Types of Foundations in Building Construction

Types of Foundations in Building Construction

The construction of any home begins with the foundation. It does not matter whether we are talking about industrial construction or a private house, the characteristics of the entire structure always depend on the reliability, strength and durability of the foundation. The types of foundation in building construction are very different, they vary in type of construction, material and other parameters. Below we consider not only the common types of foundations, but also the subtleties of their construction.

Types of foundations in building construction, their features and device

The main classification of foundations takes into account their design features. The most popular are the following types: strip , columnar, pile and slab. Various combinations are also possible.

Strip foundation

If you look at the photo of the strip foundation, it becomes clear where it got its name from. This type of structure consists of tapes dug into the ground, which take up the main load from the supporting elements of the main structure. Tapes, in turn, are based on foundation slabs. Thus, a significant part of the load from the walls is distributed over a large area.

Schematic illustration of a strip foundation device
Schematic illustration of a strip foundation device

When constructing a strip foundation, there is no need to carry out preparatory work for the soil, so it is good if you need to build a building quickly. On the other hand, it is not designed for heavy loads, so one-or two-story houses are the best option for using a strip foundation .

The depth of the foundation of the strip foundation largely depends on the materials from which it is made, as well as the type of execution chosen during construction. There are two main types of tape design:

  1. Precast foundation – made of reinforced concrete blocks. For assembly, you need specialized equipment, the blocks themselves are produced at the factory.
  2. Monolithic – made immediately at the construction site (without an intermediate link in the form of a factory).

Pros and cons of strip foundations made of various materials:

  • reinforced concrete strip foundation – has exactly two advantages: the relatively low cost of the material and the ability to withstand heavy loads. If you need to build a building with heavy load-bearing walls, a reinforced concrete foundation is your choice. The disadvantage of this option is a long time for construction work;
  • concrete concrete is another popular and relatively inexpensive type of strip foundations. It consists of concrete, which is additionally filled with boulders, gravel or brick fight. Also able to withstand heavy loads;
  • brick foundation – used for the construction of buildings up to five floors and in cases where it is impossible to use a monolithic foundation. As the name implies, it consists of clay bricks.

ribbon foundation

Useful advice! If you need to make calculations of the strip foundation, a calculator for this can be found on the Internet. With it, you will calculate the consumption of material, determine the depth of construction and other important parameters.

In general, the positive properties of the strip foundation can be distinguished by its ease of installation and the ability to use as walls for the basement. Also, this type of foundation is characterized by high bearing capacity. Cons of the tape structure – for its construction you will need specialized equipment, for example, a crane, a dump truck and a concrete mixer.

Column foundation

A pillar foundation is a pillar submerged in a specially drilled well or directly in the ground. The posts above are connected by reinforced concrete beams and are designed for houses with a relatively low weight. Such a foundation will be an excellent option for a medium-sized wooden house or other construction made of light materials. It is good for country houses or frame buildings.

device of the column foundation
The device of the column foundation

Columnar foundations for a private house are used on stable soils, which are not characterized by deformation from temperature extremes. Like strip, columnar foundations can be prefabricated or monolithic. In addition, they can be made from the following materials:

  • brick – used to support buildings and structures with brick walls up to two floors high;
  • stone – for heavy buildings;
  • wood – the best option for wooden structures, for example, baths or country houses;
  • reinforced concrete is the heaviest version of the column foundation, used in industrial structures or buildings with a large weight, which have more than two floors.
Building a columnar view of the foundation
Building a columnar view of the foundation

Calculations of the column foundation are based on the dimensions of the structure and other parameters.

The advantages of a columnar foundation include its relatively low cost, but there are more negative sides. This is a low strength, and possible problems with the construction of a basement or basement. Therefore, this type of structure is best used for small farm buildings, bathhouses, sheds and other structures that do not provide a basement and are not too heavy.

