Concrete flooring is widely used in both industrial and civil engineering. Its use is due to its high strength, reliability and durability.

There are three types of concrete screed:

Screed on a “rough” foundation made of reinforced concrete or earth

The screed is poured onto reinforced concrete floor slabs after cleaning and priming the surface. Layer thickness 50 - 100 mm. Typically, such flooring is installed in new apartments or houses.
On the ground, concrete screed is laid on the floors in the basements. First of all, the soil base is compacted, a layer of sand of 100 - 150 mm is poured onto it and compacted. Then a footing with a thickness of 40 - 50 mm is poured. After gaining the required strength (about 7 days under normal conditions), a layer of rolled vapor barrier and insulation is placed on it. Then a metal mesh frame is mounted. After this, a layer of waterproofing is rolled out and the finishing layer is poured. concrete screed 50 mm thick.

Screed on the separating layer of waterproofing

Suitable for repairing floors in garages, workshops and other premises with floors contaminated with grease and oil. A layer is laid on the surface roll waterproofing. A concrete screed with a thickness of 50 - 70 mm is poured over it.

Floating concrete screed

Suitable for repairing floors above unheated rooms. A layer of insulation is laid ( mineral wool, Styrofoam). A layer of waterproofing is laid on it. Then a metal mesh frame is mounted and poured concrete base thickness 50 - 70 mm.

Causes of destruction of concrete screed

A seemingly strong foundation can crack or completely collapse under the influence of a number of external and internal factors.

Chemical factors

For an untrained person, it will be difficult to determine the presence of damage associated with chemical reactions inside the concrete screed. This problem mainly concerns large industrial and public construction projects.

Important! During construction, it is better to use concrete that has a quality certificate produced industrially. Or mix directly at the work site, but from proven and high-quality components.

Physical factors

The cyclical process of freezing and thawing. Typical for winter concreting, when, if the pouring technology is violated, not all water participates in the chemical hardening reaction concrete mixture. Some of the moisture simply freezes. The concrete screed is destroyed due to water getting inside. Constant freezing and thawing leads to the destruction of bonds within the concrete and the formation of penetrating cracks.
Exposure to high temperatures. When a concrete floor cools suddenly, for example when putting out a fire, steam forms inside, which tears the concrete. Heating for a long time can lead to the formation of cracks. This is due to the different expansion coefficients of reinforcement and concrete. That is, at equal temperatures their size does not change equally.
Shrinkage of concrete screed. Associated with the rapid release of moisture. In hot weather, water evaporates quickly from concrete. This leads to the formation of microcracks and small dips on the floor surface.

Important! Typically, overheating cracks form in areas of the concrete floor adjacent to fireplaces or stoves. Metas where uninsulated hot or cold water supply pipes pass are also susceptible to cracking.

Excess water in the concrete solution can lead to cracking several months after pouring the screed.

Mechanical factors

Abrasion. Intensive use of the floor surface leads to the destruction of the concrete surface. A characteristic feature of such destruction are dips with rounded edges, so-called “scuffs.” The service life depends on the brand of the mixture.
Shock loads. Unlike abrasion, there is a sharp and rapid impact on the concrete surface. The result may be potholes with jagged edges and penetrating cracks.

Gender-destroying factors are rarely found in pure form. Typically, cracking or complete destruction of a concrete screed is associated with the complex effects of several reasons.

Ways to prevent destruction of concrete floor screed

Choose the right grade of concrete depending on the expected operational load. It is important to understand that the floors in the basement and garage will bear different loads. For basement Concrete grade B10 is suitable. In rooms with more intense traffic, it is better to fill floors with grade B12.5 or B15.
Using durable filler. There are many types of gravel and crushed stone. Their strength characteristics greatly influence the quality of the concrete mixture.
Introduction of plasticizing or water-repellent additives into the solution. Additional chemicals can greatly increase the concrete's resistance to moisture or mechanical stress. You can find such additives in construction stores. The main thing is to read the instructions carefully and not make mistakes with the proportions.
Impregnation of poured concrete mixture special composition for hydrophobic protection.
Mandatory waterproofing of the base before laying concrete on the earthen surface. Otherwise, it will absorb moisture and gradually collapse.
In hot weather, protecting the concrete screed from rapid evaporation of water. There are two ways:
- Covering the entire floor surface plastic film. Once upon a knock, the concrete opens and spills warm water. Exposure period is 7 - 8 days. After this, the film is removed.
- Protecting freshly laid concrete with sawdust. "Grandfatherly", but very effective method. The screed is covered with sawdust and spilled with water twice a day. Exposure period is 7 - 8 days.
Preventing freezing of the concrete screed until it reaches the required strength. To do this, you can mix concrete in warm water. After pouring, the surface is covered with plastic film. It turns out to be a “warmhouse” that will allow the concrete to gain the necessary strength. Exposure period is 3-4 days.
Isolation of communications. If heating and water supply pipes pass through a concrete screed, they are insulated. This is done to prevent cracking of the concrete floor where it comes into contact with the pipes.
Thermal insulating gaskets between concrete floors and fireplace or stove.
Protection against mechanical stress and abrasion using a finishing coating in the form of ceramic tiles, laminate, linoleum.
Device expansion joints. Concrete is poured in strips 1000 mm wide, and a galvanized profile is laid between them. Thanks to this, the monolithic concrete surface does not tear under the influence of thermal expansion.

Important! Excessive dilution of the concrete mixture with chemicals can cause the floor surface to weaken or completely collapse.

Compliance with all technological features when laying and operating a concrete floor will allow you to obtain a strong, reliable and durable foundation.

Repairing potholes and cracks in concrete screed

Even if you follow all the rules for pouring and operating a concrete screed, cracks, chips and potholes are likely to appear. The technology for repairing a concrete surface depends on the type and degree of destruction. But any work begins with preparation.

Preparatory stage. Repairing a new screed does not require special surface preparation work. It is enough to remove dust and debris.

Elimination of defects on old surface begins with removing the flooring and cleaning the floor of all paint or adhesive materials. To do this, use a spatula and a metal brush for metal.

Important! You can speed up cleaning by using special grinding attachments on a drill or hammer drill. They are sold at any hardware store.

Repair of formwork marks

Often, after dismantling the formwork, uneven areas remain on the floor surface. They are rubbed down using cement-sand mortar or repair mixture for concrete. Before grouting, the surface is dust-free and impregnated with soil. deep penetration(concrete contact) or mortar epoxy resin.

Pothole Repair

A pothole is a broken, bowl-shaped area of concrete with jagged and chipped edges. They are repaired to prevent further deterioration of the concrete surface. Repair stages:

Important! If the pothole has exposed the reinforcement, then it must be painted over open area primer for metal.

Rectangular cuts are made around each pothole using a grinder with a circle on the concrete. The depth of the cut is slightly greater than that of the pothole.
Destroyed concrete is removed from the cut using a hammer and chisel. You can also use a hammer drill with a spatula attachment.
The surface of the pothole is cleaned of dust and dirt with a regular flute brush.
The damaged area is treated with concrete contact or epoxy primer. This will allow you to get better adhesion of the repair mixture to the concrete.
The primed pothole is filled with a special compound for repairing concrete surfaces. If it is not possible to purchase one, then prepare for small potholes cement-sand mortar.
The laid mixture is leveled with the old floor. For this, a 100 - 150 mm plaster spatula is used.
After hardening, the repaired area is sanded.

Important! Drying time for soil is 45 - 60 minutes.

Crack repair

Conducted immediately after detection. Otherwise, water may get into the cracks and the process of destruction of the concrete screed will continue. Elimination steps:

Small cracks are cut using a grinder and a concrete circle or widened using a chisel and hammer. This process is called “crack bridging.” More serious areas cut out completely, like potholes.
Removes dust and construction garbage using a flute brush or vacuum cleaner.

