Choosing the type of support for your country house, many summer residents prefer columnar structures. Especially often they are used in the construction of houses. frame houses, and sometimes columnar foundations are also suitable in combination with more solid structures. An example of this is the main log house, which is placed on a monolithic recessed strip foundation, and the attached veranda is placed on pillars.

The reason why frequent builders love this type of support is its low cost and simplicity of the device, which does not affect its reliability. However, sometimes a certain problem arises with columnar supports - he starts to walk. If you have already encountered this problem and you know that the foundation walks in winter, why, what to do still do not know, then I am now on www ..

So why is he walking? Yes, the whole point is that as a result of swelling of the soil, the support of the house also changes its position, rising and falling, respectively. For those who are not too familiar with this phenomenon, we will briefly explain its essence. This phenomenon is possible on heaving soils, which, during winter freezing, tend to push denser inclusions upwards in them.

Naturally, at the same time, the soil carries with it everything that is in it - pillar supports, buried septic tanks and even reinforced concrete wells sometimes turn out to be raised to the surface during this phenomenon, that is, they become hopelessly damaged.

An additional reason why the columnar foundation under the house or extension walks in winter is the low load on it. With a large mass of the structure resting on it, the swelling force of the soil is not enough to push the support pillars to the surface. But, as a rule, frame houses or wooden verandas are lightweight and therefore their weight is not enough to hold the foundation in place.

This issue is especially relevant if the pillars are used as a support for an attached room such as a veranda. Then significant vertical movements an extension rigidly connected to the main house, the level of which remains unchanged, can lead to serious problems up to the deformation and destruction of some structures.

Therefore, it is impossible to dismiss this problem every time when the situation returns to normal after the spring floods. It is necessary to solve it ... But how to do this, you tell me, because it is not possible to fix an already exploited columnar foundation. Is that so? Yes, unfortunately it is. What to do?

The only way to fix the situation when the columnar foundation is walking is to replace it. To do this, new pillars are brought under the structure, after which the old ones are removed. At the same time, new supports should be installed not just in the ground, but in special concrete shoes.

Concrete shoes can be cast in advance using formwork, and then placed in a hole cut under the support. But then you will have to face the problem of a sufficiently large weight of the resulting shoe. Therefore, it is better to arrange shoes in place, in the ground.

In general, this procedure is as follows. The sod layer is removed from the soil, after which a well is cut through with a depth of about 1.2 m and a diameter of 0.3 m. The walls and bottom of the resulting pit are laid out with moisture-proof material, which will be reported to prevent the penetration of groundwater into concrete and thereby protect the shoe from premature destruction . Roofing material is most often used, although it can be advised to pay attention to more modern materials, for example, glassine.

Then reinforcement is placed in the well, which is poured cement mortar, before that, sticking anchors into the casting, which will serve as a connection between the shoe and the support column. When the solution hardens, an asbestos-cement pipe is installed on the shoe, the length of which is 20-30 cm longer than the depth of the well, depending on the level of elevation above ground level of the structure under which the foundation is being prepared.

You can go a little more complicated way - to arrange an unusual formwork on the resulting concrete base - from plastic bottles. Then, having installed the support pipe, the formwork is also poured with concrete, as a result of which it serves as reinforcement for the foundation leg, giving additional rigidity to all structures.

Summing up such a support under the finished, already in operation extension, is carried out in stages - the supports are installed in pairs - from the inside and outside of the veranda. When installing an external support, the issue is solved simply, but when working from the inside, you will most likely have to disassemble part of the floor and support the walls of the extension with a jack or temporary supports. When the paired supports are installed, they are combined with a concrete jumper.

After the new foundation is completely ready, it remains only to dig out the old supports. If it is impossible to remove them, you can simply chop off the upper part that touches the house.

Participant

Protruding pillars under the veranda - what to change and how to do it?

Hi all,

I immediately apologize for the possibly incorrect use (or non-use) of some terminology. If I wrote something wrong - it is better to clarify once again.

