Cheap shallow foundation for a house in a swamp. Damp house How to make a foundation in a swamp: technology for constructing a slab foundation

Any construction begins with a layout on the ground. Once the master plan has been drawn up and the necessary materials and tools have been purchased, you can begin. If the construction of a house is carried out in a place with a high groundwater level and is characterized by deep freezing, then the most suitable option would be.

To make a columnar foundation, it is necessary to remove a layer of soil approximately 2-5 meters in all directions from the planned location of the foundation.

When laying a foundation in a damp area, high-strength concrete solutions are used, and load-bearing concrete pillars are reinforced with metal rods and thick wire, and ready-made concrete blocks are used.

To perform, you will need the following tools:

• construction tape;
• plumb line;
• linen cord;
• level;
• wooden pegs 50 cm;
• square

For excavation work you will need the following tools:

• pointed shovel;
• a shovel having a straight cutting part;
• pick;
• spade.

Masonry tools:

• jointing;
• hammer;
• mites;
• brush and brush;
• mortar box;
• trowel;
• concrete mixer;
• rake;
• barrel, watering can, bucket;
• graters;
• tamping;
• chisels

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Construction of a columnar foundation

The most common type in private construction is a reinforced concrete monolithic columnar foundation. The technology for its creation can be considered in stages.

1. Preparatory work

First, the construction site is cleared. To do this, cut off the plant layer of soil (10-30 cm) at least 2.0-5.0 meters in all directions from the planned location of the foundation.

If the soil under the cut layer consists of small stone and sand (medium- or coarse-grained sand, gravelly sand), then it is used as a base for the foundation, regardless of the freezing depth, humidity or groundwater level.

If the soil is clayey (loam, clay, sandy loam), then you need to make a sand and gravel cushion. Its thickness depends on the geological characteristics of the soil.

Silty or peat soils under the cut layer indicate that a complete replacement of the base and advice from a geologist on the design and composition of the artificial base are necessary.

The construction site is cleared of debris and foreign objects. After this, horizontal planning is carried out, and the mounds are removed and soil is poured into the pits. The horizontality of the area is checked with a level by placing it on a 2-meter flat strip or board. Preparation is completed after the delivery and storage of construction materials on site.

1. Foundation breakdown

Layout of the plan is transfer from drawings to the site and securing the main axes. In front of the house, cast-offs (pillars) are installed around the perimeter at a distance of 1 or 2 meters from the building. From the side of the planned walls of the house, parallel to them, wooden slats or boards are nailed to the pillars at a level, onto which the dimensions of the individual elements of the pit (pits and trenches), future walls and the foundation itself are applied. Control the layout of the center lines using a tape measure.

It is mandatory to check the corners of a rectangular foundation. Using a theodolite, it is necessary to check the markings of the bottom of the trench, especially at the corners of the house and at the points of intersection of the tapes. It must correspond exactly to the design (if it was decided to deepen the foundations by 1.4 meters, then the bottom of the trench will be 1.4 meters below the zero level of the house).

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Next stages of construction

1. Digging holes for the foundation

Rectangular holes are dug by hand or with an excavator. They must be located strictly along the axes. Pits with a depth of less than 1 meter can be made with vertical walls, without installing fasteners. If the depth is more than 1 meter, fastenings are made from slabs (boards) or with slopes. The hole is dug 20 or 30 centimeters deeper than the foundation and made wider than the foundation, 20 or 40 centimeters in each direction, to install the formwork and spacers. The foundation must be no less than the width of the walls being built. A gravel cushion is placed at the bottom 10-20 centimeters wider than the foundation on each side. It is generously moistened with water and compacted. Ruberoid or polyethylene is laid on top to maintain the moisture content of the poured concrete.

1. Installation of formwork

The formwork for the foundation is made of boards, planed on one side (the planed part is installed on the concrete). The wood can be of any species with a moisture content of up to 25 percent. The thickness of the boards is 25-40 mm, width – 120-150 mm. Wide boards are not suitable for formwork, as cracks will form during installation. You can use metal structures, particle boards, and waterproof plywood.