Important! You can use an industrial or home hair dryer to clean cracks.

The surface of the cracks is impregnated with concrete contact or epoxy primer. Drying time is given for 45 - 60 minutes.
Cracks are filled with a special repair solution based on polymer or epoxy filler.

Important! Not deep cracks of 1 - 2 cm are filled at a time. More severely damaged areas are covered with several layers. Layer thickness 1 - 2 cm.

After complete drying, the repaired floor surface is sanded.

Important! Wide and long cracks can be strengthened using reinforcement inserts. Every 300 - 350 mm, cuts are made perpendicular to the crack. Then a piece of reinforcing wire is inserted into each and covered with repair mortar.

Repair of small spider-like cracks

This type of destruction is not dangerous for the load-bearing capacity of the concrete floor. To fix it, just make a liquid cement-sand mortar and rub over the cracked area.

Repair of irregularities

During operation, “worn” areas may appear on the concrete floor. They do not lead to the destruction of the entire coating, but create inconvenience when moving along it. Elimination steps:

Using a milling machine, the uneven area is cut to a depth of 10 - 15 mm.
The surface to be repaired is cleaned of dust and dirt. To do this, use a regular floor brush or broom.
The cleaned area is primed using concrete contact or epoxy glue diluted with solvent in a ratio of 1 to 10. Drying time is 45 - 60 minutes.
The impregnated surface is filled with mortar and smoothed using a plaster rule.
After drying, the entire repaired surface is sanded.

Major repairs of concrete screed

The methods described above are suitable when no more than 15% of the surface is destroyed. In other cases, major repairs of the concrete screed are required. For these purposes, there are self-leveling compounds. Stages of work:

The surface of the concrete floor is cleaned of dirt, dust and mortar deposits.
The screed is sanded using a grinder with a special attachment.
The base is impregnated with deep penetration soil. It is applied using a 250 mm paint roller. Drying time 45 - 60 minutes. After this, re-priming is carried out.
Self-leveling solution is poured. The layer thickness ranges from 50 to 100 mm. For removing air bubbles The poured surface is rolled with a needle roller. If necessary, apply the mixture in several layers. The drying time of the new screed is written on each bag of dry mixture. But it must be at least 7 days.

Important! Sanding the floor does not level the floor relative to the horizon, but only removes all small irregularities and bulges.

To maintain a concrete screed in good condition, it is enough to notice the beginning of destruction in time, determine the cause and quickly repair the damaged area of the floor.

Video removing cracks in screed

If the floor screed is not made correctly, then over time it can collapse: crumble, crack, buckle. In this case, there is no need to redo it.

You can simply repair the screed, which will be more economical option.

When cracks appear in the floor screed, it is necessary to initially determine the cause of their appearance, and then begin to eliminate them.

The reasons for the appearance of cracks on cement screed There may be an incorrect coating layer, rapid drying, excess or lack of water in the solution, lack of edge tape or expansion joints.

If the floor screed is cracked due to the lack of expansion joints, then it is necessary to cut through the shrinkage joints.

In this case, the depth of the cut should be at least one third of the thickness of the base. The distance between the seams should be within 5 meters. Seams are sealed using polyurethane-based sealant.

When cracks appear in them, you can make a groove, thus expanding it. It is necessary to remove dust from the walls of the groove and prime them. To seal cracks in the floor screed, it is necessary to use a non-shrinking substance, which is applied with a spatula.

If the cracks on the floor screed are minor and the floor covering is tiles, then they can be ignored.

Cracks in the floor screed must be sealed with a mixture of PVA glue, cement and water. All these components are mixed so that the mixture can be poured into the gap. After this, the solution must be allowed to harden and installation can begin. flooring.

The floor screed has burst - what to do?

If the floor screed bursts, then mandatory This defect must be corrected before laying the flooring.

If the concrete mixture is poorly compacted, air cavities may appear in the screed, which cause cracks to appear. In this case, it is necessary to remove the screed to the cavity and fill it with solution.

In order to see the cavities, it is necessary to widen the crack. If you find it, then use a pick to knock out the solution. The walls of the resulting hole must be primed and then sealed with cement mortar.

Part cement mixture, which is prepared for sealing the cavity, should include one part of sand and three cement. Before pouring the mixture, the concrete must be wetted with water.

The compaction of the mortar after pouring must be compacted using the piercing method. A metal rod is used for this purpose.

After repairing the floor screed, it is necessary to ensure not too much high temperature in room. To prevent cracks from appearing on it, it is necessary to periodically moisten the place where the cement mixture is laid with water.

The screed is leaking - what to do?

If the floor screed coils, then it is made poorly. The reason for the coiling of the screed may be a poor-quality mixture for the screed, a lack of primer on the base, a dirty and dusty base that is used for the screed, etc.

In this case, it is necessary to hit the screed with the blunt edge of a hammer. If the mixture is of poor quality, then a dent will remain at the impact site. The screed may buckle in the presence of cracks or in their absence.

If the screed coils in the presence of cracks, then you can try to eliminate it. To do this, it is necessary to widen the crack. Next, the preparation is very liquid solution from sand and cement.

It would be best to add PVA glue to this solution. Next, the resulting solution is slowly poured into the expanded mixture. It is necessary to pour the solution in small quantities, allowing it to dry in parts.

If this method does not remove the coiling of the screed, then it must be completely removed and refilled. This is a rather expensive option. That is why it is necessary to carry out the screed strictly established rules.

Also watch a useful video with expert advice on screed repair:

The reasons why the screed will be weak are different:

Failure to maintain the proportions of water and cement.
Old cement (with lumps).
Increased clay content in sand.
Improper preparation and care after installation when rapid dehydration conditions occur.

But if this happens, then something needs to be done about it - because with further finishing, difficulties are possible.

It is also impossible to leave it unchanged. Dust constantly forms on such a floor. The weak layer is easily destroyed by feet.

First way. Strengthening with primer.

The first thing most people come to is to strengthen it with a primer. The option is real, affordable and on everyone’s lips. But it rarely gives results:

A short comment on the video.

Judging by the nail test, the screed is quite suitable for tiling indoors. There are examples of a more deplorable state of the foundation, which they tried to strengthen with a primer:

For what reason did the tile bounce off the screed?

They tried to strengthen the loose screed with a primer. But primer, primer is different. Judging by the color and the resulting film, a concentrate primer was used in shock proportions. Or primed several times, allowing each layer to dry completely (as written on the canister). This gave a film on the surface. A tile with glue was attached to it. But under the film the same weak layer remained. The tile came off along it.

Alternatively, you need a deeply penetrating primer and pour it in buckets at a time. To consolidate a weak layer to a greater depth. Deep penetration primer (according to the manufacturers) has smaller particles and therefore can penetrate deeper without creating a film on the surface.

Strengthening cement screed with silicates (liquid glass).

The idea of using liquid glass to repair weak surfaces did not come out of nowhere. Liquid glass has been used in construction for a long time:

Additives to concrete and mortars to accelerate setting (1-15% by weight of cement).
Production of fire-resistant paints, putties and putties with the addition of fillers (talc, marble dust, fine sand).
Waterproofing of concrete and wooden structures.
Fighting fungus and mold.
In metallurgy, the roof of furnaces is laid out from fireclay bricks with a sodium silicate binder.

There are three main types (depending on composition) of liquid glass: potassium, sodium and lithium. They have different properties, which gives different advantages and different prices.

Sodium is more common. They are using it to strengthen screeds in garages and basements:

You can experiment with this method. It’s useful to have at least some other people’s experience.

