Basic methods and technology of work to strengthen strip foundations

A strip foundation is the most popular way to organize a strong and reliable foundation for future buildings of residential buildings or other objects.
High load-bearing capacity allows you to build walls from any materials, including heavy ones (concrete blocks, bricks).

There are often cases when there is a need to additionally strengthen an already constructed foundation on which a house has been built for many years.

Let us consider in more detail why and when additional “support” of a strip foundation is needed, what methods of reinforcement are available, and how to choose the best option.

Causes of foundation deformations

The appearance of cracks in the base or its deformation is a common occurrence.
It occurs during long-term operation of a structure without regular preventive repair work or due to the action of factors beyond human control. From the foundation, faults and wall shifts are transmitted to the structure. If this process is not stopped in a timely manner, the building will collapse. Crack in the foundation

The destruction of the foundation strip occurs for the following main reasons:

• vibrations (movements) of the soil caused by an earthquake or blasting operations near the building;
• an increase in the weight of the structure during its reconstruction (due to the use of heavier materials) or the addition of floors;
• use of low-quality materials for the construction of a supporting structure for a building;
• the location of the building on a sloping site, which can result in a landslide or slow sliding of the soil;
• digging pits and trenches at a close distance from the structure;
• deviation from construction standards and technology of work during the construction of a building;
• changes in the load-bearing properties of the soil under the building caused by rising groundwater, severe freezing and other factors;
• failure to comply with operating rules, failure to carry out timely repairs;
• flooding of the area around the building and the absence of a drainage system;
• incorrect calculation of the bearing capacity of the foundation;
• significant shrinkage of the structure.

For some reasons, in addition to restoring the foundation strip, it will be necessary to carry out additional work aimed directly at eliminating them. An example of such measures is the creation of a drainage system, strengthening of nearby soil (even a slope), waterproofing the base. Without such work, the destruction of the foundation will continue even after repairs.

Features of supporting the structure with piles

One of the most commonly used methods of strengthening the base of brick cottages is the pile reconstruction method. It will be necessary to drill holes into which the piles will be inserted. The drilling depth is calculated according to the soil characteristics. Wells are made with a diameter of up to 25 cm.

The pile frame is mounted from different types of materials. Depending on which piles are used, the method of their installation is chosen. The simplest and most commonly used in installation are screw piles. They are installed by hand. No expensive equipment or long time period is required, as, for example, for bored structures. Screw piles are pipes with a screw platform at the end, with the help of which the load of the foundation is redistributed.

Bored injection piles are made from reinforcement. They are placed in a drilled hole on the sides of the house. The recess is filled with concrete. After the cement has hardened, the base is treated with mastic and laid with a layer of roofing felt for waterproofing. Roofing felt must be overlapped. Such fortifications can be installed both outside and inside the building.

A badly damaged foundation cannot be repaired, and strengthening it will not produce the desired results. But there is a way to save the building with your own hands. To do this, you need to redo its base. Holes are made in the walls of the building into which the ends of wooden beams are inserted. The walls are temporarily reinforced with a jack. It becomes possible to completely shift its support.

The foundation of the home can and should be strengthened

But it is important not so much to perform the appropriate actions as to correctly determine the cause of the damage to the support that appears. This will avoid continuing the struggle for the stability of the house in the future.

Filling the reinforcing belt

If the platform is covered with cracks, but their number does not increase over time, then repairs are carried out by pouring a reinforcing belt. This prevents further destruction of the base and protects it from deformation at low temperatures, but its strength increases slightly. The reinforcing belt can be poured both around the entire perimeter and along one wall.

1. First of all, the foundation is excavated from the outside of the building.
   The outer part of the foundation should be completely free of soil, but you should not dig deeper than the sand or crushed stone cushion. The optimal width of the ditch is 0.8–1.0 m. The outer part of the foundation must be completely freed from the ground
2. Then it is necessary to compact the soil near the foundation using manual tamping and pour a layer of crushed stone of the 30–50 mm fraction, 10–15 cm thick. The crushed stone is also compacted. A thin layer of sand is poured over it to hide the sharp edges.
3. Dense foam plastic 5 cm thick should be laid on top of the sand and covered with a tarpaulin to protect the material from sparks during the welding process.
4. Next, you need to drill holes in the foundation with a diameter of 18–25 mm at a distance of 60–90 cm and drive pieces of reinforcement into them that will serve as anchors. The trimmings should protrude from the wall by 15–30 cm.
5. Weld external and internal meshes to them, made of reinforcement 10–14 mm thick, which should deviate from the base by 5–7 cm. The meshes are connected to each other using pieces of reinforcement.
   Reinforcing mesh is connected by reinforcement
6. At the bottom of the belt, an additional reinforcing mesh is placed for the pillow, 25–35 cm thick and equal in size to the width of the ditch. The cushion reduces the load on the ground without the need to dig up the foundation.
7. After creating the reinforcing mesh, remove the tarpaulin from the foam and install the formwork.
   Concrete is poured in two stages. After filling the pillow, you should wait 2 days and then start filling the belt. Pouring concrete is carried out in two stages
8. After 2 days, you can remove the formwork, and after another 3–5 days, fill the ditch with earth.