Wooden formwork is preferable, as it has less adhesion to concrete. The disadvantages of wooden formwork include hygroscopicity and the possibility of deformation. The formwork is installed exactly perpendicular to the base of the foundation and close to the walls of the pit.

Concrete can be poured without formwork if the walls of the pit are dry and not crumbling. In this case, polyethylene is laid around the perimeter.

Ceramic, asbestos and iron pipes can also be used for formwork. The internal diameter of the pipes can be from 100 mm or more, it depends on the design of the building. Concrete is poured into pipes and left in the ground along with the foundation.

When constructing wooden formwork, you must remember that the boards must be damp, so they are well wetted. Otherwise, dry boards will absorb water, and this will negatively affect the strength of concrete.

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How to install formwork when creating a columnar foundation

It’s good if it is possible to use ready-made panel formwork. This formwork has many installation options, and this is convenient for those who have a large number of corners The panels of inventory formwork can be flexible or rigid, length – 0.5-3 m.

1. Installation of columnar foundation reinforcement

The pillars are reinforced with longitudinal reinforcement with a diameter of 10-12 mm; after 20-25 cm, clamps with a diameter of 6 mm are made. The longitudinal reinforcement is installed vertically and wrapped with annealed wire or clamps. It is advisable to ensure that the reinforcement exits 10-20 cm above the top of the foundation, so that the reinforcement can then be welded to them. Concrete is laid in layers of 20-30 cm.

The grillage is made in the form of a prefabricated or monolithic reinforced concrete rand beam.

After creating a columnar foundation, you need to check the upper level marks and level them, if necessary, with cement mortar with a 1:2 composition. Then a prefabricated, precast-monolithic or monolithic reinforced concrete grillage (belt) is installed. A foundation with a monolithic belt has proper stability and longitudinal rigidity. Before arranging the belt, the boron jumpers must be firmly connected to each other. To do this, tie the mounting loops crosswise with wire twist or connect by welding scraps of reinforcement with a diameter of 8-10 mm.

Then they arrange formwork on top of the lintels, make a reinforcement cage and lay M200 concrete. The concrete surface must be leveled and covered with waterproofing material. After the waterproofing is installed and the concrete mixture has gained strength, they begin to install the floor slabs.

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Foundation waterproofing

When arranging a columnar foundation, in order to insulate the underground space and protect it from snow, debris, moisture, dust, etc., they build a fence (enclosing wall between the pillars). It can be made from different materials, but most often it is made from brick or stone. To create a fence between the foundation supports, a concrete screed is made as a base.

A concrete screed without deepening is placed on a sand cushion with a deepening of 15-20 cm. When installing a concrete screed, a reinforcement frame and formwork are required. The screed is laid on a concrete screed. In the entryway, as in the basement, technological windows are made to provide communications. The pick-up is not connected to the supports, since uneven settlement leads to the formation of cracks. Its height should be made at least 40 cm. The effect of moisture on the walls of the house depends on this; the higher the fence, the less the effect of moisture on the walls.

In order to do this, there are several ways:

• The upper part of the supports and the fence are covered with a layer of bitumen. A strip of roofing felt is laid on it and a layer of bitumen is applied again, then the next strip of roofing felt is laid;
• The upper part of the supports and the fence is covered with a layer of cement mortar with a ratio of 1:2. Sprinkle it on top with a layer of dry cement of 2-3 mm. After the cement has set, a strip of roofing felt or roofing felt is laid.

Construction of the foundation involves certain difficulties and is associated with financial costs. Very often, the construction of the foundation takes up a quarter of the cost of the future building. But nevertheless, saving on the base is considered unacceptable, because it is the basis of the structure, and it is on it that the entire load falls.

Therefore, any attempt to save on the foundation can have very disastrous consequences. An unsound foundation can allow cold and moisture to penetrate into the building and can also lead to cracking of walls, compromising the integrity of the entire structure.

There are times when building the foundation of a house is even more problematic than usual. We're talking about foundation in a swamp. Such soils are characterized by a number of disadvantages:

1. They are characterized by low load-bearing capacity. It turns out that when significant loads are placed on the ground, it simply cannot withstand them and the structure seems to fail.

