Partial replacement of the foundation without raising the house. How to replace the foundation under a wooden house. Types of foundations for a wooden house

Subsidence of the foundation of wooden buildings is a common occurrence. This process occurs from various kinds of hydrological and physical-mechanical changes in the lower soil, which reduce its bearing capacity. Often, changes in soil properties are caused by construction work carried out on the backyard territory. In the current conditions, replacing the foundation under a wooden house becomes the only way to prevent further subsidence, leading to destruction.

1. Cosmetic- the simplest method that does not require significant financial investments. In this situation, the rotten area is simply cut out and a suitable wooden element is inserted in its place. But it should be taken into account that with such a partial replacement, the integrity of the house is inevitably compromised.
2. Dismantling the walls- a type of construction work that involves the complete dismantling of walls, after which the lowest crown of the frame is replaced. The method is reliable, but requires a fair amount of patience and time from the craftsmen to disassemble and reassemble the structure.
3. Dismantling the foundation. To do this, it is necessary to remove a layer of 20 cm, replace the wooden crowns and restore the foundation.
4. Replacing crowns by lifting the structure with a jack- the most popular method that allows you to replace the foundation quickly and efficiently.

Replacing the foundation of a wooden house - a second life for the structure

Jacks not only greatly simplify the process, but also allow you to lift the house evenly

Important! The above methods for replacing the foundation require the use of different tools, which must be prepared in advance so that during the work you are not distracted by searching for suitable equipment. Thus, the cosmetic method can be carried out with only a chisel, a sledgehammer and a hacksaw in your arsenal.

Dismantling the foundation will require a device with which you can implement the task. The choice will depend solely on your preferences and technical capabilities.

You should also worry about temporary supports that will support the house during repairs.
If you intend to use jacks, then their number, depending on the length of the walls, can vary from two to ten.

Depending on the length of the walls, the number of jacks varies from 2 to 10

How to choose a new foundation for a wooden house?

It is important to understand that replacing the foundation of a house is a process that requires careful preparation. First of all, you should decide on the design of the future foundation that will replace the old one. There are the following types of foundations for wooden houses:

• - a structure adapted to support relatively light houses with panel, frame or wooden walls without creating significant load. Despite the apparent simplicity, columnar foundation- a sure way to provide reliable support for a garden or country house, light bathhouse or low-rise country cottage. It is represented by a system of pillars that are installed in places of maximum load, i.e. at the intersection points of the walls. The pillars are made of brick, concrete, stone and are mounted at a distance of 1-2 meters from each other.

A columnar foundation is the surest way to provide reliable support

• A bored pile foundation is a type of columnar foundation, only asbestos-cement pipes filled with a special mixture are used as load-bearing components. The design of such a foundation consists of piles and a grillage connecting them. Load-bearing elements are located under the most significant points of a wooden house, for example, at the corners of the building or at the intersection of main walls. A bored pile foundation is optimal for buildings on soils with high water levels.

Bored pile foundation is an excellent but expensive option

• Pile screw foundation is the most interesting type of foundation, originally intended for military purposes. The foundation is valuable because it can be used on any area, even uneven. The low price and the possibility of repeated use of screw piles are additional advantages in the treasury of advantages.

To build a pile-screw foundation you will need special construction equipment

• The strip foundation allows you to build heavy houses and at the same time provides a good level of reliability and security. Shallow strip foundation divided into monolithic and prefabricated. The first consists of concrete based on formwork, the second - from blocks of concrete and reinforced concrete.

Shallow strip foundation is the best option for small buildings

Main stages of foundation replacement

In order for the foundation replacement to be carried out efficiently, it is necessary to follow the sequence of stages.

We will consider the most common type of replacement - using jacks.

Stage 1. Installation of jacks

Jacks allow you to raise the house evenly, otherwise (with uneven lifting) the logs bottom trim will sag, which leads to their separation and breakage. The jack must be installed in places where the wood is not damaged by rot. Do not forget to install gaskets - steel plates (5 mm) - this is necessary for the correct transfer of force from the jack rod to the logs.

Stage 2. Raising the house

You need to raise the wall to a height of at least 6 cm, remove the rotted extensions and lower the structure onto the cuttings of beams placed on the end - temporary supports. Antiseptic-treated tow is laid between the beams and logs in a width equal to twice the thickness of the wooden beam. Bricks and a 10 cm layer of gravel are poured under the proposed foundation strip.

Start of work - lifting the house on jacks

Stage 3. Making the foundation and removing the jacks

After the frame is safely lowered onto the brickwork, they begin to make the foundation strip. It is necessary to clear the space under the walls and lay out the formwork. At this time, other walls rest on temporary supports. It is important to take care of the niches for jacks, so that later there will be no problems with lowering the building. After installing the house, the niches are sealed with bricks - the work is completed.

Temporary supports will ensure the stability of the building during repairs

As you can see, this process is painstaking and requires an organized approach, however, replacing the foundation with your own hands is quite possible if you approach the work wisely. A little patience combined with the knowledge gained will guarantee an excellent result - a new, reliable foundation for your wooden country house.

Over time, any foundation can become damaged or completely collapse. Deformation of the base leads to many undesirable consequences: skewing of the house, jamming of windows and doors, and the appearance of cracks in the material. Replacing, restoring and strengthening the foundation under a wooden house helps to significantly extend the life of the structure, as well as avoid the listed negative consequences.

Types of bases

Regardless of what type of foundation for a wooden house is chosen, it must fully cope with the following functions:

• with all loads associated with seasonal soil movement, for example, soil subsidence;
• it must remain stable and not change its horizontal position throughout the entire period of construction and operation of the building;
• it must guarantee waterproofing of the structure during floods, as well as protect materials from the effects of groundwater.

The characteristics of the foundation are also directly influenced by factors such as:

• depth of seasonal freezing and occurrence of soil layers;
• ground water level;
• average spring flood height in the area.

Depending on the material, the types of foundations can be stone (ruble, brick, block), as well as cast reinforced concrete and piles (on asbestos-cement or metal pipes).

According to its design, the base can be columnar, strip or pile.

The features are as follows:

• Tape the foundation is considered the most reliable and durable option, which can smooth out some miscalculations made during the construction process. However, it is quite difficult to mount such a base.
• Columnar base in building is a little easier and cheaper than tape. However, if the soil on the site tends to bulge, shrink or flood, then it is better to choose a different type of foundation.
• WITH Vainy the foundation is excellent for light mobile soils. However, its construction requires the use of special piles and boring work, which cannot be performed in all areas.

Construction rules

Tape

Such a foundation is made of brick, cinder block, rubble stone, reinforced concrete blocks or monolith. It should lie in a continuous strip under all structures of the building. This is necessary to ensure that the weight is evenly distributed over the entire surface of the base. The masonry is carried out using cement-sand mortar, the height of the foundation should be from 50 to 80 cm, with 30 cm falling on the buried part, and 20-50 on the above-ground part.

If the site is very hot, then the basement can be made higher.

To fasten the crown of a wooden house, threaded rods or side angles are installed in the foundation. Then a grid of reinforcement, smooth metal rods, thick iron wire or small pipes is installed. The grating is laid on the bottom of a pre-prepared trench in two rows at a distance of about 10 cm from the formwork, while the distance between the rods should be approximately 50 cm. The rods must be fastened together by welding or tying them with wire.

Depending on the depth of occurrence, it can be:

• deep-seated - for massive multi-storey buildings;
• shallow - for a one-story wooden house;
• not buried - for light outbuildings.

Columnar

This type of foundation is chosen if the upper layers of soil on the site cannot provide reliable support for the strip foundation. The pillars are made of brick, blocks or reinforced concrete. Their width should be about 20-30 cm greater than the thickness of the walls of the house, and their height should be 3 times the width. Most of the height of the pillars is usually in the above-ground part.