Below are the most interesting details using liquid glass. It’s hard to call this quality material for drawing conclusions. But still:

One could call all this fuss with liquid glass a collective farm and forget about it, if not for such a detail as recommendations for strengthening loose screeds with silicates from many manufacturers of mixtures. One of them from “MAPEY”:

Important points in the video:

The viscosity of the impregnation is more similar to a primer than to the liquid glass in jars that are used to strengthen garage floors.
Impregnation must be applied continuously, preventing the top layer from forming a crust.
Consumption can be significant, 3-4 liters per meter.

It is clear that the Prosfas strengthening primer does not consist of silicate alone. Therefore, its price differs from the price of liquid glass. If we compare the cost of strengthening a loose screed with silicate from “MAPEY” and ordinary liquid glass, taking into account its consumption and a similar consumption of liquid glass, the discrepancy will be significant:

Prosfas and liquid glass.

But Mapei is not the only company that prepares impregnations for concrete and screeds.

An entire industry has been created around this problem. Million-dollar businesses have been built on a simple chemical reaction (Ca(OH)2 converts to C-S-H) between silicate in the impregnation and calcium hydroxide in concrete. The composition of the impregnation is not disclosed, except for the name of one of the silicates on the basis of which it was created.

Like different types Various strengthening impregnations based on potassium, sodium, magnesium and lithium have also been created for liquid glass. An important difference between them is the size of the molecule. This determines how deeply the silicate can penetrate the screed:

Impregnations based on sodium silicates.

Sodium impregnations.

Here are selected examples of sodium impregnations. That's not all. New ones may appear that are cheaper and more efficient. Some are cutting production and leaving the market:

Ashford Formula– Ashford Formula brand. Manufacturer Curecrete Chemical Co (USA). The country of origin may be different.
Lithurin.
Diamond Hard(Diamond Hard). Product of the American chemical concern EUCLID CHEMICAL.
Liquid-Hard from W.R.Meadows (USA). The manufacturer may be the Czech Republic.

All impregnations are similar in the method of application:

Apply so that the entire surface remains wet for 30-60 minutes. Without puddles and drying out separate areas. This is achieved using a soft whisk, redistributing the liquid throughout the screed. The excess is moved to adjacent areas and removed with a water vacuum cleaner.

Some impregnations are diluted with water (Lithurin I). Some have features - Ashford Formula is not effective on concrete grades below M 300 and on cement-sand screeds:

Strengthening impregnations based on lithium.

According to the American Concrete Institute (ACI Concrete Institute), lithium-based impregnations have a number of advantages:

Increases the strength of concrete by more than 45% (sodium - 37%).
Compacts concrete and completes chemical reaction within 7-14 days (use after 2 hours). For sodium it is 6-12 months.
There is no need to rinse it with water.
Penetrates 1-5 mm, forming a chemical reaction with the top layer.

Lithium based impregnations.

ULTRALIT HARD (1)

If you believe the prices and consumption (for 20 squares - 1 one liter), then impregnation of one square of concrete surface costs $0.05. Country of origin: Czech Republic (technology, most likely, USA).

The production of three varieties Ultralit Hard Standard, Ultralit Hard Premium, Ultralit Hard Extra has been launched.

Mapecrete LI Hardener (2)

Lithium-based liquid for new and old concrete floors from MAPEI.

$5.8 – impregnation of one square meter, at a consumption of 0.4 kg/m2 (the real price can only be found out at the time of purchase).

"Concria Super Hard" and "Concria Hard" (5)

Country of origin: USA. Based on the consumption of 1 liter per 10-20 m2, we get the cost of one square meter: 1.2-2.2 $. C2 Hard can be used on floors that have already been treated with other silicate impregnations and the surface of which has begun to dust and peel.

In addition to these two impregnations, others are produced for strengthening, for coloring, adding gloss....

SPEKTRIN LITHIUM(4) – made in Sweden/Ukraine. Lithium impregnation for concrete and stone (marble). Penetration depth is about 7 mm. Increased strength by up to 16%. Reduced water absorption by 3.3 times. Impregnation can be used in the food and pharmaceutical industries. Costs (cost of impregnation) per 1 square meter -1.5 $. Used for interior and exterior work on durable and dense concrete (M 300 and above):

The first impregnations appeared on the American market about 50 years ago. The search for new compositions does not stop. Competition is growing. Without experience, it is difficult to understand the features of each and the veracity of the declared properties. The instruction in some of those maps of strengthening impregnations is alarming: “Do not apply to dusty, crumbling and fragile substrates.” Marketing wars lead to even greater confusion:

A good warning was placed before purchasing one of the impregnations:

As a solution, you need a test area 1.5m x 1.5m. If there are different surfaces, then for each type of surface there is a separate platform. After doing everything according to the instructions, let it dry for 3-7 days. Then draw a conclusion based on consumption, costs, obtained and expected surface strength.

Floor screed repair is a fairly common type. repair work. The subfloor experiences significant loads, as a result of which it gradually wears out and weakens. You can strengthen the concrete base and eliminate defects yourself.

Malfunctions and their causes

The most common damage to subfloors are:

general weakening of the tie. Characterized by the appearance of a large amount of cement dust as a result of a violation of the mortar preparation technology or poor quality of cement;
potholes and cracks. Formed due to excessive point load on the floor surface. The presence of voids in the top layer of the concrete base also causes the screed to crack and deform. This defect is considered the most dangerous for decorative flooring: the area located above the damage and lacking solid support quickly deteriorates and collapses;

peeling. Diagnosis of this malfunction is made by tapping the floor surface with a hammer. In the peeled areas, the sound from the impact will be muffled, and dust will begin to escape through the resulting cracks. Detachment can be expressed in visual swelling of the top layer and raising of the corners after the solution has dried. The reasons are often uneven drying of concrete, lack of a primer layer under the base and the use of low-quality cement;
excessive dust formation. Due to excessive loads and general aging of the screed, a large amount of cement dust forms on its surface. Sometimes floor dusting is associated with poor quality cement and a violation of pouring technology.

Repair composition

Mixtures for restoring cement screeds are widely represented on the modern construction market. They include polyurethane components and synthetic resins and are more intended for industrial use. When carrying out renovation work in an apartment, purchasing expensive compounds is not always rational, therefore For minor repairs, you can prepare the mixture yourself.

For this it is necessary mix PVA glue with water at a ratio of 1:3, then add one part sand and three parts cement. The resulting composition should be carefully moved using construction mixer or a drill with a blade attachment.

You can repair shallow cracks and small potholes with a homemade cement mixture. To carry out large-scale repair and restoration work, you need to purchase professional tools.

How to strengthen?

To strengthen the subfloor screed, it is necessary to drill a series of holes with a hammer drill, equidistant from each other at a distance of 25 cm and having a diameter of 20 mm. The depth of the channels made should be equal to the thickness of the screed. The work should be carried out using a drill with a slight angle of inclination of the working groove. The holes should be cleaned of dirt and, if possible, dust free.. Next, you need to prepare scraps of reinforcement equal in length to the depth of the channels and having a diameter of 12 mm.

Then a mixture of epoxy for concrete “Rizopox-350” and quartz sand should be poured into the holes, then iron rods should be inserted. The fittings must be degreased first b. The upper, widest part of the channel is also carefully filled until it is equal to the level of the base. For installation decorative covering You can start after complete drying, subsequent dust removal and priming of the screed.

If you have a “warm floor” system, this method of strengthening the screed is not suitable: drilling channels can damage the cable and thermomat, as well as pierce the water heating pipeline.

How to repair?