Strengthening the foundation

Work to strengthen the foundation begins with an inspection of its condition in places where cracks appear on the walls. To do this, pockets are dug to depth and the supporting structure is inspected. In this way, you can determine with great accuracy the amount of work to be done. Further actions are performed in the following order:

• the basement cladding is dismantled (to the foundation);
• By digging deep trenches, the foundation is exposed. The entire structure cannot be opened at once: this is done gradually, the length of one section of the trench should not exceed three meters. Its width is taken within one meter;
• the underground part is cleared of soil. If there are loose elements in it, they are removed;
• cracks are expanded and reinforced;
• the surface of the foundation is impregnated with a deep penetration primer.

The above operations relate to preparatory work. Upon completion, you can proceed directly to strengthening the foundation with a reinforced concrete frame.

First of all, a drainage pad is installed at the bottom of the trench. It will consist of coarse sand and a layer of gravel. Then through holes are drilled in the body of the old foundation.

Reinforcing bars (corrugated) are inserted into them. The purpose of these mortgages is to ensure a reliable connection between the monolithic strip and the reinforced concrete frame.

It is necessary to lay metal rods in a horizontal direction, tying them to the embedded parts using wire.

Such a connection will provide the necessary mobility to the reinforced belt. This way it will be protected from rupture under the influence of seasonal soil expansion.

Vertical belt rods are installed in increments of 400-600 mm. Their height should be such that the ends protrude beyond the zero mark.

Pouring concrete

Before pouring the concrete mixture, it is necessary to lay a layer of waterproofing between the reinforcing frame and the walls of the trench. After this, you can begin concrete work. The working solution can be prepared in a hand or mechanical mixer.

For its preparation the following materials are used in proportions:

• cement grade M500 - one part;
• sand - three parts;
• gravel - three parts (can be replaced with crushed stone).

To increase the fluidity of concrete, a plasticizer is added to the mixture. The finished mixture is poured into the trench to ground level.

By the way, by using a plasticizer, you can safely abandon the operation of concrete compaction, so mechanical vibrators will not be needed.

How to strengthen the foundation with a reinforced concrete jacket?

To increase the stability of the building, increase the service life, and add floors, it will be necessary to strengthen the foundation with a reinforced concrete jacket. The quality of construction depends on how integral and stable the sole is. Problems with the foundation are indicated by bevels, cracks, and subsidence of the building that appear on the base.

Causes of destruction

A visual analysis of load-bearing structures that have collapsed and inspection of cracks in the foundation are necessary to determine the causes and how to eliminate them. The land plot on which the building stands is also inspected to identify changes in the soil. The reasons for the destruction of the foundation of structures may be the following:

• erroneous foundation design - incorrect calculations of the planned load, failure to follow the technology when laying the foundation;
• use of low quality building materials in construction;
• a change in the degree of soil moisture, i.e. an increase in the level of groundwater, swelling of the soil, flooding, high water;
• terrain slope;
• insufficient, weak waterproofing;
• improper operation of the building, for example, lack of heating during the cold season;
• increased loads on the foundation, as happens during redevelopment;
• soil freezing;
• large construction excavation works associated with vibration, digging trenches, laying technical communications in the immediate vicinity;
• railway passing nearby.

Types of work to strengthen the foundation

There are several methods of strengthening, including the use of brickwork.

Strengthening can be done in several ways:

• Shotcreting of concrete. It is a layer-by-layer application of a cementitious composition under high pressure.
• Installation of drilled injection piles.
• Expansion of the base.
• Reinforcement with brickwork.
• Reinforced concrete jacket. This method is reliable and simple, and is used most often. To strengthen the foundation of the house, an outer shell is made of reinforced concrete. It serves as a support and protects from atmospheric influences.

Problem Analysis

Before constructing a reinforced concrete jacket, it is necessary to conduct an external study of the plinth and base, assessing the dimensions of the dwelling, the current state of the load-bearing surfaces, the nature of damage, cracks, bevels, and the load on the base of the building. An internal, underground inspection will allow you to evaluate the characteristics of the foundation, the depth of its location, and evaluate the quality of the building materials from which it is laid.

Methods of strengthening

Complete unloading of the foundation involves the use of metal crossbars that are inserted into the wall masonry.

Complete reconstruction can be avoided by strengthening the base. An important point in preparing for work is unloading the foundation, fragmentary or complete.

In the first case, you will need supports and struts made of wood or metal: support pillows are placed 2 m from the basement walls, a beam is placed on top, the racks are secured, grouped with beams with a ceiling and wedges - with a support beam. When the unloading is complete, metal crossbars are installed.

Holes are punched in the lower part of the walls, strappings are inserted into them, and transverse ones are placed on supports on the inside and outside of the walls.

Strengthening the base of a building with a reinforced concrete jacket is always carried out in stages - first the foundation is strengthened, after complete drying and hardening they proceed to the design of the basement part.