The distance between the foundation pillars along the perimeter of the house should be 2-2.5 meters, and they must be installed at open or closed corners of the house, intersections and convergences of internal walls.

The technology for constructing a columnar foundation for a wooden house involves several stages:

• creating a diagram of the arrangement of pillars;
• preparing a trench around the perimeter of the house;
• concreting pits;
• installation of studs and corners for mounting the first crown;
• laying a waterproofing layer on the sections of the pillars.

The upper part of the foundation pillars is connected by horizontal reinforced concrete beams, which form the base of the house.

Pile

Such a base can be installed at any time of the year. It is perfect for moving soils, is fast and inexpensive to install. There are two types of pile foundations.

Bored

To install it, you will need to drill several holes in the ground with a diameter of approximately 20 cm at a distance of 2 m from each other. In this case, it is important to install piles at the open and closed corners of the building’s perimeter, at the points of convergence and intersection of its walls. Then you need to lower asbestos cement pipes of the appropriate size into the prepared holes and level the height of the pipes to the required parameters. After this, three reinforcement bars should be lowered into the pipe and filled with concrete. All that remains is to install the threaded rods and anchors on the upper end of the structure.

Screw-in

Its design involves screwing piles into the ground to the required depth. Piles can be screw piles, made of iron pipes with a head, blades and a tip.

Destruction

Practice shows that of all the listed foundation options, the old columnar foundation is most often destroyed. Problems with the foundation are indicated by skewed walls, difficulties opening doors and windows, and tilting of one side of the house in a certain direction.

Causes

Below are some of the most common cases that indicate problems with the foundation.

• Strong wear of the old structure. This is evidenced by crumbling masonry and brick, rotten wood and other defects.
• Destruction of the supporting pillar. If at least one of the pillars is broken, the building structure may become deformed. Therefore, this should not be allowed; appropriate measures must be taken immediately.
• Noticeable distortion of piles. This may occur due to incorrect calculations and errors during construction.
• Occurrence of cracks and chips in strip base. Violation of the solidity of the base can lead to distortions of the house.
• Lowering the log house to the ground. This usually happens after several decades of operation.

These consequences may occur as a result of errors in the construction of the foundation or its dilapidation.

Determination of degree

If at least one of these reasons is detected, you should think about repairing or replacing the foundation. But first, it is necessary to invite a specialist so that he can draw up an accurate conclusion about the need for such work, and also clarify what is more reasonable, to redo the foundation of the old building or to build a new one.

When is repair needed?

Complete replacement of the foundation under a standing wooden house is a rather radical, time-consuming and expensive procedure. Therefore, you should regularly check the condition of the base to avoid serious problems, because repairing the material is much easier, faster and cheaper. For example, if small cracks are found in the foundation, then it is enough to fill them with cement to avoid further destruction.

If the house is noticeably lopsided, and the foundation has violated its integrity, then it will need to be completely remodeled.

Repair and strengthening of the foundation is carried out in cases where:

• the degree of subsidence of the building is higher than the permissible norms;
• there is a need to build a second floor;
• the structure is constantly exposed to some kind of vibration.

Strengthening is carried out by installing micropiles, cementing, updating brickwork, expanding the base of the house and others accessible ways. Such manipulations will help get rid of cracks that have appeared and evenly distribute the load on the foundation when the house is standing.

How to replace completely?

If the old foundation has subsided greatly and can no longer cope with its functions, it must be completely replaced with a new one.

Methods

Below are several ways to reconstruct foundations.

• Cosmetic. This method does not require large financial costs, therefore it is the most affordable. It involves replacing the destroyed or rotten part of the foundation with a wooden element. However, this method is not suitable for replacing a full-fledged base.

• With the dismantling of the walls. This is a very labor-intensive process, since you will have to completely dismantle the walls. However, after this it will be easy to completely replace the slab foundation.
• With the dismantling of the base. This option involves the dismantling of the lower crown of the building in order to fully and efficiently repair or completely change the foundation of a wooden house.

Selecting a base

To replace the base, the same material is used from which the old foundation is made. For example, for a concrete foundation you will need concrete and reinforcement.

Preparation and equipment

Before you begin, you must prepare all the required tools. To rebuild the foundation of a wooden house with your own hands, you will need a crowbar, a sledgehammer and wedges, as well as a jack for lifting the foundation, bars, beams and other materials.

If the replacement concrete slab cannot be restored manually, it is necessary to use special equipment for the work. In particular, hydraulic jacks that are capable of lifting loads of up to 10 tons are suitable. Such cars can be rented from special companies.

Wooden houses built in the middle or even at the beginning of the last century serve the current generation of owners well. But there is no escape from the ravages of time - the age of the buildings, which have witnessed an entire era, shines through the warped windows and doors, sagging foundations, and leaning walls. However, there is no need to rush into plans for new construction. Very often the fault of the unsightly appearance wooden house has a dilapidated foundation. Its renovation will provide the building with a second youth, and perhaps your grandchildren will also live in it.

Factors that indicate the need for foundation repair or replacement

Before starting restoration work, it is necessary to understand why the foundation was destroyed, how serious the damage is, and also determine how the damaged building can be reconstructed.

Brick foundation that requires complete replacement

Causes of damage to the foundations of wooden houses

To prevent a similar problem in the future, it is necessary to understand the factors that lead to the destruction of the foundation. And this happens for several reasons:

• geological and hydrological changes that lead to subsidence or displacement of the soil under the building;
• violation of construction technology and use of low-quality materials;
• absence or improper operation of the drainage system;
• time factor - even high-quality materials lose their performance properties over the years;
• weighting of the structure due to additional superstructures.

It is quite simple to determine whether the house is currently subsiding or whether the foundation has found new support points. To do this, beacons made of plasterboard or paper are installed in the busiest places. Their damage indicates that the destruction process is continuing.

What are the deformations

The second thing that needs to be done during the research process is to determine the degree of destruction. The complexity of restoration work depends on this factor. Conventionally, 4 types of deformations can be distinguished:

1. Small defects that manifest themselves in the peeling of the foundation finishing. As a rule, the strength of the foundation does not suffer from this, and problems can be eliminated without any problems.

   Peeling of plaster, as well as small cracks, are easily removable defects

2. Moderate damage, indicated by cracks in the base that appear as a result of its displacement. To reveal how much the foundation subsidence is progressing, a layer of putty is applied to the problem area. A crack that appears at the slightest deformation can tell about the rate of deformation, as well as its nature and direction of displacement.

   Cracks whose propagation has stopped at the initial stage can be sealed with mortar

3. Significant or catastrophic damage resulting from significant subsidence, displacement, or failure of the foundation. They are revealed in the violation of the geometry of the walls, the appearance of large gaps between the crowns, and the warping of windows and doors. Problems of this kind lead to the impossibility of operation or complete destruction of the house, so urgent reinforcement or replacement is necessary.

   If deformation of the foundation can lead to complete destruction of the building, repair work should begin immediately

4. Irreversible consequences. If the moment is missed, then repairing the house will most likely be unprofitable. In this case, a decision is made to demolish the building and build new housing.

After carefully analyzing the nature and extent of destruction, a decision is made on how to reconstruct the foundation. If deformations can be eliminated and prevented in the future, then the foundation can be strengthened. Otherwise you will need it complete replacement.

In some cases, it is not practical to renovate a house - it is easier to build a new one

Strengthening or replacing the foundation may be required not only when it is destroyed. Reconstruction is also carried out in cases where there is a need to build a superstructure on the house, and the existing foundation is not designed for increased load.

How to repair the foundation of a wooden house yourself

Several types of foundations are used in the construction of wooden houses, so we will select the most common cases and consider the most effective and popular restoration methods.