Eat country house in the Mozhaisk district of the Moscow Region. The house is already 20 years old. Accommodation - only in the summer. There is no full-fledged building plan at hand now, but the configuration is something like this:

The black rectangle is a frame made of timber.
The green line is veranda No. 1, frame, structurally above it and above the log house a frame attic was built under a single roof.
The red line is veranda No. 2, structurally made as an "extension", also a frame. There is a problem with it (more on this below, in the description of the foundation).

It looks something like this:

I don’t remember the exact dimensions of this whole thing, but somewhere around 10x12 meters.

Foundation:

First of all, the soil. It's clay, I don't know what it's scientifically called. In the rains, as well as in the spring, everything gets very wet and does not dry for a long time, but the groundwater, as I understand it, is not close - they dig wells for 15 meters, and not always at such a depth it is possible to get to the bottom of "living" water.

Along the perimeter of the main building (which includes a log house and veranda No. 1), I see a tape. How deep it is buried - I can not say, I do not know. At the same time, I see pillars inside the tape. Including the wall of the log house, bordering on veranda No. 1, also stands on poles.
Further in the text, the pictures are "clickable" so that they can be better viewed.

I do not rule out that the entire main structure stands on poles, and the tape around the perimeter is only a connecting / decorative link. Although I may be wrong, because the tape itself is quite wide (by eye - somewhere around 50cm.).
This part of the foundation is stable and does not cause much desire to change anything.

Veranda No. 2, marked with a red line in the first picture, stands on poles made of metal pipes, and outside filled with concrete. The problem is that the pillars under veranda No. 2 gradually, from year to year, creep up, and all at different speeds. It turns out something like this picture:

(I especially like the last photo in full-size form - a good "springboard"!)

I thought for a long time what to do with it. From the option to saw off the protruding "extra" parts of the pillars and leave for a few more years - "let them grow", to the option "demolish everything and rebuild". As a result, I still like the idea of ​​​​dismantling veranda No. 2 most of all (because it is problematic to move the entire building), remake the pillars under it, and assemble it again, while at the same time lengthening the attic so that it occupies the area above this veranda too. Dismantling the veranda, I think, will not be a problem. Uproot old poles - too. But how to make new ones (there will be a total of 18 of them) is the question.

The first option that I thought about was to make TISE pillars. I looked at the reviews here - it turns out that this is not so easy to do. Plus, the need to concrete, and this time and complete dependence on the quality of concrete. The company requested 4t.r. for a column on this technology, "on a turn-key basis". True, taking into account the height of some pillars (a site with a slope), the price will still grow.

The second option is screw piles. Curious option. In "ideal conditions" - faster and cheaper than TISE. In any case, the price on the Internet is from 2.5 to 5 thousand rubles. for a pole from the 133rd pipe up to 5 meters long, which, I hope, should be enough for me in length (and the 108th pipe can also be used in diameter, I think). True, you will most likely have to screw them in manually - the car is unlikely to drive directly to the house (in general, it depends on the car and on the weather, since arrival is possible, but through the field). Although, if there is some kind of mobile installation such as a small trailer that can be pushed by hand, options can be considered.
Also, there are doubts about the reliability of the screw foundation. True, this is not so critical for me, even if he swims somewhere in a few years, but I would still like to avoid such troubles.

The third option is to fill the tape. Taking into account the height difference, a lot of concrete will go. The mixer, again, will definitely not drive up to the place of work - you will have to knead manually. In general, this option seems to me very costly.

Potentially, maybe someday I will come up with the idea of ​​​​insulating the house and finalizing it for living in the winter. Therefore, subconsciously I want to get some kind of margin of safety and reliability of the design, but at the same time not to overpay too much for some obviously unnecessary things. I'd be happy to hear opinions knowledgeable people and discuss options.

Thanks in advance for any ideas!

P. S. Offers of services for the implementation of one or another option are also discussed (write in a personal, we will exchange contacts).

