Water is a serious danger for underground basements and cellars. Therefore, external waterproofing of the basement must be carried out even during the construction of the house. When the building is built and in use, only internal protection from water contained in the soil and falling precipitation can be organized.
Basement waterproofing from the inside against groundwater is carried out using various building materials, the choice depends on the type of foundation. The level of water in the ground is of great importance for the choice of the type of waterproofing. If they come close to the surface so much that they are above the zero level of the basement floor, they exert significant pressure on the foundation, causing the risk of flooding, especially in the off-season. When groundwater is deeper, it seeps through the thickness of reinforced concrete, thereby destroying it.
Due to moisture, metal structures crumble and become discolored, it has a negative effect on the indoor microclimate, leads to an unpleasant air odor, and mold formation in the basement. It is impossible to store food products and tools in such a basement – they quickly spoil and become unusable over time.
In addition to interior waterproofing methods, addressing water damage promptly is crucial to maintaining a dry and safe basement environment. For those experiencing significant water intrusion issues, seeking professional assistance can be invaluable. Services like Portland water damage restoration offer expert solutions to mitigate and repair the effects of water damage, ensuring that your basement remains protected against future groundwater challenges. By combining effective waterproofing techniques with professional restoration services, homeowners can achieve a comprehensive approach to basement protection, safeguarding their property from potential water-related issues.
What kind of water can harm your home?
For basements, semi-basements, and for the house as a whole, water is the main destructive factor. There are three types of threats to the house that come from water. The danger is represented by:
- Capillary water is free moisture contained in the upper layers of soil. It slowly but surely moves up the vertical and horizontal structures of the house – the process of capillary rise occurs, which occurs in the direction opposite to the action of gravity. Moisture fills the smallest pores and cracks in the walls, crosses the ceilings. Capillary rise leads to the growth of cracks, damage, defects in the walls, ceilings of the house.
- Groundwater – moisture is constantly present in the soil layers, which can reach the floor and basement walls. The level of groundwater rise is constant in the absence of floods and rains, but during heavy rains or active snow melting it can increase significantly.
- Perched water is groundwater that accumulates in the upper soil layers and is usually formed under clay and loamy soils. Perched water can only appear in the off-season.
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Types of waterproofing
We will tell you what types of waterproofing are encountered in construction practice.
Roll-on waterproofing
This method of organizing waterproofing is carried out using roll materials. They are based on bitumen-polymer mixtures or oxidized bitumen. After careful preparation of the surface for work, the rolls are unrolled, placed on the surface, and in the areas of overlaps they are glued with bandage tape.
Fused waterproofing
This type of waterproofing is a special case of the adhesive type. When it is implemented, several different layers (each one solves its own problem) of polymer bitumen are usually formed. Melting is performed, as well as fixation of the edges by heat treatment. It is the polymer additives that give the bitumen the necessary strength and plasticity. The method uses polymers in the form of thermoplastics and vulcanized rubber.
Penetrating waterproofing
This type of waterproofing, in addition to penetrating compounds, involves the use of the following materials: water repellents, bentonite cord, and hydroseal. There are many building materials for penetrating waterproofing, they differ in composition, properties, penetration depth, and durability. Such compounds are often used to waterproof a basement from the inside against groundwater, even if there are leaks, unless the basement is completely flooded during the period of high water – almost to the ceiling.
Membrane waterproofing
This is also a type of roll waterproofing, where the working material is polymer films. They are impermeable from the outside, but allow water vapor to pass through from the inside. Their main advantage is their lightness and very small thickness – a few millimeters of material are enough to provide good protection on both sides. Most membranes are used in basements for external waterproofing, but membranes (with spikes) are widely used when waterproofing a basement from the inside from groundwater.
Injection waterproofing
The technology is carried out by preliminary drilling of holes (pits) for special tubes – packers. The injection composition can flow to the protected area by gravity, then the holes are drilled at an angle of 40 degrees relative to the horizontal. Pumping equipment is also used, then injection is carried out under pressure. In this case, the work is faster, but it is necessary to assemble an injection unit. This waterproofing technology is the most modern, as well as the most effective.
External pressure-resistant waterproofing
At a high level of ground moisture rise, they resort to counter-pressure waterproofing of basements. It is capable of holding back the water pressure from the surrounding soil. However, external waterproofing works using this technology are much more effective if they were carried out at the construction stage. The point here is in the principle of action of counter-pressure waterproofing – it uses its own water pressure. The pressure presses the waterproofing materials to the surface, a dense barrier is formed that does not let the water go further.
