Coating waterproofing is one of the types of foundation protection against moisture penetration into concrete. This waterproofing perfectly protects against capillary moisture, but at the same time hydrostatic pressure should be less than 0.1 MPa. For coating protection, materials such as polymer or bitumen mastic are used, on the surface of which a film appears that does not allow water and other liquids to pass into the foundation.
The strength of coating waterproofing is low, so it is not used as the main protection for horizontal protection of the foundation. In this case, coating is used as additional waterproofing along with other types of surface protection. The coating can serve as the main surface protection for vertical (lateral) waterproofing. Today, bitumen coating waterproofing is the most affordable and popular method of lateral protection; in addition, the price per m2 is affordable for everyone.
Materials for coating waterproofing
Mixtures are made from different materials. Basically, these are mastics made from rubber, bitumen, varnishes, primers, paints for water based. Each material has its own purpose. Mastics can be cold or hot, they are produced in the form of briquettes, the consistency of the mixtures is viscous. Before use, mastics are heated to desired temperature ranging from 180 degrees Celsius.
- Rubber, having the properties of rubber, adds plasticity and prevents the appearance of cracks on the surface of the foundation.
- Polymer materials used to improve adhesion, penetration of the coating mixture into the pores of the surface of the previous layer to obtain better protection from moisture. The use of polymers increases mechanical resistance.
- Bitumen is used to create a waterproof film of a specific black color. It is added to mixtures or solutions from organic solvents, in emulsions and melts.
- Water-based or organic-based impregnations are used to increase the waterproofing properties of membrane films.
According to SNiP, waterproofing is distinguished by properties. There are anti-capillary, anti-pressure and non-pressure.
Application of coating waterproofing materials according to SNiP
SNiP is the main document regulating the procedure for performing foundation waterproofing work. In other words, SNiP is a set of rules and regulations for the implementation construction work, including laying coating waterproofing. You can do waterproofing without referring to SNiP, but then the result may not live up to expectations.
SNiP explains how to choose the right material for coating waterproofing and perform installation work. The choice of material depends on the quality of the preliminary surface (soil). SNiP states that if the soil is clayey, then anti-pressure protection should be chosen, and for sandy soil - anti-capillary protection.
The procedure for SNiP for coating waterproofing differs little from other types. To begin with, as for other types of protection, preliminary surface carefully protected from dust, dirt and debris.
Important: The surface must be as smooth as possible; for this, bulges and irregularities are removed, sharp corners and protrusions are cut off with a grinder. If this is not done, during use of the floor, strong pressure may occur on the floor, damaging the insulating layer. In addition, you should get rid of cracks on the floor, depressions and tears. They are first expanded to the base, thoroughly cleaned, and then filled with cement mortar. If you don't make a hole in the floor, air remains there. Later, bubbles appear and can damage the waterproofing surface.
The next stage of work according to SNiP will be surface treatment with primers (primers). They are used to improve the application of coating waterproofing and help improve the penetration of the mixture into the upper layers of the surface. There are several types of primers, each with its own purpose related to the type of coating used. Primers are applied to a clean surface and dry for several hours after application. For waterproof protection made from bituminous materials, primers with a similar solvent are used; for water-based ones, water-soluble primers are used.
For bitumen and bitumen-organic mastic, the surface is treated with a special varnish to improve adhesion. For further work The varnish must dry completely. The next step according to SNiP is to prepare the mixture for application to the surface. To prepare the mixture, follow the instructions on the package.
The temperature when laying coating waterproofing should be in the range from -20 to 60 degrees Celsius, concrete humidity - no more than 4%. Several layers of coating waterproofing are applied to the floor surface. To do this, use a roller, spatula or brush. There should be no missing spots on the surface; the corners are carefully processed. To apply the next layer, the previous one must be dry. To improve the plasticity of the coating material, it can be heated.
Cost of coating waterproofing per m2
The price per m2 for the work depends on many factors, one of the most important is the cost of the material for coating waterproofing. To do this, you need to find out how much materials will be spent per 1 m2. Typically, the calculation of material costs is carried out at the rate of 3 kg per 1 m2. But there are materials whose consumption is 2 kg or less per m2.
The formation of the price per m2 is influenced by the cost of the materials used, the complexity of the work, the size of the room, and others. The most expensive are polymer-bitumen and rubber-bitumen protection; their cost per m2 is almost twice as much as bitumen and waterproof-solvent based ones. You can find out the cost of coating waterproofing per m2 from the contractor.
