Floor waterproofing coating under the screed. Floor waterproofing under the screed: types, technology and procedure for installing roll waterproofing in an apartment. What materials are suitable for waterproofing the floor in front of the screed in the apartment

Waterproofing a subgrade is a job that requires accuracy and responsibility. It is possible to mount such floors when the soil on the site is dry, there is no groundwater or they lie deep. It is necessary to take into account the level of precipitation observed in the construction area. The very waterproofing of the floor on the ground does not take much time, but concrete pouring is performed along with it. It already takes almost a month to dry.

An example of a common mistake during construction: a leaking joint of a waterproofing floor on the ground with a horizontal waterproofing of a foundation wall.

The advantages of such floors are:

Lack of work on laying large and massive slabs, beams. The floor is simply poured with concrete.
High quality and durability of the resulting surface.

Of the minuses, it should be noted that the soil requires careful preparation. You cannot just start work on the ground if it is not brought in accordance with all the requirements. Laying a concrete floor on the ground can be carried out by various methods, but the most acceptable of them remains as follows:

The subgrade is carefully compacted, after which a layer of sand backfill is applied.
The second layer is expanded clay or crushed stone of small and medium fractions.
Executed directly.
After that, a rough concrete screed is laid.
There is a layer of vapor barrier material.
A heat insulator is mounted.
Reinforcement and finishing concrete screed are in progress.
The chosen floor covering is laid, but only after the concrete is completely dry.

This course of work is considered optimal. Even without much experience, such a floor can be made with your own hands, without resorting to the services of specialists.

Substrate preparation and waterproofing of the concrete layer

Scheme of a concrete floor on gravel with waterproofing.

Preparing the soil before waterproofing is the most crucial stage of the work. It is necessary to check that the soil is dry and then compact it. When it is ready, the first preparatory layer is poured using sifted river sand.

After pouring the sand is slightly moistened, carefully compacted.

The second layer is crushed stone of small and medium fractions, it is leveled and compacted. This completes the preparation of the soil surface before waterproofing, it is only necessary to additionally check the horizontal position. This is done using the usual building level.

Waterproofing a concrete floor on the ground is carried out as follows:

Bituminous roll material or polymer-based membrane is rolled out on the base, observing the overlap. All strips should go in the same direction, the overlaps are glued with construction tape, which provides reliable protection against moisture.
If the materials have been installed, it is necessary to re-check that there is no damage to the surface. If there are tears, cuts, etc., then such a film is completely unsuitable for use.
During installation, you will have to make sure that the film goes on the walls by about 15-20 cm. After installing the entire floor, small parts of the waterproofing material will remain above the surface. They are carefully cut with a sharp knife. In some cases, the use of such materials is not possible. You can replace this stage with pouring a concrete layer, for which a completely different type of waterproofing will be used. For this, coating materials are used that completely cover the concrete. This option cannot be called worse or better, since they both have their own characteristics and advantages.

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Laying a concrete sub-floor

Rough laying on the ground includes not only screed, but also floor insulation, installation of a vapor barrier layer. It is the rough screed that is the base and security layer for the rest of the floor.

If the technology is violated, the quality of protection will be poor, all work will have to be redone. Such a rough floor on the ground is made of special lean concrete with a class B 7.5-10, crushed stone is used for it with a fraction of 5-20 mm.

If the waterproofing layer is not used separately, then concrete of the M50-75 class can be taken. Such a rough filling under the floor on the ground is simple, its thickness should be only 40-50 mm, the permissible height difference is 4 mm.

The subfloor on the ground is laid in compliance with such stages as:

Installation of vapor barrier material. It is best to use polymer-bitumen membranes for this, which are made on the basis of fiberglass, PVC, polyester. All of them are of the required quality.
Next comes a layer of insulation, which makes it possible to save heating costs. This method allows you to eliminate heat loss by about 20%, which is already quite a lot. In this case, it is necessary to use materials such as PSB35 foam. If heavy loads are planned, then PSB50 is suitable. So that the foam does not collapse when it interacts with concrete, it is necessary to lay a layer of polyethylene film with an overlap from below and on top. It is important to ensure that the film is free from tears and other defects.
Instead of foam, you can use extruded polystyrene foam, which is of great quality. Such materials are perfect for working with floors on the ground, although some experts recommend replacing them with mineral wool. But cotton wool accumulates moisture, so its use is questionable.