Repair of strip foundations

Small single cracks that appeared due to sedimentary changes in the soil under the house can be repaired with mortar (provided that the process has stopped and the base of the building has found new support points). To do this, the foundation is dug to the entire depth of the defects, the cracks are cleaned and filled with a sand-cement mixture.

Strip foundations are often used in the construction of wooden houses

Serious damage requires thorough restoration work. Most often, a new reinforced concrete structure is erected next to the old foundation strip, which is combined with the existing foundation using grooves and rods. Due to the fact that the repair structure is built on a stable cushion, as well as due to the redistribution of the load over a large area, it is possible to completely stop the deformation processes and return the foundation to its former solidity.

A groove (colloquial groove) is a recess, groove or groove in a monolithic concrete base, which is intended for laying cables and other utilities, as well as embedding reinforcement elements in order to strengthen or combine reinforced concrete structures.

Repair of uniformly subsiding strip foundation

In the case when the subsidence of the house occurs evenly along the entire perimeter, work to strengthen the strip foundation is carried out in the following order:

1. A trench is dug along the perimeter of the building, which covers the old foundation to its entire depth. The width of the pit is chosen so that it is possible to work comfortably. In addition, it is necessary to take into account the increase in the thickness of the foundation during restoration activities.
   

   If the subsidence is caused by miscalculations in the design or mistakes made during the construction of the foundation, then the supporting structure is built taking into account previous mistakes. Perhaps the building began to sag due to the high groundwater level, which was not taken into account at the stage of its construction. In this case, the bottom of the repair trench should be below the freezing point of the soil.

2. Thoroughly clean the concrete surface from soil residues. Remove crumbling fragments of brick or rubble masonry.
3. The bottom of the pit is carefully compacted and covered with a layer of crushed stone 10–15 cm thick.
4. Holes are drilled in the old foundation to install the rods. It is best if the reinforcement fits into the holes made with a slight interference.

   Strip foundation repair technology

5. Individual boreholes (in a checkerboard pattern) are drilled to expand their entrance hole to a diameter of 100 mm to a depth of 100–150 mm. During the process of pouring the foundation, concrete will fill these voids, combining both structures into one.
6. Create a reinforcement belt. To do this, the driven rods are welded to a three-dimensional reinforcement grid.
   

   To strengthen a reinforced concrete base, it is best to use not welding, but connecting rods using knitting wire. Such fastening is much easier and faster to make, and its elasticity will avoid damage and displacement of the reinforced belt during concrete pouring.

7. Formwork is installed along the outer contour of the trench, for which any suitable lumber is used - boards, bars, wooden panels, etc. Before pouring concrete, the walls of the structure are covered with plastic film.
8. It is best to pour concrete gradually - in sections 1.5–2 m long. This will allow the solution to better penetrate into the grooves and fill all the voids and defective areas of the old foundation. To do this, a shield is made, which is installed across the formwork.
9. After the structure is filled and the concrete has set, the timber structure is removed and the foundation is waterproofed.
10. The remaining space is filled with soil. Of course, you should add soil gradually, adding a new portion of soil only after the previous layer has been thoroughly compacted.

    The repaired foundation will extend the life of the old wooden house

To drain water from the foundation, a concrete blind area is made around the house. If the site suffers from excess moisture, then the base of the building is protected with drainage, which can be installed in parallel with the repair work.

Repair of individual sections of the foundation strip

If individual corners or small sections of the foundation are damaged, then spot repairs can be dispensed with. It is performed in the following sequence:

If an inspection of the base reveals its weakening along the entire perimeter, then the structure can be strengthened using a narrow (15–20 cm) encircling reinforced concrete clip. It is concreted using an anchor ligament with the foundation, using reinforcement and formwork.

Replacing an old foundation with your own hands

If the foundation is destroyed or has sunk so much that it cannot cope with the functions assigned to it, then it is completely replaced. The log house does not weigh that much, so it is quite possible to do without a truck crane. To raise the walls to the required height, hydraulic jacks with a force of 5–10 tons and supports from logs or metal structures are used.

To avoid mistakes during repairs, work is carried out in stages.

1. Determine the weight of the building. To do this, the total cubic capacity of the log house is multiplied by the specific density of the wood from which the house is built. Based on the calculations, a decision is made about what lifting mechanisms will be needed and their quantity is determined.
   

   You can lift a small, light house without jacks at all, if you use a pole - a long pole with a cross-section of at least 80x80 mm. One of its edges is placed under the corner of the building and rested on a round deck, and the second is used as a lever.

2. To reduce pressure on the foundation, bulky items and equipment are removed from the house. In some cases, the floor and stoves are even dismantled. Naturally, if the heating devices are installed on separate bases, then there is no need to disassemble them.
3. Using wooden beams and boards, window and door openings are carefully strengthened. This will prevent distortion during the lifting of the building.
4. A wide trench is dug around the perimeter of the house. It will provide access to the foundation and provide convenience when replacing it.
5. The old rubble or brickwork of the base is dismantled in small areas 0.3–0.5 m long - jacks will be installed in these openings. For small houses It is enough to place lifting mechanisms only in the corners, while massive buildings will require additional supports in the middle of each wall.

   To distribute the load on the jacks, you can use a powerful angle or channel

6. Install jacks. To prevent subsidence of lifting mechanisms, they must rest on a solid, reliable foundation. Plates made of thick steel or pieces of springs from a heavy truck, which are placed under the lower crown, will help to avoid damage to the log house.
7. Slowly and carefully they raise the house. It is important that all corners rise as evenly as possible. To protect yourself in case of insufficient load-carrying capacity of the jacks or their displacement, wooden wedges are inserted between the lower rims and the foundation cushion. Spacers should be increased every 15–20 mm.
   

   When lifting a wooden house, the main force falls on the lower crowns. To prevent them from sagging, the logs are tied together with a steel hoop or reinforced with boards and bars.

8. Next to the jacks, as well as in other accessible places, temporary supports made of channel bars or powerful steel angles are placed under the frame - they will help unload the old foundation.

   Any suitable materials can be used as temporary safety supports.

9. The house is lowered, after which they begin to dismantle the damaged foundation. At the same time, you should not save money and dismantle only the damaged areas - a partial replacement will not significantly reduce the cost of repairs as it will weaken the new foundation.

   Dismantling the old strip base

10. Having reached the ground, it is excavated to a depth of 15–20 cm and a sand-crushed stone layer is created. The pillow is thoroughly spilled with water and compacted.
11. Construct corner and intermediate supports. They can be metal, reinforced concrete, stone or brick columns.
12. Reinforcement is installed and formwork is arranged. The wooden structure is made in such a way that it can combine the reinforced concrete base with the previously installed columns. To avoid leakage of the solution, the inside of the formwork is covered with plastic film.

    The formwork for the new strip foundation is constructed according to all the rules - with reinforcement and protection against leakage of cement laitance

13. Concrete is poured into the established form. The solution is compacted by bayonet, using a vibrating screed or manual rammer.
14. After the concrete has completely set, the formwork is removed and the structure is left open for another one or two days for the solution to dry completely.
15. Several layers of waterproofing are applied to the concrete surface, and the top of the foundation is covered with roofing felt. This material will prevent the spread of moisture from the base to the lower crown.
16. The gap between the foundation and the side wall of the trench is filled with soil, which is thoroughly compacted.
17. Slowly and evenly lower the house onto the new foundation.

    On a new foundation, a wooden house will stand for more than a dozen years.

After completion of the repair work, a blind area is built around the house and the surface part of the foundation is lined.

Features of leveling a skewed base

If uneven shrinkage is observed, and the foundation tape has sagged and skewed, then a jack or a wagon is also used to repair and level it. The first thing they do in this case is to determine whether the deformation processes have stopped or whether the subsidence of the foundation continues. For this purpose, the already known beacon method is used. Based on the experiment, a decision is made on the repair method:

• with strengthening the foundation using additional reinforced concrete tape;
• increasing the sagging part of the base to a new height.

