How to replace the foundation under a wooden house with your own hands

Both before and now, houses were built to last for many years, but over time, to increase their service life, some elements of the structure need to be repaired or replaced. The foundation is subject to a lot of stress and the foundation will usually be the first to need repairs.

Repairing the foundation of a wooden house is a costly and multi-stage event that requires taking into account the causes of destruction and the method of repairing the foundation. Having knowledge and timely detection of signs of destruction will greatly simplify the process and reduce recovery time.

Types of foundations for wooden houses

Wooden buildings and structural elements are especially susceptible to the influence of time, and every owner will at least once be faced with the need to restore or completely replace the foundation. Initially, an assessment is made of the general condition of the housing, its foundation, and possible ways to solve problems are determined. For the construction of wooden buildings, the following types of foundations are most often used:

1. Strip foundation. It is distinguished by a solid monolith and uniform load distribution. This type is highly reliable and wear-resistant.

2. Columnar foundation. The foundation is easy to construct and is used for utility buildings and light small houses, especially columnar wooden foundations . Vertical supports support beams that distribute the load evenly.

3. Pile foundation. Vertical elements of the base, if necessary, are made of different lengths, which is especially important in mountainous areas.

4. Monolithic foundation. It is advisable to install this type of foundation in areas of subsidence/movement of soil layers. The concrete solution is poured into the formwork, after hardening, forming a monolithic block. The most expensive type of foundation in terms of consumption of building materials.

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Today, many developers choose to build a columnar foundation for their home due to its low cost. In addition, such a foundation is built quite quickly - in just 1 day. Such a foundation is considered ideal for the construction of garden and country houses, light bathhouses, and residential buildings made of small timber on non-heaving soil. But there are times when a columnar foundation begins to quickly collapse, fall on its side or bulge. In such conditions, the only method of preventing further subsidence of the foundation is to replace the columnar foundation.

The need to replace the columnar foundation

Many rural houses that were built in the last century have a primitive columnar foundation as their foundation. Such an ancient structure consists of stands made of brick or stone, often quite dilapidated, unreliable and long outdated. They require immediate replacement with a stronger, higher quality and reliable foundation. The most important reason for the destruction of a columnar foundation is settlement, which naturally causes a change in the position of a wooden house, the appearance of cracks in the walls, and jamming of windows and doors.

This process occurs from various physical, mechanical and hydrological changes that take place in the lower soil and reduce its bearing capacity. The foundation actually ceases to perform the tasks assigned to it. Often, changes in soil properties are caused by construction work carried out on personal property. But such problems are not limited to old houses.

And when installing a new house on a columnar foundation, the latter very quickly begins to sag or sag and pull the house along with it. Especially when we are talking about large and heavy timber houses (9 by 9 meters or more) and cottages. In these cases, such a foundation is categorically not recommended, because there is a significant load, and here it is more rational to equip a pile-screw or strip foundation. It is also irrational to build a columnar foundation on heaving soil.

I would like to immediately make a reservation that this is most often not the fault of the craftsmen who carried out the construction. This is due to the phenomenon of soil heaving when it thaws after winter freezing. The ground thaws earlier on the south side of the house, pushing up the southern pillars, which end up on loose, crumbly soil, while the northern pillars stand in place on solid frozen ground.

Even if you dig 2 meters into the ground and pour concrete into asbestos pipes that are resistant to compression and bending, they will not be able to withstand soil heaving. All the same, the level of the columns along the horizon will be disturbed, and the house as a whole will become skewed. In this case, the foundation cannot be repaired and there is no point in trying to align the foundation pillars; you need to remember: if the blocks move at least once, they will change their horizontal position every year after winter, and it must be replaced as soon as possible.

In such cases, the only correct solution is to replace the foundation. This procedure is rightfully classified as a radical measure designed to restore the safety and reliability of the house, as well as increase its service life. However, it is worth remembering that it is advisable to replace the foundation for buildings whose structure can last for several decades after replacing the soil.

Methods for replacing a columnar foundation

As a rule, replacing a columnar foundation with another takes from 5 to 10 days, and the lifting of a residential building is carried out from below, which allows workers not to dismantle the floor, thus making the work easier. But replacing the base when the internal walls of a residential building are subsiding requires opening the floor covering to correct the defect.

There are several methods for replacing the foundation under a wooden building:

Cosmetic repair is the simplest technique that does not require large financial investments. In this situation, you simply need to cut out the rotten area and insert a suitable wooden element in its place. However, it must be taken into account that with such a partial replacement of the foundation, the integrity of the house is inevitably compromised.
Dismantling the walls is a type of construction work, which involves the complete dismantling of the walls, after which the lower crown of the frame is replaced. The method is reliable, but it requires a fair amount of patience and time from the craftsmen to disassemble and reassemble the structure.
Dismantling the foundation. To do this, you will have to remove a layer of 20 centimeters, replace the wooden crowns and then restore the foundation under the house.
Replacing the crowns by lifting the building with a jack is considered the most popular method, according to reviews of replacing a columnar foundation, as it allows you to replace the foundation efficiently and quickly.