Last edit: 03/04/14

Registration: 27.05.07 Messages: 32 Acknowledgments: 7

Participant

Registration: 27.05.07 Messages: 32 Acknowledgments: 7 Address: Moscow

It doesn't matter, IMHO. This soil should not endure loads, moreover bulk - lower density, less freezing therefore.

Hmm, interesting thought. Then, in many cases, is it easier to drill a hole with a drill of a larger diameter, instead of trying to open the place under the heel at a depth with a TISE drill?

In addition, it is hard to believe that the anti-corrosion protection is retained on the screw during tightening. Here is a neatly buried pillar - another matter.

Yes, I also have certain doubts about the protection of the blades and the pile itself from corrosion. However, manufacturers insist that modern technologies solve this problem. But manufacturers are interested people, and somehow I have not seen independent studies.
Pillars also have disadvantages. So which of these to prefer in this case - I do not understand yet.

By the way, about the prices. If you believe the prices on the Internet, then screw piles should come out a little cheaper, according to the sensations - somewhere by 10-20%. This is in comparison with TISE for 4 tr. for a turnkey post. Although this is highly dependent on the length screw piles...

Remove the floors again, do not disassemble the veranda. The floors can be carefully removed and put back, but the rest of the structure - nails, screws, chips, etc. - will most likely have to change part of the structure.

Yes, I thought about this for a long time. What is so, what is so - all the same, something will deteriorate, something will break. And so there is an idea in general to assemble everything a little differently - it is clear that additional material will be needed, let it be a kind of "upgrade" (in computer terminology).

Yes, and returning to the insulation of the blind area with a plinth. After all, the soil will freeze through the floor, so it will not help to the end. Insulating the floor of a cold veranda is somehow quite strange, then it’s better to insulate the ground directly under the veranda. And with anything, sawdust with clay, expanded clay, PPS granules or something else.

Let's say I have TISE pillars, or the same screw piles - both of them are still below the freezing depth of the soil. What will warm me up? The house is unheated in winter. The pillars will probably be covered with something decorative (I have not yet decided what) - all the same with slots so that the space is ventilated. As a matter of fact, water will get in there. And in autumn and, especially, in spring, water will flow like a river. Everything small that is sketched on the ground will simply wash away after a few seasons. So, the insulation must be buried in the ground. Purely psychologically, it looks somehow strange. Technically, someone will probably want to plant a flower, bindweed or something else "along the wall" - you can't keep track of everyone, so in a few years this insulation around the house will still be dug up in pieces ...
If there is a real need, you can focus on this and make a "forbidden zone" for any earthworks. But is this "real need" really there?

Registration: 15.04.11 Messages: 11.357 Acknowledgments: 7.467

yes. That's what I did in the end.

So you don't hire on a turnkey basis. Hire workers for daily wages. Bring your own supplies and go.

POLAR FOUNDATION UNDER THE GARDEN HOUSE

Many gardeners themselves build a house, a barn, a bathhouse out of bollards, but often in spring the doors of the house do not open, the windows warp. And it's all about the foundation, or rather in the ground under the structure. The most common soils in garden plots are loams and clays, which, when frozen, increase in volume and unevenly raise the foundation, warping the structure.

The wise building books say that the foundation must be buried below the freezing depth of the soil in the area. For example, for the Moscow region, this depth is 1.6 m. In most cases, this recommendation is simply not implemented. First, it takes a lot building material to bring the foundation to the surface from such a depth. Secondly, with closely located groundwater, it is generally impossible to dig a hole for the foundation, since the hole is filled with water. There are errors in the construction of columnar foundations.
So, usually foundation pillars are made of brick, asbestos-cement or steel pipes, concrete, concrete blocks. At the same time, often the disadvantage of such pillars is their small bearing area and excessive height, which over time leads to the collapse of the pillar on its side, its subsidence on weakly bearing soils, and also to the bulging of the pillar upwards on heaving soils (clay, loam).