Slab foundation

This type of foundation is a reinforced concrete slab that is laid to a certain depth. Its thickness can vary from 30 to 100 cm, and reinforcement is used to increase the strength characteristics. As a preparation, a layer of concrete is poured under the slab or sand is poured.

The pros and cons of the slab foundation can be described in a few sentences. It is good in that the load is evenly distributed over the entire area of ​​the slab, so the slab foundation tolerates both vertical and horizontal deformations. Most often it is used on weak types of soil, for example, quicksand, sand, etc. The disadvantage of such a foundation is that it is performed only in a monolithic form.

Construction of a slab foundation
Construction of a slab foundation for a country house

Useful advice! If necessary, the construction of a large area of ​​the tiled foundation applies the so-called expansion joints. This means that one large slab is cut into several smaller pieces. This technique avoids the occurrence of cracks and reduce the bearing capacity of the foundation.

Another disadvantage of the slab foundation is the high cost of installation and the materials themselves. But, if you want your house to stand as long as possible without deformation, even on the most unstable soil, this option would be ideal.

Pile foundation

This type of foundation for a private house, such as pile, is one or a series of piles that are combined on top with a special plate. The slab can be made of concrete or additionally reinforced with iron reinforcement. This option is often used when you need to erect a structure on very weak soil, under which there is a stronger one.

Structures on stilts are built on sand, quicksand, loose soils. This type of construction allows you to transfer a significant load on soft soil, and also helps the foundation to support the weight of a large building.

project of a private house with a pile foundation
3D project of a private house with a pile foundation

Pile foundations for a private house can be made of various materials:

  • wooden piles – used for small wooden buildings. They are made mainly of pine processed using special technology;
  • reinforced concrete is a good option for foundations for buildings and structures with reinforced concrete walls that are heavy;
  • metal – is used when for some reason it is impossible to use reinforced concrete structures;
  • combined piles of metal and concrete – are used in extreme conditions or on very difficult soils, for example, on marshy soils.
Combined piles of metal and concrete
Combined piles of metal and concrete are used in construction on difficult soils

In addition, piles differ in the type of manufacture:

  • indented – deepen into the ground using special hydraulic pumps;
  • stuffed – first, a well is drilled, and then concrete is fed into it, which allows you to get a pile. In this case, various brands of concrete can be used for the foundation of a private house;
  • driven – driven into the ground with the help of specialized hydraulic hammers. This type of structure can only be used when there are no other buildings nearby, since the shock wave when driving a pile can damage the neighboring structure;
  • screw piles – the price of a pile-screw foundation is higher than the previous options, but it can be used on any soil, regardless of its density and other characteristics. This type of pile is screwed into the soil like a screw. Despite the fact that there are also disadvantages, the advantages of pile-screw foundations allow their wide use for the construction of bridges, towers, power lines and other specialized structures.

Useful advice! Stacked or pressed-in piles are best used when there are old or dilapidated buildings nearby, which will keep them intact.

The disadvantage of any pile foundation is the high cost of its construction. The installation and transportation of piles requires the use of specialized equipment, which significantly increases the cost of construction work. And the undoubted advantage is that such a foundation can be built on a limited territory and with a small amount of earthwork.

How to choose the right type of foundation

There are a number of general recommendations that can be applied to the device of any type of foundation. Common factors include the following:

  1. The presence of groundwater under the future design.
  2. The general condition of the soil at the construction site.
  3. The magnitude of the load from the supporting structure.
  4. The depth to which the soil freezes as much as possible.
  5. The presence or absence of a basement.
  6. Estimated service life of the structure.
  7. What materials are used in construction.
  8. Are there any underground utilities on the site?

All these points are extremely important when choosing the best option for the type of foundation for a private house, so they should be given special attention. Below we consider each of the factors in more detail.

Assessment of soil for the presence of groundwater and the depth of freezing

Qualitative and complete soil assessment can only be done through a full geological survey. Well, if the results of such studies are available from the organization that owns the land. Otherwise, the soil must be examined independently.