We will consider the types and technologies: pasting, bitumen mastic, coating, roll. You will learn how to make waterproofing yourself, as well as current prices in Moscow for waterproofing work.
Foundation waterproofing - necessary condition strength and durability of any concrete base. On the page you will learn why waterproofing is so important, where and in what cases it is used, and also get acquainted with the main types of waterproofing - coating and pasting.
Types of foundations where waterproofing is used
Waterproofing is necessary for all types of concrete foundations:
- slab;
- tape (shallow and deep);
- collected from FBS blocks.
Let's figure it out why concrete- the strongest monolithic material, So afraid of moisture. The fact is that the surface of concrete is covered with many micropores that are difficult to see with the naked eye.
Since the technology for laying foundations requires them to be laid quite deep, the foundation concrete is constantly in contact with groundwater. The same applies to shallow strip foundations (up to 80 cm), only they interact not with ground moisture, but with precipitation, which saturates the soil.
Rice. 1.1: Micropores on the surface of heavy concrete
In the warm season, when moisture disappears into micropores, nothing negative happens - the pores are washed out, but the rate of such destruction is extremely insignificant. But in winter the situation changes dramatically.
When freezing moisture tends to increase its original volumes, that is, the volume of ice will always be slightly greater than the volume of liquid water from which it originated. In practice, this results in the following: moisture that gets into the pores freezes and increases in volume, as a result of which the pores of the concrete simply burst.
Undoubtedly, critical damage do not occur in a month or a year, however, if you ignore the waterproofing of the foundation, over time, the smallest pores in size turn into serious cracks that can lead the foundation to an emergency condition.
Foundation waterproofing, technology
The goal of any waterproofing method is to prevent moisture from entering the material from which the foundation is made. Today, in industrial and private construction, two types of moisture protection are widespread - pasting and coating, which we will discuss in more detail in the following sections of the article.
Rice. 1.2: Coating waterproofing of the foundation
Now let’s look at the basic principles and requirements that any waterproofing technology must meet:
- Waterproofing coating must be continuous. It is necessary that moisture protection covers not only the entire surface of the base, but also the places where it connects to the walls, including the base of the house;
- In places where the base is connected to other structures - walls or floor slabs, it is imperative must be present expansion joint from any elastic material, the presence of which guarantees stability waterproofing coating to deformations caused by shrinkage of the base;
- Waterproofing surface must be covered protective layer preventing its destruction under the influence of soil;
- Before applying waterproofing, the foundation of the house must be cleared of any contaminants that help reduce the adhesion (cohesion) of materials must also be sealed cement-adhesive mixture all cracks, and smooth out any detected damage with concrete mortar.
Pasted waterproofing of the foundation using rolled materials
One of the easiest foundation waterproofing methods to implement is the use of rolled lining materials. These can be either fairly cheap options - the same roofing felt or roofing felt, or modern membrane materials - glass insulation, waterproofing.
Rice. 1.3: Foundation waterproofing with built-up foundation roll material
Classification roll waterproofing is carried out depending on the method of gluing it, according to which all roll materials are divided into three types:
- Single-layer materials, installation of which is carried out using adhesive composition or bitumen mastic;
- Floating waterproofing - such materials have a two-layer design: a direct waterproofing layer and a working coating, usually made of cold bitumen. To glue such material, it is necessary to melt a layer of mastic with a burner and connect it to the surface of the foundation;
- Membrane materials - can have either a self-adhesive back surface (you just need to remove the protective paper and stick the insulation onto the surface to be treated), or attached mechanically- dowels with umbrella-shaped caps. Membrane materials are mainly used as additional waterproofing, in which case they are fixed on top of the coating layer of bitumen mastic.
Cost of work for roll waterproofing of foundations in Moscow today varies between 100-200 rubles per linear meter(the price of materials is not included in the cost of the service).
Waterproofing the foundation with bitumen mastic
Despite the widest range of moisture-proofing materials on the market, bitumen mastic has been and remains one of the most popular options for coating waterproofing. Its main advantage is its low cost and ease of use.
There are two types of bitumen mastic: hot application - a thick material that must be melted before application (a cheaper but more difficult option to use), and cold application - ready-to-use liquid formulations based on bitumen, to which a solvent is added (usually aviation kerosene).
Rice. 1.4: Bitumen mastic for foundation waterproofing
Weakness of waterproofing bitumen mastic is the fragility of such a coating. Bitumen is a material prone to losing its elasticity when exposed to low temperatures. In practice, this results in the waterproofing coating cracking in winter and losing its functional properties within 5-6 years.