Choosing a new foundation for a house

It is important to understand that the procedure for replacing the foundation of a house is a complex process that requires careful preparation. To begin with, it is worth deciding on the design of the future foundation, which will replace the old columnar foundation. There are the following types of foundations that are suitable for wooden houses:

A columnar foundation is a system of pillars that are installed in places of maximum load - the points of intersection of walls. The pillars are made of stone, concrete or brick and are installed at a distance of approximately 1-2 meters. It is adapted to support light residential buildings with wooden, frame or panel walls, which do not create significant loads on the foundation. Despite their simplicity, columnar foundations can be chosen to provide reliable support for a country house or garden house, as well as other outbuildings.
A bored pile foundation is a type of columnar foundation, only asbestos-cement pipes filled with a special mixture are used as load-bearing elements. The design of such a foundation consists of piles and a grillage that connects them. Load-bearing elements are located similarly under the most significant points of the house, for example, in places where main walls intersect and at the corners of the building. A bored pile foundation is considered optimal for buildings on soil with high water levels.
The pile screw foundation is considered the most interesting type of house foundation, as it was originally intended for military purposes. Today, such a foundation is widely used in civil engineering and is valuable because you can use it on any terrain, even on an uneven area with differences in height. In addition, the low cost of replacing a columnar foundation with a screw pile foundation and the possibility of repeated use of screw piles are additional advantages of such a foundation. The disadvantage is hiring special equipment.
The strip foundation allows you to build heavy houses and at the same time ensures high reliability and security of the house. The most popular shallow strip foundation can be monolithic or prefabricated. Prefabricated structures are made of concrete based on formwork, monolithic ones are made of reinforced concrete blocks and concrete.

Replacing a columnar foundation with your own hands

Of course, you can replace the old columnar foundation yourself, but you must be confident in your own abilities. In this case, you will need the information presented below, as it allows you to navigate the issue of replacing the foundation and control the situation.

Preparatory work

Despite the creation of a reliable foundation and the correct calculations when laying it, sometimes small cracks appear on the facade of a residential building, window sills, plinth and other horizontal lines are bent. This indicates subsidence of the house under the columnar foundation and requires immediate replacement of the foundation.

However, before starting work, you need to make sure that the deformation of the base has already stopped. To do this, install plaster beacons across the crack on a surface moistened with water. Observe these beacons for two weeks: if cracks do not form on them, then the deformation of the house is over, and you can safely begin replacing the columnar foundation with your own hands.

You can raise a house without special construction equipment; you just need to use hydraulic jacks, which are capable of developing sufficient force that allows you to lift a load weighing 10 tons. In their absence, it is not advisable to think about purchasing such equipment, since this equipment can be rented at any railway depot.

You will also need a steel crowbar, a sledgehammer, wedges - tools that are mostly needed to dismantle the old foundation. To create temporary supports, you can use massive beams, logs, bricks, as well as boards of various thicknesses that act as spacers. As a platform for installing a jack, you can use beams and boards knocked into a shield, or any durable material.

To evenly transfer the force from the jack rod to the lower crowns of the house, you will need to cut a steel plate that is at least 5 millimeters thick. If you have to work with a columnar base with a fence, then the latter will have to be disassembled before starting work. Also, at the preparation stage, it is recommended to remove all heavy things and furniture from the house and dismantle the floors.

Raising a wooden house

Raise the building using jacks. They are usually installed on both sides of the house at a distance of 0.5 meters from its corners. Jacks allow you to evenly lift the house, otherwise the logs of the lower frame will sag during uneven lifting, which will lead to their separation and subsequent breakage. The jack should be installed in places where the wood is not damaged by rot.

Remember that it is necessary to install shims in the form of steel plates so that the force is correctly transferred to the logs from the jack rod. Instead of metal plates, you can use pieces of wood. The jacks are fixed on a pre-prepared support platform; if necessary, they need to be buried in the ground to give it maximum stability.

The number of pieces of logs that are used to construct temporary supports depends on the chosen technology for raising the house. If you plan to raise the entire building at once, then the number of temporary supports should be twice the number of foundation pillars. The support is assembled from pieces of logs, like an ordinary well

The height of the supports should be 10-15 centimeters greater than the difference in distance from the soil surface to the height of the jack, because when the house is raised, the supports will settle and be pressed into the ground. If possible, raise the house on both sides simultaneously, evenly, no more than 1.5-2 centimeters at a time. The result obtained is immediately fixed with temporary supports.

If you find kinks in the lower crowns as a result of lifting the house, you should install additional jacks. At this stage, it is recommended to control the process so that the house does not move to the side, because its center of gravity will change when lifted.

The wall must be raised to a height of at least 6 centimeters, the rotted extensions must be removed and the structure lowered onto scraps of beams that are placed on temporary supports. Between the logs and beams, tow is laid, which is treated with an antiseptic, in a width that is equal to double the thickness of the beam. 10 centimeters of brick and gravel are poured under the proposed base tape.

Once you have raised the house to a sufficient height and it is securely supported with temporary supports, you can begin to dismantle the old columnar foundation. You need to break rubble and brickwork using chisels, a crowbar and other tools that are easy to use. Old pillars are dug or pulled out of the ground, swinging them in different directions. Some of the materials that have retained their quality indicators can be used to form a new base.