2. Another problem is seasonal changes in ground level. This is especially observed in the spring, when there is a significant rise in groundwater levels due to melting snow.

Considering all of the above, foundation in a swamp must meet a number of special requirements, which will be discussed in more detail below.

Choosing the right base type

Due to a number of soil imperfections, many people think about what kind of foundation is there in the swamp should be built. If the choice is made incorrectly, this may lead to the destruction of the building when the ground level changes. In addition, the building may begin to go underground under its own weight several years after construction. For this reason, the issue of choosing and calculating the foundation should be approached with all responsibility.

Today, there are several options to find a solution to this problem. Let's consider what kind of foundation is there in the swamp would be the most acceptable option:

1. Pile foundation, the price of which is the most reasonable. This solution is an excellent option if construction needs to be completed as soon as possible. There are two types of piles: bored and reinforced concrete. In the process of arranging the foundation, they are laid to a depth of about 12 meters. If we are talking about complex soils, then the depth of the pile can reach 25 meters. This is done so that the pile foundation simply passes through the unstable swampy layer and rests on a solid foundation. This approach ensures that the structure is immune to seasonal fluctuations in soil level.

Such work can be completed within two to three days, and the cost of carrying it out is low. Construction can be carried out at any time of the year, both summer and winter.

2. Monolithic base. It is the most expensive type of foundation, which is the best option for working on unstable soils. Construction of a slab foundation carried out in both single-storey and multi-storey buildings. Essentially, this is a large monolithic slab that is buried to the level of soil freezing.

Even with strong heaving of the soil around the foundation, this fact does not affect its strength in any way, and the high weight of the structure prevents the building from being lifted. Due to its high strength, such a base can withstand significant tensile or compressive loads, as well as bending, which is why it is monolithic foundation on a swamp for a house most often built on marshy soils. The disadvantages of such structures include their high cost, because pouring such a foundation requires a large amount of composition. Though strip foundation cost and lower than monolithic analogues, such foundations are not recommended to be erected on swampy soils.

3. Monolithic shallow foundation. It is considered something between the pile and monolithic options, which is reflected both in the cost of construction and in the timing. Shallowly recessed foundation on a swamp for a house has proven itself well due to its excellent resistance to soil heaving. However, its small thickness does not allow such a base to withstand severe compressive loads. For this reason, it is only suitable for small frame or wooden buildings.

Which foundation option is easiest to build yourself?

Since many home craftsmen decide to build houses with their own hands, first of all they should know what kind of foundation for a house in a swamp will be the best option, both in terms of economy and reliability.

Unfortunately, it is almost impossible to fill a pile foundation on swampy soils without involving specialists in this process. Here it is necessary to determine the thickness of the swampy layer, which will help to correctly calculate the depth of the foundation. In addition, only professional builders have at their disposal heavy special equipment that allows them to quickly drive piles underground to a depth of about 20 meters. Therefore, you should not even attempt to independently arrange such foundations without having specialized equipment.

As for shallow and monolithic foundations, they are quite suitable for pouring without the use of special equipment. However, to carry out the work you will have to rent a concrete mixer, because in order to pour foundation for a house in a swamp, tens of tons of concrete will be required.

Technology for pouring a monolithic foundation

Now let's take a closer look. The best time for carrying out such construction work is the second half of summer, since this period is characterized by a minimum groundwater level, and rains are observed quite rarely. Warm air, which is typical for this time of year, will also contribute to rapid hardening of the composition. This means that it will be possible to refuse expensive construction additives.

You should start building a house if you have a ready-made project. Only in this case will the accuracy of the calculations be ensured and all errors eliminated. When drawing up a plan, it is advisable to make indentations for the foundation of 30 centimeters beyond the perimeter of the house on each side.