To do this, a pit is being excavated at the construction site or a well is being drilled, then the height of the bulk layer, which cannot be used as the foundation for the building, is measured. With the start of construction, this layer is removed, leaving only bearing soil.

When building a foundation for a private house, it is worth considering that in the cold season, almost any type of soil swells. If this problem can not be avoided, it is necessary to ensure that the rise of the foundation in the winter occurs evenly over the entire area of ​​the building. Dry soil rises less than wet, and sand – clay.

When working with complex soils, soils containing clay inclusions, a pillow of medium-sized sand or gravel is often used.

Measuring the average and maximum depths of soil freezing can be quite difficult, as it has a wide range. This largely depends on the density of the soil: the denser it is, the stronger the freezing. It is logical that soil saturated with moisture also freezes well. This means that if there is groundwater at the construction site, the foundation needs to be laid deeper or wider.

Useful advice! Clay soils are very difficult to build a foundation, as they swell unevenly. In order to avoid deformation of the foundation, erected on the soil with clay impregnations, it is necessary to create an anti-cushioned pillow, that is, completely replace the complex soil with sand.

Sand and gravel pillow
Sand and gravel pillow is a drainage and depreciation element of the foundation

If you are creating the foundation for a frame house with your own hands, but you do not have enough financial resources for a full geological exploration, you can use the old proven method. It consists in observing the asphalt road leading to the building site. If the asphalt is cracked at the beginning of spring, this means that the soil on the site is heterogeneous.

Dips in the asphalt indicate the presence of underground water flows or places that are strongly compressed at low temperatures. You can also conduct a survey among the closest neighbors who can talk about possible problems with the foundations of their houses.

Types of soils and their features

The nature of the soil under construction is the most important factor affecting which types of foundation for a private house are better to use. There are four main types of soil:

  • sandy – has a relatively low heaving index and is one of the best options for building a foundation. On a sandy ground, you can easily build a foundation for a house from aerated concrete, foam concrete , brick, wood and other materials. Sand is good in that it is well compacted and compacted, passes water well, so that the foundation does not lock;
  • clastic or rocky soil – the stone does not freeze and does not swell, and generally weakly changes its properties under various weather conditions, therefore it is an ideal option for building a foundation. The minus follows from the plus – in this soil the foundation is quite difficult to build;
  • clay – one of the most difficult for the construction of the foundation, as it has great heaving. Dry clay soil is a good foundation if there is no underground water under it. Otherwise, you will have to either arrange an anti-cushioned pillow, or transfer the construction to another site, or use pile foundations, the pros and cons of which were discussed above;
  • dusty soils or fine-grained sands – are rarely used to build the foundation, since they are floating, swell very much in winter and freeze to great depths.

How to calculate the depth of the foundation

The depth of the foundation directly depends on the type of soil on the construction site. If it has a high heaving index, the laying depth should be no less than the estimated freezing depth. When the soil is conditionally non-porous, the laying depth can be from 0.5 meters to one meter, depending on the depth of freezing. On non-porous soil (for example, rocky type or coarse sand) the depth of the foundation should be at least half a meter.

depth of the foundation
Variants of the columnar foundation device: 1 – prefabricated reinforced concrete support pillar with a rod support frame; 2 – compacted homogeneous soil; 3 – base plate made of monolithic reinforced concrete; 4 – reinforced concrete pillar with a core of a metal pipe; 5 – prefabricated support column of a metal pipe

At any depth of foundation laying, a prerequisite for successful construction is the removal of atmospheric and surface water to protect the foundation from moisture.

