Useful Tips

Recommendations for protecting basements from flooding


The fight against destructive power begins with identifying the causes of its occurrence. Having established the source of troubles, we can talk about the disappearance of moisture in the room. Specialists distinguish 3 factors of the appearance of dampness.

  • Penetration of groundwater into the basement. In this case, flooding occurs due to an error in the geodetic survey or its incorrect reading. It is worth noting that many owners of the site completely abandon exploration work, acting on the principle - "the neighbors are doing well, which means I will do the same."
  • Penetration of rain and meltwater is the most common cause. An absent or improperly equipped drainage and drainage system makes it possible for water to accumulate at the foundation, and then penetrate into the basement.
  • Emergency condition of plumbing pipes. The most easily removable origin of moisture.

The probability of flooding the basement should be calculated at the construction stage, it is necessary to make every effort to prevent it. In the course of the work, the relief of the site, the level of groundwater, the depth of the basement, etc. It should be remembered that a person can not affect nature, so saving is not worth it.

Moisture in the basement can be avoided by the timely organization of reliable waterproofing and drainage systems. However, there are situations when the house is purchased and already in the process of operation this problem is identified. Then laborious and expensive measures are taken to eliminate the water in the basement and prevent its reappearance.

Types of basement waterproofing

Of course, today the market offers many materials, each of which is appropriate in its place. Before you go to a hardware store, you need to know that there are 3 types of waterproofing:

  • Pressure head. Such waterproofing is done with groundwater above the floor. It is used only outside the structure. Here we need materials that resist the positive pressure of water.
  • Pressureless. This waterproofing protects the basement from melt and rainwater. Basically, it is needed if groundwater is deep and there is a low probability of their rise.
  • Anticapillary. The arrangement of such a system is used as protection of dense and porous concrete, brick structures from destruction. Previously, bitumen-based materials were used for these purposes; today, preference is given to penetrating compositions.

Materials for basement waterproofing from groundwater

For work, you can apply various materials that are conditionally divided according to the principle of application:

  • rolled or sheet materials on a bitumen or polymer basis adhere to surfaces in several layers. These include: ruberoid, hydrobutyl, stekloizol and others. Before drawing surfaces are leveled, dried and processed with a bituminous emulsion. For greater reliability, it is recommended to lay out the pressure wall of brick or concrete blocks with a width of 120 mm. The resulting gap between it and the waterproofing (up to 15 mm) is filled with masonry mortar,
  • penetrating materials are used for interior work. They give concrete foundation properties that do not allow water to penetrate into it under a certain pressure. It is applied to a damp surface, such a medium creates the conditions under which the composition forms crystals that fill all the pores and cracks. You should know that this mixture is used only on concrete surfaces of good quality, where the depth of the cracks does not exceed 0.4 mm,

  • smear materials - this is a fairly extensive category, including mastics, pastes and other similar compounds. So, bitumen with mineral additives is applied to durable moistened surfaces from clinker, concrete blocks, natural stone, etc. Such a material forms a waterproof elastic film. It resists water pressure perfectly, therefore it is used for arranging waterproofing only from the outside of the structure. Often, tar materials are used for external protection against pressure waters. They are applied to the walls and floor (before pouring it). Surfaces can be made of hollow blocks, concrete, limestone, brick, etc. Polyurethane coatings are also designed for the treatment of external surfaces. But here it is necessary to create conditions under which the substrate could provide good adhesion,
  • water repellents limit the interaction of the surface with water. It is advisable to use such materials for internal work with well-equipped pressure head waterproofing.

Basement water what to do?

Often, many owners of flooded basements neglect the laborious earthworks, wanting to make waterproofing in a simpler and more economical way. But such events will only lead to a temporary solution to problems.

High-quality protection of the structure can be ensured only by performing appropriate work outside the premises. In the absence of external protection, water penetrating through the wall and floor will eventually squeeze out the internal insulation.

External basement protection against groundwater

  • First of all, excavation is carried out around the entire outer perimeter of the basement. Walls are cleaned of impurities. Large gaps are filled with sand-cement mortar. If possible, all surfaces are aligned as much as possible.

  • For outdoor work, bitumen mastic is first used, then rolled materials are glued. It is important to ensure that the ends of the material extend beyond the walls by at least 20 cm.
  • For the same purposes, penetrating waterproofing can be used. The mixture is diluted according to the manufacturer's recommendations indicated on the packaging. Clots in the solution are unacceptable. The external corners of the room are brushed. Then the walls are processed with a roller; the layer thickness should be about 1 mm.
  • Drying of the surfaces will take at least 2 days, during which time the composition will penetrate the wall thickness by 30-70 cm (depending on the manufacturer). Properly done work will protect the walls from water penetration for a period of 40-50 years.
  • There are situations when access to the external walls is absent and excavation is not possible here (buildings are located close to each other), in this case injection comes to the rescue. Holes are drilled in the wall in a specific order into which polymer resins, microcements or acrylic gels are pumped under pressure.
  • Rapid drainage of storm water will provide drainage, laid along the perimeter of the structure or basement. Minimize the ingress of water into the basement and the installation of gutters and storm water inlets. A similar system is used for wastewater disposal; it is not used as the only protection against moisture entering the premises. Its use is advisable only in conjunction with other waterproofing works.

