DIY repair of the foundation of a brick private house, strengthening and strengthening

Subsidence base repair

Methods of reconstruction of foundations that have been lopsided from time to time are quite common. This mainly happens with buildings located on a brick or rubble base. These materials often crack and form deep gaps in the surface, which over time substantially destroy the base. For information on how to repair a subsiding base, see this video:

The best option for repairing such structures is considered to be the replacement of the collapsing area with a monolithic concrete slab.

• to do this, you need to raise the house with a jack and fix it in this position;
• the collapsing section is dismantled, and a trench is dug under it, deep to the bottom of the old structure;
• holes are drilled, as described earlier, pieces of reinforcement are hammered into them;
• after which actions similar to those associated with the capital reconstruction of the strip foundation are performed.

The entire process of performing foundation repair work is relevant for the most common causes of problems with the foundation of a house. But it should be borne in mind that each situation that has arisen requires separate consideration and the adoption of measures related to reconstruction. Moreover, there are many cases when 2 houses standing next to each other with the same destruction are deformed for completely different reasons.

Therefore, in order for your renovated house not to undergo repeated destruction, you need to carefully carry out all the analyzes and necessary laboratory studies of the soil associated with the strengthening and reconstruction of the basement of the building.

Vibration Loads

An example of a site where the foundation is subject to vibration loads

Near roads, the foundations of houses are often destroyed by vibrations. Country houses are not subjected to such loads. Heavy transport passing through the city gradually destroys it.

In this case, the pit is made wider by 45 cm, formwork is placed around the corners, and after reinforcement and pouring with concrete, the resulting space is covered with sand.

Spilling it with water several times. As for the depth, the pillow should be 10-15 cm thicker, from the standard one, about 25 cm. When compaction of the pillow, the crushed stone is mixed in a 1: 1 ratio. Having carried out such simple measures, it will be possible to partially dampen the vibrations, while extending the life of your brick house.

How the time required for proper shrinkage is determined

Consequences of an unsuccessful foundation construction To determine how long the foundation should stand before erecting walls, it is necessary to carefully analyze the following factors:

• results of geodetic and engineering studies;
• average annual rainfall;
• soil freezing temperature;
• deepening the foundation;
• type of foundation;
• materials from which the foundation is made;
• the mass of the finished structure.

As a result of geodetic research and engineering surveys, the structure of the soil and its characteristics are determined. These data allow you to determine how the soil will behave under the influence of the base and the entire structure and how long it will take to compact it.

Cracks on the walls of a house are the first signs of foundation subsidence After the concrete is poured, several parallel processes occur. The strength of concrete increases and after 12-18 months reaches values ​​close to the maximum. The mass of the slab compresses the soil by squeezing particles of clay, sand and other substances. Along with the seasons, soil characteristics such as moisture and mobility also change.

The slab pushes the ground until it reaches the point where the influence of other factors becomes too insignificant.How long these processes take is impossible to determine. Therefore, the time that the foundation should stand is determined on the basis of geodetic studies.

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In regions where the temperature in winter drops below minus 10 degrees Celsius, the depth of the pit should be below the freezing depth. Therefore, the finished base should stand longer, because the temperature at such a depth never drops below 0.3 and does not rise above 5 degrees Celsius.

At such a distance from the surface, the influence of rain runoff is too little, therefore the shrinkage process occurs under the influence of groundwater. When determining how long the foundation should sag, the depth of freezing must be taken into account. Otherwise, there is a high probability of damage to the base and the walls of the house located on it.

An example of an erected building without preliminary foundation shrinkage

This also happens if there are sections of soil with different density or moisture content under the base. In this case, the concrete will sag only where the soil is drier and harder.

As a result, the foundation, which must evenly distribute the weight of the building over the entire area of ​​the soil, will not cope with its responsibilities. The house cannot stand securely on such a foundation.

If the bottom of the pit is located above the freezing depth, then correct shrinkage is impossible, regardless of how long it has stood after installation. In winter, as a result of frost heaving, the soil level rises.