In order to restore the straightness of the surface in the first case, a trench is dug on both sides of the sagging corner. Its length should be such as to cover areas where the upper part of the foundation has deviations from the horizontal. After this, the building is raised to a height of 15–20 mm above its original position, after which a repair foundation is installed next to the problem area.

You can level the foundation using brick or stone masonry

Leveling “horizontally” is carried out using brickwork and is regulated by a layer of mortar, into which pieces of steel reinforcement, crushed stone, etc. are laid. The repair is completed with waterproofing work, after which the trench is filled up and the house is lowered into place.

If the shrinkage processes have stopped, then there is no need to dig a pit. The building must be raised and the surface of the sagging section of the foundation must be brought to zero. For alignment, use the method discussed above.

Repair of columnar or pile foundations

Owners of wooden houses installed on a columnar foundation may eventually encounter certain problems:

• the tilt of individual pillars due to heaving of the soil, and, as a consequence, the tilt of the building towards the defective columns;
• subsidence of supports, which led to skewed walls or excessively close location of the lower crowns to the soil.

Such problems require strengthening the foundation and replacing individual supports. One of the most effective and at the same time simple ways is the installation of bored piles.

Foundation repair scheme using bored piles

The house is raised according to the method described above (to restore the strip foundation) and rigidly fixed in order to relieve the load on the support columns. The defective pole is dug in and removed. After this, the pit is expanded to dimensions of 400x400 mm (for columns with a diameter of 200 mm), deepened 0.3–0.5 m below the base of the old support and prepared for installation of a new pile:

An intact, skewed column can be straightened. To do this, a tunnel is made from the side opposite to the direction of inclination, the pile is installed vertically, and the space around it is filled with concrete.

What can you do to avoid future damage?

The reliability and durability of the foundation depend not only on its design and compliance with climatic conditions and soil characteristics, but also on proper hydro- and thermal insulation.

The cause of most problems associated with foundation subsidence are errors associated with choosing the depth of its underground part. Foundations whose base is below the soil freezing level require restoration or restoration work much less often than shallow foundations. At the same time, certain types of soil (for example, peat) require reclamation measures or the excavation of unsuitable earthen soil and subsequent replacement with imported soil.

An important detail on which the safety of the foundation depends is proper waterproofing. Since the foundation is affected not only by wet soil, but also by atmospheric influences, the waterproofing system must be ensured by:

• wide blind area;
• vertical and horizontal waterproofing;
• effective drainage.

For wooden houses without basements, only horizontal protection against moisture penetrating into the wood will be sufficient.

High-quality waterproofing will protect the foundation from the damaging effects of moisture

For these purposes, Bicroelast, Akvaizol, Bipol and other rolled materials are used, which are laid between the foundation and the lower crowns. Waterproofing is laid in 2-3 layers along the edge of the foundation.

Vertical waterproofing prevents moisture from penetrating into the basement of a wooden house. It is applied both to the outer surface of the foundation and on both sides. In this case, insulation work is carried out in several ways:

• installation of roll or film materials on a layer of mastic;
• coating the surface with a bitumen-rubber or bitumen-polymer mixture;
• installing geotextile membranes or arranging waterproof locks using bentonite clay panels;
• applying penetrating cement-polymer compositions.

Special attention is paid to the drainage system - it should ensure water drainage no closer than 2–3 m from the extreme point of the foundation.

If the walls of the basement suffer from excessive moisture and fungi, then in addition to waterproofing, the base of the building is also insulated. For this purpose, special waterproof boards are used, which are glued to a layer of bitumen mastic and then sealed with plastic protective materials.

When choosing adhesive compositions for installing thermal insulation boards, you must ensure that they do not contain acetone or other chemical solvents.

Video: how to repair the foundation of a wooden house

In conclusion, I would like to remind you that work related to strengthening and replacing the foundation is particularly complex and risky. At all stages of construction, safety regulations must be observed and repair technology must be adhered to. Only in this case can you count on the fact that restoration measures will take place without unpleasant incidents and will give the wooden house a new life.

Lifting a house using jacks.

Over time, the building may shrink. This occurs due to violations of construction technology, natural aging, geological and climatic conditions. Raising a house and replacing the foundation is a fairly common option for major renovations. There are other ways to restore the integrity of the base of the building. Before starting work, the main thing is to correctly determine the degree and cause of shrinkage of the building. Sometimes it is required to change the entire structure of the base under the house.

The most popular method of replacing a foundation is raising the house on jacks. They may need from 2-4 to 10-12 pieces. Raise the building by installing jacks on both sides of one wall. Lifting diagonally is unacceptable.

In one go they reach a height of 1.5-2 cm, no more. Temporary supports are immediately inserted into the resulting space. Additional jacks are installed in places where the lower edges of the frame deflect.

Another method involves removing a layer of soil under the house, 200-250 mm thick. After this, the wooden crowns are replaced and the foundation of the house is repaired.

Methods that are labor-intensive and require special skills include complete dismantling of the walls for a convenient approach to the foundation. After this, the base structure is repaired or completely replaced. Then the walls are reassembled, replacing rotten and deformed elements.

If the wear is minor, cosmetic repairs may be sufficient. This is the cheapest restoration method.

What type of base to choose

It happens that the old foundation has failed and needs to be completely replaced. Before replacing the foundation under an old wooden house, you need to decide which type of foundation is best suited for the given geological conditions and type of construction.

Types of foundations and their characteristics are presented in the table:

1	Tape	It is a monolithic or prefabricated concrete strip that can withstand significant loads. For small wooden buildings, a shallow foundation is sufficient. But if the site is dominated by heterogeneous soil or water-logged soil prone to frost heaving, then you need to choose a different type of foundation.
2	On screw piles	Screw piles are driven into the ground. They can be combined with a grillage or operated without it. This is an inexpensive type of base that can be quickly installed with your own hands. Suitable for light buildings built in areas with differences in relief, deep levels of ground freezing, and small flooded areas.
3	On bored piles	Allows you to reduce land work. It consists of wells filled with cement mortar, interconnected by concrete beams or a slab.
4	On brick, stone, concrete pillars	The pillars are mounted in increments of 1-2 m; installation is required at the points of intersection of walls and in other places with a maximum load-bearing load. Is a reliable support for small light buildings.

The type of foundation for a wooden house is chosen depending on many factors. If it is difficult to make a decision and calculate all the loads yourself, it is better to turn to professionals who will help you make the right choice.

Foundation replacement

Replacing and repairing a foundation will require some knowledge and patience. In order not to completely destroy the building, you need to do the work slowly, strictly adhering to the technology.

Jacks can be rented from the railway depot; they must be designed to lift loads weighing 10 tons.

Bricks, strong beams and boards can be used as backing elements.

Before raising the house, lighten its weight as much as possible. They dismantle the floors, take out furniture and all household items.

Under the jacks, a base is made in the form of a square of wood with sides measuring 50 x 50 cm.

Calculations

To new foundation has served as a reliable basis for the building for a long time; its parameters must be correctly calculated.

When calculating, you need to take into account:

• soil freezing level;
• proximity to underground sources;
• seismic activity;
• relief of the site;
• soil type;
• a lot of housing construction.

The foundation is buried at least 500 mm under load-bearing walls, and at least 400 mm under partitions.

Raising a house with jacks

They make a platform for jacks. Install it slightly deeper into the ground, at a distance of 50 cm from the corners of the building. The jacks are secured to a wooden stand.

The beams act as support elements to support the structure of the house.