Exist modern options bitumen mastic, to which various polymer additives are added to improve elasticity and heat resistance, but they fundamentally pose a problem don't decide.
The cost of waterproofing the foundation with bitumen mastic in Moscow is 250-300 rubles per linear meter, taking into account the price of the mastic.
Coating waterproofing for foundations
The above disadvantages of bitumen mastic significantly limit the potential of its use. As a result, today more modern materials are used for arranging coating waterproofing of foundations: polymer rubber compounds and mixtures based on synthetic resins.
They have everything advantages of bitumen mastic(except higher price):
- high-quality adhesion to the concrete surface;
- effectiveness of moisture protection;
- They have good elasticity even at sub-zero temperatures, which contributes to the durability of such a coating.
Most effective variety coating moisture protection - penetrating waterproofing. The essence of this technology is that the material that covers the surface of the foundation penetrates the micropores of concrete and clogs them, preventing any possibility of moisture ingress (unlike conventional coating waterproofing, which is a monolithic film covering the concrete surface).
Rice. 1.5: Scheme of action of penetrating waterproofing
The main advantage of penetrating waterproofing is its tendency to continue to penetrate concrete even several months after application. Crystallization of the material in the pores is activated by any contact with moisture, as a result of which, after a certain period of time, the pores of the concrete will be clogged 30-40 centimeters deep into the foundation.
Cost of work for the installation of coating waterproofing of the foundation in Moscow varies between 350-400 rubles per linear meter (including material), penetrating waterproofing - from 500 rubles. per p.m.
Rolled waterproofing for foundations
Rolled moisture-proofing materials (roofing felt, roofing felt, glass insulation, waterproofing) can be used both as the main waterproofing and as an additional layer located on top of the coating material.
Installation of roll waterproofing is performed in several stages:
- A trench is dug along the perimeter of the building. Its depth should correspond to the depth of the foundation, and the width should be sufficient for comfortable work;
- The foundation is cleaned of soil, paint and oil stains, and inspected for damage. All detected defects are eliminated: a mixture of glue and cement is used to seal cracks, and a cement-sand mortar is used to level out unevenness and potholes. Then you need to wait until the surface of the foundation is completely dry;
- Bitumen mastic is applied to the surface to be treated (used as an adhesive material) and a roll of waterproofing is glued (the coating must be monolithic over the entire surface of the foundation, no voids are allowed). The overlap at the joints of the insulation must be at least 10 centimeters;
- The insulation joints are coated with bitumen mastic;
- On top of the rolled waterproofing, geotextiles or any profiled material are glued in the same way. protective covering and soil is poured into the trench.
Rice. 1.6: Pasting waterproofing with a profiled protective membrane
Waterproofing cost when using the services of contractors in Moscow is 100-200 rubles per linear meter roll insulation(the price of digging a trench and the cost of the material used are not included in the service price tag).
Do-it-yourself foundation waterproofing
If you want to do all the work to protect the foundation from moisture yourself, choose coating waterproofing - this technology is the easiest to implement. It is recommended to give preference to bitumen-polymer emulsions and penetrating compounds.
Coating waterproofing of the base with bitumen mastic is carried out in the following sequence:
- We dig a trench around the perimeter of the house: the depth is equal to the depth of the foundation, the width is such that it is convenient to work;
- We clear the foundation from the soil, repair cracks and damage;
- Apply a layer of a special bitumen primer (primer) to the prepared surface (to the entire height of the foundation and plinth) with a roller or brush and let it dry completely;
- Let's start applying the mastic. To achieve the standard consumption (it is indicated by the manufacturer on the packaging of the mastic) you will need to cover the foundation with 2-3 layers of insulation;
- We create a protective coating. To do this, you can use extruded polystyrene foam, this way you will kill two birds with one stone - protect it from moisture and insulate the foundation at the same time. Also suitable are special profiled membranes or ordinary geotextiles, which are glued over a layer of mastic;
- We fill the trench.
A good addition to foundation waterproofing is the arrangement concrete blind area around the perimeter of the house.
Rice. 1.7: Scheme of a concrete blind area around the house
Foundation waterproofing price
Let's briefly summarize what has been said. By doing waterproofing works with your own hands, the cost of the project is only the price of moisture protective material- the cheapest waterproofing with bitumen mastic or roofing felt, however, saving on the services of contractors, it makes sense to use higher quality and durable materials- penetrating emulsion, glass insulation.