After diagnosing the emerging peelings, as well as in cases where the screed is swollen and “swobbly”, it is possible to begin repairing it only if the damaged surface is no more than 30% of the total area self-leveling floor. There are two ways to repair detachments. The first is to carry out targeted injections using a liquid repair mixture and consists of several stages. Initially, you should identify problem areas by tapping and outline them with chalk. Then, in places of delamination, channels with a diameter of 15 to 20 mm are drilled. The distances between the holes should be 25-30 cm.

Next, the channels should be cleared of dust and a primer mixture should be poured into them, trying to evenly moisten the entire surface of the internal cavity. After pouring is completed, you need to dry the treated surface with a construction hairdryer. Cement-adhesive mixtures or epoxy resins can be used as injection materials..

An important condition The maintainability of the solution is good fluidity. To fill the channels, you can use a construction syringe or a plunger pump.

Injections should be carried out slowly, allowing the solution to be evenly distributed throughout the entire internal cavity. The procedure should be carried out until the upper part of the channels is filled with the mixture to the floor level. The repaired screed must dry for at least a day, after which you can begin priming and subsequent installation of the finishing coating.

The second way to repair a delaminated screed is to completely dismantle the problem area, removing dust and priming the surface, followed by concrete pouring. The method is used in cases where spot repairs are impossible with large area damaged area.

Getting rid of cracks

Cracking of the surface of the screed can occur from uneven load on the finishing coating, impacts and poor moisture of the concrete base during drying. If the floor surface is cracked, burst or crumbles badly, it is necessary to take emergency measures, because cracks are the most serious defect of screeds. To fix the problem, you need to deepen and widen the crack with a grinder until you get strong edges, using a disk for working on stone. Then you should cut grooves perpendicular to the direction of the crack, 2 cm deep and 15 cm wide. The surface of the recesses is thoroughly dust-free and primed.

Next, the crack needs to be filled with a repair compound to half its depth and a metal bracket must be installed. To increase the strength of the solution, you can add quartz sand to it. After filling the main crevice, you need to fill the transverse grooves with mortar and remove excess mortar. Then you need to wait for the repaired surface to dry completely and begin sanding it.

When repairing deep cracks, their cavity must be drilled out to the full depth of the screed. When forming transverse grooves at the ends, you need to drill holes 2-3 cm deep. You need to fill a deep crack in several stages, giving each layer time to harden as much as possible.. The first batch of the mixture should be made a little more liquid. This will allow her to penetrate into the most hard to reach places at the base of the floor and fill them evenly. The next batch should be of medium thickness; it should be poured into the crevice to the level of the transverse grooves.

After the second layer has set, you need to install tightening metal brackets, securing their ends in drilled holes. Then a plasticizer is added to the solution and a final fill is made, which will hide the bracket underneath. After the solution has completely dried, the repaired area is sanded and the screed is prepared for installation of self-leveling flooring or installation of floor covering.

Repairing Potholes

Repair of potholes and chips should begin with their widening and deepening, which must be carried out until the edges of the deepening stop crumbling. To do this, you should use a grinder equipped diamond blades designed for working with stone. For serious potholes, the depth of which exceeds five centimeters, it is necessary to drill through the entire thickness of the screed. Then you should remove construction debris from the crevice and thoroughly dedust it. Next, you need to apply the primer mixture and let it soak in.

Filling the pothole with solution should be done in several stages, applying each subsequent layer only as the previous one dries. This will ensure uniform drying of the solution throughout its depth and prevent the appearance of cracks.

If, after drying, the screed cracks again, you should increase the area of exposure of the concrete layer and repeat the procedure. A day after the repair work, you can grind the area and prepare the screed for laying the turnkey coating.

Removing dust

Very often, an old screed, especially one that does not have a decorative coating on top, begins to gather dust. This problem is most typical for the floors of garages, warehouses and industrial premises. Constant weight loads combined with vibration and regular temperature changes contribute to the rapid destruction of the coating and the appearance of cement-sand dust. Over time, the dust becomes so much that it becomes impossible to sweep it away. If it is impossible to completely replace the concrete screed, you need to immediately strengthen the old base.

Initially, the floor should be cleaned of mechanical debris and dirt. Then the surface is dust-free and inspected for cracks and potholes. If they are detected, problem areas are repaired, and after the solution has dried, they are sanded. Then you need to cover the entire surface of the screed with a penetrating primer mixture and wait until it is completely absorbed. In rooms with high humidity, special water emulsifiers should be used.. Next, the surface is painted with wear- and frost-resistant enamel for concrete surfaces.

You can cover a dusty floor with a specialized composition that has polymer base. The solution is able to penetrate 5 mm deep into the concrete screed, completely preventing the formation of dust. The treated surface acquires excellent vapor-permeable properties and is also characterized by high resistance to chemicals, sudden temperature changes and abrasion.

To increase the anti-slip effect of the floor, quartz sand is applied to the uncured composition., which forms a rough surface after the product dries.

A more reliable method is to reinforce a dusty floor with special fiberglass.

To do this, the surface of the screed is dust-free and primed. After the primer mixture has dried, tile adhesive is applied to the screed and the fabric is laid. The canvases should be laid overlapping, leaving no open areas.

After the first layer of glue has dried, a second layer should be applied over the fabric. This will securely secure the dusting base and increase adhesion. Then, around the perimeter of the room, it is necessary to install a damper tape, which will act as a compensator. The last stage will be the installation of beacons and installation of a self-leveling mixture.

The floor screed is crumbling, what should I do?

Why does cement screed crumble, what should I do?

arturio77

4 years ago

The main reason is two factors: the incorrect composition of the mortar, that is, the proportions of the cement are not met and the mortar is not strong, and the second important factor is the drying speed of the mortar. If you create large and constant drafts, then the moisture from the solution evaporates very quickly and the cement does not have time to show its adhesion properties and turns into ordinary dust, such a solution will constantly peel off and it will be difficult and dangerous to finish it further finishing materials. Also, the cement mortar may simply be stuck a little by frost; after thawing, that part of the mortar into which the ice has penetrated will definitely peel off. If the question relates only to the screed, then you can pour a stronger one on top, of course, if the height of the thresholds allows. If the screed completely crumbles into large pieces, then in this case it is of course better to replace it completely.

the moderator chose this answer as the best

9 months ago

It is necessary to clarify, for the clarity of the answer, where your screed is located. This could be a street - an area around a house or a vestibule in a bathhouse, a screed in a garage or a screed in a bathroom, etc.

There are several main reasons for the appearance of cracks or delamination or abrasion of the screed:

Poor quality fillers. Due to the abundance of dust in the aggregates or due to the large presence of fine fractions, the grade of the solution may drop many times over. This leads to a decrease in strength, density, and subsequently all other characteristics (moisture resistance, abrasion resistance, frost resistance, etc.). This is why cracks or chips can quickly appear.
Poor quality cement. When using stale, low-quality cement (purchased from someone else), cement in which the process of hydration has begun (soft cement pellets and grains have formed), the strength of the solution drops by 2 or even 3-4 times.
Added too much plasticizer. With a large inclusion of plasticizer, separation of the mixture may occur. When it hardens in a short time (literally 1-2 months later), chips and cracks appear, and the screed peels off.
Same thing, but only with water. With a large addition of water, the solution turns out to be porous and very soft. The finished screed will not be able to withstand heavy loads. If the screed is in the open air, then it will “tear” in the autumn and spring periods.
Incorrect reinforcement. The absence of reinforcement or its insufficiency leads to the fact that the screed cannot take the load. Hence the cracks.
Thin layer of concrete. With a small thickness of the screed and significant loads, it will simply begin to crack. An example is simple: when 30 mm of concrete is poured in garages and then a dump truck is driven there. It is not surprising that the screed falls apart.
Poor preparation of the base - lack of compaction, erection of the screed on top of a soft base.
Rapid drying process, insufficient moisture after pouring the mixture or excessive exposure to sunlight.