Simultaneously, both sides are lifted to a height of no more than 2 cm in one go. Jacks are placed in places where the wood has not lost its strength. Lifting devices cannot be installed in rotten areas.

To properly transfer the load to the logs, it is necessary to provide for the installation of metal plates that perform the function of a gasket.

Immediately place strong backing elements into the resulting gap. Raise all the walls one by one until the desired height is reached. They check the stability of the building; it should not be mowed. Firmly fix the desired level by installing support elements.

Dismantling the old foundation

After raising and securing the wooden house, the foundation is repaired or dismantled. These works are quite easy to do with your own hands; you will need several assistants and simple tools: a crowbar and a sledgehammer.

If you carefully dismantle the old foundation, the remaining intact materials can be used for further construction work.

What you need to know

The degree of shrinkage of a house depends on the type of soil and the level of location of underground sources. If they are close to the surface, you need to provide a drainage system around the perimeter of the house.

If the soil is prone to landslides, it is strengthened. To do this, fill the area around the foundation with a mixture of liquid glass and water or drill small wells and pour resin into them.

If The groundwater are close, winter soil heaving will be significantly higher. Freezing groundwater increases in volume and pushes everything in it out of the soil. When melting, the volume of water decreases and shrinkage occurs.

Installation of foundation on screw piles

If you decide to build a new foundation on screw piles, you need to calculate their length and diameter. You should not skimp on material, since the reliability and safety of your home will depend on its quality.

To construct the foundation of a small wooden house you will need 8-12 screw supports.

Step-by-step instruction:

1. After raising and securing the house building, I-beams are laid under its load-bearing walls and partitions. They are cut 5-7 cm longer than the estimated length. In the future, they will serve as a grillage.
2. In pairs, at a distance of 300-400 mm from the walls, screw piles are screwed in, which are the support for the beams. Make sure that the structures are positioned clearly in level.
3. To add strength and protect against corrosion, the pile cavity is filled with concrete mortar.
4. A head is placed on the upper edge of the support, and the grillage channel is attached to it.
5. Dismantle the old base.
6. They carefully lower the house.

Raising the house.

The columnar foundation is mounted using the same technology as the installation of a screw foundation. The only difference is that you need to dig wells for the pillars, which are subsequently filled with concrete or laid out with bricks.

Installation of strip foundation

They prepare the site, remove construction debris, plant root systems, and sweep away dust.

Instructions on how to change the foundation of an old wooden house with your own hands:

1. They dig a pit below the freezing level of the soil and below the location of the old foundation. The shape of the trench should be U-shaped so that it is convenient to remove the reinforcing frame and make its bundle.
2. Pour sand onto the bottom in a layer of 150 mm. Moisten and compact. Pour a layer of crushed stone and compact it well.
3. Metal rods with a cross-section of 12-16 mm are tied into two longitudinal rows connected by vertical jumpers.
4. Formwork is made from boards; it will serve as a form for pouring cement mortar.
5. Concrete solution is poured. At the same time, openings are provided for installing jacks to lower the building.
6. After it has completely hardened, the formwork is dismantled.
7. Temporary supports are attached to the poured foundation. Work is beginning to replace the foundation on the other side.
8. Openings for jacks are filled with bricks.
9. Check the integrity of the lower crowns and floor boards. If there is any damage, the damaged elements need to be repaired. Rotten and damaged areas are cut out and replaced with new ones.
10. Work is being carried out to waterproof the foundation and basement of the building.
11. Smoothly and carefully lower the house onto the new foundation.

There is another technology, according to which support columns are first poured at the corners of the house, and then, after drying, the house is supported on them and a concrete strip is installed around the entire perimeter. All other stages correspond to the sequence described above.

You can watch the video to see how to restore and raise a house:

Replacing the foundation is a job of increased complexity. You need to realistically assess your strengths and skills in performing construction work. If a mistake is made, workers may be injured or the building may be destroyed. If you lack strength and knowledge, it is better to hire professionals with experience in this field.

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Any reliable and durable wooden house will eventually need major repairs. If technology violations were committed during the foundation of a new house, then the likelihood of large-scale restoration work increases significantly. An incorrectly created foundation affects the balance of window and door openings and contributes to cracking of walls.

When such “bells” arise, urgent action is required. Replacing the foundation is the most rational method, but it is important to pay attention to the following aspects:

• If you do the work yourself, you will need specialized tools, so you should take care of this in advance to find a complete set;
• after the old foundation is dismantled, it is necessary to install more solid foundation another type (this hard work, so professional help may be required);
• it is worth making sure that the house itself will still serve for a long time.

What does strength depend on?

The condition of the foundation is significantly influenced by changes in the soil, in particular its load-bearing characteristics. They occur mainly due to exceeding the permissible load on the foundation and subsequent loosening of the earth underneath it. The overall load is increased by outbuildings located nearby. This leads to distortion and subsidence of the main structure, since the soil is pressed under significant weight.

Replacement of the foundation may be necessary due to erosion of the soil due to rising groundwater or improper drainage of water.

Reduced strength of the base material is another negative factor. This is possible due to incorrect determination of the freezing depth, inappropriate type of foundation, and the use of low-quality materials.

Selecting a base

It is important to understand that replacing the foundation of a wooden house should be done after all preparatory work has been completed. First you need to choose the design of a new base. Belt type Ideal for large, heavy buildings. The screw base will perfectly withstand the type of construction country house. Among the advantages, it is worth noting the possibility of application in any area. Also, screw piles are distinguished by the possibility of repeated use and relatively low cost.

The columnar base is used for medium-sized houses. Despite its apparent simplicity, it has become widespread due to its reliability. The design consists of several pillars installed at the junctions of the walls - these are the areas with maximum load. Pillars are made of stone, concrete or brick. It is worth noting the need for a mandatory step of 1-2 meters. A bored pile base also refers to a columnar foundation. It got its name because asbestos cement pipes, used as load-bearing elements and filled with a specialized mixture. Soil with a high water level is the optimal place for such a base.

The above-mentioned house foundation, the replacement of which involves the use of piles, is also in demand. It requires less investment, and in the end its strength is comparable to a concrete base. The piles are screwed into the ground using levers. Their level must exceed the freezing depth. Alignment to a certain height and the use of a belt made from a channel beam are required. This type of base is suitable for subsidence and weakened soil types.

Subsidence of the base

Subsidence may be progressive or temporary. Special beacons made from different materials. It is worth considering that if water gets on paper versions, they become unusable. Plaster plasters are also used as beacons. If they are absent, you can apply an even strip of putty to the wall and make a mark, this way the places where the cracks are widening will be identified in time and the rate of destruction will be determined.

Equipment

Although the work is large-scale, you don’t have to resort to renting expensive equipment: several powerful jacks (at least 4) with a lifting capacity of about 10 tons will be enough. You also need to have auxiliary wedges, a crowbar and a sledgehammer at your disposal. To create a support, various logs, boards and a lot of bricks are required. Before installing the jack, a strong platform is knocked down, with sides of at least half a meter each. It will require a steel plate with a thickness of 6 mm.

Replacing the foundation under a wooden house means freeing it from heavy objects and furniture. Next, the covering is removed and the floor itself is dismantled.

How to lift

After completing the preparatory work, you can install the jacks. They are placed along the perimeter of longer walls, with a mandatory offset from the corners. Pre-designed sites must be stable (a small depression in the soil is possible).

It is worth paying attention to the fact that lifting a house and replacing the foundation with a pile is impossible alone. There should be one person per jack. Careful lifting of the building can only be achieved with this approach. The lifting height at a time should be no more than 2 cm. If gaps occur, prepared supports are used to close them. All actions must be performed simultaneously.

Significant sagging of the lower rims during the lifting process indicates a lack of jacks. But further actions must be as careful and precise as possible to avoid displacement of the structure.

