Online calculator for calculating monolithic slab foundation: instructions

Reliability and durability of the entire house depends on the quality of the foundation. There are different types of foundations depending on the type of soil and other technical characteristics. However, recently, slab foundations have been particularly popular, because this kind of foundation is ideal for large, complex structures with unstable soils.

Of course, if it is necessary to build a house on a slab foundation, professionals should make thorough calculations that will form the basis of the project. But just to imagine the approximate cost of materials and work, you can use the calculator foundation monolithic slab.

Online calculator for calculating monolithic slab foundation: instructions

The online calculator interface of a monolithic slab foundation

What is a slab foundation

In simple words, slab foundation is reinforced concrete slab, which is installed under the entire building or a separate part of it. A distinctive feature of this design is a shallow foundation.

The slab foundation can be either monolithic or modular - consist of several identical plates that are interconnected. Each of these options has both advantages and disadvantages. Monolithic has a high level of strength, reliability and rigidity. And when using the prefab, the presence of special equipment is required for transporting and laying the plates during the installation of the structure and other works. But prefabricated models are faster to install, as there is no need to pour concrete, install formwork and reinforcement.

The slab foundation also has an additional name - floating. This name is due to the fact that with any movement of the soil (heaving, sedimentation of the soil), the plate shifts along with it. At the same time, local deformations do not occur - even in the precast foundation, the plates are rigidly fastened together and are resistant to constant mechanical loads.

Online calculator for calculating monolithic slab foundation: instructions

Variants of the floating foundation

If you are going to install a shallow-depth slab foundation, then keep in mind that upwards it is a draft floor first floor. With this type of base there is no possibility of building a basement.

Note! On the other hand, the creation of a basement with a slab foundation is feasible in principle, but only if the slab is its floor, and therefore must be deep enough. The calculation of the base plate at the same time should be carried out very carefully and take into account all the features of the object under construction.

Advantages and disadvantages

The main advantage of the slab foundation is a significant footprint, thereby reducing the pressure on the ground and reducing the possibility of deformation of walls and other supporting structures of the building. Other advantages of this type of foundation undoubtedly include long service life, safety of use, quick and easy installation, resistance to groundwater and surface water, as well as the possibility of building a basement and the simultaneous use of plates as a basis for the floor of the first floor. But all this is possible only if the correct calculation of the base plate was made.

Online calculator for calculating monolithic slab foundation: instructions

The monolithic foundation is at the same time the floor of the first floor

The only, not unimportant drawback of the slab foundation is its high cost. However, the high price is usually justified - because it is a highly reliable, durable, solid construction with excellent technical and operational properties.

On our site you can find contacts of construction companies that offer the service of designing and repairing the foundation. Directly to communicate with representatives, you can visit the exhibition of houses "Low-rise Country".

Nuances when installing the slab foundation

If the calculation and installation of the slab foundation was carried out correctly, then the monolithic base copes well with sharp temperature changes and is able to adapt to various types of weakly bearing soils. The choice of this design is primarily due to its high reliability and attractive appearance. But when arranging a slab foundation, the following points should not be forgotten:

Even if the material from which the foundation-slab is made is correctly calculated, its thickness calculation is correct if improperly installed or technologies are not followed, all these calculations will not mean anything. For example, during construction it may be tempting to save a little and refuse to drain. In no case can this be done, as over time there is a chance to witness the transformation of the house into the Tower of Pisa.

When forming the foundation cushion, thorough work will be needed on tamping its sandy-gravel base.

Online calculator for calculating monolithic slab foundation: instructions

Tamping work for the foundation section

The monolithic foundation pillow includes a mixture of gravel, sand and geotextile. All these materials must be calculated separately, depending on the density of the soil and other characteristics. Approximate calculations that show the estimated cost and quantity of materials can be done in advance and independently - using online calculators. In the latter case, pay attention - the calculator considers waterproofing as a single or double layer.

Scopes of use of slab foundation

There are several main areas of use for such structures:

  1. When constructing large-scale, complex construction projects for which the individual parts of the structure;

  2. For the construction of multi-storey buildings located in earthquake-prone areas;

  3. Indispensable when building the foundation on weak and heterogeneous soils;

  4. In low-rise construction it can be used as an alternative to the foundation of deep laying in the northern part of the country;

  5. As a variant, is considered in the absence of a ground floor and basement.

Online calculator for calculating monolithic slab foundation: instructions

When building a house on a monolithic slab foundation, you will have to forget about the basement
This may be interesting! In the article on the following link read about foundation waterproofing.