As a result, a part of the concrete rises above the ground level, which causes a fracture force. Until the walls are built on the foundation, the heave lifts it up without issue. After the erection of the building, the mass of the base increases many times over, and frost heaving leads to its fracture.

And then there are cracks in the walls. This phenomenon is especially dangerous if not a slab, but a strip foundation is built under the house.

Uniform subsidence will avoid the destruction of buildings

All processes associated with soil compaction occur so slowly that it is impossible to visually determine their completion. Therefore, the end of shrinkage is determined on the basis of calculations, in which all factors are taken into account.

There are cases when a team of builders erected a house, but incorrectly determined the characteristics and properties of the soil.

This increases the duration of the installation of the house, but greatly reduces the likelihood of improper shrinkage of the base and subsidence of the walls.

Consequences of incorrect calculations

To determine how long the foundation should stand before installing the walls, consider the following:

1. On rocky soils 3-5 months;
2. On dry clay and sandy soils 8-12 months;
3. On wet soils 15-20 months;
4. On marshy soils 20-30 months.

This is true only after the following requirements are met:

• only high-quality materials should be used for the base;
• the foundation should be below the freezing depth;
• for strip foundations, the ratio of the width of the wall, base and cushions should be no less than 1: 2 and 1: 2. That is, the width of the base should be at least 2 times the width of the wall. And the width of the pillow is at least 2 times the width of the base;
• the foundation should stand on a splitted cushion (fraction of the lower layer is 70-90 mm, the middle layer is 30-60 mm, the upper layer is 10-20 mm);
• drainage of groundwater table must be carried out;
• rainwater drainage must be performed.

Repair of foundations in wooden houses

Now let's talk about how to repair the foundation in wooden houses. The most common problem in light timber or frame houses is the pushing out or warping of the monolith due to frost heaving forces.

The fact is that such structures do not need an unnecessarily powerful foundation, and here you can get by with laying a shallow foundation.But for some reason people forget that such a structure must be insulated.

Only insulation can save you from the effects of frost heaving forces, and you need to insulate not only the side walls, but also the sole itself. And in order to definitely sleep well, I recommend also equipping a warm blind area with drainage around the house.

Metal screw piles.

But these are all preventive measures, we are talking about how to repair already destroyed structures. The easiest and fastest way out is to use screw piles.

Pile screws have a length of about 2m.

2 - 3 strong men will be able to screw such a screw into ordinary soil:

The idea is simple, screw piles are screwed in as close as possible to the old foundation with a step of 1 - 1.5 m;

Jack installation diagram.

• Then the house is raised a little with the help of several jacks and I-beams are laid and welded on the opposite piles under the house;
• After that, the house descends on these I-beams;
• The number of jacks is determined by the condition of the lower strapping bar, as a rule, they are installed at a distance of 2 - 3m. Naturally, a powerful bar or a wide metal sheet is placed under the jacks from above and below. It is necessary to raise the house gradually by 5 mm in turn on each jack;
• At the end, this metal base is sewn up with some kind of finishing cladding, for example, siding.

Installation of I-beams on screw piles.

Pile screws are certainly a good thing, but their price is also good, so most owners of inexpensive houses choose a different path.

• If repair of the strip foundation is required, then, as in the first case, the whole house or only the problem side of the house is lifted on jacks;
• After that, the destroyed sector is completely knocked out, and in its place a rectangular frame, such as a column, welded from a 45-50 mm corner, is installed in advance;

Corner frame option.

• If there are several problem sectors, then a column from the corner is inserted under each of them;
• Now we just have to tie the reinforcement cage inside the sectors we destroyed, put this whole structure in formwork and pour concrete;

We put the frame under the damaged area of ​​the house.

• Some masters do things differently. They initially make columns from the corner slightly higher than the old structure and instead of this gap they fill in a solid reinforced concrete belt;
• Both options are acceptable, but do not forget that after such a repair, it is imperative to insulate the entire concrete structure and it is advisable to make drainage, otherwise in the first winter your repaired monolith will push out again;
• There is one more trifle, the tree should not be in direct contact with the concrete monolith, otherwise it will start to rot. To exclude such contact, concrete is covered with two layers of roofing material.