The work is carried out in several stages:

1. Using stakes and a nylon cord, the place where the foundation will be located is indicated.

2. A pit is being dug, about one and a half meters deep. To accurately determine the location of the foundation, it is best to use the services of specialists who can measure the depth of soil freezing. Such calculations can be made by specialists from the InnovaStroy company. Carrying out excavation work involves excavating many cubic meters of earth, and of course, it is not possible to perform such a volume of work with an ordinary shovel. It is best to hire an excavator for this.

3. Crushed stone is poured into the bottom of the pit, which must be evenly distributed to a thickness of about 30 cm. Then the same amount of sand is poured, evenly distributed and compacted.

Thanks to the presence of a cement-sand cushion, it is possible to solve several problems simultaneously: to achieve uniform distribution of the future building on the load-bearing soil; reduce the effect of soil heaving; quickly remove moisture from the foundation due to melting snow and precipitation.

4. A layer of waterproofing is laid on top of the crushed stone-sand cushion. For these purposes, it is best to use roofing felt, since it is not only durable, but also highly efficient and able to withstand severe tensile loads without breaking.

5. The roofing felt should not only cover the bottom of the pit, but also extend onto its walls to a height of at least 30 cm.

6. At the next stage, the reinforcement frame is prepared, for which steel rods and tie wire are used. You can connect the frame elements by welding. Such a structure should cover the entire volume of the foundation, which will ensure the resistance of the concrete to bending and tensile loads. The reinforcement is located in two layers: in the upper and lower parts of the foundation.

7. Next, the concrete solution is prepared. For this, it is best to use cement grades M400 and M500. These are the most durable options that can ensure the stability of the future building on heaving soils. To mix the composition, use a concrete mixer.

9. After this, the composition is compacted using vibration equipment, which will make its structure homogeneous, eliminating air bubbles.

10. At the last stage, it is necessary to allow the concrete to gain the necessary strength. This usually takes at least three weeks. It should be remembered that the final setting time of the composition depends on a number of factors, including air humidity, foundation thickness, temperature environment etc.

We have considered how to make a foundation in a swamp, what type of base to choose and how to carry out the work of pouring the composition. Despite the apparent simplicity, such work involves a number of nuances and the use of specialized equipment, and therefore it is best to entrust them to professionals.

Professional execution of construction work of any complexity

If you are interested, how to build a foundation in a swamp, and at the same time you do not have the necessary construction skills, then the InnovaStroy company will be able to do all the work for you. Our specialists are able to carry out construction work of any complexity, including calculating the foundation on marshy soils with its subsequent pouring.

We can implement foundation construction in the Moscow region in the shortest possible time. In this case, the work will be carried out with high professionalism. In addition, InnovaStroy specialists are able to develop a house project of any complexity and carry out turnkey construction of the building.

Construction of the foundation is one of the main construction tasks, which ensures the durability and reliability of the entire building. But the strength of the base depends not only on the correct execution of installation work. In this case, the soil plays an important role, namely its features. Therefore, when choosing the type of foundation, you need to focus on this parameter.

Features of the foundation in the swamp

The foundation for a house in marshy areas requires special attention. After all, in addition to the load-bearing load from the mass of the house, it also experiences the plasticity (mobility) of the soil, which can lead to the following problems in the future:

• Partial or complete flooding of a house during the heaving season when the groundwater level rises;
• Uneven distribution of load on the base, which can lead to destruction of the task in the area of ​​the foundation or along load-bearing walls;
• Constant dampness in the house and the spread of fungus from the floor, etc. However, such problems can be avoided if you choose the right type of foundation for a house on swampy and waterlogged soils.

The fact is that the composition of the soil in swampy areas is quite diverse and can include peat layers, sand, clay, quicksand, etc. Such combinations inevitably lead to constant soil movement. Therefore, it is so important at the design stage to conduct a preliminary soil analysis by drilling several control wells and taking soil from them for analysis. You can order soil tests on a construction site from special organizations. The service, of course, will cost a pretty penny, but in the future the architect will be able to correctly calculate the bearing capacity of the foundation.

Types of foundations for swampy soils

It is possible to build a house in a swampy area if you adhere to all the nuances of installation technology. And as the foundation for a house, you can choose these types of foundations.