The cost of waterproofing, if you use the services of Moscow companies, will cost you about 100-200 rubles per 1 linear meter of adhesive waterproofing (in this case, you will need to purchase the material yourself). Prices for driving piles. To order work on driving reinforced concrete piles, leave a request:
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Designed to protect the house from penetration of dampness, snow, groundwater, capillary water, water from oblique precipitation.
Waterproofing works in in this case involve applying a layer of appropriate compounds to the surface of the foundation without ruptures or damage. Sometimes, with a properly executed blind area, there is no need to carry out such work.
If the distance from highest level groundwater to the lowest point of the foundation above the ground less than a meter, it will be enough to carry out coating waterproofing.
If the house is supposed to be built on loamy waterproof or clay soil, which has layers of permeable soil, waterproofing work will be necessary, even if the groundwater level is below 1 m from the base of the sole. If the groundwater level is higher than the level of the building’s foundation, drainage should be installed, but this does not exclude the installation of waterproofing.
Features of foundation waterproofing
When waterproofing the foundation important depends on how aggressive the groundwater is, since this can cause corrosion of concrete and its further destruction. For this reason, if there are aggressive waters on the site, you need foundations made of materials that are resistant to aggressive environments.
Previously, it was customary to carry out the arrangement only in the upper basement part, which helped to cut off water leaks into the walls, but it is impossible to avoid wetting the structure in this way. Today, two types are used, namely vertical and horizontal.
Horizontal external waterproofing protects foundation walls from processes, including precipitation and capillary suction of liquid into the ground. One waterproofing is laid on top of the foundation slabs, and the second - under the basement floor.
If the ceiling of the basement of the house is too low, you will need to install a third layer of waterproofing. The height of the waterproofing layer should not be less than 30 cm. But if it is planned to create a hard covering around the building, in this case the splash area will increase, so the waterproofing must have a height of at least 50 cm.
Vertical external waterproofing of the foundation protects the building from the impact of water from the side. Its installation begins from the base, ending with the area where rainwater splashes.
In places where vertical waterproofing joins horizontal waterproofing, it is necessary to ensure a strong connection and protection from moisture penetration.
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Tools and materials
- rolled geotextiles;
- mesh for reinforcement;
- bitumen mastic;
- brush.
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Types of waterproofing of external foundation walls
Coating external waterproofing of the foundation is used when the base needs to be protected from capillary penetration of water, as well as the effects of surface moisture. Bituminous mastic must be applied to smooth and dry foundation walls, and more than one layer must be applied. In order to increase strength, it is possible to lay a reinforcement mesh made from fiberglass between the layers.
It is worth remembering that such external waterproofing demonstrates relatively little durability, which is limited to 5-10 years, in addition, it is characterized by low strength. So, it is quite easy to damage it during the process of backfilling the trench. This necessitates the need to provide protection against mechanical damage, which can be achieved using rolled geotextiles or extruded polystyrene foam with a density of 150 g/sq.m.
If the pit is filled with sand without additional coarse inclusions, protection of the coating can only be done on sharp corners and sharp protrusions.
Coating waterproofing is not able to completely protect the base from pressure groundwater pressure. Before deciding to use it, you need to make sure that there is little or no pressure in the area.
Waterproofing can be pasted or rolled. Rolled roofing felt acts as the most common type of protective material for foundations. You can also use other rolled materials for this type of work, such as: steklomast, technoelast, stekloizol, hydrostekloizol. The named waterproofing materials, unlike roofing felt, are based on a special polymer component - polyester, which provides increased performance characteristics and durability. That is why it is recommended to use these materials, despite the fact that their cost is higher.
There is horizontal and vertical adhesive waterproofing external walls of the foundation of the house. In the latter case, the insulation can be laid from top to bottom and along the walls. In both cases, the canvases must be glued to the surface with an overlap of 200 mm; the base must first be treated with a bitumen-based primer. Work on gluing the canvases is carried out using adhesive mastic; you can also use the fusing method using a gas torch. The upper edge of the waterproofing overlay layer should be slightly higher than the blind area.
Penetrating waterproofing involves the use of a special cement-quartz mixture. The mixture, which must be mixed with water, is applied to the concrete moistened surface in a layer of 1-3 mm.
The liquid solution is able to penetrate into the pores of concrete, using chemical additives reacting with calcium salts of the base. As a result, it is possible to obtain a high-strength and moisture-resistant compound that plugs microcracks, capillaries, and voids in the surface of the foundation walls. The depth of penetration of the mixture into concrete can be 10-60 mm.