What to do?

If cracks appear and the screed crumbles, then the destruction process cannot be stopped. This will continue. it is necessary to eradicate the cause, and this is only possible after dismantling the screed and erecting a new one. Of course, there are options where some decisions can be made. For example, if it is in the yard, then you can make a 20-30 mm mound of sand on top of the screed and lay paving stones (as an example).

To avoid the appearance of cracks, we will consider the possibilities of eliminating each of the 8 causes at the stages of screed construction.

Aggregates must be clean: free from dust, impurities and large inclusions (if sand). Recommended crushed stone fraction for screeds: 1-5 mm, 5-10 mm, 5-20 mm. It is recommended to use river sand, seeded sand - fractions 0.1 - 3 mm.
Buy cement only in large stores or directly from the manufacturer. Look at the production date. Use cement within 2-3 months after production. Recommended cement grades M400D20, M400D0, M500D0, M500D20.
Add no more than 2% plasticizer to the solution. Read the manufacturer's instructions carefully. Typically, plasticizer is added in the region of 0.5-1%. The recommended brand of mortar for screeds is at least M250, better classic version- M300.
Maintain the water-cement ratio. Recommended W/C - 0.5. One part cement, half part water (by weight).
When pouring screeds up to 50 mm, it can be reinforced reinforcing mesh with a diameter of 5-8 mm. You can get by with one plane of reinforcement. It must be located at the bottom of the screed. With a screed thickness of 50-120 mm, it is necessary to increase the cross-section of the reinforcement. When using one plane of reinforcement, use reinforcement with a diameter of 8-14 mm. If there are two reinforcement planes (top and bottom), then you can use reinforced mesh 5 mm or 6 mm. When the screed size is more than 120 mm, it is recommended to use two planes of reinforcement. The minimum diameters of reinforcement in meshes are 8 mm.
If the load on the screed is insignificant, you can limit yourself to 50 mm of concrete (this is important for leveling floors in apartments). When pouring a blind area, yard, or garage floor, the recommended screed thickness is 120-180 mm.
Before pouring the screed, remove loose, vegetable soil from the surface. It is necessary to remove it until it is tight, clay soils. Afterwards, level the base. Make an embankment of sand, 40-150 mm thick. Compact this thickness and vibrate it. Level the surface again. Lay a waterproof film or geotextile and only after reinforcement begin laying the mixture. This is for screeds outside the residential area.
Concrete should dry slowly. 2-4 hours after laying the mixture, cover the surface of the screed dark film. Water the concrete for 3-5 days. Keep away from open sunlight.

favorite link thank Kim Jong-un

more than a year ago

There are quite a few reasons for this screed behavior:

We bought cement by weight; the expiration date of the cement had expired (60 days after the date of manufacture).

Not correct proportions When mixing, the screed can burst with both a small amount of cement in the solution and a large one.

Screed too thin.

They did not give full time to dry and subjected the screed to stress.

There are warm floors under the screed, the screed is not dry, the heated floors are turned on.

The screed was dried additionally (forcibly) using heat guns, browsers, and so on.

We poured the screed in an unheated room, plus during the day, minus at night, as a result, instead of drying out, the screed froze (the water in it) the ice thaws and crumbles the screed.

But actions must be taken based on a specific reason; cracks in the screed can still be “cured,” but if the screed is crumbling everywhere, then only dismantling and pouring a new screed according to all the rules.

Crumbling means too many cracks on the surface of the screed,

tap it with your knuckles, there will probably be a dull sound everywhere, that is, it has moved away from the surface. add to favorites link thank SvetlanaSha

4 years ago

Cement screed crumbles for a number of reasons:

the proportions when preparing the solution are not met, there is a lot of sand;
low-quality cement;
the base for the screed is not prepared correctly.

If the defective area is small, you can clean the screed, remove everything that is crumbling, treat the surface with primer, dilute a new solution, slightly liquid, and make a new thin screed. If the entire floor crumbles, the screed must be completely removed and refilled.

3 years ago

This defect often occurs if sand and cement are mixed in advance, especially in warm weather, and not mixed immediately. We've already been burned by this.

Do you know the answer?

How to strengthen a concrete screed that is crumbling

The screed is leaking - what to do?

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Concrete screed is crumbling - what to do?

Concrete flooring is widely used in both industrial and civil construction. Its use is due to its high strength, reliability and durability.

The screed is poured onto reinforced concrete floor slabs after cleaning and priming the surface. Layer thickness 50 – 100 mm. Typically, such flooring is installed in new apartments or houses. On the ground, concrete screed is laid on the floors in the basements. First of all, the soil base is compacted, a layer of sand of 100 - 150 mm is poured onto it and compacted. Then a footing with a thickness of 40 - 50 mm is poured. After gaining the required strength (about 7 days under normal conditions), a layer of rolled vapor barrier and insulation is placed on it. Then a metal mesh frame is mounted. After this, a layer of waterproofing is rolled out and a finishing concrete screed 50 mm thick is poured.

Screed on the separating layer of waterproofing

Suitable for repairing floors in garages, workshops and other premises with floors contaminated with grease and oil. A layer of rolled waterproofing is laid on the surface. A concrete screed with a thickness of 50 - 70 mm is poured over it.

Floating concrete screed

Suitable for repairing floors above unheated rooms. A layer of insulation (mineral wool, polystyrene foam) is laid. A layer of waterproofing is laid on it. Then a metal mesh frame is mounted and a concrete base 50–70 mm thick is poured.

Causes of destruction of concrete screed

A seemingly strong foundation can crack or completely collapse under the influence of a number of external and internal factors.

Chemical factors

Important! During construction, it is better to use concrete that has a quality certificate and is produced industrially. Or mix directly at the work site, but from proven and high-quality components.

Physical factors

The cyclical process of freezing and thawing. It is typical for winter concreting, when, if the pouring technology is violated, not all the water participates in the chemical reaction of hardening the concrete mixture. Some of the moisture simply freezes. The concrete screed is destroyed due to water getting inside. Constant freezing and thawing leads to the destruction of bonds within the concrete and the formation of penetrating cracks.
Exposure to high temperatures. When a concrete floor cools suddenly, for example when putting out a fire, steam forms inside, which tears the concrete. Heating for a long time can lead to the formation of cracks. This is due to the different expansion coefficients of reinforcement and concrete. That is, at equal temperatures their size does not change equally.

Important! Typically, overheating cracks form in areas of the concrete floor adjacent to fireplaces or stoves. Metas where uninsulated hot or cold water supply pipes pass are also susceptible to cracking.

Shrinkage of concrete screed. Associated with the rapid release of moisture. In hot weather, water evaporates quickly from concrete. This leads to the formation of microcracks and small dips on the floor surface.

Excess water in the concrete solution can lead to cracking several months after pouring the screed.

Mechanical factors

Abrasion. Intensive use of the floor surface leads to the destruction of the concrete surface. A characteristic feature of such destruction are dips with rounded edges, so-called “scuffs.” The service life depends on the brand of the mixture.
Shock loads. Unlike abrasion, there is a sharp and rapid impact on the concrete surface. The result may be potholes with jagged edges and penetrating cracks.

Sex-destroying factors are rarely found in their pure form. Typically, cracking or complete destruction of a concrete screed is associated with the complex effects of several reasons.