The scheme of raising a house on a new concrete harness.

Monolithic bored columnar foundations usually stand quite firmly, but problems sometimes occur with pillars made of bricks, as well as a shallow strip foundation pushes them out of the soil.

In this case, I recommend doing this:

• It is useless to restore an old mowed post; it is better to dismantle it immediately;
• Naturally, it is desirable to jack up this sector;

Insulation scheme for a square concrete pile.

• Next to the old pillar, dig a square hole about 70 cm deep, as much as possible, and pour and tamp a 50 mm sand and gravel cushion on the bottom;
• Next, cover the walls and the bottom of this square pit with extruded polystyrene foam with a density of 35kg / m³, insert the reinforcement cage and pour concrete;
• The pillar can be poured completely out of concrete, but if there is no desire to mount the formwork, then it is enough to raise it 100 mm above the ground, and then cover it with roofing material and lay everything out of bricks. In this case, the main thing for us is that the underground concrete part is insulated.

A lopsided brick pile.

Why is the foundation collapsing?

There are many reasons why the base of the building begins to collapse, the main ones are:

Errors made at the design stage. It is possible that the loads on the building were calculated incorrectly, geological features were not taken into account, or the wrong design solution was chosen.

When building a house, it is very important to contact specialists in design and engineering organizations.
Violation of construction technology.
The use of low-quality building materials in the construction of the foundation.
Improper use of the building. When designing a building for calculations, loads are taken for each specific house, the mass of the structure, all structural elements is taken into account

Unforeseen changes, in the form of an extension of new premises, construction of superstructures, destruction of load-bearing walls, excessive congestion of premises and other ill-considered changes - all this increases the load on the foundation, which can lead to a violation of the integrity of the base.
Natural impact - soil erosion, water level rise, temperature influence.
Unforeseen man-made factors - vibration from industrial buildings, large highways, earthworks associated with explosive activity in quarries, construction of buildings in the neighborhood, seismic impact.

Causes and types of foundation destruction

When starting to strengthen the foundation of an old wooden house with your own hands, first of all, it is necessary to correctly determine the cause of its deformation.

The destroyed foundation of a wooden house

There can be several factors for the appearance of destruction:

• Due to changes in load, the properties of the soil may change. Such changes are caused by soil erosion, high groundwater levels. If new buildings appear near the house, then this can also lead to certain changes. The structures, as it were, squeeze out the soil and thereby violate its density. The consequence of all this is the subsidence of the house or its distortion.
• Poor initial foundation arrangement. When laying the foundation, it is possible that the work was performed poorly, errors were made in calculating the depth of freezing of the soil or in choosing a grade of concrete.

Determining the cause of structural deformation is only the initial stage. The next step is to determine the degree of destruction. They are subdivided into four types:

• Minimal damage is visible defects. These include slightly exfoliated plaster. This damage is repaired very quickly.
• Medium damage. These include different types of cracks. To eliminate defects, their nature should be investigated. Horizontal cracks pose little threat. Vertical or zigzag defects deserve more serious consideration.

• The depth can be determined using beacons. In places of cracks, a plaster putty beacon is applied - a horizontal line 0.5 cm thick. At the slightest movement, the integrity of the putty will be violated. Next, we follow the beacon. If it remains intact, then the subsidence is temporary. In this case, a small crack repair is performed. If the beacons are broken, then the elimination of the cracks will not save the day. It is necessary to strengthen the supporting structure.

• Catastrophic deformations lead to the fact that the house can be completely destroyed. In this case, it is urgent to carry out work on the capital strengthening of the foundation.
• Fatal damage. In the event of such damage, the supporting structure must be completely replaced.

Identifying the problem

The first signs that it will be necessary to strengthen the foundation is the appearance of cracks and depressions at its base. However, before deciding how to strengthen the defective base of a brick house with your own hands, you should determine in what condition it is, and how much damaged.You may only need to do cosmetic repairs. It happens that cracks appear during shrinkage, in the future they do not expand, and do not pose a threat to the integrity of the base. To check this, you need to install "beacons" on all cracks that you find (they can be gypsum, alabaster, or paper with an adhesive base).