Waterproofing the floor before screed: how to make a concrete base waterproof

Screed waterproofing can be carried out in various ways. The main condition for a high-quality waterproofing coating # 8211; its layer should be continuous and free from any defects.

The main goals of waterproofing works:

Improving the quality of the screed and creating the necessary moisture level for the subsequent installation of various types of floor coverings. Thanks to the protective layer, the percentage of moisture in the building mixture will not decrease rapidly, which will protect the screed from cracking and increase its strength characteristics.

Protection of lower floors from the flow of mortar and water.

Protection of the room against moisture capillary penetration.

Today, the construction industry offers a large selection of various waterproofing materials, which can be divided into several groups:

Only a continuous waterproofing coating can be a reliable protection against moisture penetration

Roll waterproofing

The most economical and simple option is a dense waterproofing film, it is available in gray, black or brown colors. Roll glued waterproofing # 8211; more durable and reliable protection. It is produced on the basis of bitumen, fiberglass or synthetic compounds.

Surface preparation for work with pasting insulating material is as follows. First, the base is cleaned of debris and leveled, covered with a bitumen emulsion and only after that the installation is started. The layers are glued with an overlap; for greater strength, the entry is made up to 30 centimeters. Do not use a coating that has a cardboard base.

Roll-up waterproofing is easy to install and reliably adheres to the base

Liquid waterproofing

It is produced in the form of a mixture - bitumen-based mastic. Such a mixture is applied with a brush to a surface previously cleaned of dust and debris. Ordinary molten bitumen can be used, but it should be borne in mind that such a coating is short-lived.

The sub-floor must first be leveled. To correctly determine the slope, the thickness of the leveling layer and the thickness of the screed, mark the floor level on the wall surfaces. After that, the surface is cleaned of debris and dust, and the existing defects are sealed with tile glue. If there are protruding and sharp elements, they need to be dulled, otherwise they will break the integrity of the layer. If there are a lot of such irregularities, you can sprinkle the surface with a layer of sand.

Screed waterproofing

Protection of all elements of any building from moisture penetration is done without fail, regardless of the characteristics of the soil of the area on which the house stands or is being built. There is an opinion that if in a private building there is a basement that is well insulated, then this can be neglected, saving on material and labor costs. This reasoning is wrong.

Waterproofing under the screed protects not only from the penetration of liquid and, as a result, the appearance of dampness in rooms, mold and unhealthy air. This leads not only to a violation of the comfortable microclimate in the house and reduces the life of the things in it, various machinery and equipment. Particles of various substances, many of which are aggressive, "come" along with the water.

Acids and alkalis, penetrating into the structure of finishing and building materials, are destructive. Even a concrete slab, which is widely used as an interfloor overlap, will not be able to resist them. It will gradually "weaken". And if we take into account that all the constituent parts of the structure of the structure are designed for a certain load, it becomes quite clear that without high-quality waterproofing under the screed, the reliability of the entire building, which means that the service life without major repairs, will begin to decline sharply.

It is also necessary to take into account the fact that the heat loss in the premises is increasing. Indeed, in the floors, shells and cracks form over time. The screed itself, also under the influence of constant dampness, will begin to be covered with fractures, which may affect the state of the "finishing" finish. For example, if the owner chose to arrange self-leveling floors. If logs are installed on top of the screed under the wooden floors, then the wood will begin to rot. Hence the deformation of the floorboards. the appearance of a squeak and musty air.

In addition, waterproofing under the screed is a reliable protection for various types of insulation. With proper flooring, such material is used regardless of what kind of "construction" the flooring will have. After all, no one needs a cold floor in the house, especially if there are small children in the family who constantly play on it.

If at the site where the house is located, subsoil waters come close to the surface, then additional measures are taken when arranging waterproofing under the screed. It is also necessary to consider whether there is a room with high humidity on the lower floor (for example, an unheated basement). In this case, the insulation is made especially reliable.

With special care, such work must be carried out in those rooms where excess moisture will constantly be present. For example, bathroom, shower, swimming pool, laundry and others. More reliable methods are impregnation or coating. The use of roll materials will require additional measures to seal the joints of the strips.

Waterproofing under the screed has another practical value. Private houses are now mainly built on two floors. And if the building is one-story, then the owners use the basement all the more. Each dwelling has its own engineering systems. Among them are those in which there is water (plumbing, sewerage, heating).