Construction of a new foundation

Let's consider replacing a columnar foundation with a shallow strip foundation, which is best suited for one-story houses. As the name suggests, this type of foundation is considered a cross between a non-recessed and a solid recessed strip foundation. It consists of monolithic strips of reinforced concrete that run along the perimeter of a residential building and in places where load-bearing walls will subsequently be located.

Now let's talk about the advantages of a shallow strip foundation:

A strip shallow foundation is an economical solution. If you compare this foundation with buried types of foundation, it will cost you two to three times less.
A shallow foundation requires less work than the construction of a deep foundation. This includes modest excavation work and the ease of arranging formwork. Therefore, the time required to replace the foundation is significantly reduced.
A shallow foundation of a strip type allows, in contrast to non-buried foundations, to make a small basement in a residential building, and it is also less susceptible to heaving phenomena.

The construction of a new foundation should begin with excavation work: dig a trench, the depth of which must necessarily exceed the depth at which the base of the old foundation was located. A U-shaped trench is dug - this is necessary to form a frame with reinforcement to combine all sections of the foundation into one rigid structure.

If it is planned to erect new buildings adjacent to the house, then it is necessary to dig a trench based on the design documentation. Place a sand cushion at the bottom of the trench. Then they begin to manufacture and install the formwork. The easiest way to make it is from boards that are planed on one side. They are easily assembled into shields of the required size. In this case, the cost of replacing a columnar foundation will be lower. To install them, spacers and support stakes are used, which need to be driven in around the perimeter of the trench.

Carefully check the correct vertical and horizontal position of each shield. Then you need to waterproof the internal parts of the formwork with roofing felt or other material and begin reinforcing the new shallow foundation. For this purpose, steel reinforcing bars are used, which have a diameter of approximately 14-16 millimeters. The rods are tied into a frame using smooth rods with a cross-section of 8-10 millimeters.

At this stage, it is very important to maintain the distance from the longitudinal rods to the future surface of the strip foundation. Usually it is taken equal to 5 centimeters - this is enough to provide reliable protection of the metal from corrosion. When the frame is ready, you can fill the formwork with concrete. At the same time, avoid the formation of air voids in the solution, so compact the solution every 200 millimeters.

The formwork can be removed 3 days after pouring the concrete. Then the upper and side parts of the foundation should be waterproofed with roofing felt or mastic. Fill the sinuses with sand and protect them from the outside with a blind area. After the concrete has acquired sufficient strength (about two weeks), you need to lay boards on the first element of the strip foundation, on which temporary supports should be installed.

New foundation load

After installing the new foundation, you can begin loading it. Proceed according to the scheme for replacing the columnar foundation - simultaneously with two jacks or with each of them sequentially. Raise the corner of the building until the wedges are free, carefully pull them out, then gradually release the jacks, lowering each corner of the building onto the new waterproofing foundation.

When loading a new foundation, monitor the elevations of the top of the foundation and, if necessary, use antiseptic-impregnated wood spacers or corrosion-protected metal elements if, after applying the load, the top elevation is lower than required. Or trim the lower crown if it turns out that the top mark is higher than necessary.

Thus, if you find that the old columnar foundation has begun to collapse, cracks have appeared on the base of the house, and the building itself has begun to slant on one side, you should immediately replace the old foundation. You can choose the type of new foundation from several options - a columnar foundation similar to the old one, a bored pile foundation, a screw pile foundation or a strip foundation. But it is preferable to equip a shallow strip foundation.

Types of foundation damage in a wooden house

Initially, the condition of the foundation is assessed and the severity of the violations is determined. Deformations of the foundation of a wooden house can be of varying degrees of severity:

1. Minimal damage - peeling and damage to the external finishing of the foundation, which do not pose a threat to the destruction of the foundation and can be eliminated in a short time.

2. Moderate collapses - the presence of cracks and slight subsidence of the base. Horizontal cracks require cosmetic repairs.

3. Sheer or zigzag cracks are another matter. If such cracks are present, you can use homemade beacons, which are made from plaster plaster or paper. Putty on which control marks are applied is ideal. With the help of such beacons you can see the speed and direction of destruction. The installed signs are mounted on a dry wall with an optimal thickness of about 5 mm. In case of ruptures that appear over time, it is necessary to begin repairs and reconstruction as a matter of urgency.

If the lighthouse remains in its original form, it means that the soil has shrunk and movement dynamics are not observed. Then it’s worth starting the current repair:

• clean the crack, remove the layer of collapsing mortar;

• treat the surface of the crack with a primer;

• close the crack with cement mortar or building mixture.

4. Catastrophic violations occur in the absence of regular repairs and monitoring of the dynamics of the appearance and growth of cracks and lead to the complete destruction of the foundation and the house itself. The methods and stages of restoration work in this case depend on the type of foundation. Each specific case requires an individual decision - to strengthen or lay a new foundation.

5. Uncorrectable violations – the feasibility of reconstruction is questionable.

Types of foundation deformation

The second point to consider is identifying the extent of damage to the foundation. According to the criterion of maintainability, they can be divided into 4 types.

Minimal damage.

These include partially exfoliated finishing of the foundation of a wooden house. Such defects do not have a significant effect on the bearing capacity of the foundation. In addition, they are visible to the naked eye and can be removed without any problems.

