What concrete is needed for the foundation: the dependence

Before the construction of the monolithic base of any building, the question arises of which concrete to make the foundation. Its choice depends on the type of construction, as well as the conditions of use of the building.

The main factors influencing the definition of the brand of building material:

• pressure load on the foundation, depending on the weight of the future structure or building;
• geological conditions at the construction site;
• type of underground part of the house: a monolithic pillow, tape, pillars, piles, basement, etc.

How to choose concrete, based on the load on the foundation

The projected load on the base is the most important parameter that determines the brand of solution to be used. So, the frame building has a mass that is several times smaller than a brick or concrete building.

Therefore, it is possible to choose a low grade solution for it.

1. For frame and panel buildings The instruction recommends the use of concrete mixes M-200.
2. For the bases of timbered and cobbled buildings The best choice is concrete grades 250 and 300.

Note! The same solution is also suitable for the construction of foundations for houses made of light types of concrete - foamed, gas silicate, expanded clay. These building materials, like wood, have low specific mass and density.

1. Thinking which concrete is better for a brick or reinforced concrete foundation, choose a heavy and durable solution - from M-350 and above. The same goes for a two-story house.

Soil type

Soil characteristics are also an important factor determining the choice of grade of mortar for the foundation.

How does the type of soil affect the choice of solution

1. If the house will stand on rocky or sandy soil, which is convenient for the operation of monolithic bases, you can not think for a long time which concrete to use for the foundation. It will suit its low marks –M-200/250.

But very often the soil consists of loam, clay and other complex soils. Their main problem is strong heaving. In other words, during freezing such a ground expands significantly.

In winter, a shallow bottom can rise by 5/15 cm. This happens unevenly and depends on the amount of moisture in the soil. In the process of heaving, along the perimeter of the basement, unequal loads act on it.

The only correct solution to this problem is to deepen the base below the freezing point of the soil. Relying on the non-freezing layers, the strip foundation will almost not experience the effects of frost heaving.

1. Proceeding from all of the above, it follows that the clay soil is more demanding on the foundation concrete. To hedge, you can always order a solution that has a larger brand than you need. At the same time, the price of M-350 concrete is only 150/200 rubles (for 1 m?) Higher than M-250.

Note! As a result, construction estimates will increase only marginally. However, the strength, frost resistance and water resistance of the foundation will improve significantly.

We give a specific example.

1. When thinking about which concrete for the foundation of the house should be preferred, note that the material M-250 has a waterproof W-4 ​​and frost resistance F-100.
2. The analogue M-350 indicators, respectively, are equal to W-8 and F-200. This means that it has a service life, 2 times longer, and twice as effectively resists moisture.

Sulfate resistance design

1. If the foundation is laid in an aggressive chemical environment (subsoil water with a high content of salts, alkalis, etc.), the sulphate resistance of the base should be increased.
2. This can be done in two ways. In the first case, a concrete mix on sulphate-resistant cement is used for pouring the foundation. In the second case, special modifiers are added by hand to the usual solution.
3. The first option is not very convenient, because there is no similar cement in hardware stores. You can only purchase the mortar under the order in a concrete plant.

Concrete and type of construction

Another parameter influencing the choice of concrete is the absence or presence of a basement in the future house. Here the water-tightness of the solution has an important role.

For a building with a basement, it is best to choose concrete M-350, which has a high coefficient of water resistance. To increase its base should be waterproofed. This method is the cheapest and reliable.

What composition of concrete for the foundation to apply for a building with a basement, determine the same way, given the level of groundwater.

1. You can use a mixture of any category, and then protect the foundation with obmazochnoy or roll waterproofing. If it is combined with warming the base with plate materials, diamond drilling of holes in the concrete can be used to fix them.
2. You can apply a medium grade solution to the foundation and protect it with additional special impregnations. The disadvantage of this method is that condensate can then settle on the basement walls.

1. You can apply the composition of the high brand, which has a large coefficient of water resistance. It is worth considering that these solutions have two drawbacks: they are expensive, and the foundation should be poured with their help quickly, because they have a short setting period.
2. The last method is the use of special concrete created for the construction of hydraulic structures. The composition of such solutions contains modifiers that increase the water resistance and density of structures.

In any of these cases, in case of need, reinforced concrete cutting with diamond circles is applied.

Conclusion

When designing a monolithic base type, pay special attention to the composition of the mixture from which it will be poured. From this will depend on the strength, moisture resistance and durability of the foundation of the house. Check out the video in this article. It contains a lot of useful information.