Pile base

The best option for foundation for a house in a swamp. This foundation is based on monolithic reinforced concrete or bored piles. Sometimes their depth can reach 15-20 meters, depending on the amount of groundwater in the area and the degree of heaving of the soil. But a house on such stilts will feel safe and strong for many years. Even with severe heaving, the building will remain in place. The pile foundation can be installed both in summer and at sub-zero temperatures. The work is completed in 2-3 days.

Important: below the 20-meter mark, the pile has simply already overcome the marshy soil layer and rested on dry layers, which makes the supports even more reliable. However, it is worth remembering that it is impossible to build such a foundation on swampy soil on your own. This will require sophisticated drilling equipment. Although the cost of purchasing all the material itself is not that high.

However, it is worth remembering that piles are not recommended to be installed in soils that are prone to horizontal shifts. In this case, even the strongest piles over time may not withstand the horizontal pressure of the layers and simply break. Which will lead to the destruction of the house over time. On such soils it is better to install a foundation slab.

Slab monolithic foundation

This type of foundation fits perfectly on swampy soil and is a monolithic reinforced concrete pad. It is also called a floating foundation, due to the ability of the base to maneuver in the soil during heaving seasons. That is, the base will simply follow the movement and direction of the soil, withstanding significant loads. The depth of such a slab should reach 1.5-2 meters in order to go into the ground below the soil freezing level. It is better to pour a slab-type foundation in the summer, when the groundwater level in a swampy area goes as deep as possible and gives craftsmen the opportunity to work dry.

Important: it is desirable that the base of the foundation extends beyond the design parameters of the building by 40-50 cm.

As another type of foundation for construction in swampy areas, a shallow slab foundation can be presented. This is the same floating slab that goes only 50 cm into the soil. But it is worth remembering that such a foundation can only be built for lightweight frame or timber houses on one floor. The large mass of the house (if you install a brick or block cottage) will simply break the foundation due to resistance from the soil during heaving seasons.

Do-it-yourself foundation installation: choosing the type of work

If you don’t know which foundation is best to install in swampy areas with your own hands, then give preference to a slab. This type of base, even with large volumes of work, can be completely done with your own hands. As special equipment you will only have to rent an excavator to prepare the pit and a construction mixer with ready-made mortar. Otherwise, you can do everything yourself

If you prefer a pile foundation, then you should know that it is better to entrust the work to professionals. Since only craftsmen can clearly control the evenness of the well under the pile, its depth and the uniformity of filling the column with mortar. In addition, only a competent operator can work with drilling rigs.

Carrying out work on the installation of a slab base

In this section you will learn how to make a monolithic floating foundation in a swamp. First of all, it is worth understanding that it is better to carry out work in the second half of summer in dry weather. It is during this period that all groundwater is located as deep as possible.

• It’s good if the developer already has design documentation on hand. It is along it that the axes are broken down in the area under the base. That is, stakes are installed along the entire perimeter of the future foundation and control cords are pulled between them. Do not forget to increase the base slab by 30-50 cm on all sides.
• Now is the time to remove the soil to the specified design depth. For this, it is better to use a bucket, since you will have to do the excavation work yourself within 2-3 weeks. Yes, and physically it is quite difficult.
• The bottom of the prepared pit is well compacted and covered with a layer of crushed stone 20-30 cm thick. It is also compacted well. And the next layer of the pie becomes a layer of sand of the same thickness. It is moistened and compacted until there are no traces on the sand when stepped on. When performing this stage of work, you need to use a shovel to clearly level the walls of the pit for installation of formwork.
• Now formwork is installed in the pit, which should be higher in height than the ground. This is done to form a base 30-50 cm high.
• The bottom of the pit and the walls of the formwork are covered with roofing felt, the joints are overlapped and coated with bitumen mastic. Such waterproofing will prevent contact of the concrete base with groundwater and prevent the flow of concrete milk into the ground, which could reduce the final strength of the foundation.
• Then steel reinforcement is installed in the pit in the form of meshes connected from steel rods. For every 50 cm of foundation thickness there should be one mesh connected to a cell size of 20x20 cm. All transverse meshes are connected to each other by longitudinal rods. It is important to remember that the reinforcement should be buried in concrete 5 cm from the top and bottom and 2-3 cm from the sides of the slab.
• Now you can fill the monolithic base with the prepared solution. Taking into account the fact that tens of m3 of it will be required, it is better to order ready-made concrete. Grade 400 or 500. This type of mixture will provide greater load-bearing capacity of the base. The solution must be poured in one stage, since step-by-step mixing of the solution and its pouring lead to a violation of the technology for installing the slab base and a decrease in its final strength.