Foundation replacement: dismantling

Once the house is raised and firmly secured, the old foundation is removed. Some items may be useful for recycling, so they should be folded separately. After dismantling, a deeper trench is dug in the shape of the letter P. Thanks to the use of this shape, it is possible to connect sections of the foundation laid at different times. If an extension is needed in the future, it is better to immediately lay the foundation for it, so that in the future there will be no need to replace the foundation under the house due to the increased load.

Completion of work

It will take about two weeks for the poured base to completely harden, then it is covered with boards and temporary supports made of brick or wood are placed on top. After replacing the foundation under the wooden house, it is repeated on the other side. Long sections of walls require digging straight short trenches and then joining them together using reinforcement.

After completion of all work, the lower rims are checked for quality and, if necessary, they must be replaced. Next, the building gradually lowers evenly on all sides, after which the replacement of the foundation can be considered complete.

A common problem with old wooden houses is high wear of the foundation. Such changes are visible to the naked eye: the house is askew, walls or doorways are sagging. If such problems are multiple in nature, it is necessary to urgently repair the foundation. The house is in danger of being destroyed if the work is delayed for another couple of years. For this reason, restoring the foundation is in many cases a pressing and important task. Before laying the foundation for an old wooden house, it is necessary to conduct an inspection and assess its condition. A thorough analysis will allow you to decide on further work.

Foundation inspection

When assessing the foundation, it is worth adhering to a certain technology. The foundation inspection is carried out as follows:

• a trench 50-70 cm wide is dug around the foundation;
• the foundation material is determined;
• inspected for damage.

Attention! In case of minor damage, you can do without replacing the foundation: it is enough to strengthen the existing foundation of the old house.

Types of foundation

After inspecting the old base, you need to decide what type the new one will be. The choice of design depends on many factors, such as the type of soil and the weight of the house. As a rule, the following types of foundations are used in the construction of wooden houses:

• stone (usually brick) - brick is an inexpensive material, but it is destroyed by moisture;
• reinforced concrete - the most durable of all types of foundations, it can be strip and monolithic;
• pile - a foundation constructed of metal piles is very practical and quickly erected;
• wooden - oak columns (blocks) are placed along the perimeter of the foundation; such a base is very susceptible to fungi and moisture.

The modern variety of materials makes it possible not to use outdated types of foundations in construction. The most practical and durable options are reinforced concrete and pile foundations. Some foundations can be properly strengthened.

Lifting the house

When the question arises: “how to make a foundation for an old house?”, you immediately need to decide how to raise the house. These works are carried out regardless of the type of future foundation of the building.

Preparatory work

To raise an old house, it is not necessary to use expensive special equipment. The most democratic option is jacks. To determine the load capacity and number of jacks, you need to calculate the approximate weight of the house. All furniture and household items are removed from the building - this will lighten its weight.

The work will require a large number of wooden or brick support pillars; they are prepared in advance. The height of the supports should correspond to the height of the future foundation. The number of supports depends on the length of the walls. To regulate the minimum difference in the height of the supports, you will need pads; the best option is boards.

During the lifting process, the lower crowns of the house are the most vulnerable place. To protect the logs from scattering and cracking, they are fastened with metal staples. If the house structure has an old foundation, it is necessary to destroy its outer foundation, approximately 50 cm along each side. This is done for further installation of jacks. To figure out how to add a foundation to an old house, it’s worth knowing all the intricacies of raising a building.

Installation of jacks

Jacks exert very strong pressure on the logs, so they are installed on unbroken logs. Installation of jacks is carried out as follows:

• under the place where the jack will stand, place a strong support in the form of sheet iron, thick plywood or a timber base (size 50x50 cm);
• The most sagging corner of the house is determined and a jack is installed under it, on the prepared support;
• install jacks at subsequent corners.

Note! Raising an old house with your own hands is problematic - for safety reasons the work is carried out by 2-3 or more workers.

Lifting process

The lifting of the house begins from the most sagging corner. All actions are performed very smoothly so as not to damage the walls of the house. In the first approach, a lift of 2 cm is performed, this will prevent cracking of the walls. Wooden blocks or planks are placed in the resulting gap.

When the first corner is raised, the subsequent ones are raised one by one to the same height. Supports in the form of planks are laid along the entire perimeter. The lifting is carried out gradually, placing supports in the gap to lighten the load on the jacks.

After the house is raised to the desired height, brick or wooden supports-pillars are installed. Just like for jacks, support platforms from solid material should be prepared for support pillars. Only after this can you begin repairing the old foundation.

The entire process of raising the house is completed within 24 hours. The last stage is preparing the site for the future foundation. If the house is dilapidated, it is raised with extreme care.

Destruction of the old foundation

After raising the dilapidated house, they begin to destroy the old foundation. The traditional and less expensive way is to work with a sledgehammer and wedges. Wooden stakes are driven into seams or cracks in the foundation using a sledgehammer. To destroy the remaining cement elements, a hammer drill and a crowbar are suitable.

A shovel is used to remove the resulting debris. After the foundation of the old house is destroyed, they begin to prepare a place for a new foundation.

Important! As the destruction of the base of the building progresses, brick or wooden supports are installed along the entire perimeter.

Pouring strip foundation

The most reasonable option for one-story wooden buildings is a strip reinforced concrete foundation. It is suitable for any type of soil. The construction of such a foundation is carried out as follows:

• Digging a trench. The basis for the new foundation should be 10-20 cm wider than the previous one. If in the future it is planned to build other buildings on the site, the foundation should be poured for them as well;
• A U-shaped trench is created under the longest walls;
• The first layer of sand (10-15 cm) is placed in the trench;
• The next stage is the installation of a frame made of reinforcement;
• Formwork assembly;
• Laying waterproofing inside the formwork;
• Pouring the solution.

After the solution has completely hardened, boards are laid on one section of the foundation, on which temporary supports are laid. All sections of the base are poured one after another. The reinforcing mesh of each new section of the foundation is connected to the outlets of the rods of the previous sections.

With another method of constructing a foundation, the corners of the structure are poured first. Limited sectors are created in the formwork at the corners of the proposed foundation. They are poured first. After the solution has hardened, fill in all remaining areas of the base.

After pouring, the openings for the jacks are paved with brick or mortar. When the base has completely hardened, the lower logs are re-inspected and replaced if necessary. The final stage of work is installing the house on the foundation: the work is carried out smoothly, gradually lowering the structure by 3-5 cm.

Replacing an old foundation with screw piles

With the fast speed of work, installing a pile foundation takes a day. This type of house foundation is quite suitable for sandy and marshy soils.

Before buying piles, you need to calculate the weight and area of ​​\u200b\u200bthe house and study the type of soil under it. The average bearing capacity of screw piles is from 5 to 14 tons, depending on the span of the blades and the diameter of the pile itself.

Work on installing the pile foundation is carried out as follows:

• raise the house using jacks;
• mark places for future piles (more number falls on the places of load-bearing walls and corners of the house);
• piles are installed manually or with the help of equipment (deepening of structures above the level of soil freezing);
• after screwing in all the piles, they are combined with a metal frame by welding;
• The final stage is installation of the house on a pile foundation.

To reduce heat loss and improve the appearance of the building, the structure is covered with bricks or decorative panels.

Results

To arrange a new foundation under your house, you first conduct a series of studies. They are aimed at determining the condition of the foundation. It is also necessary to know the intricacies of lifting a structure using jacks. They begin to lift from the more sagging edge. Care should be taken when working with the lower crowns. Experienced builders use brick as a material for temporary supports.

It is easier to replace a strip foundation than other types of foundations. It is necessary to competently approach the installation of formwork and pouring concrete. When installing a house on a foundation, it is also worth considering several features of the process.

