Wall drainage of the foundation: technology and device diagrams

Country areas with ideal hydrogeological conditions are extremely rare. Basically they come with natural flaws, which can and must be dealt with. So, to combat the groundwater and flood water, wall drainage of the foundation is constructed. To work effectively, you need to know the specifics of the device. Do you agree?

We suggest to get acquainted with the rules of the construction of near-wall drainage, tested in practice. Reliable information is useful to owners who want to make their own water drainage system. The article will also be useful for those who order work in a profile company in order to control their quality.

We have spelled out a step-by-step technology for the installation of a system that drains the soil next to the base of the house. The article provides recommendations for the operation of drainage. In the analysis of a difficult topic will effectively help photo and video applications.

Purpose of wall drainage

Quite simple, but designed according to a precisely calculated project, the drainage system performs several important functions.

For example, it effectively protects the basement (if available) from the basement or the basement, which is usually equipped with both cottages and small country houses of temporary residence.

Deciding on the need for construction activities should be based on two "signals": the location of water horizons at a distance of less than half a meter from the lowest point of the foundation or the probability of the appearance of a water pipe in dangerous proximity to the building.

Another reason for the device of the wall drainage of the foundation - an aggressive composition of groundwater. The substances dissolved in a liquid medium have a negative effect on the base material, destroying it over time. In this case, it is necessary to calculate the feasibility of double protection - drainage and reliable waterproofing.

In case of violation construction of a blind area or permanent water leaks in the basement zone (for example, in case of improper installation of drainage equipment) shifts occur in heaving soils saturated with excess moisture. To avoid deformation of concrete or brick structures, drainage is also necessary.

Sometimes in the process of building a building it is necessary to carry out activities that provoke a change in the location of groundwater. Accordingly, in these cases it is also necessary to take care of the functional drainage system.

Here is a list of some unwanted design decisions:

• the device near the construction of closed areas without proper pumping of fluid;
• insufficiently thought-out system of drains and elements of storm sewer;
• equipment near the house of a pool, pond or other reservoir with a disturbed filtration system and emergency drainage;
• violation of building construction technologies (backfill filtration coefficient is not considered);
• retaining walls are installed in the ground to prevent the outflow of water.

Each of these factors at any time can cause flooding of the foundation, which will later be difficult to cope with.

Measures for the installation of drainage structures are performed, based on the provisions of SNiP 3.07.03-85 (specifically on drainage) and SNiP 3.05.05-84 (on pipelines).

The principle of the drainage system

The action of drainage is fully consistent with its main purpose - the removal of excess moisture to a safe distance. It would be a mistake to assume that one pipe laid along the perimeter of the house can cope with this problem.

In fact, it is a whole engineering and construction complex, which fights against an excess of moisture, protecting foundations and basements, but without overdrying the surrounding area.

Wall drainage type is advisable in conditions of clayey soil and loams, when thawed, rainwater and groundwater cannot independently leave the zone located around the building. The complex construction of pipes, wells and outlets removes excess water quite effectively, despite the budget cost.

One of the popular schemes involves the connection of two systems - drainage and storm - in the zone of the accumulation well, which is usually located at the lowest point of the territory adjacent to the house.

In practice, it is often used option when the drainage pipe is cut into the manholes storm sewer. However, this is possible only under one condition - if the total amount of waste does not exceed the norms calculated for the installed equipment.

If the discharge zone is located above the water level in the tank, it is necessary to install pumping equipment. The popular option is the submersible. drainage pumpmatched by power.

There are two options for arrangement drainage around the foundation: traditional and more reliable. Traditional - is the installation of pipes with gravel filling, filter and clay lock. Its performance has been proven for decades.

More reliable modern drainage differs in design of the base. A geomembrane is fixed over its entire width, the characteristics of which are not inferior to a clay castle.

The installation process is much simpler if only because it is not necessary to do calculations and calculate the angle of inclination of the clay “plug”. Now almost all wall drainage schemes include the use of a geomembrane, because it is reliable, practical, fast and efficient.

Step-by-Step Technology

The process of the device drainage for the foundation can be divided into several stages. The first step is to create a project that is best left to a professional engineer. The project should contain general drawings and diagrams, a detailed description of the drainage equipment, an action plan, an estimate.

Step # 1: Planning and Performing Calculations

According to the standards, the drains are laid along the walls of the building at the level of the foundation base or below it on 0.3-0.5 m. This prevents the accumulation of moisture in the upper layers and provokes the drainage of groundwater to the lower levels. Slope parameters are standard - 0.02 m per meter of pipe.