Cladding works

Having certain skills in working with bricks, you can cladding the house yourself. Moreover, facing bricks are made with more careful adherence to dimensions than ordinary building bricks.

Since it is desirable for a house lined with brick to be not only aesthetically pleasing, but also warm, various insulation materials are used for this purpose. The best option is sheet mineral insulation. It is produced in various thicknesses and is easy to install. The insulation sheets are attached to anchors appropriately located in the wall, which are driven into the wall every meter and every sixth row of brick. This could be wire cut into pieces. Its length should be enough for reliable fastening in the wall (5 - 8 cm), a layer of insulation (10 cm) and laying in the facing masonry, that is, about 30 cm. Also, the insulation sheets should be pressed with mounting dowels and umbrellas (5 pieces per 1 m. sq.). The anchors provide additional strength and stability to the façade wall.

It is also necessary to ensure ventilation of the insulation. For this purpose, holes (vents) are left in the façade wall along the upper and lower cornices. They are protected with a mesh or special plugs are placed on them for ventilation. You should also worry about the eaves overhang - it should overlap the new wall by at least 25 cm, so you may have to cover the roof.

There are some subtleties when cladding a house made of wood, which relate to the structure itself. Before covering a wooden house, you should make sure that all its elements are in good condition - there is no fungus, signs of rotting, or serious damage. All these places need to be removed/repaired and, if necessary, replaced.

Cladding a wooden house with bricks

The wood of the walls must be treated with fire-resistant impregnation and an antiseptic (maybe twice). Before you cover a wooden house with bricks, you should ensure its ventilation. Slats are placed along the walls in increments of 1 m, and a vapor barrier is placed directly on them. Holes are left in the façade wall. These actions will ensure air circulation between the façade wall and the wooden elements, which will protect the latter from moisture.

The laying of facing bricks itself differs little from the traditional one. The brick is placed with a spoon in half a brick, using various dressing options. However, you should be extremely careful and, if this is the first time such work is being done, take your time. This will allow you to create a beautiful facade without annoying flaws. You should also follow a few simple rules:

1. Bricks of the same color may differ in shade (permissible differences are specified in the technical data sheet of the product). The difference will be especially noticeable over a large area. To avoid this, you can mix bricks from different pallets.
2. The solution should not contain impurities, such as lime. Otherwise, efflorescence may appear on the wall.
3. The brick should be stored covered from rain - moisture that gets on it will negatively affect the setting of the mortar, and subsequently, because of it, a white coating may appear on the finished wall.

In this video you can watch the process of cladding a house:

Causes of deformation and destruction of the foundation

Subsidence of a structure due to leaching of soil under the foundation as a result of suffusion that arose due to miscalculations in the installation of the drainage system, or changes in the behavior of groundwater. Ground movements can also be caused by a man-made factor - perhaps large construction was taking place nearby. Some soils, in particular clay soils, are prone to destruction and frost weathering in a water-saturated state, and each cycle they lose part of their bearing capacity.

Ground movements can also occur as a result of the forces of frost heaving. If frozen clays have the ability to suck in water from the lower horizons, and the drainage of the foundation has not been organized or has become unusable, then these clays can cause an abyss of tens of centimeters.

The pressure here is considerable - up to 200 MPa (more than 3 tons/cm2), and in order to push a building out of the ground, less effort is often sufficient. After the spring thaw, the foundation undergoes uneven subsidence, and deep cracks are visible on the walls of the house.

Therefore, it is so important to choose the right type of foundation for the specific soil conditions of the site, and to design the foundation taking into account all loads - both from the building and from the soil. All mistakes lead sooner or later to the fact that the foundation will lose part of its bearing capacity

The situation described above is also possible, when the owners make redevelopments, extensions and add floors or mezzanines without resorting to the help of specialists. The design strength margin of the foundation may be insufficient if, during the design, no calculation was made for the prospect of rebuilding the house. Most likely, this will be the case, because the construction budget is always to varying degrees, but limited, and the foundation is the most expensive part of the house, from 25% to 50% in difficult soils.

Unfortunately, it is not uncommon to save money when materials of poor quality or non-compliant technical specifications are used.

The natural reason is that the house is old, it has been used for many decades without inspection and repair of the foundation, and the subsidence is caused by wear and tear. The destruction of a reinforced concrete foundation often occurs due to the lack of concrete waterproofing or its destruction. Groundwater can change not only its height, but also its composition and aggressiveness towards concrete.

Destruction of the foundation of structures

1. Untimely reinforcement leads to dire consequences.
2. Errors in the design of the construction plan.
3. Incorrect foundation of the building.
4. Changes occurring in the soil that contribute to the manifestation of other properties of the soil mass. This includes swelling, heaving, wetting and increasing the level of water deposits.
5. Construction work carried out near the building.
6. The load is greater than the use of this building suggests. More precisely, improper operation of the building.
7. Impacts of vibration nature both inside and outside the building.

Why do you need to strengthen the foundation from screw piles?

Pile-screw foundation with screw piles is a very common option in the construction of low-rise buildings, especially in rural areas and in summer cottages.