Ways to prevent destruction of concrete floor screed

Choose the right grade of concrete depending on the expected operational load. It is important to understand that the floors in the basement and garage will bear different loads. Concrete grade B10 is suitable for the basement. In rooms with more intense traffic, it is better to fill floors with grade B12.5 or B15.
Using durable filler. There are many types of gravel and crushed stone. Their strength characteristics greatly influence the quality of the concrete mixture.
Introduction of plasticizing or water-repellent additives into the solution. Additional chemicals can greatly increase the concrete's resistance to moisture or mechanical stress. You can find such additives in construction stores. The main thing is to read the instructions carefully and not make mistakes with the proportions.

Important! Excessive dilution of concrete with seven chemicals can cause the floor surface to weaken or completely fail.

Impregnation of the poured concrete mixture with a special composition for hydrophobic protection.
Mandatory waterproofing of the base before laying concrete on the earthen surface. Otherwise, it will absorb moisture and gradually collapse.
In hot weather, protecting the concrete screed from rapid evaporation of water. There are two ways:

Covering the entire floor surface with plastic film. Once upon a knock, it opens and pours warm water onto the concrete. Exposure period is 7 – 8 days. After this, the film is removed.
Protecting freshly laid concrete with sawdust. "Old-fashioned" but very effective way. The slurry is covered with sawdust and spilled with water twice a day. The aging period is 7 – 8 days.

Preventing freezing of the concrete screed until it reaches the required strength. To do this, you can mix concrete in warm water. After pouring, the surface is covered with plastic film. It turns out to be a “warmhouse” that will allow the concrete to gain the necessary strength. Exposure period is 3-4 days.
Isolation of communications. If heating and water supply pipes pass through a concrete screed, they are insulated. This is done to prevent cracking of the concrete floor where it comes into contact with the pipes.
Thermal insulating gaskets between concrete floors and fireplace or stove.
Protection from mechanical stress and abrasion using a finishing coating in the form of ceramic tiles, laminite, linoleum.
Construction of expansion joints. Concrete is poured in strips 1000 mm wide, and a galvanized profile is laid between them. Thanks to this, the monolithic concrete surface does not tear under the influence of thermal expansion.

Compliance with all technological features when laying and operating a concrete floor will allow you to obtain a strong, reliable and durable foundation.

Repairing potholes and cracks in concrete screed

Preparatory stage. Repairing a new screed does not require special surface preparation work. It is enough to remove dust and debris.

Eliminating defects on an old surface begins with removing the flooring and cleaning the floor of all paint and adhesive materials. To do this, use a spatula and a metal brush for metal.

Important! You can speed up cleaning by using special grinding attachments on a drill or hammer drill. They are sold at any hardware store.

Repair of formwork marks

Often, after dismantling the formwork, uneven areas remain on the floor surface. They are rubbed down using cement-sand mortar or concrete repair mixture. Before grouting, the surface is dust-free and impregnated with deep penetration soil (concrete contact) or epoxy resin solution.

Pothole Repair

A pothole is a broken, bowl-shaped area of concrete with jagged and chipped edges. They are repaired to prevent further deterioration of the concrete surface. Repair stages:

Rectangular cuts are made around each pothole using a grinder with a circle on the concrete. The depth of the cut is slightly greater than that of the pothole.
Destroyed concrete is removed from the cut using a hammer and chisel. You can also use a hammer drill with a spatula attachment.

Important! If the pothole has exposed the reinforcement, then you need to paint over the exposed area with metal primer.

The surface of the pothole is cleaned of dust and dirt with a regular flute brush.
The damaged area is treated with concrete contact or epoxy primer. This will allow you to get better adhesion of the repair mixture to the concrete.

Important! Drying time for the soil is 45 - 60 minutes.

The primed pothole is filled with a special compound for repairing concrete surfaces. If it is not possible to purchase it, then prepare a cement-sand mortar for small potholes.
The laid mixture is leveled with the old floor. For this purpose, a plaster spatula of 100 - 150 mm is used.
After hardening, the repaired area is sanded.

Crack repair

Conducted immediately after detection. Otherwise, water may get into the cracks and the process of destruction of the concrete screed will continue. Elimination steps:

Small cracks are cut using a grinder and a concrete circle or widened using a chisel and hammer. This process is called “crack bridging.” More serious areas are cut out completely, like potholes.
Dust and construction debris are removed using a brush or vacuum cleaner.

Important! You can use an industrial or home hair dryer to clean cracks.

The surface of the cracks is impregnated with concrete contact or epoxy primer. Drying time is given for 45 - 60 minutes.
Cracks are filled with a special repair solution based on polymer or epoxy filler.

Important! Cracks that are not deep, 1–2 cm, are filled at a time. More severely damaged areas are covered with several layers. Layer thickness 1 – 2 cm.

After complete drying, the repaired floor surface is sanded.

Important! Wide and long cracks can be strengthened using reinforcement inserts. Every 300 - 350 mm, cuts are made perpendicular to the crack. Then a piece of reinforcing wire is inserted into each and covered with repair mortar.

Repair of small spider-like cracks

This type of destruction is not dangerous for the load-bearing capacity of the concrete floor. To fix it, just make a liquid cement-sand mortar and rub over the cracked area.

Repair of irregularities

During operation, “worn” areas may appear on the concrete floor. They do not lead to the destruction of the entire coating, but create inconvenience when moving along it. Elimination steps:

Using a milling machine, the uneven area is cut to a depth of 10 - 15 mm.
The surface to be repaired is cleaned of dust and dirt. To do this, use a regular floor brush or broom.
The cleaned area is primed using concrete contact or epoxy glue diluted with solvent in a ratio of 1 to 10. Drying time is 45 - 60 minutes.
The impregnated surface is filled with mortar and smoothed using a plaster rule.
After drying, the entire repaired surface is sanded.

Major repairs of concrete screed

The surface of the concrete floor is cleaned of dirt, dust and mortar deposits.
The screed is sanded using a grinder with a special attachment.

Important! Sanding the floor does not level the floor relative to the horizon, but only removes all small irregularities and bulges.

The base is impregnated with deep penetration soil. It is applied using a 250 mm paint roller. Drying time 45 – 60 minutes. After this, re-priming is carried out.
Self-leveling solution is poured. The layer thickness ranges from 50 to 100 mm. To remove air bubbles, the filled surface is rolled with a needle roller. If necessary, apply the mixture in several layers. The drying time of the new screed is written on each bag of dry mixture. But it must be at least 7 days.

To maintain a concrete screed in good condition, it is enough to notice the beginning of destruction in time, determine the cause and quickly repair the damaged area of the floor.

Video removing cracks in screed

How to strengthen a screed

03.04.2015

A loose, crumbling, uneven screed needs to be knocked down to the ground in a good way. And pour on top concrete slab new.

However, the best, as we know, is the enemy of the good. And there is far away the financial opportunity and time for a major renovation. In this case, I suggest using the following method of strengthening the screed.

We remove dust from the loose base (necessarily construction vacuum cleaner, a broom will not be enough. You can also use a regular household vacuum cleaner, but keep in mind that concrete dust is harmful to its motor. But if you’re old, you don’t mind...)

We prime with deep penetration soil. Let it dry for at least 3-4 hours. It is also not worth tightening too much, so that dust does not appear again. Next comes the stage of reinforcement and preliminary leveling. The floor is puttied with a layer of tile adhesive. A plastic facade mesh with a 5x5 mm cell is embedded in the glue.

As a result, our crumbling screed is covered with a layer of sufficient durable material. In addition, thanks to the mesh, the floor becomes solid again, rather than large pieces of screed separated by cracks.

We carry out the final leveling using a self-leveling method. The dried layer of glue is also prepared. Dust removal and soil. How to do this is described here.

The presence of tile adhesive will not allow the hardening self-leveling material to tear off the weak and loose upper layer screeds. The glue also covers the deepest irregularities, which helps the self-leveling product to spread. thin layer(as practice shows, 3-5 mm - optimal height layer of self-leveling mixture. If somewhere the layer thickness turns out to be 10-15 mm, cracks, as a rule, also appear there.)