If an emergency occurs and the entire floor is flooded, then the rooms located at the lower levels will also, albeit partially, be flooded. As a result, things and finishing materials will suffer. Having saved on waterproofing, there is a risk of subsequently "parting" with even more money. And nerves too.

Screed on a separating waterproofing layer

A screed on a separating layer is nothing more than a screed with waterproofing. It must be performed in the floors of the bathrooms. It is advisable (but not necessary) to use it under self-leveling mixtures for self-leveling floors, since in this case it is better to play it safe when pouring the screed and not pour the neighbors on the floor.

Waterproofing is for pressurized and non-pressurized waters, gluing and coating, membrane and from separate panels. Almost any of them can be used for the construction of a waterproofing layer in the floor structure. Previously, the floors of the bathrooms were waterproofed from roll materials, most often from roofing material, with gluing the joints and the entire panel with hot bitumen mastic. Roofing material is a dense construction paper impregnated with a bituminous binder. Since the composition of the roofing material contains a cellulose component - paper, sooner or later it begins to rot and the roofing material is destroyed.

2. Preparation of the base.

We remove debris from the ceiling and fill up all clearly visible holes with cheap tile glue. Next, we inspect the overlap and knock off or blunt sharp irregularities. In order for them not to break through the film, on which you will have to walk a lot during the installation of the screed.

If there are too many sharp irregularities, then it is advisable to sprinkle them with sand, that is, to make a thin sand preparation for the overlap. In most cases, no sand is needed; the top of the floor slabs is usually fairly flat. Mounting hinges, if they are not bent into holes specially designed for them in the slab, in this case it is better to cut and grind flush with the top of the slab. Otherwise, the plastic film during operation may catch on the mounting loop and break. If, due to the height differences between the floor slabs, a breakthrough of the film is possible, then they must be eliminated, for example, by sprinkling with sand. In other cases, eliminating differences is a waste of time and effort.

3. Laying the separating layer.

We use polyethylene film with a thickness of at least 0.2 mm. If the area of the room allows, then we lay the film entirely in one piece over the entire area, leading the ends to the walls above the intended screed by 100-150 mm. We straighten the film, but lay it without tension. The installed waterproofing should form a trough around the entire perimeter of the room. In the doorway, pre-install the boundary board. The board must be installed flush with the wall surfaces of the room where the screed will be laid. In bathrooms, a door with a threshold will need to be installed, the threshold should be protected by waterproofing, and not installed on top of it. If there is already a door, then we put the waterproofing on it in the same way as on the walls. Then we cut off the excess. For guaranteed waterproofing work, it is better to make it in two layers.

If the width of the room exceeds the dimensions of the film, then we use self-adhesive roll-up waterproofing materials, or waterproofing membranes, or coating waterproofing, forming a single carpet after drying. If, nevertheless, plastic wrap is used, then we lay the pieces of the film with an overlap of at least 20 cm and glue the seams with tape, or better, glue them together or weld them with an iron through a newspaper and only then additionally glue them with tape. Without fail, we lay the second layer of film. We lay the second layer parallel to the first, but with a shift of the weld seam relative to the seam of the lower layer by half the width of the panel.

3. Installation of beacons.

A screed on a separating layer, like a connected screed, can be made of two types of materials: from home-made or purchased cement-sand mixture and from ready-made non-shrinking dry mixtures. Thin leveling screeds are made from self-leveling mixtures.

When pouring the screed with a semi-dry cement-sand mortar or a non-shrinking leveling mixture, it is impossible to install pin beacons! They will make holes in the film, so we make ordinary mortar beacons. Along the opposite walls, we lay mortar heaps on the film or make a bed and rub a plaster profile or a profile used for gypsum plasterboard structures into the solution. To determine the mark of the top of the screed level, the film, which has been adhered to the walls and covering the markings of the screed level, can be temporarily folded back. Screw the self-tapping screws into the nylon dowels drilled into the walls along the marking lines and pull the fishing line between them. First, a beacon is made along one wall, then along the other, then beacons are made between them.