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Sometimes owners of country houses are faced with the problem of subsidence of the foundation. This occurs as a result of changes in the underlying soil, construction work on the land or in the house itself. For example, the addition of the second or attic floor increases the load on the foundation, and if it was not designed for such a mass, it will begin to settle. In addition, improper installation of the base and lack of high-quality thermal and waterproofing lead to similar problems.

To avoid the problems listed above, it is important to choose the right materials, install and finish the base. Read here which foundation is suitable for a wooden house. For minor damage, cosmetic repairs can be made or the base can be strengthened. But if the structure has already begun to settle, cracks have appeared at the base or the walls are warped, a complete replacement of the foundation under the house is needed. Otherwise the building will soon collapse.

In the article we will find out when it is really necessary to replace the foundation under a wooden house, and when you can get by with a simple repair. Let's look at how to change the foundation of a house with your own hands, if necessary.

Types of foundation damage

• Minor damage includes peeling trim. These defects can be easily noticed and eliminated without problems. They do not affect the load-bearing characteristics of the structure, they simply violate the aesthetics of the appearance;
• Moderate damage includes cracks that appear due to structural failure and ground subsidence. Vertical cracks and cracks in the form of zigzags are considered the most dangerous;
• Severe damage includes a large number of cracks, fractures in the foundation and distortion of the walls of the structure. Then the foundation is strengthened or completely replaced;
• Irremovable deformation mainly occurs in old buildings and foundations. There is nothing left to repair here. It is necessary to completely dismantle the structure and build a new, high-quality wooden house in compliance with modern building codes and rules.

How to repair cracks in the foundation

Cracks at the very beginning of formation can be easily eliminated. Do not miss the moment and do not delay repairs, as the cracks will grow and increase. Then the damage will develop from moderate to severe. To determine the degree of danger of cracks, the rate of subsidence and the nature of destruction of the foundation, beacons are made.

Apply a little putty to a clean, dry foundation wall, use a spatula to draw a straight line and make a mark up to 5 mm thick. Such a beacon will break with any movement of the surface. Instead of putty, plaster plasters or plain paper are also used. But if the paper gets wet, it will no longer provide reliable results.

If the subsidence is temporary and does not pose a threat, the mark remains motionless. This means that the foundation has moved along with the soil and taken its place. In this case, cosmetic repairs of the cracks can be carried out. To eliminate the defect, the crack is widened, cleaned and sealed with a primer. The resulting seam is secured with cement.

Strengthening and strengthening the foundation

Strengthening the structure is used if there is deformation, but the soil is stable. In addition, the foundation needs to be strengthened if it is planned to add another floor. Strengthening will help the foundation cope and redistribute the increased load. Then the structure will not collapse and settle. Strengthening includes the following actions:

• A trench is made along the perimeter of the base. The surface is cleaned of soil, dirt, debris and dust;
• Drill holes whose diameter should be 1 mm larger than the reinforcement. Reinforcement is hammered into the holes;
• They make a reinforced belt. The reinforcement is welded to the installed pieces in several places, and secured with wire in the rest;
• The formwork is installed and the concrete mixture is poured. After it hardens, the formwork is removed. The structure is then left to dry for another two to three weeks. While drying, cover the surface with film and periodically water it with water.

After installation, waterproofing and a drainage system are made. To do this, along the perimeter of the foundation in the interval of 70-100 centimeters, you need to dig a trench 20-30 centimeters wide. The depth of the trench should not be lower than the concrete pouring level. Geotextiles are placed at the bottom with an overlap on the walls. Gravel is poured on top and a drainage pipe is installed. The angle of inclination of the pipe is 5 mm per 1 m.

The pipe is covered with gravel from above, the protruding edges of the geotextile are wrapped and rammed with earth. The drainage pipe will collect water in the future and divert it from the house to a pit or a special well. To enhance waterproofing, you can cover the outer walls of the foundation with protective solutions, plaster, bituminous mastic or primer and liquid rubber.

Waterproofing can be done before installing the foundation. To do this, roofing material is laid at the bottom of the pit and formwork, the joints between the materials are coated with bituminous mastic. High-quality waterproofing will prevent the appearance of cracks and distortion of the walls. In addition, without proper protection, the basement and first floor will be cold and damp.

At the end of the work around the house and the foundation, blind areas are made to divert water from the building. They will prevent flooding of the basement and building. The blind area is a horizontal strip 60-120 centimeters wide, which runs along the perimeter of the house at a slight slope. The path is made of concrete, crushed stone, paving slabs or stone paving stones.

Partial and complete foundation replacement

Replacement of the foundation is resorted to in case of serious defects and destruction of the structure. In case of partial replacement and cosmetic repairs, part of the structure is dismantled, the deformed element is removed and a new one is inserted. This dismantling can be done independently, but it is not suitable for every type of base. For example, a reinforced concrete strip foundation or a monolithic slab cannot be partially disassembled.

Partial dismantling also requires lifting the house and using special equipment. Therefore, the cost of work will not decrease significantly compared to the complete disassembly of the foundation. At the same time, partial replacement reduces strength and reduces the operational life of the base. In addition, it violates the integrity of the structure. Therefore, experts recommend resorting to the method of completely replacing the foundation.

Complete replacement of the base is a complex job that is difficult to do on your own. It includes lifting and lowering the house, dismantling the old and installing a new foundation. Let's look at how to properly raise the building and how to replace your foundation under a wooden house.

Technology for raising a wooden house

To raise a house from a bar or log, you will need at least four jacks with a lifting capacity of 10 tons each. Before starting work, check and evaluate the corners of the building. It is important that the log house does not fall apart when moving. Window and door frames are removed from the house, furniture and other items are pulled out. It is important to leave the room empty. To prevent damage to the roof, the chimney is separated from the ceilings.

A trench is made around the house to simplify access to the foundation. Jacks are installed along the long walls of the house at a distance of 0.5 meters from the corners of the building. A solid platform with parameters of 50x50 centimeters is made for each jack. The bases can be recessed to prevent equipment from slipping.

Temporary supports are installed in the corners of the house and where walls intersect. The materials used are timber, logs or brick. The log house is lifted simultaneously with support on the lower crown of logs. To prevent the lower crown from bending, it is tightened with a steel hoop. Or, when lifting at the bending point, use another jack.

The first rise should not exceed two centimeters. The structure is installed on temporary supports, then the house is raised another 1.5-2 centimeters. Thus, the frame is gradually raised up to 10-15 centimeters and securely fixed on temporary supports.

How to dismantle the old and install a new foundation

To disassemble the foundation from cement mortar or rubble materials, wooden wedges are hammered into the seams of the base. To work, you will need a hammer drill, sledgehammer, crowbar, hammers and other tools. The structure must be dismantled down to the ground.

After dismantling the old foundation, they begin to install a new one. The space is cleared, a bed of gravel and sand is made, formwork and reinforced lattice are installed. The formwork is poured with concrete and waterproofing material is laid on top in several layers. Roofing felt is good for this. During work, make sure there are niches for jacks to lower the house safely.

The log house is lowered smoothly and gradually also by 1.5-2 centimeters. After this, the foundation is finished, which includes the installation of waterproofing and insulation, cladding, drainage and blind areas. Niches for jacks are sealed with bricks.

Replacing an old foundation, raising and lowering a house, and installing a new foundation is a labor-intensive and dangerous process. It is important to carry out high-quality work and follow safety precautions. To get a reliable and solid foundation and avoid problems during construction work, contact professionals!

Masters of the MariSrub company will qualitatively and quickly replace the foundation, install a new foundation for a wooden house, select materials and finish it. We carry out waterproofing and insulation, organize a drainage and blind area system. As a result, the foundation will last a long time!

Houses built of wood several decades ago, thanks to modern building technologies, have the right to a new life. Especially if such a building requires replacement of the foundation.