Screen waterproofing is a modern analogue forgotten method protection of the base from groundwater, for which it was used clay castle, protected after brickwork. Today, when you need to arrange effective protection from pressure and aggressive water under pressure, it is customary to use bentonite (clay) mats. Laying of this material There is an overlap of 20 cm on each other, and fastening to the surface of the walls is done with dowels.
Afterwards, a concrete supporting wall with gaps should be erected around it; it will act as a reliable obstacle when the material swells. As a result, you can get a locking lock. This technique is in no way suitable for individual construction and, as a rule, is used together with other types of waterproofing.
Foundation waterproofing in modern low-rise construction is an almost integral part of the construction process zero cycle. This is due to the presence of moisture in the soil in the vast majority of territories of our country. Water itself is not particularly dangerous for concrete; on the contrary, in a slightly moistened state, concrete continues to gain strength over many years. However, there are three big “BUTs”.
Firstly, concrete has the property of capillarity. This is the rise of water up through the smallest pores located inside the material. The simplest example of this phenomenon is wetting a piece of sugar slightly lowered into a glass of tea. In construction, the capillary rise of water leads (unless, of course, waterproofing is done) to the penetration of moisture, first from the outer layers of concrete to the inner ones, and then from the foundation to the walls that stand on it. And damp walls mean increased heat loss, the appearance of fungi and mold, and damage to interior finishing materials.
Secondly, modern foundation— it’s still not concrete. This is reinforced concrete, i.e. it contains reinforcement, which upon contact with moisture begins to corrode. In this case, the iron in the reinforcement turns into iron hydroxide (into rust), increasing in volume by almost 3 times. This leads to the formation of strong internal pressure, which, when reaching a certain limit, also destroys the concrete from the inside.
Thirdly, we do not live in the tropics, and subzero temperatures for our climate in winter period- this is the norm. As everyone knows, when water freezes it turns into ice, increasing in volume. And if this water is deep in the concrete, the resulting ice crystals begin to destroy the foundation from the inside.
In addition to the above, there is another danger. It is not uncommon for groundwater in a site to contain chemical elements(salts, sulfates, acids...) that have an aggressive effect on concrete. In this case, the so-called “concrete corrosion” occurs, leading to its gradual destruction.
High-quality waterproofing of the foundation allows you to prevent all these negative processes. And how it can be accomplished will be discussed in this article.
By and large, you can protect the foundation from moisture in two ways:
1) when pouring, use the so-called bridge concrete with high coefficient waterproof (about various brands concrete and their characteristics will be discussed in a separate article);
2) cover the foundation with a layer of some waterproofing material.
Ordinary developers most often now follow the second path. What is this connected with? At first glance, it would seem that it could be simpler - I ordered waterproof concrete from the factory, poured it and that’s it, sit back and be happy. But in reality, not everything is so easy, because:
- price increase concrete mixture with increasing water resistance coefficient it can reach 30% or more;
- not every plant (especially a small one) can produce a grade of concrete with the required water resistance coefficient, and attempts to produce such concrete on your own can lead to unpredictable consequences;
- and most importantly, there are problems with the delivery and placement of such concrete (it has very low mobility and sets quite quickly, which in most cases limits the possibilities of its use).
The use of a waterproofing coating is accessible to everyone and, with certain skills, can be done even with your own hands.
Materials for foundation waterproofing.
All materials used to protect foundations from moisture can be divided into the following groups:
- coating;
- sprayable;
- roll;
- penetrating;
- plastering;
- screen waterproofing.
Let's take a closer look at each of them.
I) Coating waterproofing is a bitumen-based material that is applied to the surface (often in 2-3 layers) using a brush, roller or spatula. Such coatings are usually called bitumen mastics. You can make them yourself or purchase them ready-made, poured into buckets.
Recipe for homemade bitumen mastic: buy a bitumen briquette, split it into small pieces (the smaller the smaller, the faster it will melt), pour into metal container and put on fire until completely melted. Then remove the bucket from the heat and add waste oil, or better yet, diesel fuel (20-30% of the volume of mastic), and mix everything thoroughly with a wooden stick. How this is done is shown in the following video:
Ready-made bitumen mastic is sold in buckets. Before use, for more convenient application, it is usually mixed with the addition of some solvent, for example, solvent, white spirit, etc. This is always indicated in the instructions on the label. There are several manufacturers of such mastics with at different prices And different characteristics finished coating. The main thing when buying them is not to make a mistake and not take material, for example, for roofing coverings or something else.