• The poured base is covered with film and left for 3-4 weeks until completely dry. In the first days, the slab must be periodically moistened to prevent the mixture from drying out suddenly. After a month, the slab is completely ready for further construction work.
• Once the slab has completely hardened, you can backfill the base. For these purposes, you can use clay soil, which will act as additional waterproofing for the monolith. In this case, the clay must be compacted well when backfilling.

Important: shallow slab foundations are also installed using the same principle. Remember, a well-made base is the key to the longevity of a house on marshy soil.

A foundation with a high groundwater level is one of the most complex and critical structures.

Such a foundation for a house must be built taking into account many different factors, each of which must meet all the requirements associated with the danger of flooding and premature destruction of the building.

Accordingly, it is important to correctly determine the level of soil freezing, select the most suitable foundation design and ensure the presence of an effective drainage system.

Determining groundwater levels and possible concerns

The construction of the foundation at a high groundwater level must be stable and reliable. The extent of the threat of subsidence and destruction of the building is determined long before the start of construction work. For this purpose, in the spring or autumn (at a time when the amount of moisture contained in the soil reaches its maximum level), in the place where, in accordance with the construction plan, the basement will be equipped, a hole should be dug at least 3 m deep.

To obtain accurate data, you will need to reliably protect the pit from weather precipitation. After a few weeks, a certain amount of water will appear and settle at the bottom. Perhaps the bottom will remain dry, and then the foundation does not require additional protection.

If the water is located at a distance above 2 m from the surface, it is necessary not only to calculate the depth at which the foundation will be built, but also to choose the right design.

What should the foundation be like in case of high groundwater, experts can say after conducting geological surveys.

Among the existing foundation structures on high-level groundwater, pile structures are especially popular and trusted by consumers.

Their arrangement will help ensure high-quality and reliable protection of the foundation of the house from the negative influence of groundwater:

• flooding of basements;
• destruction of concrete structures;
• the occurrence and development of fungus and mold;
• violation of the integrity of the foundation itself when freezing during the cold season.

In addition, high groundwater level causes the walls of the pit to melt and a sharp reduction in the bearing capacity of the soil. This will require additional work to develop an effective drainage system, including wells and catch basins.

The most dangerous process is the leaching of minerals from the soil, which significantly worsens the strength characteristics of the soil and leads to a change in its structure. Installing a foundation in such conditions has a number of limitations. Calculation of the depth at which the supporting structure will be poured is carried out taking into account the qualitative characteristics of the soil:

• loams;
• sandy;
• clayey;
• mixed.

The level of heaving and the depth of soil freezing depend on this. If the freezing depth is less than the ground level, then there is no need to make adjustments for soil characteristics when planning.

The calculation is carried out with adjustments for soil type and possible subsidence of soft soils.

The data obtained most often forces one to abandon the construction of a strip structure, since the associated work will be very labor-intensive and require significant material costs.

A variety of foundations and the correct choice of the desired design

What kind of foundations are needed for houses, if groundwater is close, is chosen depending on the various features of the site itself on which construction is being carried out. A foundation on water is a structure that should ensure the stability of the building, its durability and reliability. To do this, it is necessary to take into account both the quality of the soil and the upcoming loads coming from the building.

Construction of a foundation on clay soils with a high groundwater level involves the construction of any type of foundation:

• belt, the trenches of which are deeply buried;
• pile;
• slab (shallow).

The strip base requires the creation of a monolithic reinforced concrete structure located under the external and internal load-bearing walls.