  • Upon completion of all work, the pit is filled up and the blind area of ​​the building is restored.

Basement groundwater protection

  • Getting started, you need to get rid of water. It can be scooped up with improvised means, which is very inconvenient, or use a pump. The choice of a drainage pump should for pumping water out of the basement is based on the degree of water pollution. If it contains fibrous inclusions, sludge and other large particles, then it is better to use a fecal pump. For example, a conventional drainage pump is capable of pumping water from a basement with a particle content of up to 7 mm, then the fecal aggregate will cope with particles of 50 mm.

  • Next, the room is dried. You can simply ventilate the room or use forced drying using infrared heaters, heat guns, etc.
  • The weakest points of the room are the corners. They are recommended to be laid with a waterproofing cord, swelling, it makes problem areas impervious.
  • It is advisable to fill the floor with concrete again, previously all the cracks in the old base are repaired. A layer of sand or expanded clay is filled up with a thickness of 5-10 cm, any waterproof roll material is laid on top. After processing with bituminous mastic, screed is filled with the addition of water repellents and modified fiber fibers, which will give it water resistance. Instead of concreting, you can install logs, and on them a plank floor.
  • Vertical surfaces are also cleaned of impurities, all large cracks are repaired by masonry mortar. Be sure to treat the walls with antifungal drugs. Bituminous mastic or other similar material is applied to the surface with a roller or brush.
  • Great attention should be paid to ventilation. Her job is to normalize the humidity in this difficult room. It prevents mold, eliminates the musty, unpleasant odor of dampness.

  • Supply and exhaust ventilation can be performed in a simplified form. One pipe should be placed parallel to the wall almost from the floor with an exit to the outside, using an elbow, the second should be placed under the ceiling, also with access to the street. The outer parts of the pipes are protected from ingress of melt and rainwater.

If the building is quite old and due to some circumstances it is not possible to carry out all the recommended repair work, then here you can advise the following:

  • fill large cracks with rags and coat with bitumen mastic,
  • organize a pit, that is, dig a hole about half a meter deep, the walls must be strengthened with masonry. Pour crushed stone of coarse fraction about 10 cm thick to the bottom. Install a drain pump equipped with an automatic switch-on system. As soon as the water reaches a certain level, the pump pumps it out. It is better to position the hose for draining water coming from the pump as far as possible from the structure.

Delivering yourself from time-consuming and quite expensive work, protecting things or winter blanks from spoilage with water, will help timely organization of waterproofing. During the construction process, all of the above activities can be carried out with great convenience.

1 How to pump water from the basement?

If at one fine moment you find that your basement or cellar is filled with water, then first of all you need to pump it out of the room, thereby preparing the front for further work on arranging the drainage system and waterproofing.

To pump water, you need a water pump. There are many varieties of such units, but in this case, two of them are best suited - drainage and surface pumps. Surface-type equipment pumps water through a hose, while the mechanism itself is located on dry ground. Such pumps are designed to work with relatively clean liquids; from pumping water containing a large amount of mechanical impurities, they can clog and fail.

However, if the water in the cellar is dirty, or you encounter regular flooding, you need to use a drainage pump, preferably with a float switch. Such equipment is classified into two varieties - pumps with upper and lower water intake, the differences between them are in the location of the suction pipe. To pump out the flooded rooms, a drainage device with a lower water intake is necessary, because if the pipe is located on the upper part of the body, you cannot get rid of all the water.

Varieties of drainage pumps

Pumps with a float switch are preferable due to the fact that by turning on such equipment you can leave it and go about your business, and the pump itself will turn off after water is pumped out. The float switch, visually representing an ordinary plastic box, opens the power supply circuit of the pump engine when it falls out of the water onto a dry surface, thereby preventing the equipment from running on dry run.

The pump power must be selected based on the size of the flooded room. If the problem is the water in the basement of the garage with an area of ​​up to 20 m, then a drainer with a capacity of 100-120 l / min will be enough, for small cellars you can take the cheapest vibration pumps at 40-50 l / min.
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2 Basement flood protection

To prevent further flooding of the basement or cellar, an integrated approach is needed, namely the arrangement of two protection systems - the installation of a drainage drainage system and the waterproofing of the basement walls. In already constructed buildings, it is best to do the internal drainage, since it is less time-consuming due to the lack of the need to dig the foundation around the perimeter of the house. Also, internal drainage should be equipped in cases when groundwater enters the basement of a residential building from the lower layers of soil, which happens with vertically directed hydrostatic pressure in the area.