Suppose, when taking into account the norm, the difference between the beginning and the end of the 40-meter pipeline is 0.8 m (2 cm x 40). These calculations are important for trenching equipment.

If the house is a simple rectangular configuration, manholes arrange only 2 corners. Larger buildings with a more complex shape are equipped with 4 wells.

When calculating the total length of the pipeline, we do not forget that it will be located at some distance from foundation, that is, the length of a branch along one wall will be at least 2 m longer than the length of the walls.

If it is not possible to provide a gravity system, it is necessary to connect pumping equipment. When choosing a drainage model, pressure (height of water rise) and performance are important. The optimal power of household models is 400-1000 watts.

Step # 2: Preparing Materials and Tools

With the advent of new building materials on the market, designing a drainage system has become much easier. Polymer pipes and fittings for them, elastic insulation, geomembrane, geotextiles - all of these products can be purchased at the building supermarket.

You do not need to prepare, as before, special solutions for waterproofing the foundation or look around the area for clay with special technical characteristics.

So, to trench the device will need the following tools:

• level;
• perforator;
• shovel;
• bucket;
• pickaxe or crowbar;
• wheelbarrow;
• tamper for sealing backfill.

The main tool - working hands, the more of them, the faster the process of digging and backfilling.

For the pipeline system, polymer pipes (HDPE, polyvinyl chloride, polypropylene) are needed, as well as couplings and elbows of similar material. Does not interfere and sealant for exterior work.

If the area of ​​pipe laying is not below the level of freezing, as recommended by SNiP, and at a shallow depth, artificial insulant may be required to prevent the formation of ice and ice plugs.

The device of the filtering layer is made with the help of geotextile and crushed stone (gravel) backfilling with a fraction of 0.3-0.4 cm, you will also need coarse sand. For waterproofing, you can use traditional bitumen mastic or profiled membrane, but it is better to use the combined method of protecting the foundation.

Step # 3: Select Drainage Pipes

Separately, we will focus on the choice of drainage pipes, because they are the main parts of the drainage system. According to the recommendations of the SNiP, it is possible to use ceramics, asbestos cement and plastic, but recently the first two options are practically not used.

Ceramic and asbestos-cement products are heavier than polymer analogues and have a more fragile structure. Plastic pipes (drains) differ in small weight that is welcomed when transporting and installation, and also high rates of durability and wear resistance.

Material for the production of pipes - PP, HDPE and PVC. Plastic drains are not deformed under the pressure of the soil, they tolerate an aggressive composition of groundwater, have a long service life (up to 40-50 years).

The main difference between drains and ordinary pipes is the cuts, which, when laid, are located on the sides. To protect the holes from clogging with soil and sludge pieces, an effective geotextile filter is used. There are smooth and corrugated types, the latter are more elastic and at the same time rigid.

The choice of the type, section and method of installation of drains depends on the type of soil and volume of water. For example, if macadam soil predominates at the construction site of a building, no additional measures are needed to create a filter - just dig a trench and install a pipeline.

For pipes located in clay soils, crushed stone is required, 0.20-0.25 m thick, and in loams additional protection is required against silting in the form of geotextile winding. The structures placed in sandy ground require maximum attention: crushed stone and geotextiles are also needed.

Step # 4: Trenching Device - Excavation

Having prepared the material, you can begin to mark the place for laying drains. To make it easier to determine the scope of work, pegs are placed along the contour of the trenches and a string is drawn between them. Earthworks is the most labor-intensive part of the drainage device.

Pulling trenches, you need to follow a slight slope of the bottom in the direction of the drive. For accuracy use a level and landmarks with which it is easy to determine the height difference.

For more accurate slope compliance usually use sand, which is part of the filter. By the way, when using factory-made decks, equipped with a geotextile layer, another “cushion” will not be needed - rather sandy.

Having equipped a trench along the foundation, it is necessary to dig a pit for an accumulation well and another ditch - for diversion of water outside the fence (if all the water is not planned to be used for irrigation or technical needs).

A few tips with an eye to SNIP:

Step # 5: Waterproofing the foundation with a membrane and bitumen

Waterproofing concrete parts of the foundation is necessary in any case: even if there is no utility room or storage for canned vegetables inside the basement. A dense layer of protective material will increase the strength of concrete structures and protect them from regular washing out with groundwater, if the drainage system does not cope with their volume.