House on screw stilts

Screw piles have certain positive properties: light weight, ease of installation, use on soils of any density. To ensure the strength and stability of screw piles, before installing the pile foundation under the building, it is necessary to carry out test drilling to study the soils lying on the building site

The composition of the underlying soil is taken into account when selecting screw supports of a certain length, helping to find the optimal option for using pile structures with the determination of measures for the necessary reinforcement of the base with screw piles

The thing is that individual supports cope well with vertical loads; lateral loads must be carefully balanced, otherwise a slight distortion will cause a violation of spatial rigid connections and can have a very negative impact on the stability of the building. In such cases, it may be necessary to strengthen the foundation.

Types of hardening technologies

Any building renovation must include strengthening the foundation

Any building renovation must include strengthening the foundation. This is necessary in the following situations:

• When planning the completion of a building, for example, the second floor;
• With the negative impact of the natural environment and violation of the integrity of the structure;
• When building elements settle, which can cause destruction.

So, when performing work to strengthen foundations, the following types are used:

1. Standard method;
2. The original way.

For example, the first method was used in the reconstruction of the Bolshoi Theater, which breathed a second wind into it. Specialized companies are improving methods, because as practice has shown, it is much cheaper to repair a building than to build a new one.

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Strengthening the base of the strip base

The basement is an above-ground continuation of the building's foundation. Its structure can be strengthened after the “jacket” of the base has hardened. Horizontal metal rods are tied around the perimeter of the house to the vertical reinforcement of the reinforced concrete belt and the embedded parts of the base. Instead of bulky rods, you can use a steel lattice or chain-link mesh.

Along the entire perimeter of the house, formwork is constructed from wooden panels at the height of the base. The width of the strapping belt is 20–25 cm. The panels are installed vertically at a level and fixed on the outside with bars, which rest at an angle against the upper edge of the formwork.

Important! The more stops, the more stable the shape for a monolithic structure. Transverse strips are placed inside the formwork to prevent distortion of the shape.

The formwork parts are fastened with self-tapping screws.

A horizontal guideline is applied to the wall, starting from the top point of the existing foundation. At the same time, the filling level of the new base is drawn along the walls of the formwork. The cement mortar is prepared with a more liquid consistency for better penetration into cracks and recesses in the base.

The formwork is removed when the concrete has completely hardened. Subsequently, a basement flashing and blind area are made to drain stormwater from the foundation. The concrete surface of the base can be covered with decorative tiles or siding.

Recommended video to watch:

The phased implementation of the work makes it possible to strengthen the foundation of the house with a reinforced concrete jacket with your own hands in a short period of time.

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Replacing the base

If collapse or destruction of the platform occurs in the area of ​​the base, this part must be replaced. It is easiest to replace under a wooden structure, since it weighs less than stone or brick.

The easiest way to replace the base is under a wooden building

Under a structure made of stone or brick, the base is replaced in parts no longer than 1 m with intervals between sections of at least 3 m. To carry out the work you will need:

• fittings;
• cement;
• sand;
• crushed stone;
• plasticizer;
• concrete mixer;
• chain saw for concrete to cut out the necessary sections of the base;
• perforator;
• welding machine for fastening reinforcing elements.

How to replace the base yourself

1. To install the formwork, you need to go down into the underground, so disassemble the section of the floor in the house where the foundation is strengthened.
2. Make 5–10 cuts with a chain saw, maintaining a distance of 1 m between the outermost ones.
3. Divide the area into small pieces with several horizontal cuts.
4. Place the cut pieces aside and clean the surface of the base as well as the underside of the building.
5. Build the formwork in two parts: one for the outside of the house, the other for the inside. There should be holes for reinforcement on the sides of the formwork. The formwork should be 5–7 cm wider than the wall on the outside and inside.
6. Remove the prepared formwork and install the vertical pins of the reinforcing structure into holes with a diameter of 18–22 mm.
   The pieces of reinforcement should rise 10–15 cm above the foundation. Attach long pieces to them. After this, weld the horizontal rods so that they coincide with the holes in the formwork. It is not recommended to connect reinforcement with tying wire, as this reduces the strength of the structure. If the base is made of reinforced concrete, the house can be raised with jacks
7. Install the formwork and pour the concrete using plasticizers and a minimum amount of water.
8. Remove the formwork after 2 days.
9. After 25 days, begin replacing adjacent sections of the base.

Types of foundation deformation

In addition to finding out the reasons that led to the destruction of the foundation, it is necessary to give an adequate assessment of its extent. This will allow us to determine the possibility of strengthening the foundation and the feasibility of this event. Maintainability is determined in accordance with the following criteria:

1. Damage is minor

This includes violating the integrity of the foundation finishing. The presence of phenomena of this kind does not affect the strength of the foundation and does not reduce its bearing capacity. Eliminating them is easy.