Only in exceptional situations is external pressure-resistant waterproofing carried out after the house or building has been put into operation. There are many difficulties here, because in order to carry out preventive maintenance or repairs later, it will be necessary to excavate the structures, that is, to carry out complex underground work. Therefore, it is extremely important to initially install such waterproofing with high quality. High-density concrete and some roll materials are used in the work.
Internal pressure-resistant waterproofing
Backpressure waterproofing of the basement from the inside from groundwater will put a reliable barrier in the path of the latter. It is worth resorting to the method when groundwater rises above the basement floor, especially its walls. For a long time, such a waterproofing technology could not be implemented – the method was considered almost impossible. The problem was in the negative pressure of the water that surrounds the basement from the outside. Later, building materials appeared that have an effect even under negative pressure. Such materials are universal – they can be used outside and inside.
In internal pressure-resistant waterproofing compositions, a polymerization reaction is triggered upon contact with moisture. Each pore, hole, crack begins to quickly fill with a moisture-repellent substance located on the inside of the basement. Any leaks after the completion of pressure-resistant waterproofing are excluded.
Waterproofing to protect against capillary moisture
Serious problems can be caused by the rise of moisture contained in the soil through capillaries. These are narrow channels, porous bodies, voids that penetrate the concrete inside. According to the laws of physics, the pressure that pushes moisture up and to the sides increases as the size of the capillaries themselves decreases. Water begins to threaten the integrity of the concrete structures of the house, causing damage to the walls, internal partitions, supporting rafter beams located along the perimeter of the house.
The most effective protection against this undesirable effect will be external waterproofing, correctly performed at the construction stage. For such waterproofing, bitumen mastics, liquid rubber, and some cement-containing penetrating compounds are used. Of course, it is possible to treat the external surface of the walls with water repellents, but it is still much better when everything is done in advance.
When waterproofing the basement from the inside against groundwater, the only type of protection against their capillary rise will be penetrating waterproofing. The compositions used in this case fill the smallest cracks, up to four tenths of a millimeter in diameter.
Types of wall protection
The walls of a house or building, especially those located in a basement or cellar, i.e. below ground level, require waterproofing. As applied to basements, there are two types – anti-capillary and non-pressure waterproofing.
Anti-capillary protection
The effect of capillary rise of groundwater is not limited to the consequences already mentioned. This effect significantly impedes the permeability of walls for water vapor. The reason is the salts of groundwater, which seal the cavities of the walls after the evaporation of moisture from their surface.
Injection waterproofing is effective against capillary rise . All moisture contained in the thickness of the basement walls and ceilings is completely displaced by polymer-based working compounds. A screening shield is formed that withstands low temperatures, significant mechanical loads, and is impermeable to water. Additionally, it serves as an element that strengthens the entire structure from the inside.
To implement this method of basement waterproofing from the inside, two-component solutions containing acrylates and polymers are used. Pumping equipment and injection tubes are involved in the work. Polymerization occurs inside: the process usually lasts from several minutes, but sometimes lasts up to one hour.
Injection of acrylate-based gels is used for volumetric, veil and cut-off waterproofing. The latter effectively combats strong pressure leaks.
Non-pressure waterproofing of walls
This type of waterproofing involves using bitumen-containing mastic, which is applied in several layers to the surface of the walls and floor of the basement. It is used only if there are no leaks. In addition to basements, this type of waterproofing is used if it is necessary to protect ceilings located in humid conditions from water. This type of waterproofing is also used in underground parking lots, on fields with installed drainage systems. After applying bitumen mastics, sand consisting of relatively large fractions is immediately laid out on the surface.
Types of wall coverings
The main purpose of materials used for waterproofing basement walls is to seal cracks. The most difficult, but very important, is to introduce protective coatings into the areas where blocks join and into corners.
Roll and welded materials
The most commonly used building materials are roofing felt and the already described bitumen mastic. Roll materials are glued directly to the heated bitumen mastic. They are overlapped, and the joints (as well as the places where the walls connect to the base) are melted with a blowtorch. If the groundwater pressure is not high enough, this method is quite applicable. However, these materials are often used for external waterproofing of the basement.
Waterproofing plasters
These are substances that necessarily include elastic components. Waterproofing plasters include cement-sand, polymer-cement, and glass-cement mortars containing sealing additives, and shotcrete from a cement mortar with colloids. Asphalt concrete with small fractions is also used. Asphalt plaster waterproofing is performed using such a composition.
