The foundation of any home is the foundation. Not only the longevity of the entire building, but also the comfort for living depends on its strength and stability. An unprepared person might think that the foundation of a house serves only as a building "site" for the foundation of the walls, but this is not so.
Thanks to the foundation, all the huge load that the house informs the soil is evenly and accurately distributed over the entire surface of the soil, which prevents the structure from sagging and falling apart due to seasonal heaving of the earth. However, foundation pillows are much more reliable in this regard.
Over the millennia of building practice, many generations of builders have developed a huge number of techniques for the correct construction of such structures. Using the accumulated knowledge, it is possible to build a house even in permafrost conditions, but we will not go into such complex areas. It will be enough to discuss the question of what foundation pillows are.
Most often in our area they use convenient and versatile strip foundations.Their disadvantage is that there are often situations when they distribute the pressure on the soil unevenly. To avoid many unpleasant consequences, the foundation of the house has to be placed on a solid concrete slab. If you have serious doubts about the quality of the soil, the base under the slab has to be additionally fixed with piles driven into the depths of the earth.
One should not think that foundation pillows are used only in the tape variety. It is often necessary to install such a pillow under the column base, which is used in the construction of small cottages. It saves the building from "floating" that can happen on unstable soil types.
By the way, let's immediately define what should be understood by the term "foundation cushions": GOST has one definition, but it often causes difficulties and confusion even among professional builders. As a rule, they believe that this should be called a well-packed layer of clay, crushed stone, or even sand. This should be considered a gross mistake, since in fact the foundation pad is a powerful solid concrete slab, although there may be exceptions here.
So, the use of sand is acceptable, but its minimum thickness must be at least a meter. Concrete is used much more often, and it is not always used when the soil is in poor condition: it often happens that unnecessarily narrow load-bearing walls of buildings are erected on such a foundation. It should also not be assumed that it must necessarily be monolithic, since oftenbuilders use prefabricated structures from several plates at once. We will give the simplest information on which the foundation cushion is calculated, the GOST dimensions of which are used in construction.
Let's take random values as initial data. We have that 15 meters of the wall weighs 25 tons, while the soil has a bearing capacity of 4 kg / cm. The calculations themselves are carried out in this case as follows: we translate tons into kilograms, distributing them over the area. We get 250 kg / cm, which must be divided by soil characteristics (4 kg / cm 2), we get 62.5 cm as a result. Align all the numbers to the right of the decimal point in the direction of their increase. Watch the multiplicity, which should be equal to a hundred. Thus, we got a value of 625 mm, which we will round up to 700 mm. Such foundation pillows will be as reliable as possible, but for even greater reliability they should be reinforced.