The construction of any residential building or production structure is carried out by the project. It must be agreed and approved. Documentation relating to the design and calculation of the foundation for the house is made and drawn up by engineers – designers. But most often it is necessary to independently build such structures as a bathhouse, garage or house for a summer residence and therefore, you need to take care of a qualitative basis.
Calculation of the foundation for the house
In the event that the calculations are not made correctly, then the alteration will require not only extra time, but also additional financial costs. Therefore, before construction, it is better to find out how to properly make all the calculations, because the foundation is intended for uniform distribution of the load on the soil, and protects the structure from flooding with soil waters.
Factors that take into account when calculating
Soil features in a particular area;
type of base for the house;
the depth of the base of the base;
width and height of the groove;
maximum load.
If the site is located in a swampy area, then measures are used to change the type of soil. For example, they make a partial recess and durable material falls asleep in them. For these purposes, a granshlak is used, which, after entering the humid environment, gradually hardens, and becomes like concrete.
Depending on the type of soil, freezing depth, level of groundwater and others., Apply changed or modified types of bases.
To find out the depth of the foundation for the house, first determine the groundwater, the load on the base, and how much (in a particular region) the soil freezes.
The whole structure has a weight to which the mass of doors, frames, ceiling, etc. is added. If the material has already been selected, they know the size of the area and its density (selected from the tables in a special directory or on the Internet), then they independently calculate. Also, when calculating the load, the approximate weight of furniture and household appliances are taken into account.
Before laying the foundation, they dig a trench. Consider its indicative depth:
If the site is sand or gravel, then it is necessary to dig up into up to 1m;
if the sandy is 1.25 m;
with loam up to 1.5 m.
At the same time, some minimum values are taken into account, for example, with dry soil, the depth of the ditch is 70 cm, and with a moist 120 cm.
The reinforcement of the foundation for the house
And in the event that the basement is provided for the project, then the distance from its floor should be 40 cm.
The total mass of the structure should not be more than can withstand the soil. For example, if there is large sand on the site, then 1 cm² can arrive from 3.5 to 4.5 kg, with wet sand from 2 to 3 kg. If the clay is solid, then it can withstand from 3 to 6 kg, and if there is crushed stone or gravel on the site, then 1cm² can withstand up to 6 kg. Here also taken into account the weight of the base. This calculation of the load on the foundation is made individually for each construction.
How to calculate the pressure on the base ourselves
Of course, professionals will do this accurately and efficiently, since not only special programs, but also geological research use for this. But if they try to independently make it, then it is taken into account that all the calculations are approximate and, that the load is distributed evenly.
Consider what you need to know to calculate this value. The total load consists of:
masses of the house with contents – a constant parameter;
Snow load and wind pressure – alternating factor.
For calculation, reference data reflecting the specific gravity of materials is used. The approximate weight of a two -story house with a size of 5×8 m with two internal walls 5 and 8 m is calculated, while the floor height is 2.8 m.
First, the wall area is calculated:
The perimeter of the structure will be (5+8) x 2 = 26 m;
The area of the external walls: 26 x 2.8 (ceiling height) x 2 (floors) = 145.6 m²;
The length of the internal walls: (5+8) x 2 = 26 m;
basement area: 5 x 8 = 40 m²
The area of the inter -story ceiling: 5 x 8 = 40 m²
attic area: 5 x 8 = 40 m²
The area of the roof, which protrudes for 0.5 m: 6 x 9 = 54 m²
Determine the approximate load on the base under the house, taking into account 2 options, that is, the calculation is made for 2 types of material. In the first option:
External and internal walls are made of complete brick 510 and 150 mm thick, respectively.
Overlapping of a basement of reinforced concrete, and inter -story – from hollow plates.
Office overlap: along wooden beams using insulation, density up to 500 kg/m³.
Shifer roof, slope 30 °.
The second option is as follows:
External and internal walls from the beam, the thickness of which is 18 and 14 cm, respectively.
Clothing is produced by beams (density 500 kg/m³).
Intersective and attic overlap: by wooden crossbars, up to 200 kg/m³ density.
Sheet steel is used on the roof, and the slope is 27 °.
Type of the house
I option
II option
Wall weight (kg)
145.6 x 1000 + 26 x 270 = 152620
145.6 x 100 + 26 x 70 = 16380
The mass of the basement (kg)
40 x 500 = 20,000
40 x 300 = 12000
The weight of the inter -story floor (kg)
40 x 350 = 14000
40 x 100 = 4000
The mass of the attic (kg)
40 x 200 = 8000
40 x 100 = 4000
Roof weight (kg)
54 x 50 = 2700
54 x 30 = 1620
Operational loads
40 x 210 + 40 x 210 ++ 40 x 105 = 21000
40 x 210 + 40 x 210 + 40 x 105 = 21000
The weight of the snow coating
54 x 100 x 0.8 = 4320
54 x 100 x 0.8 = 4320
All
222640
63320
Calculation of a slab base for the house and the depth of its laying
In order to build a quality building, you need to make the correct calculations. For example, for a slab foundation with a size of 5 × 8 m, it is necessary to take into account the mass of the materials used: sand, concrete, reinforcement, waterproofing, etc.
In order for the calculation of the slab foundation to be correct, at first they calculate:
How much thermal insulation will be needed: 5 x 8 = 40 m²;
The required amount of waterproofing (it is made in 2 layers) therefore: 5 x 8 x 2 = 80 m² plus for an overlap 15 cm;
In the event that the frame is with 15 cm cells, then for one belt (transverse direction) it will be required (5: 0.15) + (8: 0.15) = 87 rods, and for the longitudinal direction, too, you need as much. For two belts you need 107 rods with a length of 8 m and 67 pcs. – 5m Prutiki;
Concrete consumption: 40 x 0.3 (base height) = 12 m³. This value is multiplied by the shrinkage coefficient of 1.02 and receive: 12 x 1.02 = 12.24 m³.
Consider how the foundation volume is calculated for this:
The length of the base, along with the dimensions of the internal walls, is multiplied by its height (soil freezing depth of 1.5 m + 0.4 height above the ground) and width (0.6m), that is:
(5+8+5+8+5+8) x 1.9 x 0.6 = 44.46 m³.
SNiP provides that in order to make the correct calculation of the depth of the foundation, first pay attention to:
house project;
soil freezing depth;
engineering communications that should not be carried out below the sole of the base;
The relief of the territory.
Basically, the precipitation of the foundation is determined based on the load, which is distributed throughout the area. During its calculation, the method of layout of the values, subsidence of individual soil layers is used.
When erecting a house or other structure, they are guided by SNIP, sanitary standards and special tables that make it possible to perform the correct calculations.