After applying the primary layer to the prepared and dry surface of the walls, you need to wait 2-3 days, but take care of the constant moistening of the first layer. Otherwise, the walls may become covered with cracks. The next layer or two are placed using the “wet” method. Each of them is kept for about a day. Such plasters simultaneously level out minor irregularities in the walls and on the floor.
Membranes
Thin membrane materials perform, in addition to waterproofing, functions that protect the insulation. If the insulation layer gets wet, it will lose its inherent heat-insulating properties. Then additional heating will have to be installed in the basement. Membranes used to waterproof the basement from the inside against groundwater are made of polymer thermoplastic vinyl chlorides (PVC) or olefin (TPO), or synthetic rubber. The latter is supplemented with additives that improve the elastic and strength properties of the material.
Injectable formulations
The materials used for wall injection are mineral and polymer. In the first case, the result (waterproofing) is achieved by crystallization of the mineral base of the substance, which forms a water-impermeable, rigid barrier. Microcements and silicate materials (emulsions) are classified as minerals.
Elastic polymers are polyurethane, epoxy resins, acrylate-based gels, bentonite clays. Polymer compositions are characterized by excellent adhesion to all building materials, high penetrating ability, and strength.
Penetrating mixtures for basement waterproofing
We are talking about composite compositions consisting of a cement base and polymer components. Penetrating substances for waterproofing are produced as dry mixtures. They must be diluted with water in the correct proportions, which are specified by the manufacturer in the attached instructions for use. Such materials for waterproofing are applied manually, using a spatula or brush. Pneumatic distribution is possible, using a pump.
Among the ingredients of penetrating mixtures for waterproofing are mineral salts, which, obeying the effect of osmosis, enter the capillaries and small cavities in concrete or brickwork. When they encounter moisture on their way, they crystallize, preventing water from getting into the pores.
Liquid rubber
This is the professional slang for an instant-hardening compound based on a bitumen-polymer emulsion. It can be single-component or include two components. It is applied using the cold method, and does not contain solvents. Liquid rubber has many properties similar to regular rubber – elasticity, water resistance, and black color. An additional advantage of the material is its non-toxicity – even when exposed to oxygen, it does not emit volatile poisons. Liquid rubber can be based on natural rubber, but it is more often bitumen.
Ribbon products
In essence, these are adhesive tapes designed to seal seams, joints, problem areas where building elements or structures are connected. Waterproofing a basement from the inside against groundwater rarely does without special treatment of hard-to-reach areas. It is for such areas that tape products are needed that provide additional antifungal action and prevent the appearance of mold. The base is a polyester fabric with a mesh structure or thin aluminum foil.
Bitumen or butyl rubber is applied to the base. Sometimes bitumen acts as both an adhesive base and a sealant in such materials. Decorative finishing applied over such waterproofing materials will retain its original appearance for a very long time.
Sanitary and technical norms and rules
Waterproofing of basements and ground floors in buildings related to individual housing construction (IHC) must comply with the provisions of SNiP 2.03.11-85.
Sealing of the basement in buildings that are individual housing construction (IHC) objects must comply with the requirements of SNiP 2.03.11-85. The set of sanitary rules prescribes preliminary preparation of surfaces.
It is necessary to widen, clean and seal all cracks. It is necessary to remove concrete slabs, rust particles, dirt from the surface. It is also necessary to prime as a preliminary preparation for the installation of waterproofing. According to the specified SNiP, the degree of humidity of concrete cannot exceed 4%. It is often necessary to reduce the humidity of the building material, for this purpose they use large fans, heaters, construction hair dryers.
Joints are sealed separately for waterproofing. For this purpose, each corner is sealed with an additional sealed layer. SNiP recommends using hydrosol, the layer thickness should be two centimeters.
How to protect the basement from the outside from groundwater
We have told a lot about the technologies and materials used to waterproof the basement from the inside against groundwater. As already mentioned, external waterproofing of the basement must be organized even during the construction of the house or building. The method depends on the type of foundation, the nature and severity of defects on its surface.
If the foundation is monolithic (strip), roll materials for waterproofing are installed on the bottom of the pit. Some sprayed materials are also used. With a prefabricated strip foundation, many seams are formed, which are sealed from moisture with bitumen compounds. Other types of waterproofing will not be effective.
Slab foundations are initially covered with sand (compacted with M-100 concrete). Sprayed or rolled materials are used for waterproofing.