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Major repairs of concrete floors: strengthening the peeling screed

Popular methods for repairing concrete floors work effectively provided that the floor surface has retained at least seventy percent of its integrity. If the concrete screed is destroyed by more than thirty percent, it makes sense to replace it with a new one.

The pouring process itself is quite simple, but certain rules must be followed when performing it. The surface on which the screed will be poured must be absolutely clean. For better adhesion of the mixture to the rough surface, it is necessary to use a primer mixture. If the room is observed high humidity– preference should be given to a primer with water-repellent properties.

After the steps described above, the starting floor is filled with a small layer (5-10 cm) of a self-leveling composition, from which air bubbles formed during the filling process are removed using a special needle roller. It is permissible to apply a second layer of composition if necessary.

After the screed has been poured, it needs to be given time to settle. It is not recommended to allow any impact on the coating for a month, because... It is during this period of time that the filled layer finally hardens and acquires all its inherent properties. However, despite observing the technical rules for pouring concrete floors, after some time it becomes necessary to repair them. Let's look at the types of damage and repair methods.

Steps to strengthen a weak concrete floor

Strengthening the screed may become necessary if low-quality cement was used when pouring it or the floor surface is constantly exposed to high external loads(for example, in workshops and industrial premises). It is best to dismantle the poor-quality base and fill in a new screed rather than repair the coating on large damaged areas, but there is not always enough time and money for this.

Strengthening technology

The first step is to drill a series of holes in the screed to be renewed, 20 mm in diameter and located at a distance of 25 cm from each other. The holes are drilled all the way to the base. Professional hammer drills, equipped with a special drill with a small angle of inclination of the working groove, cope well with this task.

Next, in each hole (in its upper part) you should drill a support bowl, the depth of which is 30 mm, and the diameter is twice the size of the hole itself. The drilled holes are cleaned of dust and undergo a priming process, after which grease-free reinforcement is inserted into them, the diameter of which is ~ 12 mm, and the length is equal to the depth of the hole.

After this, each hole is filled with epoxy mortar (Rizopox 3500) and a filler is added, which is quartz sand. At the final stage, the surface is polished until a smooth plane is obtained.

Repair of peeled coating layer

Quite often, during operation, the screed can peel off from the subfloor. This happens due to the impact of unevenly distributed loads on the concrete floor. It is not always possible to visually see the problem area. You can detect peeling by lightly tapping the entire floor with a hammer. The peeling zone will indicate itself with a dull sound. In addition, it is not uncommon for peeling to occur in areas of the floor that have cracks, from which a cloud of cement dust flies out when tapped. Once all areas of the floor requiring repair have been identified, you can begin injecting the screed.

The essence of the method is quite simple and does not take much time. In those parts of the floor where signs of delamination were found, holes are drilled at a distance of 250 mm, the diameter of which varies from 12 to 20 mm. Then, using a construction syringe, the composition is poured into them to epoxy based. The mixture is poured several times as it is absorbed into the concrete and fills the voids created by the peeling process.

The undoubted advantage of the described method is its speed, because the very next day after repairing concrete floors, a protective layer can be applied to the screed.

vest-beton.ru

How to strengthen a screed that is crumbling, and how to repair cracks? The floor screed bursts or buckles - what to do?

How to strengthen a screed that is crumbling?

If the floor screed is not done correctly, it may collapse over time. crumble, crack, buckle. In this case, there is no need to redo it.

You can simply repair the screed. which would be a more economical option.

How to repair cracks in screed?

When cracks appear in the floor screed, it is necessary to initially determine the cause of their appearance. and then begin to eliminate them.

The reasons for the appearance of cracks in a cement screed may be an incorrect coating layer, rapid drying, excess or lack of water in the solution, lack of edge tape or expansion joints.

If the floor screed is cracked due to the lack of expansion joints, then it is necessary to cut through the shrinkage joints.

If the cracks on the floor screed are minor and the floor covering is tiles, then they can be ignored.

The floor screed has burst - what to do?

If the floor screed has burst, then it is imperative to correct this defect before laying the floor covering.

The composition of the cement mixture, which is prepared for sealing the cavity, should include one part sand and three cements. Before pouring the mixture, the concrete must be wetted with water.

The compaction of the mortar after pouring must be compacted using the piercing method. A metal rod is used for this purpose.

After repairing the floor screed, it is necessary to ensure that the temperature in the room is not very high. To prevent cracks from appearing on it, it is necessary to periodically moisten the place where the cement mixture is laid with water.

The screed is leaking - what to do?

If the screed coils in the presence of cracks, then you can try to eliminate it. To do this, it is necessary to widen the crack. Next, a very liquid solution of sand and cement is prepared.

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Also watch a useful video with expert advice on screed repair:

Based on materials from the site: http://glavspec.ru

fix-builder.ru

The screed is crumbling, how to strengthen it?

The content of the article:

Violation of technology during construction and repair work inevitably leads to large or small troubles, which subsequently have to be eliminated, spending a lot of effort and considerable money. This axiom fully applies to incorrectly performed floor screed, as a result of which various defects. It can crumble, crack and, as builders say, buckle.

If cracks appear in the floor after screed work, then the simplest, and most importantly, inexpensive option would be to make regular repairs.

How can you repair small cracks?

Firstly, after detecting such a defect, it is necessary to carefully examine the floor and determine the root cause of the cracks. There are several reasons why this problem can occur. This is a poorly measured coating layer, rapid drying of the applied layer, problems with moisture in the solution - too much or, conversely, too little water. Forgetting to install the gasket also leads to cracks. edge tape, as well as the absence of expansion joints.

If it turns out that the cracks were due to unmade seams, it is necessary to urgently make the seams for shrinkage. The depth of such a shrinkage seam should be no less than a third of the base. They must be done in increments of up to 5 meters. The seams must be sealed with a sealant based on polyurethane.

We will find cracks, especially if they are very thin, they need to be widened, for which we can groove them. Remove any dust that has formed in the crack and prime it. Such cracks must be sealed with non-shrinking material using a regular staple. Some subtlety - if tiles are laid on the floor, and the cracks that appear on the screed are very small, then you don’t need to do anything with them. Larger cracks are sealed with a special compound that is easy to make with my own hands. It includes cement, PVA glue and water. The resulting mixture must have a liquid consistency so that it can be poured into the cracks formed without any problems. After the poured mortar has hardened in the cracks, you can begin all subsequent work, for example, covering the floor.

What to do if the tie breaks?

A broken screed is a serious defect that requires mandatory elimination. The reason for such a big problem may be unsatisfactory compaction of the mixture, as a result of which air cavities can form in it - cavities, leading to cracking on a large scale. In this case, the screed is removed until an unfilled cavity is discovered, and the cavity is filled with solution. You can find a cavity by deepening the crack using a tool, such as a pick. Accordingly, the test pit must subsequently be covered with soil and filled with solution. The solution used to fill the cavern should consist of sand and cement in a ratio of one to three. Before filling, the cavity is moistened with water. After the cavity is filled, you need to make sure that the filling is of good quality, for which you try to seal the hole using the appropriate rod. The room temperature should not be too high. The screed must be periodically moistened using water.

The screed buckles - how to deal with it?