Rice. 38. Marking the level of the screed for self-leveling mixtures

When pouring a screed with a self-leveling mixture, you can use a "spider" beacon. Usually, this type of beacon is used for screeds of large areas and is not used for leveling floors in an apartment. One lighthouse is installed on 2–3 m² of the screed area. The "spider" lighthouse is made from a regular nut with a bolt screwed into it. Three or four legs of thin reinforcement are welded to the nut. To prevent the legs of the lighthouse from tearing the waterproofing film, their ends are bent up. A bolt is screwed into the nut, which is aligned with the height of the tie on the bottom of the bolt rod (Fig. 38). That is, the installation horizon of the beacons is checked along the top of the bolt head, adjusted for the length of the bolt, and the level of the screed filling is checked along the bottom of the bolt. "Spiders" for self-leveling screeds are installed in any place. They will not need to be driven with a rule and a spatula, their purpose is to visually indicate the height of the screed when it is made far from the walls on which lines are drawn indicating the border of the top of the screed. Moreover, these lines will be closed with an overlap of waterproofing carpet. When installing the screed, carefully pour the solution around the "spiders" so that they are not washed away from the marked place.

4. The device of the damper seam.

Along the perimeter of the room (along all walls), around the columns, pilasters and other protruding parts, we glue on the film or temporarily press in any other way strips of rolled insulation with a height exceeding the height of the screed, and with a thickness of 10 mm. The damper layer will make it possible to avoid cracking on shrinkage screeds and will help with sound insulation - on non-shrink screeds.

5. Screed device.

A screed from a semi-dry cement-sand mixture and a prefabricated leveling mixture is made using the method described on the previous pages. That is, the mixture fits into the lighthouse gap and stretches according to the rule along the lighthouses. The thickness of screeds made of cement-sand and leveling mortars along the dividing layer of waterproofing is made at least 30 mm - for bathrooms (under the tiles) and at least 40-50 mm - for other rooms. The thickness of the ready-mix screeds is determined by the dry mix manufacturer. It can be different, to determine the thickness of the screed, read the annotation on the bags with mixtures.

Rice. 39. Laying self-leveling mixtures

Self-leveling mortar mixtures are very plastic; they do not need to be stretched with a rule. The most that you need to do for them is to correct the thickness of the screed with a wide spatula (fig. 39) and make sure that the screed level coincides with the bottom of the "spider beacons". Self-leveling mixtures are brought to the installation site in buckets and poured onto the base. Each subsequent bucket should be poured next to the previous one with a partial overlay of the solution. The pouring process must be continuous. You need to work, at least, together: one mixes the solution, the other distributes and pours. The self-leveling mixture itself spreads into the horizon under its own weight. You just need to make sure that the level of the screed is topped up to the desired limit and not overflowed. Control by beacons. In the process of filling the screed with self-leveling mixtures, sequentially remove the "spiders" from the places already filled with the screed.

6. Care of the screed.

For cement-sand screeds, it is necessary to ensure that the screed does not dry out before the time for three days. Cover it with plastic wrap and prevent drafts at the top of the screed. To care for self-leveling solutions, read and follow the instructions on the bag.

Do I need waterproofing 1

Alexey Guest

Sergey Alexandrovich Guest

Renovating an office, going to do a screed. The craftsmen advised to do only a primer under the screed (Prospectors). A friend also advises to make waterproofing to protect against odors from the basement. (The basement is empty and there are occasional puddles.) Is it worth it? And if so, what is better? And what comes first: primer or waterproofing?

Alexey Guest

Waterproofing Center Guest

/// If there is moisture in the basement, then it is worth making the basement waterproofing, because there is a chance that the floor and bottom of the walls may be damp. It will be literate.

The basement is not mine - the housing office has the key 🙁 But the moisture is there only periodically.

If economically (as usual.) - then make a vapor-proof waterproofing under the screed.

It's not about saving, I just can't fix my basement, and there is no admission there :-(.

And what material (materials) would you recommend to an amateur? And what comes first - a primer or waterproofing? Or is there no need for a primer at all?

Cement-based penetrating waterproofing materials.

Has a double protective effect:

- capillary, as a result of deep penetration into the pores of the material to be insulated,

- armoring, as a result of the formation of a mechanically and chemically strong layer on the surface.

Contents Waterproofing laminate floors video. Waterproofing the floor How to level the floor under the laminate: recipes for concrete and wood Waterproofing - the floor How to prepare the floor under the laminate Waterproofing the floors under ...

Before leveling and screed the floor, special waterproofing work is required. Waterproofing the floor in front of the screed will prevent the mortar used for the screed from flowing to the lower floor and help to make the screed better. It is especially important to have a special protective layer in rooms with high levels of humidity, where there is a risk of water leakage - kitchens, toilets, bathrooms. Waterproofing the floor in a private house will protect the building from moisture. Penetrating into concrete, alkalis, acids and salts contained in moisture destroy its structure. Within a few years, microcracks may appear in the concrete, and its integrity will be violated.