Before applying bitumen mastic, it is recommended to clean the concrete surface from dirt and prime it. The primer is made with a special composition, the so-called bitumen primer. It is also sold in stores and has a thinner consistency than mastic. Coating waterproofing is applied in several layers, each of which after the previous one has hardened. The total thickness of the coating reaches 5 mm.
This technology is one of the cheapest compared to those described below. But it also has its drawbacks, such as the short durability of the coating (especially when prepared independently), the long duration of the work and high labor costs. The process of applying mastic with a brush is shown in the following video:
II) Sprayed waterproofing or the so-called “liquid rubber” is a bitumen-latex emulsion that can be applied to the foundation using a special sprayer. This technology is more progressive than the previous one, because allows you to perform work with better quality and in a fairly short period of time. Unfortunately, mechanization of work significantly affects its cost.
Characteristics liquid rubber and the process of its spraying are shown in the following video:
III) Roll waterproofing It is a modified bitumen or polymer material, previously applied to any base. The simplest example is the well-known roofing material with paper base. In production more than modern materials Fiberglass, fiberglass, and polyester are used as a base.
Such materials are more expensive, but also much higher quality and durable. There are two ways to work with roll waterproofing - gluing and fusing. Gluing is carried out on a surface previously primed with a bitumen primer using various bitumen mastics. Fusing is carried out by heating the material with gas or gasoline burner and its subsequent gluing. How this is done is shown in the following video:
The use of rolled materials significantly increases the durability of foundation waterproofing compared to, for example, coating materials. They are also quite affordable. The disadvantages include the difficulty of performing the work. It is quite difficult for an inexperienced person to do everything efficiently. You also can't do the job alone.
The appearance of self-adhesive materials on the market several years ago made it much easier to work with roll waterproofing. How to protect the foundation with their help is shown in the following video:
IV) Penetrating waterproofing is a coating of concrete special compounds, which penetrate 10-20 cm into its thickness through the pores and crystallize inside, thereby clogging the passages for moisture. In addition, the frost resistance of concrete and its protection from chemically aggressive groundwater increases.
These compounds (Penetron, Hydrotex, Aquatron, etc.) are quite expensive and have not found wide application for complete waterproofing of the foundation in a circle. They are more often used to eliminate leaks in already built and operated basements from the inside, when it is no longer possible to repair the waterproofing from the outside using other methods.
Learn more about the properties of penetrating materials and their correct use says in the following video:
V) Plaster waterproofing By and large, it is a type of coating insulation, only here it is not bituminous materials that are used, but special dry mixtures with the addition of waterproof components. Prepared plasters are applied with a spatula, trowel or brush. For greater strength and to prevent cracks, a plaster mesh can be used.
The advantage of this technology is the simplicity and speed of application of materials. The downside is the low durability of the waterproofing layer and lower water resistance compared to the materials described above. The use of waterproofing plasters is more appropriate for leveling the surfaces of foundations or, for example, for sealing seams in foundations made of FBS blocks, before subsequently covering them with bitumen or roll waterproofing.
VI) Screen waterproofing- this is sometimes called the protection of foundations from moisture using special swelling bentonite mats. This technology, which is essentially a replacement for traditional clay castle, appeared relatively recently. The mats are attached to the foundation with dowels overlapping each other. More details about what this material is and its properties are discussed in the following video:
How to choose waterproofing for the foundation?
As you can see, there are currently a huge number of all kinds of waterproofing materials to protect foundations. How not to get confused in this variety and choose exactly what is suitable for your specific conditions?
First, let's look at what you need to pay attention to when choosing waterproofing:
- presence or absence of a basement;
- ground water level;
- type of foundation and method of its construction
The different combination of these three factors determines which waterproofing should be preferred in this case. Let's look at the most common options:
1) Columnar foundations.
can only be protected with roll waterproofing. To do this, cylinders are pre-rolled from it. required diameter, fix them with tape, lower them into drilled holes, install reinforcement cages and pour concrete.
Most cheap option- use of ordinary roofing felt. If it has sprinkles, it is better to roll it with the smooth side out so that in winter, when it freezes, less soil will stick to it. It is advisable to ensure that the thickness of the waterproofing along the entire circumference is at least two layers.
When used for columnar foundation asbestos or metal pipes, they can first be coated with any coating bitumen waterproofing in at least 2 layers.