Experts use the word “bukhtit” in cases where, when tapping the screed, there is a feeling that there is a void in the depths of the coating. Also, this term is used when a spring effect occurs under the foot, a certain pressing of the surface. If the screed buckles, there can be many reasons for this. The main reason is non-compliance with process technology. If signs of bubbling are detected, you need to break through this place, expand it and fill it with a liquid solution, which consists of cement and sand. The optimal solution will add PVA glue to the solution. There is a subtlety here - you need to pour the solution in small portions, giving each of them the opportunity to harden. If this method does not help, then we follow the “scorched earth” method - we break the screed and start all over again. To prevent this, do everything correctly and according to technology right away.

fortstroi.com.ua

Floor screed repair: do-it-yourself production

Read in this publication:Repair of floor screed: about its feasibilityRepair of cement floor screed: preparatory work How to repair a floor screed: the main stage of work

A cracked or crumbled screed is not only an uneven and uncomfortable floor, but also an undistributed load on the floor slabs in the house. If you can more or less put up with the first point, then with the second things are a little different - excessive loads on the floors, despite the fact that they have a fair margin of safety, can be catastrophic, especially when it comes to old houses. The screed must be kept in order - in case of major repairs, it must be changed or at least repaired. In this article from the site stroisovety.org we will deal with the question of how to repair a floor screed with your own hands?

Repair of cement floor screed photo

Floor screed repair: its feasibility

Before you begin directly solving the question of how to repair a floor screed with your own hands, you first need to understand its feasibility - perhaps things are such that there is no point in it, and what is needed is not restoration of the surface, but its complete replacement. In what situations does it become necessary to install a new floor screed? There are not many signs indicating that the screed has already outlived its usefulness.

By and large, there are no specific criteria according to which it is necessary to completely change the floor screed. There are simply regulations and common sense that suggest that new surface better than the old one. It can last a long time, and if you intend to live in an apartment or house for a long time, then the best option would be to completely replace this surface - of course, if we are talking about major repairs. It is better to spend money once on a new screed than to repair an old floor screed with enviable regularity. Restoration is primarily a temporary measure that resolves the issue for a short period of time.

Repair of cement floor screed: preparatory work

Preparing an old screed for repair is not a difficult task, and in most cases it comes down to just two steps.

You don’t have to wait for the second layer of primer to dry - while you prepare the solution, it will be absorbed into the old screed and that will be quite enough. Such repair of cracks in the floor screed (or rather, the preparatory work associated with its implementation) will give you a guarantee that the base of the floor will last at least another ten years.

How to repair a floor screed: the main stage of work

This stage (as, in general, the preparatory stage) can be divided into two substages - fastening the broken floor fragments and finishing leveling the base. These are two different technologies, which should be dealt with separately.

In principle, this is the entire repair of the floor screed. It seems to be not difficult, but there are plenty of nuances - they are not obvious. We can say that the subtleties are almost all individual. For example, depending on the degree of destruction of the old floor screed, reinforcement may be needed - naturally, it is better to replace such a floor covering entirely, but situations are different and even with large damage, repairs may be advisable.

stroisovety.org

How to strengthen a screed that is crumbling, and how to repair cracks? The floor screed bursts or buckles - what to do?

How to strengthen a screed that is crumbling?

If the floor screed is not made correctly, then over time it can collapse: crumble, crack, buckle. In this case, there is no need to redo it.

You can simply repair the screed, which will be a more economical option.

How to repair cracks in screed?

When cracks appear in the floor screed, it is necessary to initially determine the cause of their appearance, and then begin to eliminate them.

The reasons for the appearance of cracks in a cement screed may be an incorrect coating layer, rapid drying, excess or lack of water in the solution, lack of edge tape or expansion joints.

If the floor screed is cracked due to the lack of expansion joints, then it is necessary to cut through the shrinkage joints.

If the cracks on the floor screed are minor and the floor covering is tiles, then they can be ignored.

The floor screed has burst - what to do?

If the floor screed has burst, then it is imperative to correct this defect before laying the floor covering.

The composition of the cement mixture, which is prepared for sealing the cavity, should include one part sand and three cements. Before pouring the mixture, the concrete must be wetted with water.

The compaction of the mortar after pouring must be compacted using the piercing method. A metal rod is used for this purpose.

The screed is leaking - what to do?

If the screed coils in the presence of cracks, then you can try to eliminate it. To do this, it is necessary to widen the crack. Next, a very liquid solution of sand and cement is prepared.

You might also be interested in:

Also look at this useful article with expert advice on screed repair:

http://glavspec.ru

legkoe-delo.ru

Floor screed what to do if it crumbles

Articles

When cracks appear in the floor screed, it is necessary to initially determine the cause of their appearance, and then begin to eliminate them.

The reasons for the appearance of cracks in a cement screed may be an incorrect coating layer, rapid drying, excess or lack of water in the solution, lack of edge tape or expansion joints.

If the floor screed is cracked due to the lack of expansion joints, then it is necessary to cut through the shrinkage joints.

FLOOR REPAIR (BROKEN, BROKEN, FLAWING SCREED)

cement screed after treatment with liquid glass

If the cracks on the floor screed are minor and the floor covering is tiles, then they can be ignored.

If the floor screed has burst, then it is imperative to correct this defect before laying the floor covering.

The composition of the cement mixture, which is prepared for sealing the cavity, should include one part sand and three cements. Before pouring the mixture, the concrete must be wetted with water.

The compaction of the mortar after pouring must be compacted using the piercing method. A metal rod is used for this purpose.

If the screed coils in the presence of cracks, then you can try to eliminate it. To do this, it is necessary to widen the crack. Next, a very liquid solution of sand and cement is prepared.

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Strengthening weak screeds with primer, liquid glass and silicate impregnations. Strengthening a concrete floor What to do if the floor screed crumbles

There are three types of concrete screed:

Screed on a “rough” foundation made of reinforced concrete or earth

Screed on the separating layer of waterproofing

Floating concrete screed

Causes of destruction of concrete screed

Chemical factors

Physical factors

Mechanical factors

Ways to prevent destruction of concrete floor screed

Repairing potholes and cracks in concrete screed

Repair of formwork marks

Pothole Repair

Crack repair

Repair of small spider-like cracks

Repair of irregularities

Major repairs of concrete screed

Video removing cracks in screed

The floor screed has burst - what to do?

The screed is leaking - what to do?

First way. Strengthening with primer.

Strengthening cement screed with silicates (liquid glass).

Impregnations based on sodium silicates.

Strengthening impregnations based on lithium.

Malfunctions and their causes

Repair composition

How to strengthen?

How to repair?

Getting rid of cracks

Repairing Potholes

Removing dust

The floor screed is crumbling, what should I do?

Why does cement screed crumble, what should I do?

How to strengthen a concrete screed that is crumbling

The screed is leaking - what to do?

Concrete screed is crumbling - what to do?

Screed on the separating layer of waterproofing

Floating concrete screed

Causes of destruction of concrete screed

Chemical factors

Physical factors

Mechanical factors

Ways to prevent destruction of concrete floor screed

Repairing potholes and cracks in concrete screed

Video removing cracks in screed

How to strengthen a screed

Major repairs of concrete floors: strengthening the peeling screed

Steps to strengthen a weak concrete floor

Repair of peeled coating layer

How to strengthen a screed that is crumbling, and how to repair cracks? The floor screed bursts or buckles - what to do?

How to repair cracks in screed?

The floor screed has burst - what to do?

The screed is leaking - what to do?

The screed is crumbling, how to strengthen it?

How can you repair small cracks?

What to do if the tie breaks?

The screed buckles - how to deal with it?

Floor screed repair: do-it-yourself production

Floor screed repair: its feasibility

Repair of cement floor screed: preparatory work

How to repair a floor screed: the main stage of work

How to strengthen a screed that is crumbling, and how to repair cracks? The floor screed bursts or buckles - what to do?

How to repair cracks in screed?

The floor screed has burst - what to do?

The screed is leaking - what to do?

Floor screed what to do if it crumbles

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