Screed waterproofing can be carried out in various ways. The main condition for a high-quality waterproofing coating is that its layer must be continuous and free of any defects.

Types of waterproofing under floor screed

The main goals of waterproofing works:

Improving the quality of the screed and creating the necessary moisture level for the subsequent installation of various types of floor coverings. Thanks to the protective layer, the percentage of moisture in the building mixture will not decrease rapidly, which will protect the screed from cracking and increase its strength characteristics.
Protection of lower floors from the flow of mortar and water.
Protection of the room against moisture capillary penetration.

Today, the construction industry offers a large selection of various waterproofing materials, which can be divided into several groups:

Only a continuous waterproofing coating can be a reliable protection against moisture penetration

The most economical and simple option is a dense waterproofing film, it is available in gray, black or brown colors. Roll glued waterproofing - more durable and reliable protection. It is produced on the basis of bitumen, fiberglass or synthetic compounds.

Roll-up waterproofing is easy to install and reliably adheres to the base

Liquid waterproofing

Bituminous-rubber mixtures are best suited for this purpose. Their cost is slightly higher, but when using them, heating to a high temperature is not required. The bitumen-polymer mixture is also widely used in waterproofing works. The synthetic resin that is included in its composition ensures the durability and effectiveness of the coating.

Liquid waterproofing mixes provide durable, reliable coverage

Plaster as waterproofing

The waterproofing of the floor screed can also be carried out using dry plaster mixes that contain special additives that prevent moisture penetration. Such mixtures, called "waterstop", are diluted in the required proportion with water before application. Depending on the purpose of the room, one to three layers of the diluted mixture are applied, with each subsequent layer being applied perpendicular to the previous one. The consumption of the mixture is 1-1.5 kg per square meter of floor surface.

Waterproofing coating VODOSTOP is made on the basis of cement, fractionated filler and a complex of polymer additives

Stages of waterproofing works

When choosing a method and material for waterproofing, first of all, one should proceed from the following factors: humidity in the room, its purpose, thickness and characteristics of the floor covering. High-quality waterproofing under the floor screed is provided only if all stages of work are carried out correctly: preparation of the base, laying a protective layer, and subsequent installation of the screed.

How to prepare the floor surface

First of all, you need to make accurate measurements of the floor level.

Laying the protective covering

Liquid waterproofing is applied with a regular brush; if ordinary bitumen is used, it must be warmed up before use.
Film materials are laid in two layers with an overlap at the joints of up to 20 cm and an approach to the surface of the walls up to 30 cm, after which they are glued.
Rolls of glued waterproofing are rolled along the room, making sure that the material enters the walls, and then glued to the floor surface. At the end of the work, all excess material is carefully cut off.

Applying liquid waterproofing with a brush

Waterproofing the floor in front of the screed is an important stage in the construction work. The protection of the room from moisture penetration, the durability and performance of the flooring depends on how professionally and competently the waterproofing is performed. To be sure of the high-quality performance of waterproofing under the floor screed, it is better to entrust this work to professionals. Only in this case you will receive a guarantee that the work has been done professionally, competently and taking into account all the features of the premises.

Waterproofing the floor in front of the screed is necessary for two reasons: firstly, it prevents moisture vapor from the basement or from the lower floor from entering the concrete screed, and secondly, it protects the floor slabs from possible water leaks in wet rooms. It is especially important to perform high-quality waterproofing of the floor in front of the screed on the first floor of a private house that does not have a basement. Water vapor and capillary moisture rising from the ground often have an acidic or alkaline environment, they actively interact with concrete components, and after a few years the screed can become covered with a network of cracks and begin to collapse.

Types of floor waterproofing in front of the screed

There are several ways to waterproof the floor in front of the screed. In private houses without a basement, a gravel-sand cushion is often used as the first layer of waterproofing. Gravel or crushed stone is first poured under the base of the floor, tamped down, and then covered with sand. The resulting cushion, due to the presence of air gaps between the particles, prevents the capillary rise of moisture from the ground. At the same time, it practically does not protect against water vapor, therefore, additional film vapor-waterproofing is required.