If you are going to build on pillars, before pouring it, for greater reliability, the tops of the pillars also need to be covered with coating waterproofing (even better, not as in the figure below, but directly from the ground). This will prevent possible capillary rise of water from the soil into the grillage.
2) Shallow strip foundations(MZLF).
inherently must always be above the groundwater level. Therefore, for its waterproofing, ordinary roofing material and bitumen mastic are quite enough to prevent capillary suction of moisture from the soil.
The figure shows one of the working options. Before installing the formwork, a folded roofing material with a small outlet is spread on the sand cushion. Then after pouring and setting the concrete, side surfaces the tapes are covered with coating waterproofing. Above the level of the blind area, regardless of what kind of base you have (concrete or brick as in the figure), cut-off waterproofing is done by gluing 2 layers of roofing material onto bitumen mastic.
3) Recessed strip foundations (house without a basement).
Waterproofing of a buried strip foundation, regardless of whether it is monolithic or made of FBS blocks, when the house does not have a basement, can be done according to the scheme shown above for MZLF, i.e. the bottom is rolled material, and the side surfaces are covered with coating insulation.
The only exception is the option when the foundation is not poured into the formwork, but directly into a dug trench (as you understand, coating cannot be done). In this case, before installing reinforcement cage and pouring concrete, the walls and bottom of the trenches are covered with rolled waterproofing with gluing or fusing joints. The work is certainly not very convenient (especially in a narrow trench), but there is nowhere to go. This was discussed in the article.
Also, do not forget about the layer of cut-off waterproofing above the level of the blind area.
4) Recessed strip foundations, which are the walls of the basement.
The use of coating and spraying materials to waterproof basement walls from the outside is permissible only in dry sandy soils, when groundwater is far away and the perched water quickly drains through the sand. In all other cases, especially with a possible seasonal rise in groundwater, it is necessary to do roll waterproofing in 2 layers using modern materials based on fiberglass or polyester.
If the foundation is made of FBS blocks, before waterproofing it, it is advisable to cover the seams between the individual blocks with a plaster waterproofing mixture, at the same time leveling the surface.
5) Slab foundations.
Foundation slabs (basement floors) are traditionally protected from moisture from below by gluing two layers of rolled waterproofing onto a previously poured concrete preparation. The second layer is spread perpendicular to the first. This was discussed in more detail in the article.
To avoid damaging the waterproofing layer during subsequent work, try to walk on it as little as possible, and cover it with extruded polystyrene foam immediately after installation.
At the end of the article, let us pay attention to two more points. Firstly, when the groundwater level rises above the basement floor level, drainage must be done (a system of drainage pipes laid around the perimeter of the house and wells for inspection and pumping of water). This is a big topic that will be discussed in a separate article.
Secondly, the layer of vertical waterproofing of the foundation requires protection from damage that can occur during backfilling and soil compaction, as well as during frost heaving of the soil in winter, when it sticks to the waterproofing and pulls it up. This protection can be achieved in two ways:
- the foundation is covered with a layer of extruded polystyrene foam;
- install special protective membranes that are currently commercially available.
Most builders prefer the first method, because... it allows you to “kill two birds with one stone” at once. EPS also protects waterproofing and insulates the foundation. The insulation of foundations is discussed in more detail
To achieve the maximum possible service life of reinforced concrete underground structures, foundation waterproofing is necessary. The cheapest option for an individual developer is to coat the concrete surfaces of the slab, strip or pillars with mastic. You don't need any skills to do this. plastering works, buy or rent gas-burners necessary for other waterproofing technologies.
The main requirements for waterproofing protection are continuity of the layer and a maximum between-repair period. As coating waterproofing, mastics are used, classified according to state standard GOST 30693 from 2000 according to the following criteria:
- composition – polymer, bitumen, combined, one- and two-component;
- solvent – organic or water;
- hardening – non-hardening, hardening upon evaporation of the solvent or due to a chemical reaction;
- Method of use: cold, hot.
Cold mastics are more convenient to work with; they do not need to be heated with special equipment. They are only hot bitumen mastics or combined mixtures in which rubber crumbs or polymer granules are added to bitumen.
Important! Mastics are applied to the foundation with a brush, spray or roller in at least two layers. If the base of a concrete structure is insulated with rolled material, the edges of which run onto vertical surfaces, a minimum of three layers are required at the joints.