2. The damage is moderate

The occurrence of cracks is associated with the process of subsidence or destruction of the base. Before starting work, it is necessary to differentiate the nature of the cracks. Their horizontal arrangement poses less danger compared to vertical or zigzag

In addition, it is important to find out what the nature of the process of foundation subsidence is. That is, this phenomenon is temporary or progressive

Average damage

To clarify this circumstance, beacons are used. Plain paper can be used as them, but there is a risk of it getting wet. The use of plaster plasters is recommended. The simplest method involves applying a small amount of putty to the surface. Then, using a spatula, a mark is made in the form of a straight line. Even a slight shift of the tested surface will be noticed. In addition, when using this method, you can find out at what speed the destruction process occurs.

Temporary subsidence will not be detected by beacons. In this case, most likely, some shift of the soil located under the foundation occurred, it was fixed in a certain position and the probability of further movement is low. Therefore, to eliminate defects, it is sufficient to carry out routine repairs.

When lighthouses are destroyed, it can be argued that the destruction process is progressing. Sealing cracks will not give the required effect, since the deformation is close to catastrophic.

3. The damage is catastrophic.

The presence of defects of this kind can cause destruction of the structure. Timely work to strengthen the foundation will prevent extremely negative consequences from occurring. However, in practice there are situations in which this opportunity is missed.

The choice of technology depends on the type of foundation. In this case, each specific case considers its strengthening or replacement.

4. It is not possible to eliminate deformations

The condition of the foundation is so poor that repairs are impractical. In such situations, the most correct solution is to demolish the building. From an economic point of view, dismantling a house is much cheaper and simpler than measures to strengthen the foundation. The construction of a new cottage on the site of the previous one in accordance with building codes and regulations will allow you to have comfortable and safe housing.

Sometimes the only right solution is to demolish the building

Shotcrete

Strengthening the foundation with this method is carried out by applying a special concrete mixture to its surface under high pressure. The effect is achieved by filling cracks and voids formed on the foundation surface with a concrete mixture. Typically, such a mixture contains additives that increase the water resistance and frost resistance of the material.

This type of foundation strengthening is used when the destruction is represented exclusively by cracks and craters on the surface of the base. However, if there is uneven subsidence of the foundation, then this strengthening method will not work.

Types of shotcrete

Based on application technology, a distinction is made between “wet” and “dry” shotcrete.

With the “dry” method, a cement-sand mixture with additives is sprayed under pressure from a hose onto the surface. The peculiarity of this method is that water enters the mixture at the very last moment. The result is a solution with optimal density and good adhesion.

Pros:

• The spraying unit is easy to use and clean after finishing the job.
• It is possible to apply a layer up to 6cm thick.
• The material has excellent adhesion.
• There is no need to pre-prime the surface.
• The mixture can be supplied to different distances.
• The amount of waste after the procedure is minimal.

Minuses:

• Preparing the mixture requires maintaining precise proportions.
• Operating a sprayer requires special skill.
• Such work to strengthen the foundation is considered quite “dirty”.

The “wet” method involves strengthening the foundation of a private house by applying a ready-made solution from a concrete pump.

Pros:

• The mixture is homogeneous, so working with it is quite easy.
• There is no such amount of dust as in the case of the “dry” method.
• No additional finishing required.
• If you still have some solution left after completing the work, it can be used for other purposes.

Minuses:

• The layer thickness is small - up to 3 cm.
• Significant duration of work.
• Cleaning the installation after wet spraying is much more difficult than after dry spraying.

How to strengthen the foundation using shotcrete techniques?

Strengthening the foundations of buildings with this method is carried out according to the following algorithm:

1. Before strengthening the foundation of the house, you need to prepare the surface. First, the base is cleared of soil. A trench is dug around the building “at full height” of the foundation, the width of which, for convenience, is at least 80 cm.
2. The concrete surface of the foundation is thoroughly cleaned, washed and blown.
3. Next, the fittings are installed. For work, take rods with a diameter of at least 7 mm. The edges of the gratings are connected by knitting or welding.
4. Then the solution is prepared. Standard proportions of cement and sand are 1:3 (atmospheric spraying) or 1:4 (mechanical processing). It is permissible to add special additives. The solution must be used within 3 hours.
5. Strengthening foundations using this method is carried out in stages. First, apply one layer no more than 7 cm thick. If special additives are used, the next layer can be applied after half an hour. If you use a solution without additives, you will have to wait a couple of hours.
6. The solution is applied starting from the bottom in a circular motion in a horizontal direction. The installation nozzle is kept at a distance of approximately 1 m from the surface at a right angle.
7. After the coating process is completed, the wall must be moistened daily for a week. This helps strengthen the applied layer.

Causes of crack formation

The need for foundation repair sometimes arises earlier - this is due to the appearance of cracks

The need for foundation repair sometimes arises earlier - this is due to the appearance of cracks. Where do they come from? This is what we will now find out in this section.

So, there can be many reasons for this, let’s name the most common situations:

• If the foundation is built on bulk moving soil, then soil subsidence may occur;
• In strip construction, if the bricks are not reinforced, then cracks in the structure are possible over time;
• If the concrete slab does not have a strong metal frame;
• If a foundation made of bricks does not have a metal mesh in its design, then it is quite possible that the structure will diverge and there will be many cracks;
• If the ventilation passages were not closed during the winter period;
• Incorrect load calculations were made;
• The building does not have a drainage system to remove water.