Steam-waterproofing films as a waterproofing of the floor in front of the screed are used not only in private houses, but also in city apartments. Films allow you to create a moisture-proof coating and protect the screed from water vapor and moisture emanating from the floor slabs, as well as the slab itself from water leaks in damp rooms.

The third type of floor waterproofing in front of the screed is coating waterproofing. It is performed with mastics based on bitumen or rubber, applied in several layers. A distinctive feature of such a screed is the ability to fill any uneven surfaces, which is especially convenient with a large number of pipe penetrations.

In addition, to impart waterproofing properties to concrete slabs, they can be treated with an impregnating waterproofing solution. This technology is relatively new, but has already gained popularity among builders due to its simplicity and efficiency. Concrete is impregnated with a solution of penetrating waterproofing along the surface from either side of the floor, after which needle-like crystals begin to grow in the pores of the concrete when interacting with its components, preventing the penetration of moisture into the concrete.

Gravel-sand cushion technology

Floor waterproofing technology with roll materials

A damper tape is laid along the perimeter of the walls. It is necessary to compensate for the expansion of the concrete screed under the influence of temperature fluctuations. Fastened with an adhesive layer or dowel-nails.
Level the base if necessary, rubbing the potholes with a cement-sand mortar or filling them with sand.
When using polymer waterproofing films, primer treatment of concrete slabs is not necessary. Optionally, the concrete slabs can be treated with a penetrating waterproofing mortar. If ordinary roofing material is used, the floor must be pre-treated with a bitumen mastic primer.
Roll waterproofing is laid on the prepared floor in strips, forming an overlap on the walls of at least 15 cm. The strips are also overlapped, the width is at least 10 cm.
The materials to be welded, for example, glass insulation, are fixed to the base using a gas torch. Polymer films are overlapped and welded together with a construction hairdryer.
The number of layers of waterproofing depends on the type of material: roofing material is put in at least two layers, fused films and polymer materials - in one layer. After installing the roll waterproofing, you can perform the reinforcement and screed of the floor. After the screed hardens, the protruding roll-up waterproofing and damper tape are cut flush with the floor.

Floor waterproofing technology with coating waterproofing

For reliable waterproofing of the floor in front of the screed, you can use not one, but several methods. For example, when waterproofing a floor in a private house without a basement, you can make a gravel-sand pillow, lay a layer of insulation, a waterproofing film on top of it, and only then mount the reinforcement and fill the screed. In an apartment on the ground floor, located above the basement, it is possible to use penetrating waterproofing of floor slabs in combination with roll or coating waterproofing. In wet rooms of apartments located on the upper floors of an apartment building, where any leakage can entail compensation for damage to neighbors, it is better to equip double waterproofing: before and over the screed. In this case, roll materials are used under the screed, and coating waterproofing is performed on top of the screed.

If you read any reference materials related to overhaul, they necessarily mention the waterproofing of the floor under the screed. This procedure is considered an integral part of the work package. If you carefully examine the issue, the rationality of this opinion is beyond doubt. Waterproofing will not only eliminate problems with neighbors or damage to the finish of the lower floor, but also significantly increase the life of the floor and the building as a whole, while protecting the concrete structures.

What tasks does waterproofing perform?

The conventional wisdom that waterproofing the floor in the apartment in front of the screed prevents only leaks to neighbors is not entirely true. Water ingress protection fulfills a wide range of functions.

For instance:

a properly organized structure of waterproofing vapor permeability will ensure the screed dries out. This is important in houses with a damp basement or - built on the ground;
waterproofing the floor in the apartment in front of the screed will protect the interfloor slab from water penetration. This guarantees the absence of internal corrosion and destruction, which can significantly reduce the life of the building as a whole;
the waterproofing in front of the screed acts as a stress damper. It will significantly increase the service life of the floor and prevent cracking. The waterproofing screed is floating, mechanical stresses and deformations of the floor structure are transferred to it to a lesser extent;
waterproofing under the screed in the bathroom, laundry or kitchen is a must. In these rooms, a large amount of water is often spilled, which, without protection, will flow to the lower floor and literally saturate the ceilings.

High-quality waterproofing in front of the screed is important both for residents of apartments in multi-storey buildings, eliminating many problems with neighbors, and for residents of private buildings. In this case, the number of storeys of the latter does not matter.

Why high-quality waterproofing is needed in a one-story private house

Leaks and damage to floor slabs are not the only problems caused by a lack of waterproofing. In one-story private houses without a basement, moisture protection is necessary. Moreover - double, from the penetration of water, roughly speaking, up and down.

