It is difficult to overestimate base role at construction of the house. It is, neither more nor less, basis of future construction. From that, the base is how precisely calculated, the correctness of load dispatch on soil will depend. And from it, in turn – stability of all design.
1. Soil on which it is necessary to lay the foundation can be various on the structure: soft, semisolid or dense clay, fine or medium sand, gravel and so forth. This distinction affects its ability to resist loadings which will arise by means of house pressure. Therefore it is necessary to find out the rated resistance of soil.
2. To count the base, it is necessary to calculate its approximate area. For this purpose use the following formula: S = K · (MD/PR), where K – reliability coefficient which is standard size and considers possibility of deviation of size of loading from standard value. For the houses of small number of storeys and small cottages popular with residents of country areas, the value of coefficient is accepted to 1.1.
3. MD – the approximate mass of the house, calculates approximately, proceeding from summation of weight of all components of design (walls, overlappings, ladders, roof and so forth) taking into account the used construction material and its volume, including the mass of the base. Keep in mind that calculation for the building on average climate has to provide as well snow load which can be very notable.
4. Pr – the rated resistance of soil which is standard table value. If with determination of this rated size there is problem, then it is better to address experts as, unfortunately, there are such types of soil on which construction is categorically impossible, for example, myagkoplastichny clay, or is accompanied by imposing of additional restrictions and, respectively, expenditure.
5. The second not less important component of calculation of the base is the forecast of amount of the used concrete. For this purpose it is necessary to find base volume for what increase the square by underlay depth. Keep in mind that the foundation is laid lower than frost depth to avoid "movement" of the house on soil with high water saturation.