What to do if the foundation is cracked

The problem of a crack that has appeared in the base can be eliminated in different ways, it all depends on the material used in construction.

The main reason for the appearance of cracks in masonry is shrinkage of the structure or moving soil. In this case, digging to create a cushion cannot be carried out, so you can strengthen the foundation of a house that has already been built using a concrete belt.

For a wooden structure, you can use the pile method.

When using piles, you must remember that they must reach solid ground, otherwise they will sag under the weight of the house.

If cracks appear in a monolithic building, the reinforcement options described above will not be suitable. Here you will need to completely replace the stove.

Amplification methods

There are different ways to strengthen all kinds of foundations. For example:

1. Increasing the sole.
2. Laying new foundations.
3. Cementation.
4. Use of piles, flashings, cages, shotcrete.

Methods for strengthening foundations are chosen based on:

1. Type and design of the foundation.
2. Degree of destruction.
3. The material from which the house is built (wood, brick, concrete).
4. The reasons that led to the destruction.

But with houses made of brick or concrete you need to be much more careful, since a mistake here can destroy the wall.

Cementation and injection

Strengthening the foundation by cementation is carried out as follows:

1. Pits are being dug. Their depth should be slightly less than the depth of the base.
2. Wells are drilled in the foundation at a distance of 25 cm to half a meter. The drill should not reach the sole by 30 centimeters.
3. A liquid solution is prepared (the ratio of water and cement is 0.9 to 1), with which the channels are filled under a pressure of 0.2 MPa to capacity.
4. Next, thicker solutions are prepared, with which the wells are again filled to capacity. Thus, cement fills cracks and cavities.
5. After two days, the base is considered strengthened.

Strengthening the foundation using the injection method looks a little different. Here, wells are drilled from different sides of the building down to hard layers of soil. The channels are filled with a solution, and then reinforcing drilled injection piles are inserted into them, into which concrete or a cement mixture is supplied under pressure. In this way, the soil under the foundation is strengthened, and the foundation itself is strengthened with reinforced concrete piles.

Shotcrete

But here you also cannot do without specialists,

Strengthening foundations with shotcrete is carried out using a special gun, which applies the solution to the base under pressure. For greater strength, it is recommended to first create a reinforced structure. The advantage is that concrete applied in this way is very durable.

Shotcrete can be dry or wet. In the first case, you can apply a thick layer with the same density and consistency in one approach.

This result is explained by the fact that the composition is not mixed with water, but mixed with it in the nozzle. But this approach has significant drawbacks: for example, high consumption of material and dusty areas.

In addition, the workers must be highly skilled, since the mixture must be prepared on site. Therefore, many resort to the wet method, when the material prepared at the enterprise is brought to the site by special machines. This way, the consumption of concrete is significantly reduced, and the loss of rebound particles is also small.

Reinforced concrete shirt

This method is suitable for those who want to strengthen their foundation themselves. No equipment or assistants are needed here. You can do everything yourself. So let's start with the corners. It is necessary to make excavations near them and clean the foundation: from above - from the cladding, from below - from the soil. The depth of the hole should be half a meter deeper than the base.

Next, a frame is made from metal rods. Some people use a crochet hook, others use a welding machine. There is no need to skimp on fittings. The finished structure is lowered into a hole, which is filled with concrete. This way the corners are protected.

Now that the corners are protected, you need to divide the entire perimeter near the base into segments of one and a half meters. Then the first such section is dug out to a width of half a meter. Holes are drilled in the base into which reinforcing bars are installed.

As with the corners, a frame is made. The finished parts are placed in a trench and tied to the reinforcement with wire. The trench is then filled with concrete. Having finished with one segment, proceed to the next and so on the entire perimeter.

For example, strengthening a columnar foundation is easier. For example, one pillar can be replaced with bored or outrigger piles. But strengthening the old strip foundation will not be so easy. Here they resort to shotcrete, reinforced concrete frames, piles: bored, drilled - injection, etc. Strengthening foundations with cementation is also used.

Dependence on the material of the house

When strengthening the foundation of an old house, you need to take into account what it was built from. This factor influences the choice of method and other features. Let's take a closer look at them.

Tree

Actually the easiest situation. The fact is that a wooden house can be raised above its foundation using jacks. In this position, you can easily carry out the necessary work. How to strengthen the foundation of a wooden house needs to be decided differently in each individual case.

Somewhere you need to replace a pile, somewhere you need to create an additional monolithic belt. You can sheathe the base with a reinforced concrete jacket. And all this is done easier if the building is in an elevated state. As you can see, strengthening the foundation of a private house made of wood is relatively easy.

Brick

But here everything looks more complicated. The fact is that you can’t lift such a building, and you need to be careful with the material itself. Therefore, strengthening the foundation of a brick house is in most cases fundamentally different from a wooden one. Which method should you choose in this case? It all depends on many factors, such as the degree of destruction, type of foundation and others. All this must be taken into account before strengthening the foundation under a brick house.

