Sometimes owners of private houses face a serious problem - the need to repair or restore the foundation. If the house was built on its own and the owner knows exactly what materials were used in the construction process, then it will be easy to solve the problem. It is much worse if the house was bought, so to speak, ready-made, and the new owner does not know in what state the foundation is. Signs that directly indicate the need to strengthen or repair the foundation can be skewed window and door openings and cracks in the walls.
Strengthening the foundation - a set of works that are carried out to repair or restore the base of the building. The main goal of the work is to identify and completely eliminate the damage and defects that have arisen in the process of operating the house.
Strengthening the foundation is most often done during the construction phase. As for restoration and repair, these works require significant financial expenses and attracting specialists. How to strengthen the foundation, what methods and materials are used for this - this will be discussed in this publication.
Content
Calculation of reinforcement
Prior to the design of reinforcement of the base of the building, the study of the current state of the foundation and the elevated part of the walls, and engineering and geological investigations are carried out in a necessarily order. The methods by which the foundation will be strengthened directly depend on the results of the research.
For old buildings, the task is greatly complicated by the lack of foundation drawings. So, in the XIX century, the type of foundation, its depth and material was chosen by the contractor, relying on their own experience and local traditions.
In such a situation, the necessary information on the foundation material, the soil, and the waterproofing of the underground part of the base can only be obtained by excavating trenches on both sides of the base. In some cases it is necessary to dig trenches up to 3-4 meters deep.
After the opening of the base, appropriate measurements are made, on the basis of which the drawings are made, the type of material and solution is determined, soil samples from under the sole for research are taken.
The most accurate results are obtained by drilling out from the body of the basement samples of cylindrical shape, the so-called core.
The obtained samples are tested for strength in laboratory conditions. With the help of drilling, you can determine the presence in the foundation of a foundation of wooden or other piles or grills, the position of their points, etc.
Methods of strengthening the foundation
There are several ways to strengthen the ready foundation of a private house:
• Extension of the sole.
• Use of gunite concrete.
• Strengthening the foundation with piles.
• Strengthening the foundation with a reinforced concrete jacket (cage).
Reinforcement with gunning concrete is recommended, mainly for brick foundations. At the same time, along the perimeter of the house, a trench about 2 meters wide is being excavated. Further, the base is thoroughly cleaned of debris, all the destroyed and damaged fragments are removed. On the surface of the foundation, incisions are made so that the concrete adheres well to the surface. The mixture is applied with a cement gun, under pressure.
In addition to the aforementioned reinforcement methods, basement carburizing is used. This method allows you to quickly and effectively strengthen the base of the house, but it is used only if the monolithic foundation is broken throughout its thickness.
To strengthen the base make holes of small diameter, into which a special syringe under high pressure is pumped liquid concrete mixture.
reinforcement of the foundation technology with the use of piles
Damage to the foundation in most cases occurs due to errors made at the design or construction stage. But it also happens that you need to complete one or two floors, thus increasing the load on the foundation.
In both cases it is necessary to significantly strengthen the base of the building. One of the best solutions in this case is the reinforcement of the foundation with piles. Used screw, bored, boring and punching piles.
Applying bored piles, first along the entire perimeter of the base, both outside and inside, make wells in a certain step.
The depth of the wells is about 2 meters. In the borehole is placed a structure of reinforcement with a diameter of 10-12 mm, after which the well is poured with concrete. The finished piles are connected to the base of the house with strong anchor bolts.
Sometimes it is impossible to perform drilling operations near the building (the foundation is seriously damaged, the building is very dilapidated, etc.). In this case, you can use the piles to be pressed.
This option is one of the most difficult, since it requires the use of special equipment - piles are pushed into the ground with the help of powerful jacks. Therefore, the piles to be pressed are used only in cases where there are no other options.
More often, the foundation is strengthened with screw piles - 2-3 people are enough to install them in light soil. The screw pile is a simple tubular structure equipped with a screw platform at the end.
It is not only designed to screw the pile into the ground, but also to distribute the load evenly to the ground. Screw piles can be made independently. The screw tip-screw is manufactured by welding a metal strip to a steel pipe, which serves as a support.
Buroinetic piles, or, as they are called, micro-piles, are a hybrid of bored and screw piles. In hollow piles, which are screwed into the ground, the concrete is poured.
In this case, the pile itself serves as a reinforcing element, which remains in the ground. Bored piles can be installed both outside and inside the building.
reinforcement of the basement by carburizing
One of the most popular ways to strengthen foundations. Materials for strengthening in this case are: sand, sandy loam, cement, water, stone flour, clay, various kinds of additives. The use of sandy loam and or loam makes it possible to increase the water-retaining capacity of the solution, but reduces the strength of the solution. Clay stabilizes the solution, making it plastic. Such a solution is conveniently pumped into the holes and cracks in the basement. Chemical additives accelerate or slow down the process of solidifying the solution.
The process of cementation of the foundation is carried out as follows. First drill the wells through the entire foundation under its sole.
After that, using a mortar pump under high pressure, a solution is pumped into the wells.
Sometimes, with the help of cementation, the foundation of the house under construction is strengthened - at each site a well is drilled in several stages, each time deepening through the previously cemented part of the well.
When reconstructing a house, which includes the reinforcement of an existing foundation, if cracks appear in the uneven shrinkage, it is reinforced with cages of concrete or reinforced concrete.