Moderate damage.

These include the appearance of cracks in the foundation of a house due to subsidence or destruction of the foundation. In this case, you should be careful, because... crack crack discord. First of all, its direction is determined. As a rule, horizontal cracks in the foundation are the least dangerous, but vertical or zigzag cracks should alert you. It will also be determined whether the subsidence of the foundation is temporary or whether it is progressive.

The nature of the destruction can be determined using beacons installed on the crack (see photo).

You can use ordinary paper as beacons, but it is worth remembering that when moisture gets in, the paper gets wet and will no longer give a complete picture of the behavior of the crack. Plaster plasters are suitable for use. But the easiest way is to apply a little putty to the wall and use a spatula to draw a straight line and make a mark. Such a beacon is good because it breaks at the slightest movement of the surface. Installing a beacon will not only allow you to notice the enlargement of the crack, but also determine the rate of destruction.

Important. The beacon must be installed on a clean, dry wall to prevent it from moving. The thickness of the beacon should not exceed 5 mm.

If the foundation temporarily settles, the beacons will remain motionless. That is, there is a high probability that the soil under the foundation has moved a little, has taken its place and does not intend to move anymore. Therefore, you only need to perform routine repairs to foundation cracks.

Repairing cracks:

widen the crack;
clean it from falling parts and dust;
treat with a primer;
seal the seam with a special mixture or cement mortar.

The destruction of beacons indicates that the fault in the foundation or wall is increasing. This means that sealing cracks will not help, it’s time to take urgent measures - this type of deformation can be classified as catastrophic.

Catastrophic damage.

These are foundation defects that can lead to the destruction of the house. Of course, it is advisable to repair the foundation under a wooden house in a timely manner, but there are times when the moment is missed.

Then the technology for carrying out repair work will be determined by the type of foundation. The most popular of which are columnar and ribbon. In each individual case, each owner decides for himself whether he needs to strengthen the foundation or completely replace it.

Unremovable deformations.

In this case, the condition of the foundation is so deplorable that there is nothing to repair. It is usually easier and cheaper to destroy an old house and build a new cottage in its place that meets all the requirements of a modern person.

Repairing the strip foundation of a wooden house is somewhat more complicated, so we will dwell on it in more detail.

Reasons for the destruction of the foundation in a wooden house

To increase service life and minimize deformations, it is necessary to eliminate the causes of their occurrence:

1.Reducing soil density:

• soil erosion due to incorrect water drainage;

• soil erosion due to rising groundwater levels;

• change in soil load near the foundation (construction of new buildings or engineering structures).

2. Destruction of building materials caused by:

• incorrectly selected building materials;

• violation of foundation construction technology;

• errors in calculations of key parameters of soil characteristics.

Identifying the cause is the main point of eliminating it, and a detailed inspection of the foundation and an adequate assessment of the extent of damage will lead to timely elimination of violations and keeping the house in excellent condition.

Basic recommendations for restoring and strengthening the foundation

1. Repair work should always begin with determining the type of soil and its stability. This is best handled by professional engineers and surveyors - independent assessment of the condition of the soil is almost impossible. It is the type of soil that will dictate the depth of the foundation and the required characteristics.

2. It is rational to restore/strengthen the foundation if the first crown of the foundation is not broken. Otherwise, repair work is considered inappropriate.

3. Wooden piles must be provided with sufficient waterproofing, and thermal insulation material will protect the base from temperature fluctuations.

4. On sloping and swampy soils, when restoring the foundation, it is recommended to screw in screw piles, which will last up to 100 years and will not damage the soil layers. The pile foundation is easy to reconstruct - it is not necessary to replace all the piles, it is enough to replace only the destroyed ones.

Causes of destruction

What usually causes deformation of a foundation structure? It is necessary to highlight two main factors.

The bearing capacity of the soil has become less.
The material from which the base was assembled has lost its strength.

In the first case, there are several positions, which are often ignored by the developer when constructing a wooden building.

The type of soil and its bearing capacity were not taken into account. For example, the soil on the site is weak and soft, but the building turned out to be large and heavy. It puts pressure on the foundation, which in turn puts pressure on the soil, which is pressed under the total weight of the structure.
Storm and drainage sewerage were not organized . Precipitation washes away the base and it begins to sag. Groundwater has risen, and the soil and foundation structure are also weakening.
If another heavy structure is being erected next to the house , which puts pressure on the soil layer in its own way. He, in turn, begins to move, rising under lighter buildings.

In general, the situation with the loss of strength of the foundation material is not easy. Therefore, when there is a conversation about its construction, you need to contact a specialist. And the reasons for the appearance of defects in this regard are as follows:

The type of foundation structure is incorrectly selected.
The concrete mixture was mixed incorrectly in violation of technological rules.
The wrong grade of concrete was chosen.
The soil freezing level was determined incorrectly.
Violations were made during the process of pouring concrete into the formwork of the foundation structure.

Therefore, the reconstruction of the foundation of a wooden house begins with identifying the exact causes of damage.