All these markers are installed across the cracks; if the gap is large and complex in shape, markers are installed on each of the sections. It is necessary to monitor the paper marks for at least 10 days, and the plaster or alabaster beacons are left for 2-3 weeks, after which it will be possible to assess the amount of destruction and decide whether the foundation needs strengthening. In the event that during the specified period the markers have remained in their original state, it will be sufficient to cover the cracks with cement mortar, or install the formwork and concrete the damaged area, having previously hammered a construction battle with a cement mortar into the crack - this will depend on the volume of the crack.

When examining the above-ground part of the foundation, it is necessary to pay attention to the condition of the windows and doors. Deformations occurring underground may be indicated by distortions of door or window openings.

When inspecting the underground part from the outside, it is necessary to open control pits, a small hole near the base in order to inspect it and assess its condition, check for cracks, chips, depressions. It is advisable to dig pits in places where the maximum damage to the base is observed.

In addition, it is necessary to inspect the inner underground part. To do this, inspect the walls of the basement, you need to assess their condition, humidity in the room. If there is water in the basement, it is possible that the waterproofing of the base of the basement is broken, or there is a rise in groundwater.

Concrete works and reinforcement

The device of a new blind area

It is not difficult to equip the repair of only the foundation of a private brick house with your own hands. After dismantling the concrete blind area, excavating the soil and treating the foundation with a primer, there is a stage, ligaments, reinforcement.

Reconstruction should be complete, reinforcement should be made of reinforcement with a diameter of 8-12 mm. with one-story and light wooden structures. If you are repairing the foundation of a two-storey summer cottage or residential building, use 14 mm reinforcement. and more.

It is necessary to make a frame between the existing (burst) base and together with the occurrence of retaining dimes, under the base. It will not work to repair the burst house, just pouring concrete between the existing foundation and the ground, you still have to tighten the armo with a belt. The base is drilled to a depth of 200 mm. rods with outlets are driven into the holes, and the main runs from the rods are already knitted to them.

Concrete, repairing the foundation with your own hands, can be ordered. But it is better to do it yourself at the rate of 210-230 kg. cement, per 1 m3 of ready-mixed concrete. It's easier to say 1.5 buckets of sand, 4.5 buckets of rubble, 1 bucket of M-400 cement and water. Add additives for plasticity.

Do-it-yourself repairs to the foundations of a country house can also be carried out using the combined method. It is easy to repair it using simple manual drilling of wells around the entire perimeter of the base, in the ditch itself. Filling it with concrete, we get an additional emphasis. An excellent method to repair a country house, a foundation.

Advice: After pouring, it is impossible to leave without a blind area the areas on which the reconstruction was carried out. It is advisable to compact the soil and pour new ones around the house. Cutting expansion joints along the surface.

Reconstruction of monolithic houses is rarely done, it is much more difficult to do it. Do-it-yourself repair of the foundation of a brick house occurs more often. In such cases, the reconstruction of the base involves the use of heavy equipment.

Reasons for the destruction of the foundation

The foundation is negatively affected by moisture, soil pressure, structural loads

Brick structures are quite heavy and the base must be quite solid. Builders recommend carrying out preventive maintenance every 3 years.

The most common factors that have a negative impact on the foundation are:

• groundwater;
• actions when carrying out earthworks near the base of the building;
• errors in calculating the load on the base;
• non-compliance with the rules and regulations in the construction of the foundation.

An additional trigger for the destruction of the foundation of the house is:

• pressure of heaving soil during freezing;
• house weight;
• soil resistance force.

Repair of a brick foundation is carried out when the first signs of destruction appear: cracks, swells or depressions. Not all defects require full intervention. A fixed beacon will help you understand the severity of the situation. Stick a strip of paper on the problem area, securing the edges to undamaged areas.

If after a while, usually a week or 10 days is enough, the strip breaks or sags, then the problems are serious and thorough work will be required. Otherwise, you just need to restore the surface layer.

