Foundation-slab: do-it-yourself

Foundation-slab: do-it-yourself
Foundation-slab: do-it-yourself

One of the most important elements of any home is the foundation. If you perform it correctly, then the structure will not become unusable in a short time. The slab foundation is characterized by high reliability and strength, so it is most often chosen by home craftsmen and builders.

But if you use the services of specialized companies, they will ask for more than a third of the cost of the building for such a design. On your own experience, you can see that the cost of this part of the building is not so great. You can make a slab foundation yourself.

When used?

foundation slab

Monolithic foundation - a slab that is suitable for the construction of residential and non-residential buildings. This applies to those buildings that will not have a basement. One of the main advantages is that you don’t have to lay logs under the floor, since concrete can act as a ready-made rough coating.

Such a base is seismic resistant, high strength and is not washed away by water, becausearea is large enough. This construction under the house will be appropriate if there is problematic soil on the site.

Technology Features

monolithic slab foundation

Monolithic foundation - a slab that can be created using one of two technologies. If the structure is planned to be made monolithic, then first you must install the formwork, and then assemble the reinforcement cage. Concrete is poured in one pass. When the foundation is planned to be prefabricated, it is constructed from reinforced concrete slabs, the seams of which are poured with concrete. The design does not require formwork, as well as the installation of a reinforcing cage.

But this approach has its drawbacks: you will not be able to achieve the desired thickness, because the plates are made at the factory and have certain parameters. In fact, such a design will not be monolithic, which makes it less durable. A crane is required for laying the tiles. If the ground has irregularities, then it will be quite difficult to lay the products, you will have to level them, which is almost impossible to do manually.

How to make a stove

construction technology

A monolithic foundation slab is made using a technology that provides for the preparation of a foundation pit of the desired depth and size. A layer of sand or gravel is poured to the bottom, after which communications are laid, for example, water and sewer pipes. A concrete screed is placed on top. This structure must be insulated, and then formwork should be installed, as well as a reinforcing cage. The slab can be filled with concrete in the next step.

Determination of slab thickness

foundation slab calculation

The thickness of the foundation slab depends on what kind of house you plan to build. The heavier the building, the thicker the slab should be. If the structure is shallow, then the thickness should not exceed 30 cm. However, the foundation can be made deep. In this case, its thickness will be 1.5 m.

For a private building, a foundation is usually used, the thickness of which is not more than 40 cm. The foundation slabs are poured with M-200 grade concrete. The mobility of the solution should be P-3, and the resistance to cold is equal to the F200 limit. It is also important to take into account the water resistance marking, which should not be less than W8.

Construction stages

foundation slab thickness

The first step in the construction of a slab foundation will be the marking of the territory. In order to make it more convenient to work with the formwork, it is necessary to add about a meter on the sides of the pit. The site needs to be leveled: this is the only way to normalize the pressure on the plate, which should be uniform. The bottom of the pit is leveled, it is important to get rid of drops and bumps.

To form a drainage system, it is necessary to dig transverse trenches through which water will be drained. Geotextiles are laid at the bottom of the trench. Then you should lay plastic pipes with perforations. All this is covered with fine gravel, and then covered with geotextile.

Formwork installation

monolithic foundation slab

The foundation slab is poured into the formwork. It is knocked together around the perimeter of the boards. outdoorside must be reinforced with struts. As soon as the fence is ready, it is necessary to make a pillow, which consists of a layer of sand and gravel. Such preparation is needed to remove moisture from the structure and depreciate the soil. The pillow can have a thickness ranging from 15 to 30 cm.

If the ground is wet, then you can add fine gravel. The preparation is well compacted. There should be no footprints on the sand. After you need to do waterproofing. It is necessary to prepare a solution of sand and cement, which is poured into the pillow. The thickness of this layer will be 5 cm. After that, waterproofing can be laid in the form of a rolled material, such as roofing material. It is laid with an overlap on the formwork.

After the waterproofing is ready, you can start reinforcing. For this, reinforcement is used, welding is excluded. The rods are pulled together with wire. At the next stage, you can start pouring the foundation slab. It is better to order a machine with a ready-made mortar, in this case you can work out the concrete at a time, it will turn out to be homogeneous and not covered with cracks.

Thickness calculation

do-it-yourself slab foundation

The simplest calculation of the thickness is carried out by summing up the gap between the reinforcement meshes, the thickness of the reinforcement and the concrete layer. The optimal value is 30 cm. The final result is determined by the composition of the soil and the uniformity of the occurrence of rocks. You must consider the width of the sand cushion and the drainage layer.

For a slab foundation, remove the top layer of soil and dig a pit, the depth of which canbe 0.5 m. This value is determined taking into account that the crushed stone is located in a layer of 20 cm, and the sand is 30 cm. If you add up the available data, you can understand that the minimum thickness of the foundation slab cannot be less than 60 cm. This the indicator varies depending on the characteristics of the soil and the weight of the future building.

For a brick building, the slab can be 5 cm thicker than the same base for a foam concrete house. If the building has a second floor, and the walls are made of brick, then the thickness of the monolithic slab can be increased to 40 cm. This value can be greater, depending on the configuration of the building and its weight. When building a two-story foam concrete house, it can be 35 cm.

Example of volume and thickness calculation

If you intend to carry out the calculation of the foundation slab, you can determine the amount of concrete to pour. To do this, the sole area is multiplied by the thickness. You can understand the calculation by referring to a specific example. If the house is 10 x 10 m in size, and the monolithic foundation is 0.25 m thick, then the volume of the slab will be 25 m3. This value is obtained by multiplying the three digits mentioned.

If you plan to build a foundation slab with your own hands, you should know how much concrete is required for the work. It is also necessary to take into account the installation of stiffeners, which are necessary to ensure resistance to deformation. They will be located along and across the plate at a distance of 3 m, forming squares. For the calculation, you should determine the height and length of the ribsrigidity. The last indicator is 10 m. In total, 8 ribs are required, so the total length will be 80 m. For rectangular ribs, the volume will be 16 m3. This value is obtained as follows: 0.25 x 0.8 x 80. For trapezoidal ribs, the lower base is 1.5 times the thickness of the foundation, and the upper base is 0.8.

Slabs for strip bases

Slabs of strip foundations are also called foundation pillows and are used as foundation bases for low-rise buildings. With their help, you can extend the life of the supporting foundation and distribute the load between the elements. This approach to building a building is especially relevant if the soil on the territory tends to sag in the winter. The foundation blocks are rectangular in shape, so the load on the soil from the lower product increases with each row laid.

If the foundation is too high, then due to the load on the ground, subsidence of the structure may occur, which will lead to a distortion of the geometry of the building. The only sure way out of this situation will be to reduce the load on the soil. This can be done by reducing the mass of the foundation structure or increasing the area. For the second method, tape plates were invented, which act as an adapter between the soil and the foundation blocks.

In conclusion

The foundation, which is based on the slab, is a solid foundation. It contains reinforced concrete, which is laid over the entire area of ​​\u200b\u200bthe building. Such structures are very durable and exert less pressure on the ground. But suchonly that monolithic foundation has advantages, the thickness of which is determined taking into account the depth of laying and loads, the nature of the soil, as well as the weight of concrete.

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