In winter, the soil under the sole of the pillar freezes, increases in volume and bulges the pillar up. In spring and summer, the pillars partially and unevenly settle. Especially actively warps fence posts made of asbestos-cement pipes.
And here is our wooden house 6 × 6 m in size, based on nine pillars of red brick (non-silicate), although built on heaving soils, has been standing for more than 30 years and the mobility of the pillars and the house has not been noticed. At the same time, the base area of ​​one column is 0.384 m2.

During construction, pits for poles were dug, removing only the top fertile soil layer (approximately on a spade bayonet). The depth of each pit was different due to a small slope, but the bottoms of all the pits were in the same horizontal plane, which was checked by a hydraulic level (a rubber tube with glass tubes at the ends, filled with tinted potassium permanganate water). At the bottom of each pit, a layer of cement-sand mortar (1:3) 1 cm thick was laid and a brick pillar was laid out with dressing of the seams according to the figure.

Foundation pillar (a) and its ordering (b)

Then the space around the pillars was covered with soil taken out of the pit. It is clear that the pillar can be made of concrete, but it must be made stepwise, as in the figure.
What is the highlight of such a pillar, the construction of which took only 55 bricks?

Firstly, the stepped design of the column provides a large bearing area of ​​​​the column with a low consumption of material, which is very useful when the soil has a low bearing capacity (low and wetlands).
Secondly, the mass of backfill soil is added to the mass of the column, which increases the stability of the column during tipping over in summer.

Thirdly, the shallow depth of the pole support platform provides a small height of the pole, which, in turn, reduces the likelihood of the pole tipping over on its side.

Fourthly, the backfill soil on the surface freezes first, and the soil under the base of the post freezes last. As a result, the frozen backfill of the soil, leaning on the steps of the pillar, like a shell, keeps it from sticking up.

Thus, the frost, while fettering the filling of the column, works against frost, which causes the column to bulge, uniting the soil-pillar system into one. That is, frost works against frost.

Advice:
Silicone-organic enamels of grades KO-168 are also suitable for; KO-174; KO-835A and KO-1112.

Perhaps, each school had its own loser, which, the maximum that teachers predicted, was a “fence-building institute”, which emphasized the frivolity and even primitiveness of this design. True, those who in practice happened to be faced with the construction of fences, realized that in order to solve this problem, they had to seriously “wiggle the gyrus”. And the real test of professionalism is spring with its floods and thaws, when the posts begin to bulge out of the ground, breaking and warping the entire fence.

The most common solution to this problem is to deepen the hole below the freezing level of the soil and fill it with concrete. But for some reason, these events have to be repeated annually. The conclusion suggests itself: if everything is done correctly, then for what reason are frosts accompanied by bulging of securely fixed pillars? It turns out that this method is not so good ...

A favorite method of installing a fence for many summer residents is to drill a well where a pole is installed, after which the free space is filled with concrete. But has anyone thought about what, in fact, concrete “clings to”? For the same soil that was recently easily removed with a drill or a shovel! That is why the pillar, along with concrete, is pushed out of the ground. The strength of the heaving of the soil is such that it can easily cope even with foundations multi-storey buildings, what can we say about lighter buildings! The heaving process occurs due to the moisture contained in the earth (clay accumulates it). Therefore, heaving does not happen only in sandy soils.

Trying to protect the fence posts from the action of heaving soils, many increase the depth and diameter of the holes, which leads to a huge consumption of concrete. The method is partially effective, but there is a solution that is less expensive and more effective. If the soil on which the site is located and the fence enclosing it is non-porous, then concreting can be generally excluded due to uselessness. It is enough to drill holes that exactly correspond to the dimensions fence posts. True, drilling should be perfect: strictly in a straight vertical line.