Let's consider the most common situations and the ways out of them.

Damage types

Cracks are formed due to a violation of construction technology. The fault of the destruction of the foundation is often incorrect calculations. Before the construction of the foundation, a detailed diagram is drawn up with a load calculation. The peculiarity of the local soil, the mass of the support itself, the weight of the house together with decoration, furniture, and appliances are taken into account.

The unevenness of the loads of the strip base is a vivid example of erroneous calculations. You cannot fill all stripes using a single parameter - each stripe must correspond to the width and weight of the wall under which it will be located.

Irregularities on the surface occur in the absence of markings inside the formwork, leveling. The horizontal can be disturbed if the tree is left without polyethylene before concreting - the formwork will draw a lot of moisture from the solution.

Side bends are formed due to illiterately placed formwork - lack of strong shields, lack of side supports, the presence of gaps between the boards.

The skeleton can bend if the deepening corresponds to the level of the groundwater, but does not reach the degree of freezing - sometimes these parameters differ. Their compliance is a variant of the norm.

Breakdowns occur among homeowners who save a lot on building materials - low-quality raw materials quickly render the structure unusable. You will have to constantly repair it or completely redo it - in both cases, the costs will come out more than when purchasing high-quality raw materials.

Features of foundation repair, depending on the problem

The service life of the base of the house directly depends on the quality of its installation and the materials that were used for this.

Survey of foundations

It is recommended to carry out several inspections before repairing the foundation. This will allow you to determine the causes of the destruction, as well as decide whether it is possible to carry out repairs yourself.

When a crack appears, it is imperative to determine whether it increases. For this, so-called markers are installed. In order to check if the crack is progressing, it is necessary to stick a paper tape across it and leave it for 10 days. If the tape remains intact, then the crack can be filled with fragments of bricks, and then concreted. If it became clear that the development of the crack is progressing, then it is necessary to come to grips with repairing the foundation or replacing it in the case when reconstruction is impossible.

As a beacon, you can use both a gypsum solution and a ready-made mixture for plaster. The composition should not be plastic after hardening, it should be as fragile and susceptible to mechanical damage.After preparing the mixture, it must be applied to the crack in a layer of 3-5 mm, 100-120 mm long. You need to apply across the crack, and in such a way that it is approximately in the middle of the marker.

For greater accuracy of the result, it is recommended to apply several markers to each crack.

For greater accuracy of the result of markers on the foundation crack, there should be at least two

There is another way to survey the foundation. Although it is more time consuming, it is more informative. The method consists in preparing pits. A pit is a pit, the depth of which coincides with the height of the foundation. The length of each pit (there should be at least two) is 100 cm. The width is selected strictly individually. After the pit has been dug, it is recommended to strengthen its walls with unedged boards. This measure is needed to prevent land collapse.

The size of the pit depends on the height of the foundation and the size of the person who will carry out the work

It is recommended to make pits only in problem areas. This will allow you to gain access to the walls of the foundation and determine the quality of the installation, the materials used, and also give information about the depth of the groundwater (they can be checked for acidity or alkalinity).

This method allows you to start repair work almost immediately.

Possible causes of destruction

At the moment, there are three main reasons that provoke the destruction of the foundation of varying degrees:

• human activity;
• shortcomings in the very process of work, careless attitude to installation, violation of technology, use of cheap low-quality materials;
• the influence of external natural factors (rain, frequent temperature drops, rise in groundwater).

Most often, it is water that becomes the main reason for the collapse of the base of the house. Ground or tap water can get into the ground under the building, while in winter it freezes, increases in volume, and in the warm period causes the destruction of the base of the house.

The cause of the destruction of the foundation can be groundwater or a change in load.

Similar processes occur during seasonal heaving of the soil. It also happens that the foundation as a result of this rises by more than 10 cm. However, the most serious problem for the foundation of any house is soil subsidence.

Signs of destruction

Each owner of the house can independently determine that the foundation of his house is beginning to collapse. Cracks or depressions appear. But remember that not every crack that appears when the foundation shrinks is a sign of failure. Sometimes, just a cosmetic repair is enough to solve the problem.