Important factors for choosing a foundation

The choice of the type of foundation for a private house depends on the following factors:

  • engineering and geological situation on the site. For its study, it is best to hire a team of professional geologists who will take a soil sample and draw up a detailed report based on the research results. The report should include the thickness of the various layers of the soil, the depth of the groundwater, the heaving of the soil. The study will show which foundation is better for houses made of aerated concrete or any other material in this area;
  • collection of loads – that is, the sum of the weight of all structures of the future structure. This parameter is most important when choosing the area of ​​the foundation, as well as the material for its construction. The calculation of the parameter should be carried out by an experienced design engineer who will select the best material and type of foundation. For example, given the pros and cons of a pile-grill foundation, you can use it for relatively heavy structures;
  • foundation laying depth – the need for waterproofing and drainage for the foundation should always be added to this parameter. This is necessary if there is a river or lake near the house, as well as in the presence of an elevated groundwater level;

Useful advice! Drainage and waterproofing are most effectively used in the complex. That is, simultaneously drain water below the mark of the lower part of the foundation and protect its base with the help of special waterproofing materials.

  • taking into account the load from nearby structures – if heavy structures are nearby, the soil is already deformed, so when building your building next to others, the soil load must be summed up;
  • probability of an accident – this includes the possibility of a breakthrough in water communications, which can significantly change the structure of the soil and cause subsidence of the foundation.
Foundations from various building materials
Foundations from various building materials: a – rubble; b – concrete; c – brick with concrete; d – brick; i – brick with but; f – rubble on a sand cushion

The choice of poor-quality material or negligent work is a factor that can play a cruel joke even if you are as attentive to all of the above points. Therefore, it is best to choose specialists with good recommendations or proven construction companies as contractors for laying the foundation.

It is also very important to adhere to the materials and technologies that are indicated by the design engineer in the project.

What is better not to do when building a foundation

There are a number of points that you should refrain from if you want your foundation to become a reliable and durable foundation for construction:

  • foundations for a house from a foam block should not be made from piles. They are designed for heavy loads, which means that you will only spend your money in vain;
  • strip and column foundations should not be used on silty soils or soils with a high heaving index – piles are better here;
  • do not save on preparatory work and the construction of the foundation, as these are the most important stages of any construction. If you are not familiar with the technology of the device of the strip foundation with your own hands, step-by-step instructions, photos from the Internet will help you with this. In the absence of sufficient experience and equipment, it is better to order the services of a design engineer and a construction team;
  • the choice of pile foundation is not always justified. This type is quite expensive, and in the presence of good soil it is quite possible to do with a relatively cheap and simple strip foundation.
main reasons for the destruction of foundations
The main reasons for the destruction of foundations (forces: a – gravity, b – soil resistance, c – frost heaving): 1 – soil subsidence; 2 – pushing the foundation; 3 – frosty heap; 4 – tipping support

Foundation insulation and waterproofing

The foundation is not the final stage of work. After it has stood for about a month, it is worth taking care of the organization of its waterproofing and insulation.

Foundation waterproofing can be done in various ways. The most popular and simplest of them is the use of a special film that does not allow moisture to pass from the outside, but also does not interfere with the removal of condensate. It is also worth taking care that the foundation of your house is not exposed to moisture from the environment (rainwater, melt water). For this, a drainage system is arranged, and if necessary, drainage works are carried out.

You can insulate the base of the house by making a fixed formwork for the foundation, on which layers of mineral wool, polystyrene foam or expanded clay are mounted. The choice of material for creating a heat-insulating layer depends on natural conditions, foundation material and many other factors.

Useful advice! Interior and exterior decoration is a much more difficult stage than the construction of the foundation itself, so it needs to be given as much attention as possible. In addition, such work takes a lot of time. This should also be taken into account when calculating the overall project deadlines.

To calculate the amount of materials needed to build the foundation, it is best to use various options for online calculators. So, a calculator for calculating concrete on a foundation will help you not to be mistaken with the amount of building material, which means saving your money. Calculators can also be used to calculate slab, strip, grill foundation, formwork, tiles.

Remember that the foundation is the most important part of any building. If during its design or construction you decide to save, this could negatively affect the house in the near future. Therefore, you should not spare money or time – then your house will stand as long as possible, regardless of environmental conditions.

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