Creating formwork and strengthening the foundation

Minor violations in the solidity of the base, cracks, are not a reason to panic. It is enough to strengthen the foundation by performing the work in the following sequence:

1. Dig a trench 30-40 cm wide close to the foundation.

2. Place metal pipes or suitable fittings with a diameter of up to 20 mm inside the trench.

3. Fill the trench with concrete solution, which will be absorbed into the ground. Add solution as needed until the trench is completely filled. Be sure to monitor absorption over 48 hours.

4. Install beacons, thereby checking for foundation shifts. If no gaps are observed, it means that the strengthening has yielded results.

Concrete mortar can be prepared by taking water and cement 1:1. To impart plasticity, it is necessary to add a plasticizer in an amount of 100 grams per 15 liters of solution. By adding sand and crushed stone you can ensure frost resistance.

Repair of brick and rubble foundations

The main reasons for the destruction of foundations
Despite the fact that brick and rubble foundations are cheap and durable, even they deform over time. Moreover, there is no point in repairing them due to the complexity of the technology, the need to completely dismantle the reinforced foundation or cut out one part of it. And it’s impossible to do this kind of work with your own hands. In such cases, replace the damaged rubble concrete foundation with a monolithic one. The base replacement technology is as follows:

The old masonry is dismantled evenly in small sections;
Jacks are installed in the vacated areas, which temporarily take on the load of the building;
A concrete base slab is then made where the foundation is destroyed. It must be wide enough and strong, the diameter can be up to half a meter;
When all the slabs are installed and the jacks are connected, the building rises evenly. Moreover, this is done simultaneously in all areas.
In place of the old rubble foundation, a classic strip reinforced concrete foundation is poured. You can also use a pile-grillage foundation here if there is enough space for installing the piles.
The house is transferred to a new foundation, reinforced and strengthened with metal anchors and intermediate vertical reinforcement. All foundation repair work is done by hand.

As it became clear, repairing the foundation of a wooden house will not be difficult. All work can be done in a matter of days with your own hands, but such pleasure is not cheap through the use of powerful lifting mechanisms.

Only local restoration of a damaged strip grillage is simple, because then you only need to repair the resulting cracks and ensure that they do not reappear.

Reconstruction of the foundation with screw piles

Strengthening the foundation with screw piles must begin with preparatory work:

1. Disconnection of communications - gas pipelines, electrical networks, and so on.

2. Reducing the weight of housing - remove all heavy objects from the house.

3. Removing the floor covering.

To lift the box at home, mechanical or hydraulic jacks for light-duty trucks are used. The weight of the house is preliminarily determined - this is simple, knowing the density of the wood and the total volume of the tree, calculated from the thickness of the walls and the size of the house.

When lifting a house, it is important to consider the following nuances:

• it is necessary to arrange a wooden platform for a jack for the foundation pillars;

• the jack can only be installed under entire walls;

• lift the building only from the corner side;

• the selected part of the crown must withstand the load from lifting;

• the lower crown of the foundation is preserved by removing the brickwork and making a closed base;

• experts advise digging a trench along the length or at restoration points, which provides easy access to the foundation and the ability to measure the level of groundwater rise.

Important! Wooden wedges between the base and walls of the house will provide a safety net during the restoration process.

Stages of work to strengthen the base with screw piles:

1. Selection of typical piles of the required number, taking into account the characteristics of the soil, the depth of the soil freezing layer and the load on the future foundation.

2. Dismantling the old foundation - raising the house and removing elements of the worn-out foundation.

3. Installation of screw piles. It is necessary to initially install piles under load-bearing walls and their joints, screwing them deeper than the freezing layer of the soil.

4. Checking the horizontal placement of the top of the elements with a level.

5. Coupling of piles with a metal profile, the thickness of which depends on the future degree of load on the entire structure.

6. Installation of the house on a finished foundation.

Stages of work execution

The simplest and most affordable way to raise an old log structure is to place car jacks under all four corners of the base, and then remove the rotten beams from under the frame.

It is difficult to carry out such types of work on your own; if the owner decides to raise the foundation of a wooden house with his own hands, you should invite helpers and study the step-by-step instructions.

Raising the house

Work begins on the side that is tilted. Using a lever, two corners of the house are lifted alternately and jacks are brought in. The mechanisms must stand on tightly compacted soil, a wide stone, or a wooden board. Thick metal plates with sides measuring 10x10 cm are laid between the log and the jack.

The house rises gradually, 2 cm at a time. Immediately, supports are installed into the resulting gap. To change the foundation under a wooden house, you will need to raise the frame by at least 6 cm.

To restore the foundation of a wooden house, you need to get 4 jacks for heavy vehicles. Mechanisms suitable for changing wheels on passenger cars may not withstand the weight of the log house.

To bring the jacks under the house, cuts are made on two opposite sides in the second crown, at a distance of 30-40 cm from the corners.

A strong beam made of metal or wood is inserted into the resulting holes, and jacks are installed under the ends. The building is being raised from all sides simultaneously. After this, the frame is fixed and the dismantling of the log frames that have become unusable begins.

Dismantling the old foundation

If the building stood on a foundation, it will have to be dismantled. The old base is removed, the sand cushion poured under it is raked out, along with the remnants of rotten wood chips.