To resist heaving soils, a drainage method is suitable. It consists in the fact that the column is installed in a dug hole, which is then covered with rubble. Drainage replaces heaving soil around the post, so when freezing, moisture will not try to push it out along with the concrete pad, but will pass through the rubble without causing serious damage to the post. This method is also successfully used to repair the fence, the base pillars of which have already been kicked out. If they were concreted, then it is better to remove the concrete (beat off), and fill the vacant place in the soil with crushed stone, compact it. Naturally, the hole should be deeper than the freezing level of the soil, and it is enough to immerse the columns by only a third of the length.

Today, many developers choose to build a columnar foundation for their house due to its cheapness. 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, a light bathhouse, residential buildings from a small bar on non-rocky soil. But there are cases when the columnar foundation begins to quickly collapse, fall on its side or bulge. In such conditions, the only way to prevent further subsidence of the base is to replace the columnar foundation.

The need to replace the column foundation

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

This process comes from various physical, mechanical and hydrological changes that take place in the lower soil and reduce its bearing capacity. The foundation actually ceases to fulfill the tasks assigned to it. Often, changes in soil properties are caused by construction work that is carried out in the backyard. But such problems are inherent not only in old houses.

And when installing a new house on a columnar foundation, the latter very quickly begins to squint or sag and pull the house along with it. Especially when it comes to large and heavy log houses (9 by 9 meters or more) and cottages. In these cases, such a foundation is categorically not recommended to be used, 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 masters who carried out the construction. This is due to the phenomenon of heaving of the soil during its thawing after winter freezing. The earth thaws earlier on the south side of the house, pushing up the south posts, which end up on loose, sized earth, while the north posts stand in place on the hard frozen ground.

Even if you dig 2 meters into the ground and pour concrete asbestos pipes that are strong in compression and bending, they will not be able to withstand heaving of the soil. All the same, the level of the columns along the horizon will be violated, and the house as a whole will be skewed. In this case, the foundation cannot be repaired and it is pointless to try to align the foundation pillars, you need to remember: if the blocks have moved at least once, then 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 referred to as radical measures designed to restore the safety and reliability of the house, as well as increase its lifespan. However, it is worth remembering that it is advisable to replace the base for buildings whose construction, after replacing the soil, can last for several more decades.

Methods for replacing a columnar foundation

As a rule, the replacement of a column foundation with another one 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 facilitating work. But the replacement of the base during the subsidence of the internal walls of a residential building requires to open 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 involve large financial investments. In this situation, you simply need to cut out the rotten area, and instead insert a suitable wooden element. However, it must be borne in mind that with such a partial replacement of the base, the integrity of the house is inevitably violated.
• The dismantling of the walls presents a view construction works, which involves the complete dismantling of the walls, after which the lower crown of the log house is replaced. The method is reliable, but it requires a fair amount of patience and time from the masters to disassemble and assemble 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 base under the house.
• Replacing crowns by raising a 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 quickly and efficiently.

Choosing a new foundation for the 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 such types of foundations that are suitable for wooden houses:

1. The columnar foundation is a system of pillars that are installed in places of maximum load - the intersection points of the walls. The pillars are made of stone, concrete or brick and set at a distance of close to 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 and other outbuildings.
2. bored pile foundation is a type of columnar base, only asbestos-cement pipes are used as load-bearing elements, which are filled with a special mixture. The design of such a foundation consists of piles and a grillage that connects them. Bearing elements are similarly located under the most significant points of the house, for example, in places where the main walls intersect, and at the corners of the building. A bored pile foundation is considered optimal for buildings on ground with high water.
3. pile screw foundation It is considered the most interesting type of the basis of the house, as it was originally intended for military purposes. Today, such a foundation is widely used in civil engineering and is valuable in that you can use it on any terrain, even on uneven terrain with height differences. In addition, the low price 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 the hiring of special equipment.
4. The strip foundation allows you to build heavy houses and at the same time provides high reliability and security of the house. The most popular shallow strip foundation is monolithic and prefabricated. Prefabricated structures are made of concrete based formwork, monolithic - from blocks of reinforced concrete and concrete.