A diagram of the internal drainage system is shown in the image. To equip such protection, you will need drainage pipes, inspection and collector wells, which can be purchased in ready-to-install form in construction stores.

Basement drainage system

Drainage pipes, if there is a screed, can be placed above the level of an existing floor, adding soil and building a second floor. However, if the height of the room is not enough, then the channels are laid below the floor, which will require partial disassembly. This is not a problem if there is no floor or screed in the basement as such.

PVC pipes with perforations with a diameter of 80 mm and more are used as drainage channels. To avoid clogging with soil, they must be wrapped with a layer of geotextile, which will act as a filter. It is necessary to lay the channels with a slope of 0.5 cm per linear meter of the pipe (towards the collector well). Keep in mind that drainage pipes, like their gravel bedding, must be above the foundation level, it is strictly forbidden to violate the integrity of the sealing pillow under the foundation.

Layout of drainage pipes

In places where the pipes change their direction (in the corners of the house), you need to equip the inspection wells. The soil that has penetrated through the filter layers will accumulate in them. Periodically, you will need to open the wells, pump out the accumulated water and rinse them with a strong stream of water. The bottom of the wells must be lowered below the level of the drainage channel by 30-50 cm. As the wells, you can use ready-made structures with a diameter of 300 mm, or you can independently cast them from concrete.

To equip the filtering bedding around the drainage channels, expanded clay, coarse sand or crushed stone should be used. The layer should surround the pipes 20 cm on each side, and the geotextile is isolated from the surrounding soil.

Filtration layer around the drain pipe

Water from drainage pipes must gravity drain into the collector well. As a collector, you can use any tank dug below the level of drainage pipes outside the basement. You will need a drainage pump to pump out accumulated water from the well in the future as it is filled.

The final stage of the installation of the drainage drainage system is the arrangement of the floor. The easiest way is to make an ordinary screed with a thickness of 5 cm or more. Basement floor waterproofing with the help of special membranes that fit directly under the screed on the surface of the soil will not be superfluous.
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2.1 Waterproofing the basement from the inside from groundwater

If a drainage water outlet is equipped, the likelihood that the cellar will flood again is practically reduced to zero. However, you may still be disturbed by fungus and mold in the basement, which are formed due to condensation on the walls due to the penetration of soil moisture through the walls of the room.

In this case, you need internal waterproofing of the basement, which is carried out with coating materials. Most often used bitumen mastic, which is the cheapest option. Previously, waterproofing the basement from the inside with liquid glass was practiced, but due to the availability of more effective analogues, its use is irrational.

The best quality basement interior waterproofing is obtained using penetrating compositions based on Portland cement and active chemical additives.

Penetrating waterproofing action

Penetrating basement waterproofing can be used in buildings constructed of heavy and cellular concrete. Such mixtures are supplied in liquid form, after application to the wall, the substance penetrates the pores of the concrete and expands, thereby clogging them and preventing the possibility of moisture seeping through the walls.

If you decide how to process the cellar and at the same time are not financially limited (penetrating mixtures are much more expensive than bituminous mastic), then compositions like Penetron, Dehydron and Kristallizol will be the best choice in terms of effectiveness.

Keep in mind that with internal waterproofing you only limit the possibility of moisture penetrating into the room, but its walls are also exposed to groundwater. Potentially, this significantly reduces the durability of the basement, because when freezing inside the concrete, water expands and breaks it, which causes cracking of the material.

Waterproofing the basement from the outside eliminates the negative effects of moisture on concrete, but its implementation, especially when working with an already built building, is extremely time-consuming due to the need to dig a trench around the perimeter of the foundation to gain access to its walls.

The exterior waterproofing of the basement with your own hands is done according to the following algorithm:

  1. The walls of the room are cleaned of soil and washed out, if any defects (cracks, chips) are found on the walls, they must be repaired with a sand-cement mortar.
  2. Bitumen mastic, acting as a bonding layer, is applied to the surface of the walls with a roller.
  3. Without waiting for the mastic to solidify, the roll waterproofing material is glued to the walls (work is carried out sequentially on wall sections equal to the width of the insulation roll).
  4. Mastic covers the joints between the waterproofing.

It will also be necessary to build a clay castle that will protect the material glued to the walls of the foundation from damage by soil masses. The castle is made of oily clay (sand containing less than 15%), its thickness should be at least 20 cm. The castle can be shaped and tamped both in the formwork and directly to the foundation pit.