To do this, in the basement or in the basement part of the walls, do stitches, then drill holes, into which trim thick fittings or beams are installed. These details will later link the clip and the foundation and ensure their joint work. Before pouring concrete into the cage, a frame of reinforcement is installed, which will increase the strength of the walls in the longitudinal direction.
With this method, a substantial increase in the working area of the foundations is achieved, thereby reducing the pressure on the base and preventing further shrinkage of the house. Cementation of the foundation is not such an easy way to enhance, as it might seem at first glance. Without the relevant experience of carrying out such work, it is necessary to turn to professionals.
Strengthening of the ribbon foundation
Strengthening of the reinforced concrete foundation tape is carried out by various methods:
• Filling cracks with mortar.
• Tightening with metal strips.
• Filling cavities and plastering the surface.
• Filling voids under the tape.
• Complete dismantling of the foundation, pouring a new tape.
causes of damage to the foundation tape
On the need to repair the tape foundation can be judged by the appearance of deep cracks on its surface. The reasons can be the following:
• Ground subsidence.
• The use of brick for masonry of the upper part (tape from FBS blocks) during construction of the tape.
• Absence of a framework of reinforcement from the concrete foundation.
• Non-closed ventilation ventilations during the cold season.
• Wrong calculations of loads on the foundation.
• Incorrectly made drainage system or lack thereof.
What measures should be taken if cracks appear in the foundation tape? There are several ways to combat this problem, it all depends on the causes of deformation.
In most cases, it is enough to pull the cracks with metal strips, pour them with a solution of concrete.
To do this, the entire surface of the foundation is carefully inspected, and all damage and cracks are noted. Then all the cavities are filled with concrete, in which it is necessary to add chemical components to protect the solution from temperature and humidity changes. After that, the edges of the cracks are pulled together by metal strips.
reinforcement of the strip foundation - protection from sagging
Sometimes over time, some parts of the foundation tape begin to crumble. The reasons can be several:
Filling the foundation in the cold season without the addition of antifreeze means of protection - concrete does not freeze, but simply freezes and with the onset of heat collapses.
Surplus water in the solution, as a result of which the concrete grade is lowered, strength decreases. Do not rule out banal theft, when when pouring the foundation workers "save" quality cement. Therefore, such responsible work is necessary or monitored personally, or trust reliable reliable companies. The foundation can also be crumbled due to the addition of high clay sand to the solution. This is not difficult to check, even with a superficial examination of the surface - clay lumps leave behind a cavity inside which is a piece of clay.
Autumn clay actively absorbs moisture, which in winter freezes, increases in volume, and begins to chip out fragments of concrete. As a result - the appearance of excavations, cracks, shedding of concrete. This is especially noticeable at the corners of the tape. Low quality cement can also cause premature failure of the tape, so you need to pay attention to the brand, the manufacturer's coordinates, the availability of characteristics and conditions of use of the material.
To save from shedding and strengthen the tape foundation can be as follows.
To begin with, carefully inspect the entire surface of the tape, mark the places of damage. Cosmetic repair in this case is completely useless. The large-sized voids are filled with a solution specially designed for such work.
The tape itself from the outside is insulated and reliably protected from moisture to prevent further destruction.
In the future, the tape will still have to be completely re-cast, but the lifetime of the foundation can be substantially extended by filling all the cavities with concrete, and using a quality insulation, waterproofing, periodic inspection and removal of damages, the foundation will last long.
what measures to take if the foundation has become soft
Cases when from a tape of the base it is possible to pinch off a piece of concrete with your fingers and stretch it, like clay, very rare. This state of concrete is due to the fact that when it was mixed in the rough way, the technology was violated, the necessary quantity of cement was not added to the solution, instead of quality sand its mixture with clay was used, which is strictly forbidden to add to the concrete solution.
In this case, the only reliable way out is to completely dismantle the old foundation and fill the new tape.
No reinforcement and restoration in this case will not help. Such a defect in the tape is usually noticed during the drying phase, especially when the solution does not set for a long time. Build a house on such a foundation is impossible - it just collapses.
Dismantling work can not be called simple and easy - it is necessary to completely remove the defective foundation and fill a new one, already with the technology of mixing concrete mortar.
reinforcement of the ribbon foundation on one side
It happens that even in the process of exploitation, the foundation ribbon can be lifted from one side. The reasons can be both flooded with violations of the foundation, and negligently carried out design work, resulting in one part of the house is too light. As a result, after the winter punching of the soil, the building can not properly put the foundation band in place.
It is quite difficult to repair the foundation in this case - it is required to fill the void under the sole and align the building itself.
Before starting the restoration work, the entire tape is carefully inspected, and if it is very damaged and deformed, it is required to completely replace the foundation - and this is an expensive and time-consuming process. If there is no significant damage, the tape can be leveled. To do this, the concrete is poured into the voids under the foundation, thus raising it to the desired height. In the process of restoration work, it is necessary to constantly monitor the condition of the foundation.
The cost of such work can vary greatly for each specific case, since it is possible to use different materials, often the presence of specialists is necessary.
Strengthen the foundation is necessary in many cases, especially with obvious damages and the appearance of cracks in the structure. But even if there are no signs of damage, it is necessary to regularly conduct a preventive examination of the substrate, to identify possible deformations and determine the degree of danger of damage.
In the overwhelming majority of cases, there is a slight damage to the tape, which is eliminated by the above-described methods.
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