The ditch is deepened by no less than 30-40 cm. The soil at the bottom of the trench is compacted. The soil surface is covered with a layer of new sand and fine gravel.

Replacing the foundation with:

After this, a new stage begins. The progress of further work depends on the chosen type of foundation.

Tape

Formwork made of boards and supports is installed along the bottom and sides of the trench.

Important. To give the base strength and wear resistance, reinforcement is carried out. To do this, you need to prepare in advance the knitting wire and reinforcement with a cross-sectional diameter of 18 mm.

When the preliminary work is completed, concreting begins. The concrete mixture is prepared in such quantity that it is enough to fill the foundation in one go. If the technology is not followed, seams will form.

Concrete is poured to the edges of the formwork, leveled using improvised means, a spatula, and left for a while. When the foundation begins to harden, it is covered with plastic film, oilcloth, or roofing felt.

The formwork is dismantled after the concrete has hardened. This usually takes several days. Complete drying of the foundation will occur in 30-50 days, depending on weather conditions. In summer, when the air temperature is above +30, the process occurs quickly; in a month the base will be completely ready.

When pouring a new foundation under an old wooden house, the two lower crowns of the frame are replaced along with the old beams. The lower logs deteriorate along with the base. Construction material is prepared in advance. Resinous types of wood are well suited:

larch;
pine;
spruce.

The logs are dried before laying.

Columnar

A small house can be placed on a columnar foundation. This option allows you to save money. Such a foundation requires less concrete, reinforcement, and sand. The work proceeds in several stages:

at a distance of 1.5 m, holes are dug, the bottom of which is thoroughly compacted;
a sand cushion is created in each hole and formwork is installed;
4 reinforcement rods are inserted into the formwork and tied with wire;
the pits are filled with concrete mixture.

When the concrete sets, the formwork is dismantled. The log house is installed on poles after complete drying.

Some craftsmen create a concrete frame for each pillar. This measure allows you to give them additional strength and prevents distortion. The building is lowered onto a columnar foundation gradually, simultaneously from all sides.

Pile

Raising the foundation of a wooden house can be done using screw piles. This is an inexpensive and relatively simple way to solve the problem.

Reinforced concrete piles are manufactured in a factory manner and can withstand heavy loads. The low cost of the building material makes it popular among consumers.

Before raising a wooden house and making a foundation, it would be correct to choose piles that correspond to the weight of the building and the density of the soil. Further work is carried out in stages:

the house is raised using four jacks;
areas on the crowns where the piles will be screwed are determined and marked;
the pillars are screwed into the ground using special devices;

The pillars must be recessed to a depth greater than the freezing level of the soil.

The height is set using a hydraulic level, it should be the same. The piles are connected to each other using a steel channel.

The log house will stand more stable on the piles if thick steel plates are screwed to the base at the points of contact with the top of the piles.

The old foundation under a wooden country house can be built of brick. In this case, only the destroyed parts are removed. After this, they are replaced with new masonry.

Repair of a columnar foundation of a wooden house

If the displacement of parts of the base of the house occurred due to the influence of natural factors, then most likely the destruction began on the lower crowns that hold the base of the building. The only way out is to replace the lower wooden crowns.

Foundation pillars can become deformed when the soil freezes regularly.

Pillars need to be replaced if they are damaged:

• tilt of individual pillars – as a result, the entire structure tilts;

• pillars sink into the ground due to poor waterproofing or changes in the structure of the house.

Preparatory work is being carried out and the house is being raised from its foundation. To do this, metal profiles are placed under the crowns around the perimeter of the house with an interval of 2 meters. Then they carefully lift it with jacks and install temporary support posts. You can use metal or wooden blanks. Having fixed the house, they remove the destroyed pillars and install a replacement, deepening it 30-50 cm below the previous one. Then fill is performed.

Important nuances when replacing poles:

1. The dimensions of the foundation area should be 40x40 cm with the size of an asbestos pipe having half the diameter.

2. You need to place a sand cushion under the support and compact it thoroughly.

3. Initially, the pipe is inclined for ease of pouring the concrete solution that forms the bottom of the pile. After the concrete “sets,” the supporting element is strengthened, filled with mortar until it stops, and fixed vertically.

4. The pit is filled in when the post is securely fixed.

Main question

How to raise a house for major work to replace the foundation?

Cranes are not suitable due to the incredible cost of work. The most popular method is the use of jacks, which can be rented from specialized organizations or from the railway depot. Most likely you will need more than four of them - about a dozen, depending on the massiveness of the building. Furniture should be removed from the house and floorboards removed to lighten the overall weight. The crowns, especially the lower ones, are fastened with steel brackets.

ATTENTION! Raising the house diagonally is not allowed.

Jacks are placed on both sides of the wall, on supports made of metal sheets, thick plywood, boards, or tightly spaced beams. It would not be superfluous, in order to avoid the logs falling off the jacks, after installing the jacks, put a load on them so that the substrates are firmly sunk into the ground, release the pressure and install the jacks again. The emphasis is made only on well-preserved logs, starting from half a meter from the corners; worn-out ones must be replaced along with the foundation. In places of emphasis, it would be correct to install elongated metal plates to distribute the pressure of the jacks on the logs.