One of the most reliable methods is shotcrete. In this case, the masonry achieves not only strength, but also water resistance. Also, many resort to cementation, since this method is more economical both in time and in finance. For those who are wondering how to strengthen the foundation of a brick house with their own hands, you can suggest creating a reinforced concrete pad - this option is used quite often.

One could go on to describe possible methods such as using piles or widening the sole. All these methods can be used to prevent cracks from occurring on the walls. So strengthening the foundation of an old brick house is quite possible, and in some cases even simple.

Diagnosis of the problem

Diagnostics is a set of measures aimed at obtaining complete information about the condition of the supporting structure, the presence of mechanical damage, cracks or deformations.

The condition of the underlying soil, sand cushion and other elements that bear the load from the weight of the house is examined.

The procedure is carried out in stages:

• External inspection of visible parts of the tape. Visual detection of tape damage is carried out from the outside, from the basement (if possible). Looks for visible signs of problems with adjacent layers of soil - subsidence, gullies, etc.
• Underground inspection. The tape is dug around the perimeter, the condition of the trench is checked, the surface of the tape is inspected and any damage that has occurred is detected. The immersion depth of the tape and the base material are assessed.

A defect report is drawn up, which includes all detected damage. A foundation plan is drawn up, on which points of damage, cracks, and deformed areas are noted.

Based on the documentation compiled, a decision is made on measures to solve the problems that have arisen.

During this work, a monthly check of the belt immobility is carried out. Special control beacons are installed on the surface and their condition is recorded.

After a month, their position is checked. If there are no changes, it means that the tape has completed settling.

To perform complex work, unloading of the foundation is required. Its purpose is to transfer the weight of the house to an auxiliary support system, allowing the soil under the tape to be removed for replacement or waterproofing.

When is amplification required and what is it?

The need to strengthen the foundation arises in different situations:

• When it is planned to build an additional floor, an extension, or otherwise change the size of the house.
• When cracks appear on the walls or foundation strip.
• If the waterproofing of the tape is broken, causing the concrete to crumble.
• Mechanical damage to the tape.
• Rising groundwater levels destroying the tape.
• Aggressive environmental influences.

All these cases require immediate intervention. Reinforcement is an increase in the load-bearing capacity of the strip base by installing additional elements, increasing the cross-section of the strip, injecting special substances or other measures.

The choice of a specific method depends on the condition of the belt, the cause of the problem and the extent of the intervention required. In any case, before starting work, it is necessary to thoroughly examine the structure and make a decision with the participation of experienced specialists.

NOTE!

Self-indulgence in such matters is absolutely excluded, since instead of the expected results, you can get exactly the opposite consequences.

Main types and methods

Strengthening the foundation can be carried out using various methods depending on the degree of destruction of the foundation, material and many other factors

In addition, the cause of structural failure is of no small importance.

From weathering

Protection of the foundation from weathering is carried out during chemical and physical weathering of the foundation material, when the masonry is superficially affected by weathering processes, and there are no through cracks in the foundation. As a rule, this happens if the foundation is made of brick or rubble masonry, which has low strength and water resistance.

Chemical weathering can occur when the resistance of cement or a substance added to the cementitious mass is unsatisfactory against aggressive environmental influences.

To restore the surface of the foundation, shotcreting (plastering with cement mortar) is used on the cleaned (prepared) side surface of the foundation or shotcreting on a steel mesh fixed on its side surface.

If weathering processes have affected the entire thickness of the foundation, it is necessary to either cement the masonry, thereby strengthening the existing foundation, or strengthen the foundation with clips, restoring the load-bearing capabilities of the foundation.

Strength due to expansion

This method is quite difficult to do with your own hands, but several people are able to solve this problem. The sole is a reinforced concrete pad that serves as a support for the base. First of all, it is necessary to mark the foundation every 2.5-3 meters, excavate the soil on the sides of the foundation and under it.

You should lay a reinforced screed under the foundation, fill it with a solution that must be distributed evenly, and remove air bubbles. To do this you will need a concrete vibrator. On the sides, the sole must be raised approximately 15 cm above the base.

Injectable

Strengthening the foundation using a method such as injection is one of the most innovative methods. You won't be able to do it with your own hands. To implement this method, special equipment is required. The essence of the technology is that wells with a diameter of 16-24 cm are drilled from different sides in the foundation at an angle (approximately 45), the diameter is selected depending on the conditions. The depth of the wells varies depending on the soil characteristics. To more reliably strengthen the foundation of the house, it is recommended to drill to solid layers of soil. After this, the wells are filled with solution.

Bored injection piles made from reinforcement are placed in wells filled with mortar. Cement mixture or concrete is poured into them under a pressure of 1-3 MPa. This process is called “well testing”.

According to shotcrete technology

As a result of using the above method you get:

• strengthening the soil under the house;
• additional strengthening of the base with reinforced concrete piles.

If you are convinced that you can cope on your own, then you will need:

• perforator;
• installation for applying concrete or mortar mixture (shotcrete gun);
• cement, gravel and sand;
• shovel.