First of all, markings are made on the site, according to which they dig trenches for the strip foundation. Their depth must exceed the freezing height. The calculation is carried out adjusted for the characteristics of weather conditions (temperatures in winter) and soil.

If groundwater is close, and construction is to be carried out on clay, a strip foundation will perfectly replace a “floating” monolithic slab. The weight of the building is evenly distributed over the entire surface of the slab, which is laid on a sand and gravel bed.

Before making such a foundation, you will need to remove soil from the entire area of ​​the future foundation. The pit is dug to a depth 50 cm greater than the thickness of the slab. The calculation is based on the soil freezing depth.

A pile foundation for a house is the best option for creating a high-quality, reliable foundation on clay soils.

By changing the parameters of the piles, it is possible to install supports on hard rocks that are not subject to destruction under the influence of groundwater.

To carry out work in an area with high groundwater level, it is necessary to calculate the load on each individual pile.

Construction of various types of foundations

If groundwater is close to the foundation site, then before you begin constructing a slab foundation, you will need to prepare ditches along the entire perimeter of the future building. It is better if it is a trench 20-30 cm wide and at least 50 cm high (depth). The ditches will be filled with rain or melt water, and thus drainage will be carried out. For more information about the preferred type of foundation, watch this video:

The “floating” slab does not lie on clay soil, but on a cushion created from sand and gravel. This type of foundation must be poured by building it on bulk soil. Before pouring, install a drainage system, laying drains at a slope of at least 5 cm for each meter of pipe. To protect the slab, it is necessary to line the inner surface of the base with waterproofing materials. Most often, roofing felt is used, laying overlapping sheets 10-15 cm wide. Fastening is done using bitumen.

A reinforcing frame is laid on the waterproofing and filled with concrete, the filler for which is fine gravel. It is better to fill the entire base in one day.

A strip foundation requires careful preparation of the pit trenches. They must be deep and wide enough to exceed the freezing depth of the ground and allow the formwork structure to be assembled efficiently.

The monolithic tape is poured, taking care of the correct filling of its bottom, high-quality compaction and installation of waterproofing. A frame is installed inside the formwork, connected from reinforcing bars of various sections. Concrete is poured in layers with mandatory compaction of each layer. For useful tips when building a house on soil with high groundwater level, watch this video:

The pile grillage foundation is recognized as the most reliable when constructing buildings in areas with high groundwater level. When making such a foundation, it is important to follow soil indicators, depending on which the size of each of the piles used is determined. Piles are used:

• screw;
• bored;
• driving.

Screw structures can be installed independently without the involvement of heavy construction equipment. After installing all the piles, a grillage is assembled on them or a beam is laid, which is necessary to tie the entire structure together.

Construction on marshy soils can be compared to an extreme sport due to the unpredictability of the results. The main problem of a house on swampy soil is the very poor bearing capacity of the soil and excess moisture. It is possible to build in such conditions only using a guaranteed effective and stable foundation. Not all options for foundation structures will be able to hold the building in a stable position for a long time.

Which foundation is best to use in swampy areas?

In each specific case, the choice of a specific foundation scheme depends on the condition of the soil, the level of groundwater and the types of soil in a particular area. Therefore, before making a decision, it is necessary to conduct exploration and assessment of the nature of the soil, sources of groundwater that flood the area, and the depth of solid rock layers.

Advice! If you can qualitatively assess why a given area is flooded and how to deal with the causes of flooding, you can reduce the cost of a foundation in a swamp several times.

Depending on the results of the study, you can choose the most optimal option for the foundation for the house:

• Strip foundation with enhanced drainage and deep drainage. Although experts do not recommend using strip foundation systems for waterlogged areas, it can be used for a certain type of soil in a swamp. For example, for soil with a large amount of coarse river sand, with deep aquifers and the absence of natural springs and springs on the surface in close proximity to the building;
• Pile foundation on bored or concrete supports. When building in a swamp, such a construction of a foundation block is often the only correct and reliable option if the soil gets wet to the point of a watery porridge. In this case, the piles are driven to the level of hard layers under the bottom of the swamp;
• Floating or slab foundation can be used on very viscous and dense soils in the absence of flooding of the area with flood and rain water.