Signs of destruction can be overt and subtle. Among the main ones are:

• thin cracks that can appear not only on the basement, but also on the walls;
• violations of external or internal decoration in the area of ​​destruction;
• visible deformations of the floor covering, possible failures;
• collapse of the building, which at the first stage of the destruction of the foundation can only be partial;
• deformation of individual sections of the foundation;
• sinkholes next to the damaged foundation.

To identify hidden signs of destruction, it is necessary to conduct a special examination, for which it is better to invite specialists with equipment.

The technology of the classical method of strengthening the strip foundation

Laying a girdle foundation along an existing one is the most popular way to strengthen the foundation of an old house with your own hands. It can be used to repair a country house, brick or wooden. The technology includes the following stages:

1. Dig voluminous holes 100 × 100 cm in the corners of the house so that they are completely exposed. The excavation depth is determined by the depth of the foundation, in which you need to add another 50 cm.
2. Make a reinforced frame with cells with an area of ​​20 × 20x20 cm.Connect the intersections of the rods with wire or welding. The main thing is that the fasteners are strong.
3. Place the grate in the hole and cover with concrete.

To do the repair of the tape base with your own hands in this way correctly, it is important to adhere to two rules:

• do not stretch the process over time, since the base of the house will remain bare, without backing up with soil;
• use the reinforcement of maximum rigidity, since the strength and efficiency of the structure depends on this.

If there is a danger of further collapse due to the significant weight of the building, strengthening the foundation of a brick house must be done along the entire perimeter of the base, connecting the corner structures to each other. For this you need:

1. Conditionally divide the entire length of the tape into segments of 1.5-2 m.
2. On one of the sections, excavate the soil according to the type of trench up to 0.5 m wide and with a depth at the level of the old foundation.
3. Drill holes in the old foundation and place pieces of reinforcement up to 40 cm long in them.
4. Install a ready-made reinforcing cage with the same parameters that were used to strengthen the corners into the groove.
5. Fill the trench with concrete.
6. Carry out such a strengthening on all sections of the foundation in turn.

Concrete work should be carried out at an air temperature within +5 - + 30˚С.

Sometimes a lightweight, timber house begins to sag due to the movement of groundwater closer to the surface of the earth. To minimize their impact on the foundation, it is necessary to carry out drainage work. How to strengthen the foundation of a wooden house using conventional drainage? Consider below:

1. Carry out excavation in the form of an annular trench to the depth of the possible appearance of water.
2. Connect the trench with a drainage well, which will be correctly removed outside the site.
3. Lay a geotextile with permeability to one side on the bottom of the trench, fill it with a layer of rubble and put a drainage pipe in the recess.
4. Connect the pipe to the well with a main pipe with a slope of 1 cm by 2 m of pipe.
5. Pour a layer of rubble on top of the pipe, and cover everything with geotextiles. Fill the drain with a drainage mixture.

Such repairs will help reduce soil swelling and the effect of excessive moisture on the foundation and plinth.

Strengthening the foundation of a brick building

Before you strengthen the foundation of a brick house, you need to decide on the way of work. The repair of the brick structure is complicated by the heavy weight of the building. You can quickly strengthen the foundation using one of three methods:

1. Reinforcement of the old foundation with a new concrete belt. This is the classic version described above.
2. Additional reinforcement.
3. Introduction of piles.

You can use ready-made piles of one of three types:

• screw (piles are screwed into the ground, leaving a small section above the ground);
• pressed (used only under the guidance of specialists and cannot be used for dilapidated buildings
• bored.

For a brick house, the use of bored piles is the most high-tech and effective option that allows you to significantly extend the life of the structure, even if the foundation of the house has settled, which can still be used for full-fledged living. Repair includes the following stages:

1. Drill the old foundation under a strong slope on both sides to the point of detection of solid ground in increments of 1.5-2 m.
2. Pour cement into the wells formed as a result of drilling.
3. Install a reinforcement frame in them and wait for the structure to completely harden.

This repair of the foundation will help to move the pressure of the brick house from the base area to the corners of the piles.