Strengthening the foundation is carried out in 2 stages: initially work is carried out on one side of the base and only after a week they switch to the opposite side. Such a temporary pause makes it possible to strengthen the structure as much as possible.

The areas to be captured must be at least 2.5 m in length. A trench 2 m wide and 1.5 m deep is dug, the masonry freed from soil is cleaned, and notches approximately 1.5 cm deep are applied to it.

They make a concrete solution by mixing cement, sand, gravel and water and apply it to the foundation using a shotcrete gun, filling all the cracks and crevices. Reinforcement using shotcrete technology is one of the optimal reinforcement schemes, because it significantly increases not only the load-bearing capacity of the base, but also its moisture resistance.

Another way to restore an old foundation

To save a sagging foundation, you can use technology that is developed for the restoration of old architectural buildings that have historical value. Moreover, this method makes it possible to strengthen the foundations of buildings of any number of storeys.

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A few final words. The use of any of the technologies described above must be justified by special studies, measurements and calculations. It is almost impossible to produce them yourself with the required degree of accuracy, and acting at random can aggravate the situation to the point where weak sections of the walls may collapse. Therefore, restoration with strengthening and strengthening of the foundation is best entrusted to qualified specialists who are able to objectively assess the situation and make a decision on one way or another of carrying out the work.

And to supplement the information received, watch a video in which an experienced master shows the process of strengthening a strip foundation.

How to strengthen walls

The technique in this case is quite simple. It is necessary to dig a trench between neighboring “bulls”. You need to do everything so that the old tape is completely exposed. How to carry out this work - either in one day along the entire perimeter or in sections - must be decided directly on site, after assessing the settlement and destruction of the foundation.

Much depends on the goals you are pursuing when strengthening the foundation. The point is to place a strong iron frame in the dug trench, which will be fastened not only to the wall, but also to the nearby “bulls”. In order to find out how to correctly calculate reinforcement, you need to use a special formula. Next, the concrete solution is poured.

In this case, several digressions should be made:

1. After you finish working on one area, be sure to order it and then move on to the next one. In the protein case, the building can simply “float”. Then the consequences will be simply disastrous.
2. The walls should be strengthened “crosswise”. In other words, when you're done in one place, move on to the next side. This will help improve security.

In principle, these tips will be enough to strengthen the foundation walls. This stage can be replaced by installing ebb tides. But this technology is very complex. You can ask construction companies about this. The fact is that only professionals using professional equipment can correctly install slopes. As you can understand, the cost of such strengthening will cost you a very large sum. This process is also not very short in terms of time. Piling can also be used.

When do you need to strengthen the foundation?

Strengthening existing foundations may be required during the process of rebuilding a house by changing the design by adding additional side rooms or expanding the attic floor. But much more often, these works are ordered for old or incorrectly designed buildings, the foundations of which, for various reasons, have weakened or partially become unusable.

The following defects indicate the need for reconstruction or strengthening:

• Cracking or crumbling of concrete monolith, brick/block masonry.
• Visible displacement of supports or the tilt of the building signaling this, the appearance of cracks in load-bearing walls.
• A clear violation of the waterproofing layer with the appearance of leaks in the basement.

Strengthening can be a preventative measure. The main goal here is to protect the existing foundation from possible damage due to compaction of the site's development, increased loads from ground structures, or deterioration of the soil under the house (soil erosion, subsidence or shifting).

But in order for the chosen reconstruction method to be implemented in practice, it is necessary to first remove the load - jack up the entire building. Strengthening and raising sagging foundations is done in two ways:

1. Partial unloading - involves only the basement floor. In the basement, vertical posts of suitable height are installed on support pads. Then wedges are driven under them, and the weight of the building is transferred to temporary supports.
2. Complete unloading - this process is more complex, since it requires first cutting through the foundation in several places so that metal rand beams can be placed under the building and strengthened. They actually separate the walls from the weakened base and take the entire load on themselves.

Methods for strengthening strip foundations, strengthening technology and problem diagnosis

The main advantages of a strip foundation are high load-bearing capacity, strength, resistance to all loads with a minimum amount of building materials.

This combination of qualities rightfully makes the tape a leader among all other types of supporting structures.

At the same time, the tape is constantly exposed to multidirectional loads from the soil and influences from the weight of the building, snow, wind loads, etc.

Situations often arise when the strength of the tape is at its limit, especially when seasonal ground movements occur.

Such cases necessitate strengthening the tape, which must be discussed in detail.

Increasing sole width

Reinforcement of shallow foundations with prefabricated monolithic reinforced concrete frames can be done with an increase in the width of the base. This is especially true in cases where the bearing capacity of the soil is lost as a result of erosion or changes in the mineral composition.

The widened sole partially compensates for the load and distributes it more evenly. The widening banquets are connected to the base structural elements with a rigid coupling. Their dimensions are calculated based on the actual volume of loads and data obtained during surveys.

The technology must be carefully followed. Any deviation from it leads to the resumption of the deformations that have begun. The formation of new drawdowns cannot be ruled out.