In buildings built on the ground, the following happens:

when the air temperature drops, the soil cools;
condensation forms, an air gap between the surface of the earth and the overlap of the first floor, saturated with water vapor;
moisture penetrates from below and is capable of destroying a poorly protected screed.

On the example of the first floor of houses built on the ground, it is possible to clearly illustrate the answer to the question of where to make the waterproofing layer: before or after the screed. In the simplest case, the protection is placed under the screed. But it is recommended to ensure the removal of excess moisture by placing a separate layer of waterproofing after the screed.

It is created using one-sided vapor permeability membranes, drying the concrete at a low speed. At the same time, no harm is done to the floor coverings - the movement of moisture occurs in very small volumes.

If the floor is on the ground

If we approach the issue of waterproofing the floor screed of the first floor in a building on the ground, it is necessary to take measures to prevent the so-called reverse capillary movement of moisture.

To do this, proceed as follows:

waterproofing the floor from below using impregnations, roll materials, bedding;
a fine gravel pillow is poured directly onto the slab or sub-floor, carefully compaction;
a layer of sand up to 100 mm high is applied on top and compacted.

Geotextile is laid on top of the formed base, a layer of insulation and waterproofing is done with roll materials. A layer of gravel and sand will prevent vertical movement of condensate.

Acting according to the above scheme, it is possible not only to improve the thermal characteristics of the house as a whole, but also to guarantee a long service life, which will be shown by the waterproofing of the floor in front of the screed and the cement-containing layer on it.

Floor preparation: general work

Before waterproofing is done before creating a standard concrete, insulated screed or thin reinforced screed, it is necessary to do a number of floor preparation work.

Their list is unchanged, regardless of what material will be used as a means of protection against moisture:

Floor coverings, if any, are removed.
The floors are thoroughly cleaned. Oil stains are degreased, traces of paint and glue are removed.
The surface is inspected. Cracks and seams are cleared, rotten planks are replaced on wooden floors, areas of weakened concrete are chipped off. The lines of convergence of the floor and walls must also be free of any extraneous contamination and materials.
Rubbish is removed in rough form with a broom.
The surface is leveled. The protrusions are cut or chipped off, the seams and depressions are sealed with putty. After the solution has solidified, it is cleaned with a sandpaper.
Rubbish is removed completely. First by sweeping, then using a vacuum cleaner, then wet cleaning of the floor is performed.

Thorough cleaning of the floor is imperative. Waterproofing under the screed, in order to avoid damage to it, should lie flat, adhere to the base over the entire surface, this will allow the insulator to show its maximum service life and show all the positive characteristics.

Roll materials for waterproofing

Waterproofing the floor in front of the screed, if you want to spend money wisely and save money, is done using roll materials of various kinds.

How exactly insulators are applied will be discussed later, but now it is worth dwelling on their properties:

The most inexpensive and widespread are roofing felt and glassine. These roll-on waterproofers are easy to buy, they are easy to apply, and bituminous mastics are used during work. The disadvantage that is characterized by waterproofing to a screed made of roofing material or glassine is low durability. Made on a cardboard base, roofing felt and glassine have one weak point: over time, the paper begins to crumble and rot.
Bituminous waterproofers on fiberglass and fiberglass look better. The former are cheaper, but their base tends to exfoliate over time. The latter are somewhat more expensive, the fiberglass is strong, but because of the small holes in the structure, the layers of bitumen cannot join over the entire surface, therefore, over time, the waterproofing in front of the screed begins to lag behind the base. This does not happen in one or two years, the process can take decades. A slight drawback of fiberglass-based materials is that they are easily damaged when laid, the insulator breaks if force is applied in a certain direction.
Polyester based materials are an excellent choice for private home owners. They have a maximum tensile strength to break: up to 30% in length. The waterproofing of the floor screed made with polyester roll material will not be damaged if the beam or timber floor is deformed due to excessive or resonant loading.
One-sided membranes. This modern material is used when it is required to ensure the reverse movement of moisture. The wetted screed will dry out, since the membrane on its side is impervious to water. But if condensation forms from below (from the basement, cold soil), the moisture will pass up. One-sided membrane should be used very carefully. Excessive saturation of concrete with moisture can lead to rapid loosening and destruction of the screed.
The last and most understandable material is ordinary plastic film. Such waterproofing of the floor in the apartment in front of the screed is very simple, has acceptable characteristics and will help to save money if repairs are made in the bedroom, hall, nursery, rooms where a large amount of water is leaking is more of an emergency than a standard situation.