Bitumen mastic is traditionally used to treat the walls of the foundation - to increase its water-repellent qualities, it is applied in several layers. In the joints of concrete structures can additionally be made of fiberglass reinforcement.

The thickness of the bitumen layer depends on the depth of laying: up to 3 m is enough 2-millimeter bitumen layer, more than 3 m - up to 4 mm. When the bitumen dries, PPM is fixed over the entire width of the foundation - a profiled polymeric membrane of the roll type.

More expensive types of PPM are initially equipped with a layer of geotextiles. There are three-layer products, further reinforced with plastic wrap. Roll roll along the basement, trying to leave as little as possible docking places.

The principle of membrane protection is simple: water seeps through geotextiles, collides with waterproof polyester material and rolls down to drainage pipes.

Depending on the method of hydroprotection of the foundation and laying of drains, it is necessary to prepare separate construction materials:

Step # 6: Laying the pipeline around the perimeter

Suppose that the required slope of the trench bottom (2 cm / 1 m) is taken into account even at the digging stage.

The conventional method of laying pipes looks like this:

• A layer of sand (0.15-0.20) m is filled to the bottom.
• Spread geotextiles roll over the entire length of the trench, the edges of the canvas are fixed in the upper part of the trenches.
• A thick layer (also not less than 0.15 m) of clean rubble is poured on the cloth. After each event, check the magnitude of the slope.
• Lay pipes with a diameter of 0.11-0.20 m with holes in the side, short fragments are connected by couplings.
• If the pipes do not have a protective layer, they are wrapped with geotextile and fixed with polymer twine.
• On turns, in places of drops and connections of drains, inspection wells are arranged. It is possible to use pipes of wide section, equipped with covers (further they will be required for flushing the pipeline).
• The drains are covered with a layer of pure rubble (0.15-0.20 m).
• The free edges of geotextiles are laid with an overlap on top, for fixation they are covered with a heavy layer of clean river sand (in some cases, to the level of the ground).

At the very end, when all pipes are laid and mounted inspection wells, make backfilling - return part of the soil to the place, slightly stamping it.

When installing pipes, do not forget about the concrete pavement - a necessary protective element that is laid along the wall of the house. The blind area - from 0.5 m to 1.0 m.

Step # 7: Installing a Drainage (Manifold) Drive

The simplest is the scheme in which the highway is taken out of the line without equipment. drainage well. However, its presence is still necessary if:

• derived drainage water is necessary for irrigation of crops or plantings;
• additional storage is a backup storage of technical water;
• There is no way to discharge water outside the site.

In the latter case, they often equip not a reservoir, but a filtering well, which, instead of the bottom, is equipped with a powerful gravel-sand backfill filter.

For the construction of the tank using brick, concrete rings, but in connection with the progress in the manufacture of special equipment increasingly began to install ready-made factory tanks from polymer material.

A solid plastic barrel is mounted on a flattened bottom and covered with soil. In the upper part there is a hatch through which it is easy to access the water and equipment.

Valuable tips and tricks

If you follow the rules below, the problems with the functioning of the drainage system will be much less.

• Drainage pipes are mounted along the lower boundary of the foundation base. The permissible step up / down is from 0.3 m to 0.5 m. If you lower the drains below, the groundwater and rainwater will systematically flush out the soil from under the foundation, which is fraught with the building subsidence.
• If it is not possible to protect the foundation with a geomembrane, it will be necessary to construct a clay castle.
• The level of accumulation of drainage water (drain zone) should be below the level of the clean floor in the basement or cellar.
• Backfilling with river sand is more effective than backfilling with “native” soil.

Considering the dynamic movement of groundwater, be sure to fix geotextiles when installing the pipeline. It should tightly, without gaps, cover the filter "roll".

For more effective removal of excess moisture along with the wall drainage install gutter system and stormwater - underground or outdoor.

Conclusions and useful video on the topic

Three interesting videos will help you learn more about drainage systems.

Video # 1. Useful information about the purpose of drainage systems:

Video # 2. Nuances of the choice of drains:

Video # 3. Drainage Tips:

A professionally designed and installed wall-mounted system is the guarantee for the protection of the foundation and basement room.Equipping your own water disposal, remember that it is better to entrust the calculations and preparation of the project to specialists, and you can implement the plans yourself.

Tell us about how you organized the drainage system for the removal of groundwater and flood water from the foundation of the house. Please write comments in the box below. Here you can ask questions, share useful information, post a photo on the topic.