The most popular mastics are the following modifications:
- polymer – does not destroy polystyrene foam glued on top of it to insulate structures;
- bitumen-polymer – plastics improve the properties of the film, for example, the tensile strength of such a material is 300% compared to conventional one;
- rubber bitumen - filled with EPDM crumbs, there are hot and cold mixtures;
- bitumen-emulsion - ready for use, hardens quickly.
The film made from pure bitumen without modifying additives has low mechanical strength and is therefore not used in foundations.
Mastics are ideal for protection against capillary groundwater. When the hydrostatic pressure from groundwater is within 5 m, polymer modifications should be used, and within 2 m - . The thickness of the layer depends on the depth of the structure and is 2–4 mm for 3–5 m foundations, respectively.
The one-component mixture has an almost unlimited lifespan (time before application). In two-component mixtures, after mixing the compositions, chemical reaction, therefore the entire volume must be completely exhausted before setting begins.
The industry produces three categories of cold coating waterproofing materials:
- budget - cost 20 - 30 rubles / kg, consist of tar, construction bitumen;
- standard – have a sharp bad smell, contain bitumen BN 70/30 or BN 50/50; with average characteristics, naphtha petroleum fraction is used as a solvent, cost 50 - 85 rubles / kg;
- Premium class - the composition includes rubber-modified bitumen BN 90/10 or BN 70/30, hardening for 12 - 18 hours, the cost of the mastic is 100 - 140 rubles / kg.
Important! Budget mastics, despite the presence of packaging and the manufacturer’s brand, do not meet the requirements of GOST. Therefore, you should not skimp on the quality of the waterproofing layer; you should buy either standard coatings or Premium products.
Products based on tar harden for up to 5 days and flow down from the vertical walls of the foundation under their own weight in the heat, since these materials have practically no heat resistance. After 8 weeks of use, elasticity decreases sharply and unexpectedly.
Foundation waterproofing technology
Since coating waterproofing is applied to underground structures, maximum adhesion of the film to concrete and mechanical protection coatings from the effects of heaving forces. Therefore, first the base is prepared, after the film layer has hardened, the foundation is covered with polystyrene foam on the outside. In addition to protecting the waterproofing from mechanical damage, the insulation moves the dew point outward (important for a used basement and underground) and prevents freezing of concrete.
Preparing the base
Concrete foundation surface before coating waterproofing mastic must be carefully prepared:
- grouting large surface pores cement-sand mortar or cement paste;
- removal of “ridges” that appear in the cracks of the formwork;
- drying the concrete surface (humidity for bitumen-emulsion compositions 8% maximum, for all others 4%);
- cleaning oil, grease and dirt stains;
- dust removal of the foundation.
The moisture content of concrete is checked by gluing it to the surface. polyethylene films. Within 12 to 24 hours, condensation should accumulate under the patch without forming drops.
Important! It is prohibited to apply coating compounds to the interfaces of structural surfaces without pre-treatment. In internal corners fillets (fillets) are made, and chamfers with a radius of 3–5 mm are rounded on the outer ones.
Primer
Foundation waterproofing will have maximum adhesion to concrete only when using a primer. For this, special primers or diluted mastic are used. Unlike conventional primers, primers have dark color, adding color to control untreated areas is not required.
The primer increases the roughness of the foundation, binds remaining dust particles, and reduces the consumption of coating waterproofing. Depending on the composition of the primer, the drying time is not the same. Therefore, the structure should be coated in accordance with the manufacturer’s instructions.
First layer
Foundation waterproofing is less expensive when applied by roller, brush or trowel. Sprayers must be purchased or rented and washed to remove oil-containing viscous products after use. It is recommended to apply vertical stripes from bottom to top, overlapping the layer by 3 - 5 cm. It is necessary to maintain the same thickness of the waterproofing layer, to smooth out drips and sagging on the foundation surfaces.
Finishing layer
Before applying the second layer separate areas or the entire surface of the foundation is usually reinforced. For this, polymer, fiberglass meshes or fiberglass are used. Reinforcement is mandatory in the corners and interfaces of the coating waterproofing of the foundation with rolled materials.
The grids are recessed into the first not dried layer, the mastic protruding through the cells is leveled with a brush or spatula. Many craftsmen practice dipping the mesh into a container with coating, and then gluing it to the surface and rolling it with a roller or leveling the material with a spatula.
Thus, coating waterproofing is carried out with special mastics on top of a primer primer layer. The mating surfaces of the foundation are reinforced in mandatory, work planes - as needed. The choice of mastic is made depending on the developer’s budget and the availability of pressure water.
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