Additional properties

Modern roll materials are available in different designs. When working with roofing material or glassine, they act by standard methods, gluing them with bituminous mastics.

But materials based on fiberglass and polyester are also available in a self-adhesive format: waterproofing in front of the screed is done by gradually deploying, releasing the insulator and pressing it to the floor surface for gluing. This allows you to work really quickly and dispense with the procedure for sealing the seams.

Special mixtures

A group of modern materials for waterproofing is presented in the form of semi-liquid mastics. One-component, all-polymer formulations are expensive and show excellent results. But it is more rational to use more universal and inexpensive means:

Cement-polymer mastics are obsolete, but they are used quite often.
Bituminous waterproofing (not to be confused with mastic) is designed to form a layer of protection by coating. To start applying, the mixture must be heated to a temperature of 160 degrees, which complicates the apartment renovation.
A bitumen-polymer mixture is almost ideal if the floor is waterproofed in an apartment. This composition adheres perfectly to concrete without the need for special adhesion increasing agents, and has a good level of strength.
Water-based acrylic waterproofing is a versatile and popular product. It is odorless, quick to apply, safe for health. The formed insulation layer is plastic and at the same time durable.

Special mixtures for waterproofing are supplied both in buckets, ready to use, and in the form of dry mixtures. The main rule when working with waterproofing of this class is to strictly observe the preparation recipe, temperature regime and rhythm of work recommended by the manufacturer of a particular product.

Preparation of the base

It is imperative to prime the floor before waterproofing. To ensure good adhesion, especially when working with polymer compounds, you can use special means of the "Betonkontakt" class - mixtures of a primer with quartz sand. When dry, such compositions not only penetrate deeply into the floor, but also form a rough, durable surface.

How is waterproofing done with different materials

Let's consider how to waterproof the floor under the screed after preparing and cleaning the base using different materials.

The perimeter of the room is glued with a special construction tape for waterproofing along the line of convergence of the floor and walls.
When working with rolled materials, a special damper tape must be laid around the perimeter of the room. Its task is to compensate for the thermal expansion of the screed.
The plastic foil is applied in strips directly to the floor. In this case, it is necessary to get rid of air bubbles between the insulation and the base. The strips are arranged so that each next one goes on the previous one by 10-15 cm. The seams are glued with wide tape. The waterproofing layer should go on the wall by 10-15 cm, forming a kind of bath for laying the screed.
When working with roofing felt, glassine, other materials of the bituminous group, the base of the floor is covered with mastic. It is recommended to use formulations from the same manufacturer as the roll insulator. The strips are laid with an overlap with an overlap of up to 10 cm, this zone is heated with a construction hairdryer for fusion. The rules for entering the wall are the same as for plastic film.
It is not recommended to use roll materials that provide fusion in an apartment. They work with them according to the same rules as with roofing material, glassine. However, after applying a layer of bitumen mastic, it is warmed up with a gas burner, and a waterproofer is prepared in the same way. The strip is applied gradually, rolled with a roller until it cools. This ensures complete adhesion to the floor surface.
Semi-liquid special mixtures are applied in thin layers in compliance with a number of rules. Work should be done with a roller or a wide brush. The first thin layer is applied in one direction. After 3 hours - the second is formed, in the opposite direction. The process is repeated until a reliable waterproofing of the floor is formed, with an even surface. Areas of pipes and other engineering networks are processed with a thin brush. When working with one-component polymer mastics, the number of layers is unlimited. The composition can be used for leveling and lightly raising the floor level; it is allowed to lay tiles on it without a screed.

Rules for applying waterproofing

The requirement for a pause of 3 hours between the application of layers of waterproofing by the coating method must be met. With a shorter drying time - lubrication, mixing of layers, formation of "sagging" is possible. If it is larger, the polymerization process will begin, the waterproofing of the floor may delaminate. After applying all layers, the waterproofing must be thoroughly dried, the manufacturer indicates the time of full polymerization, usually it is about 48 hours.

Floor waterproofing is an important part of modern floors. Do not be lazy and do not skimp on quality material. Choosing quality materials, you can be sure that the waterproofing will not fail in the most unforeseen situations.