Depth of the slab foundation

The first thing to note when describing the depth of the slab foundation is the characteristics of casting such monolithic structures. They are forbidden to be installed on arable soil, because of this it is necessary to completely remove the black soil from the pit. At the same time, the average depth of one layer is 40 centimeters (they are filled with non-metallic composition without clay content).

The following features are typical for shallow slabs:

  1. For country houses, summer houses and garden houses (where there is no heating), it is necessary to pre-lay polystyrene foam under a blind area or a single plate;

  2. If there is a permanent heating system in the house, in order to protect the soil from freezing, it is enough to warm the blind area at a depth of 30 centimeters (to completely eliminate the causes of swelling);

  3. The most budgetary option for the construction of this kind of design - with a plate, recessed below marks of freezing. However, this method is suitable only for buildings with a basement or ground floor.

Online calculator for calculating monolithic slab foundation: instructions

Monolithic foundation for a house with a basement

How to calculate the thickness of a plate

When calculating the thickness of the foundation slab, the following scheme is followed:

First step : The geological analysis of the site shows the appropriate value of the optimum specific pressure on the soil. In the course of work, a sufficient depth of foundation is also determined.

Second stage : Possible weight loads are calculated. The tables show average values ​​for most building materials - it is not difficult to calculate their weight depending on the size of the floors, walls and other structures. Next to the resulting figure is added the average load of snow cover in accordance with the region of residence and the slope of the roof. Do not forget about such a criterion as the payload - for the basement floors, it equals 210 kg / cm² (this parameter is determined for each floor of the building, after which it is summed up).

Third stage : The area of ​​monolithic length is calculated (to do this, multiply the length of the house by its width). To calculate the specific load value per 1 m², simply divide the total weight data by the previously obtained value.

Online calculator for calculating monolithic slab foundation: instructions

There is usually no problem with calculating the dimensions of the slab monolithic foundation

Fourth stage : Calculation of the optimal foundation volume (divided by the average specific weight of the reinforced concrete), and also the preliminary thickness of the monolithic slab of the foundation is determined - and the resulting figure is increased by five centimeters (with a margin).

Fifth stage : After the weight of the base is clear, it is added to the average weight load. Further, the indicator of the specific pressure on the ground (about three) is compared with the preliminary results for a particular locality (the deviation should be no more than 25%).

Determining the magnitude of the load affects the choice of concrete mix grade, and the thickness of the foundation affects the choice of reinforcement scheme (as well as calculating other components will help to calculate the reinforcement on the monolithic slab calculator), according to which the diameter of rods and from the placement. To simplify the entire calculation process, you can use a simple mechanism - online calculators.A special calculator will help to calculate the monolithic overlap of and other components, to calculate the thickness of the plates and the foundation cushion. To do this, you only need to drive in reliable indicators in the specified cells and wait for the results.

How the foundation is calculated on an online calculator, see the video:

Professional Tips

Experts recommend that you advance your calculations the number of materials for the construction of the foundation, while taking into account all the features of the soil of a particular plot. For example, heaving soil has a characteristic feature - ups and downs depending on seasonal changes. If you forget about this nuance, after a while the base will begin to experience exorbitant power loads, cracks will appear and the base will begin to burst. It is also recommended to tie the reinforcement wires - this will give it greater mobility. Thus, the frozen concrete mix, even with strong deformations of the soil, will be able to preserve the desired structure and will not lead to the formation of microcracks.

As the foundation is actually calculated, professionals are clearly shown in the following video:

It can be interesting! In the article on the following link read about the reinforcement of strip foundations.


From the above, it can be concluded that although the slab foundation has a very high cost, it has high strength, rigid construction, long service life and other positive operational properties. Installation of this type of foundation is not an easy task. But Counting materials on a slab foundation, calculating the thickness of slabs and other components of the base sometimes takes a lot longer than expected. Therefore, it is reasonable to use an online calculator for preliminary calculations, and to entrust a full-fledged design and installation to specialists in this field in order to get a really high-quality and reliable foundation.


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