Then low, repeated lifts of 1-2 cm are made, carefully monitoring the condition of the logs, walls, roof, and distortions of door and window openings. In these cases, they must use a level or an observer who, from a distance of ten to twenty meters, evaluates the synchronicity of the rise. It is extremely important to install and change supports each time you lift. Bricks and oak boards are ideal (you can use floorboards from home). In case of unexpected deflections of the logs, the lower crowns should be supported by two free jacks. The entire structure is raised to a height of 15 cm.

IMPORTANT! The process of raising a wooden house takes about a day and is not rushed.

Replacing the old strip foundation of a wooden house

The initial preparation and raising of the house is carried out in the same way as in previous cases. Only the entire structure is raised and the entire strip foundation is completely dismantled down to the ground.

Partial dismantling and subsequent replacement are allowed, which does not significantly reduce the cost of work, but reduces the service life of the foundation and the strength of the structure.

Stages of work on installing a strip foundation:

1. The trench is prepared.

2. Sand and cement are poured into the trench and compacted.

3. Supports are installed at the corners of the house with a height equal to the height of the foundation; you can use both brickwork and concrete structures. If desired, piles can be installed. Such support pillars will reduce the pressure on the strip foundation.

4. Reinforcement is installed using wire, which will add strength to the base.

5. The formwork is installed and the concrete solution is poured.

6. The concrete structure of the strip foundation will gain strength in a couple of days, after which the formwork is removed and the base is left for another 2 days.

7. Waterproofing is installed, for example, roofing felt.

8. The house is carefully lowered onto the finished foundation, and the final work is carried out on complete waterproofing, drainage, installation of a blind area and cladding of the foundation.

How to add a foundation to an old wooden house?

Sometimes there are situations when a wooden house seems to stand with its bottom crown on the ground. So 50 - 100 years ago they were built on hills where water did not accumulate in the ground. That is, they did without a foundation. Such buildings could not stand for a long time, because the lower crown of the wooden house gradually rotted.

You need to approach the renovation of an old house from the perspective of pouring a new foundation. And this will have to be done almost exactly the same as in the case of dismantling the foundation structure. That is, it will be necessary to raise the building and pour a strip foundation under an old wooden house with the installation of formwork and a reinforcing frame. Of course, we need to make sure that maybe there is some kind of foundation under the structure.

To do this, you need to dig holes in several places near the walls of the house. The easiest way to do this is with a garden drill. If the foundation is found, then it is necessary to examine it for integrity and identification of defects. This means you will have to dig a trench along its entire perimeter.

If no major damage is found, then concrete mortar can be poured along the upper plane of the structure with the installation of shortened formwork and a reinforcing grid or mesh. Such repairs to the strip foundation of a wooden house must be approached from the position of raising the entire structure so that the lower crown does not touch the ground. And this is within 30 - 40 cm.

Waterproofing the foundation for increased service life

Properly performed waterproofing significantly extends the life of the foundation. The side surfaces of the foundation and concrete structures are coated with bitumen. Next, roofing felt or sheet polystyrene foam is glued on. This insulation insulates the foundation, protects against moisture and increases frost resistance.

Important! It is strictly not recommended to apply bitumen at sub-zero temperatures; it loses its properties.

If there is a basement, then it is worth insulating it from the inside from moisture. To do this, the soil is deepened, three layers of waterproofing material are laid, while gluing the joints with bitumen. The sheets should overlap the wall, to a length of about 30 cm. A screed of cement and sand is poured on top with a minimum layer of 5 cm. The finishing can be done with any materials - ceramic tiles, linoleum and other facing building materials are suitable.

Progress of work to repair the damaged section of the base

Pillar foundation repair

To repair the structure of the foundation of a house, jacks with increased load capacity are used. The process begins with freeing the building from heavy and fragile things, furniture, appliances, dishes, mirrors. In special cases, window sashes are removed to prevent deformation. Next, the main repair activities begin:

The bundle of pillars that serves as protection for the underground space is removed.
At least 4 jacks are installed under the walls of the house.
Slowly, with the help of hydraulic installations, the entire house is raised above the level of the existing piles by 10 centimeters.
To prevent sagging of the lower crowns along the perimeter of the building, they are nailed together with the above parts using long boards.
Damaged parts are dismantled, and lopsided pillars are leveled. The soil is dug up around them and concrete is poured into the pit.
For new piles, pits are dug, new parts are installed in them and filled with concrete. Their upper edge should correspond to the level of previously installed supports.
After the concrete gains strength over time, the house also slowly lowers to its original location.
Finally, a bunch of posts made of new material are installed.

Strip foundation repair

This action consists of several processes:

Repair of the damaged part of the structure with reinforcement. This includes cleaning the structure area from plaster, filling cracks, and then filling them with a special repair mixture based on cement and glue. If there is doubt about the reliable outcome of the event, the structure is reinforced with concrete.

Repair of the damaged part of the supporting base with its partial replacement and reinforcement along the entire perimeter of the foundation. This is a more complex process that requires complete dismantling of the damaged section of the foundation. It is necessary in the future to dig out the trench again and install the formwork.

Pour the concrete and give it time to gain strength.

If the cause of damage to the foundation is identified, for various reasons, it is necessary, in addition to repairing the area, to strengthen the entire perimeter of the foundation.

