How to make a slab foundation with your own hands

The slab foundation is a shallow base, which ensures the reliability of the building when the ground moves. The base has a "floating" ability, which minimizes the risk of the structure warping during seasonal freezing or thawing of the soil. Thus, the foundation and the building installed on it, as it were, "float" on the upper layers of the soil. This is optimal for heaving, clayey areas, but such structures are practical on any other type of soil.

The device of the slab foundation is simple, but ensures its stability

The foundation slab has a simple design that is efficient in operation. This is due to the following advantages of such a foundation compared to other options:

• the minimum amount of earthwork contributes to savings in the construction process;
• ideal for complex, heaving soils, as it ensures the stability of the structure;
• the service life of a high-quality slab foundation is more than 150 years;
• the possibility of using any material for building a house;
• a simple device does not require a lot of time to build.

In the process of creating a slab foundation, a large amount of concrete, reinforcement and other materials are needed. This leads to significant financial costs, which is the disadvantage of such a foundation for a house. To equip the plate, you need the most even initial surface. Otherwise, laying the foundation layers will be impossible or of poor quality. At the same time, all communications calculations must be planned at an early stage. The disadvantages of the slab construction are pronounced, but when building on heaving soils, the base is the only option.

Slab base suitable for flat ground

The stability of the slab base allows you to build houses with a height of 2 floors. At the same time, it provides protection of the structure from distortions as a result of soil freezing, as well as the durability of structures.

Features of the floating foundation

The floating foundation is a type of slab construction. Often floating is synonymous with slab, but they have some differences. The floating version is presented in several forms with the following features:

A floating foundation differs from a slab foundation in that it can be created in several ways. The choice of a particular one depends on the material of the building, the characteristics of the soil, the weight of the structure. In any case, an accurate calculation of all parameters is needed, otherwise the structure may squint as a result of soil movement.

Finnish foundation

The foundation, in which the slab is not connected to the basement / foundation part, perceives only operational loads. Communications in the form of a warm floor do not pass through the base, because they are mounted at the stage of finishing the building. The Finnish version is designed for the subsequent arrangement of a warm floor. The base is suitable for buildings without an underground floor.

For the Finnish stove, the inside is covered separately

The Finnish base involves insulation with foam or other materials for arranging the foundation. This process is carried out from the inside of the structure. At the same time, the bottom plate does not have thermal insulation, and for waterproofing, welded or glued films are used.

Foundation device monolithic slab

The slab type base includes several layers, each of which performs a specific function. The key to proper organization is the preparation of the pit, because the foundation should be as even as possible. The design is a "pie" consisting of several layers of materials. The peculiarity lies in the fact that when the soil is displaced, it is not the “pie” layer that moves, but the entire slab along with the structure. Thus, the distortion of the building, the appearance of cracks are prevented.

The slab foundation device includes several layers of materials that perform certain functions.

The slab base is optimal for a two-story building made of blocks or bricks. In this case, the house can be installed on loose or subsidence soils. To achieve the greatest reliability of the structure, it is necessary to carefully calculate the parameters of the foundation, determine the composition of the “pie”, and select materials.

Swedish plate: foundation features

The base, equipped according to the type of Swedish plate, involves insulation and is suitable for low-rise buildings. At the same time, the main slab is isolated from the ground with a layer of insulation made of extruded polystyrene foam. The layer thickness is 200 mm. It serves for thermal insulation, distribution of the load on the soil, depreciation of frost heaving of the soil.

The device of the Swedish plate involves a layer of insulation

The Swedish plate is distinguished by a short construction period, which is about 14 days. One of the main requirements for the construction is the preliminary leveling of the soil, which is the key to the reliability of the foundation. The structure is a combination of a strip base and a concrete floor, but there is a good thermal insulation layer.

Construction technology

The exact technology for erecting a slab base depends on the type of soil of the site, the features of the future building, and the quality of the materials used. The main stages of construction are adjusted depending on these factors, and the key to quality is the correct calculation of the thickness of each layer and other parameters of the foundation.

For a wooden house, a slab foundation is well suited.

You need to create a foundation on the most flat area. To do this, dig a pit, the depth of which is determined when calculating the parameters of the base. The perimeter of the pit should be 1–2 m larger than the dimensions of the future foundation on each side. The most even surface of the recess will ensure the correct distribution of the load on the ground. After using special equipment for digging, you can process the surface manually, removing irregularities with a shovel and other tools.

The pit must be larger than the perimeter of the future foundation

The second stage of work involves laying sand and gravel backfill. This layer is necessary to drain groundwater, compensate for the load when the soil moves, and prevent the rise of water to the bottom of the foundation slab. For sandy soil, the thickness of the backfill layer is about 15 cm, heaving soils require an increase in this indicator to 30–45 cm. A mixture of sand and fine gravel is distributed along the bottom of the pit and compacted. This will protect the structure from moisture and deformation.

Gravel and sand provide drainage for the base of the house

After preparing the surface, you should proceed to the direct construction of the foundation. Perform the following actions:

After preparing the frame, concrete is poured. The mixture must be grade M200 or more. It is important to fill at one time, because this affects the strength of the structure. Intervals between fillings should be kept to a minimum, as long interruptions have a negative effect on the adhesion of the material. After pouring, the surface should be leveled using the rule, and then the prepared base is left for 28 days to fix.

Filling is performed as evenly as possible, using the rule for surface treatment

The ideal conditions for fixing the structure are an air temperature of +20 °C and a humidity of about 80%. At a higher temperature, the next day after pouring, pour the foundation with water and cover with a film. In cold weather, the base needs heating. With prolonged "preservation" you need to cover the foundation with a film.

Video: pouring and slab foundation

Calculation of the slab base

The durability of the structure depends on the exact determination of the parameters of the foundation. For the calculation, you should know the bearing capacity of concrete, as well as the soil on the site. The main characteristics can be found in SNiP and other regulatory documents.

An example calculation looks like this:

• with a bearing capacity of soil of 2 kg / cm 2 and concrete of 150 kg / cm 2, the foundation should not exert a load on the soil exceeding 2 kg / cm 2. Therefore, during the construction of a two-story house with a size of 10x10m and an area of ​​100 m 2, a foundation slab 200 mm thick is created. The approximate weight of the base is 100 tons;
• the weight of the building, the walls of which are 250 mm thick, is 200 tons, and the total mass of the foundation and the building is 300 tons. This indicator is divided by the area of ​​\u200b\u200bthe building and it turns out that the pressure on the ground is 0.3 kg / cm 2;
• professional calculation involves taking into account climatic factors, the depth of groundwater and other factors.

To determine the thickness of the foundation slab, it is necessary to take into account the type of building under construction. For example, for a residential two-story house made of frame materials, an indicator of 200–250 mm is optimal. In this case, volumetric reinforcement in two rows is used. For a residential building, the height of which is 2 floors, concrete, brick, timber or logs can be used in the construction.

Reinforcement in two layers increases the reliability of the structure

For light structures, such as a garage, porch or utility buildings, a lighter foundation is used. In this case, the thickness of the plate is 100–150 mm, the reinforcement is carried out in one row using metal meshes.