When choosing a specific scheme, it is advisable to perform full deep drainage and drying of a small area of ​​soil of several square meters. By digging a hole one and a half meters deep, you can try to get an idea of ​​the soil of the swamp on which you plan to build a house.

Which foundation in a swamp will be most effective?

The main problem in the construction of any buildings is not the technical or technological issues of arranging foundation systems in areas where swampy soil dominates, but the huge costs associated with a large amount of additional work and the need to ensure effective drainage from the basement parts of the foundation. A strip foundation may seem like the cheapest option, but not every swamp can build one.

Strip foundation for a house in a swamp

The construction of a foundation in the form of a strip in terms of the volume of materials used and the amount of work will be the cheapest from the list above. If the results of a study of soil geology show the presence of coarse-grained sand layers up to one and a half meters deep, it is quite possible to get by with the construction of a classic strip foundation. Most often, this situation arises if the owners of the future building choose an area for construction in the floodplain of a river, in a lowland, where swampy and waterlogged soil is associated with the presence of a river.

The construction of a strip foundation in such a swamp is possible only if the following measures are taken:

• The site must be equipped with a very powerful drainage system using hydraulic barriers to prevent the penetration of water from nearby areas;
• The foundation for a house on the site is installed in the highest place, taking into account the possible direction of rain flow;
• Highly efficient drainage system for soil adjacent to the foundation.

Before starting work on building a foundation in a swamp, it is very important to make sure that there are no underground springs, of which, as a rule, there may be a lot in such an area. If reconnaissance confirms their presence, it is better to abandon the use of this type of structure in the swamp in favor of other options.

Pile foundation in a swamp - the optimal solution for heavy houses

If you are planning to build a solid brick house with an attic, you will need to use foundation systems with maximum load-bearing capacity. For a swamp, this is the pile version of the foundation. The essence of the design of such a foundation in a swamp is to install the required number of concrete or bored piles resting on solid layers of rocky soil under the bottom of the swamp. The cost of such a foundation block for a swamp will be many times higher than the previous option. Unlike strip schemes, which can support relatively small frame-type houses in a swamp, a pile version of the foundation for a house in a swamp can easily support a brick building of several floors for many years.

In this case, to build the foundation you will have to use special equipment with which you can drill and fill bored piles. Doing this amount of work manually is quite difficult. The depth to which the pile support is installed can reach 5-7 meters, which is determined by the geology of the swamp.

If hard soil layers are located at a relatively shallow depth of 2-3 meters, you can use screw piles. They are much cheaper, and in some cases you can even install them yourself. As a preventive measure, the top layers of soil to a depth of 60-70 cm are often removed, road geotextiles are laid and backfilled with a sand-crushed stone mixture. The upper heads of the piles are connected by a powerful grillage or a steel frame made of paired channels No. 200.

If the swampy area has a top layer of hard soil, which is often found on peat bogs and lake remains, it makes sense to use it as it is simpler and more accessible to make with your own hands.

Slab foundation for a small house

The advantages of a foundation system in the form of a continuous monolithic slab include enormous rigidity and strength. Such a foundation structure will not float up and will not tilt, even if the water level of the swamp rises. A good slab foundation is suitable for frame, aerated concrete, foam concrete houses that require special measures to ensure frame rigidity.

The cost of building a slab foundation in a swamp will cost you 20-25% less than the pile version. If we compare the construction of a foundation system on pile supports and a slab version in ordinary dry soil conditions, then the cost of the slab will be as much as 40% more than the pile system.

The slab construction technology will require digging a pit 60-70 cm deep, filling it with a layer of sand and a layer of crushed stone, laying film waterproofing and installing panel formwork around the perimeter of the pit. For a slab foundation structure in a swamp, in addition to high-quality waterproofing, it will be necessary to lay more powerful steel reinforcement. Most often, reinforcement with 12 mm rods is used with the installation of lintels and crossbars. The base and top of the slab must be insulated with expanded polystyrene or foam glass.