Replacing the 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 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 the subsidence of the house under the columnar foundation and requires an immediate replacement of the base.

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

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

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

For uniform transfer of force from the jack rod to the lower rims of the house, it will be necessary to cut a steel plate that has a thickness of at least 5 millimeters. If you have to work with a columnar base with a pickup, then before starting work, the latter will have to be disassembled. Also, at the preparation stage, it is recommended to remove all heavy things, furniture from the house and disassemble the floors.

The rise of a wooden house

Raise the building with 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 raise the house, otherwise the logs of the lower strapping will bend during uneven lifting, which will lead to their separation and subsequent breakage. The jack should be installed in places where the tree is not damaged by rot.

Remember that it is necessary to install spacers in the form of steel plates so that the force is correctly transmitted to the logs from the jack rod. Instead of metal plates, you can take pieces of wooden blocks. 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 lifting the house. If you plan to immediately raise the entire building, 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 exceed by 10-15 centimeters the difference in the 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. Raise the house, if possible, from both sides at the same time, evenly, no more than 1.5-2 centimeters at a time. The result obtained is immediately fixed with temporary supports.

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

The wall must be raised to a height of at least 6 centimeters, the rotten extensions removed and the building lowered onto the trimmings of the beams, which are placed on temporary supports. Tow is laid between the logs and beams, which is treated with an antiseptic, in width, which is equal to the double thickness of the beam. Brick battle and gravel of 10 centimeters are poured under the proposed base tape.

When you have raised the house to a sufficient height and secured it securely with temporary supports, you can begin to dismantle the old columnar foundation. It is necessary to break the rubble and brickwork using chisels, crowbars and other tools that are easy to use. Old poles are dug out or pulled out of the ground, swinging them in different directions. You can use some of the materials that have retained their quality indicators to form a new base.

Building a new foundation

Consider replacing a columnar foundation with a strip shallow foundation, which is best suited for one-story houses. As the name implies, this type of foundation is considered to be something between a non-buried and a capital buried strip foundation. It consists of monolithic reinforced concrete strips 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 tape shallow foundation:

1. Tape shallow foundation is an economical solution. If you compare this foundation with recessed types of foundation, then it will cost you two to three times cheaper.
2. A shallow foundation requires less work than a deep foundation. This includes both modest earthworks and the ease of arranging formwork. Therefore, the replacement time of the foundation is significantly reduced.
3. A shallow foundation of a strip type allows, unlike non-buried foundations, to make a small basement in a residential building, and it is also less prone to heaving phenomena.

The construction of a new foundation should begin with excavation: dig a trench, the depth of which must necessarily exceed the depth at which the sole 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 project documentation. At the bottom of the trench, arrange a sand cushion. Then proceed to the manufacture and installation of formwork. The easiest way is to make it from boards that are planed on one side. They are easily knocked into shields of the desired size. In this case, the cost of replacing the columnar foundation will be lower. For their installation, spacers and support stakes are used, which must be driven in along 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 paper or other material and proceed to reinforce the new shallow foundation. For this, steel reinforcing bars are used, which have a diameter of about 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 bars to the future surface. 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 the concrete has been poured. Then the upper and side parts of the foundation should be waterproofed with roofing material or mastic. Cover the sinuses with sand and protect from the outside with a blind area. After the concrete has acquired sufficient strength (about two weeks), it is necessary to lay boards on the first element of the strip foundation, on which temporary supports should be installed.

New foundation load

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

When loading a new foundation, check the marks of the top of the base and, if necessary, use antiseptic impregnated wood gaskets or corrosion-protected metal elements if, after applying the load, the top mark 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 began to collapse, cracks appeared on the basement of the house, and the building itself began to squint to one side, you should immediately replace the old foundation. You can choose the type of a new foundation among several options - a column foundation similar to the old one, a bored pile foundation, a screw pile foundation or a strip foundation. But it is most preferable to equip a shallow strip foundation.