Often the reasons for the need for such work are:

• Natural shifts and subsidence of soil;
• Illiterate performance of any land work on the site, which leads to a violation of the integrity of the foundation of the house;
• Ignoring waterproofing work when installing the initial foundation;
• Violation of construction technologies;
• Depreciation of the initially created foundation over time, especially if it was a pile frame (the metal in this case undergoes changes over 4-5 decades and may lose its integrity).

Important: a clear sign that the house needs a foundation replacement is the appearance and increase of cracks in the outer part of the base, cracks on one of the walls of the house, the departure of door jambs and window frames from their “habitable” places.

Methods for performing repair work

• Frame cosmetic update option. In this case, only the damaged part of the base is dismantled and sealed with new building materials. Although this method of repair is economical, it is still not reliable. After all, internal changes in the foundation design still take place. And in this case, the structure of the house may be completely destroyed over time.
• Dismantling the walls and then replacing the base. This is the most time-consuming and expensive repair method. You definitely can’t cope here alone and with your own hands. Not only will you have to invite helpers to dismantle the house, but you will also have to pay them for reassembling the building.
• A method of removing the top layer of soil with subsequent renewal of the foundation crowns. Not a particularly popular method, because if you really use it, then it is better to completely replace the frame.
• An option for lifting a wooden house using special jacks and completely replacing the foundation with a new one. This method is used more often than others, since it makes it possible to operate a wooden structure for more than a dozen years after repair.

Important: the last repair option takes a minimum of time and is highly effective.

Advice: before deciding to completely replace the foundation of the house, it is better to make sure that such work makes sense at all. That is, a wooden house must be suitable for further living in it; the wooden walls must be intact and not rotten. In addition, for a new foundation it is better to immediately provide a high-quality waterproofing system in order to extend its life to the maximum.

Types of foundations for a wooden house

Work to change the foundation under a wooden house should be carried out only when the building material is completely prepared. And for this you need to decide in advance on the type of frame. So, for wooden buildings the following are often preferred:

• Belt prefabricated or monolithic. This type of foundation is good for particularly heavy houses and calm sandy soils with low groundwater levels. The foundation can either be poured into prepared shallow formwork with mandatory reinforcement, or assembled from special concrete blocks.
• Pile foundation good if the wooden house has one level, and the terrain of the site or the composition of the soil on it is quite complex. An exception for a pile foundation is soil that is prone to horizontal movement. From the point of view of financial benefits, such a frame for a wooden house is the most economical.
• Columnar frame. This type of foundation for a wooden house is suitable if the building is made of lightweight panels or panels. Here the pillars do not need to be deepened too much into the ground. A height of 60-70 cm will be sufficient. In this case, it is important to place the foundation pillars at all corners of the building and under the points of intersection of the walls of the house. The distance from column to column should be in the range of 1-2.5 meters. If the soil on the site has highly located groundwater, then you can use bored piles, which are mounted in asbestos-cement pipes.

Important: columnar and pile types foundations require special care when installing them yourself. Otherwise, non-compliance with construction technologies will lead to vertical misalignment of the columns, which will lead to the burning of the house.

Execution of work: stages

Carrying out the entire repair process consists of four important stages:

• Lifting the building using jacks (depending on the length of the walls, you may need from 2 to 10 pcs);
• Dismantling of broken or sagging old foundation;
• Installation of a new foundation;
• Installation of a wooden house in place.

Let's take a closer look at the entire work process.

Lifting the building

To lift the house you need to use jacks, each of which can lift 10 tons of weight. In this case, lifting devices must be placed exclusively along the long walls of the building in such a way that the mechanisms recede 50 cm from the corners of the house. To operate each jack, one master operator will be required.

• Under the jacks you need to install a strong support platform (concrete slab) with a section of 50x50. For greater reliability and to eliminate the possibility of the machine slipping, the slab can be slightly deeper into the ground. And so that the metal rod of the lifting device does not damage the wood of the lower crown of the house, you can use a special metal plate-gasket under it.

Important: you need to lift the house only in a lightweight state. That is, if possible, you need to remove everything from it, including furniture and household appliances. If possible, you can dismantle the plumbing and also disassemble the wooden flooring.

• Bricks, cinder blocks, wooden logs or chocks can be used as temporary supports for a wooden house.
• The house must be raised from all sides at the same time. However, there is no need to rush. A one-time lift of the building should not exceed a height of 2 cm to avoid distortions or collapse of the structure.

Important: it is worth knowing that if the synchronism of the building’s rise is not observed, then with a discrepancy of only 1 cm at the level of the crown of the house at the level of the ridge, this difference will already amount to several cm.

• The house is being raised in stages. First, when lifting by 2 cm, it is necessary to place temporary supports and check the level of the building. Then they raise the house again, re-laying temporary supports. Thus, it is necessary to raise the building to a height of 10-15 cm, after which the building is installed on temporary pillars with mandatory dislocation at the intersection of the walls and in the center.

Important: if, when lifting the house, there is a bend in the lower log, then you should use another jack in this place.

Dismantling the old base

You can dismantle the old foundation with your own hands using tools such as a hammer drill, crowbar, chisel, and shovel. At the same time, do not rush to throw away construction waste. It may still be useful. To dismantle the old monolithic or rubble foundation, use the method of driving wedges into all horizontal and longitudinal fill joints.

Installation of a new foundation

Here, the nature of the construction work will depend entirely on the type of new foundation chosen. But it is worth knowing that installation should be carried out alternately for each side of the house.

Tape frame

In this case, a trench under the tape is dug around the perimeter of the building. Here it is worth taking into account the depth of soil freezing, but the optimal depth for central Russia is a strip frame depth of 60-80 cm.

Important: if it is planned to increase the area of ​​the house due to extensions, then it is necessary to form a trench for the foundation for new premises.

• The bottom of the trench is well compacted and covered with layers of sand and gravel, 10 cm each. These layers of the cake are also compacted.
• After that, formwork and reinforcing mesh are installed in the pit. At the same time, it is worth knowing that the rods at the corners of the foundation must only be bent for tying. It is forbidden to join reinforcement bars one to another in the corners of the house.
• Concrete is poured into the formwork with reinforcement and waited for it to dry completely.
• After one part of the poured foundation has dried completely, temporary supports are installed on it and the construction of the foundation on the other side of the house begins.

Important: when pouring the foundation, it is worth considering the space for the jack. In this case, it is left unfilled, and after the house is lowered, this part of the foundation is simply laid with bricks.

• Upon completion of the work, it is necessary to carefully waterproof the foundation and lower logs of the crown of the house with your own hands. After this, the remaining soil voids must be filled with soil and compacted well.
• As soon as the foundation is completely ready, the house is also gradually, synchronously and smoothly lowered into place.

Pile foundation

In this case, from 8 to 10 piles are used to construct the foundation. The works look like this:

• I-beams are driven under the already raised house, which will play the role of a grillage. They are located under load-bearing and external walls.
• Now the piles are screwed into the ground in pairs at a distance of about 20-30 cm from the outer walls of the building. The level of the piles in the horizontal plane is controlled so that they become supports for the grillage. Vertical piles are controlled by level.
• After installing the piles, their internal space can be filled with concrete mortar with your own hands for greater strength.
• The top of the excess metal is cut off and a head is welded onto it, on which the grillage will rest.
• Upon completion of the work, the old frame is dismantled, and the house is smoothly lowered onto the new foundation.

Important: a columnar foundation is installed according to the same principle, with the only difference being that instead of piles, pillars of the selected type (brick, monolithic, etc.) are installed in prepared pits.

Carrying out work to replace an old foundation with your own hands requires caution, professionalism and mandatory adherence to all technologies. Therefore, if you have even the slightest doubt in your abilities, it is better to invite specialists to carry out the work.