by its design, can not be used to reduce the level of groundwater. It is effective only for the drainage of water falling in the form of precipitation, and in the areas located on the slope.

The cost of installing an open drainage system is minimal. The construction of such a structure without taking into account the design will cost you about 1000-1200 rubles per running meter.

Closed drainage

If groundwater approaches too close to the surface, the best solution is to arrange closed drainage. Its design involves laying a trench system with a width of 0.3-0.4 m at a depth of 1.5 m. They are excavated under a slope in the direction of the drainage pit. Closed drainage, in addition to channels located along the perimeter, usually provides for internal channels located throughout the site in the form of a herringbone.

The bottom of each trench along the entire length is first covered with a layer of sand, and after it - a layer of crushed stone. Above such a "cushion" are laid special drainage pipes, wrapped in geotextiles. Above, the pipe is again covered with a large rubble, forming the upper water-bearing layer. Completes the construction of a ball of soil or turf.

What is the drainage pipe

A few years ago, drainage pipes were made of asbestos cement or ceramics. Naturally, the arrangement of the drainage system required significant costs, and could not always be carried out by own strength. Today everything is much simpler. Plastic designs have almost supplanted asbestos and ceramics. A modern drainage pipe is a reliable and durable element, easily mounted and repaired.

On sale you can find two types of pipes: conventional plastic with perforation and corrugated. The latter are considered more durable due to the use of stiffeners.

Drainage pipes laid in sand, clay or loamy soil, before installation are wrapped with geotextile. This is done so that the soil particles do not clog the holes through which moisture seeps. In other words, geotextiles serve as a kind of filter.

The cost of building a closed drainage is much higher. Here for the meter you have to pay 1500-2000 rubles. The estimate for the installation of the drainage system also includes the cost of pipes and geotextiles. On average, the running meter of the pipe will cost 40 rubles, and the geotextile - 30 rubles / m. Etc. The construction of a well with a depth of 3 and a diameter of 1 meter costs about 400 thousand rubles.

Backfilling drainage

The construction of a drainage system on the site with their own hands is best done using a backfilling drainage system. Structurally, it differs from the closed one in that no pipes are used here. Their role is played by large rubble or broken brick. The top layer is crushed stone of fine fraction and turf. The depth of the trenches and the location of the channels are the same as those of the closed drainage.

Water, seeping from the surface into the ditch or rising from the lower level, enters the channel and slopes toward the drainage well. Taking into account that free space is formed between the large rubble, the water practically does not encounter any resistance in its path, so the efficiency of such drainage is not inferior to the closed drainage system. But the prices for the installation of a drainage system of a back-up type are much lower, since this does not include the cost of geotextiles, pipes and their installation.

Wall-mounted drainage of buildings

If it is determined that the groundwater is approaching too close to the surface of the soil on the site, it is worth considering the organization of wall drainage. It will help to protect the foundation of the job from the formation of cracks in it and subsidence of the ground beneath it. By the way, the level of groundwater can be approximately determined by measuring the distance from the surface to the water in a conventional well. Do not forget to take into account that, in spring, the level will necessarily rise due to meltwater.

The installation of a drainage drainage system from the foundation of buildings begins with the determination of the penetration of its lower point. In other words, we need to know how deep the foundation goes into the ground. It is recommended to place the drainage system at a depth of at least 0.5 m from the bottom of the base of the building. Only in this case groundwater will be diverted earlier than they come to the foundation.

The drainage system around the house starts with excavating trenches along the perimeter of the building at a distance of 0.5-0.7 m from the walls. To ensure that water does not stagnate, the channels must have a certain slope in the direction of the location of the drainage well. If the site already has a drainage system, the wall drainage can be brought to it.

The drainage system of the foundation is built on the same principle as the closed drainage, i.e. using special perforated pipes wrapped in geotextiles.

To protect the foundation of buildings, it is not enough to use drainage only. A gutter system must be added to it in addition, which will divert water to the stormwater. At the same time, it is impossible to combine the two systems in any case, this will lead to the reverse effect. In the event of a large amount of precipitation, the drainage simply will not cope with its task, which will cause a significant overmoistening of the soil around the basement.

Calculation of slope

The effectiveness of the diversion of water from the foundation and the site as a whole largely depends on the correct organization of the slope, and the more it is, the better. What should be the deviation? The minimum normalized value of this value for clay soils is 2 mm, and for sandy soils - 3 mm for each linear meter of the system. But in practice, the incline is usually 5-7 mm per meter. To calculate it, the entire length of the drainage is taken, starting from its highest point and to the drainage well. If, for example, its length is 20 meters, then the minimum design slope should be 0.4 m, and the practical slope should be 1-1.5 m.

Common errors in the installation of drainage systems

In the construction of drainage systems, the following errors are most often admitted:

• Device for wall drainage without drainage system;
• Use of drainage pipes in geotextile winding in sandy loamy or loamy soils;
• Application in the design of drainage systems of liquid levels in place of the level and theodolite;
• Installation of stormwater wells instead of drainage.