To do this, dig a trench along the entire perimeter of the existing foundation. Clean it of plaster and soil. Install adhesive reinforcement pins into the walls of the old foundation. A reinforcing structure is tied to them with wire. The formwork is placed and concrete is poured. After seven days, the formwork frame is removed. The new reinforced foundation is subject to finishing and further operation.

Complete replacement of the entire foundation

Large-scale restructuring involving complex processes:

Dismantling sections of the base for installing jacks.
Slowly raise the building at least 15 centimeters from the previous level.
Complete dismantling of the emergency foundation.
Device with strengthening of the trench for a new foundation. Providing measures for drainage of groundwater, melt water and precipitation.
Installation of formwork around the entire perimeter with reinforcement with steel cores with a diameter of at least 12 mm. It is planned to construct a larger foundation to increase the safety margin.
Then concrete is poured using a deep vibrator to remove air bubbles. Time to gain strength is given for at least 14 days.
The formwork is dismantled. The foundation remains in this condition for another 10 days.
Next, coating and adhesive vertical waterproofing of the supporting base is carried out with bituminous materials, followed by backfilling with soil.
To protect the walls of the house from getting wet, roofing material is placed under the crowns on the foundation.
The house is slowly lowered to its original location.
Finally, the outside of the foundation is finished.

The cost of repair work on the foundation of a wooden house

The final estimate for repairs depends on the degree of destruction, the chosen technology of work, the area and overall dimensions of the building.

An approximate calculation can be made based on the cost of individual stages of work:

• dismantling the foundation - from 700 to 1000 rubles. per cubic meter meter;

• lifting the building from 35 to 50 thousand rubles;

• purchase of construction materials.

On average, restoration of a strip foundation with an area of 1 sq. m costs from 4 to 5 thousand rubles, and a pile from 3.5 to 4.5 thousand rubles.

Features of a strip foundation and its repair

For complex, moisture-saturated soils that are susceptible to heaving to this day, construction experts recommend pouring a strip-type foundation. Since a building structure made of wood does not have much mass, this foundation can be made shallowly buried, which will not only save on cement and reinforcement, but also avoid the harmful effects of unstable soil. But even a reliable strip foundation under a wooden house loses its operational properties over time, and it needs repair work.

First of all, it is necessary to inspect the base to find out how complex the work may be required. For these purposes, a narrow trench is dug around the perimeter from the base. In sunken sections, the old foundation can be raised and strengthened. If some parts are destroyed, they are removed and connected to each other through the supply of reinforcement or anchor fasteners. Next, in order to update the structure of the base, the dug trench is filled with a concrete composition of liquid consistency, designed to fill all defects and cracks. The mixture is poured into sections one and a half to two meters long, which are connected by reinforcing bars. As a result, without installing a new foundation under the structure of an old wooden house, we will be able to strengthen the old structure and prevent subsidence of the surrounding soil for many years to come.

Replacement of the foundation under a wooden building with its uniform subsidence is carried out using a monolithic concrete belt with additional reinforcement. Its depth should be approximately 25 centimeters, and the bottom of the trench is covered with a sand-crushed stone cushion that acts as drainage. The base of the structure is equipped with a drip to prevent destruction from excess moisture.

In case of uneven distortions, the use of hydraulic jacks will be required. Before lifting the building, a support made of metal profiles or timber is installed under the jack. The building should be lifted very slowly so as not to destroy the interior decoration, flooring and roofing. After lifting, the old structural elements are additionally reinforced and bonded to the new coating. A waterproofing layer is installed between the house structure and the base.

Reconstruction of the foundation for the construction of the upper floor

In order for the upper floor to appear, the load on the foundation has to be reconsidered. By increasing the weight of the structure, the load on the foundation increases; it is necessary to improve its design by strengthening it or increasing the perimeter of the foundation. If the strip foundation is being strengthened, then it is necessary to install additional support pillars.

To calculate the load and distribute the volume of work, it is better to involve professionals who, after assessing the structure, will consider the feasibility of the superstructure and offer possible options for implementing the plan.

Restoration of a columnar foundation

The process of repairing a columnar foundation consists of the following steps:

The old wooden structure is raised to a certain height. Proper calculation of the required height allows you to carry out repairs and prevent the lower crown from sagging. Leaning pillars are dismantled.

If the support has become dilapidated, it is replaced with a new one. In other cases, the repair consists of leveling the pillars. The soil at the installation site is removed. Mandatory points for installing supports are the corners of the old wooden building and the junction of the internal walls. A cement-sand cushion is placed under the pillar. Repairs continue by reinforcing the pillar, after which concrete mortar is poured. Beams made of wood or steel are installed, which transfer the load from the old wooden dwelling to foundation made of pillars. The house is returned to its original location.

Repairing or completely replacing a pile support structure takes much less time and effort than strengthening a strip base.

From the following video you can learn more about how to add a foundation to an old wooden house:

Older homes often have foundation problems. Due to problems with the foundation, the walls may begin to move, or they may even collapse.

In addition, the destruction of the foundation is fraught with destruction of other important parts of the structure. But don’t panic and immediately demolish the house. This can often be avoided.