The choice of the type of foundations and the material for them is an important task for any builder. If the base for the house is not suitable, then during the operation problems may arise that will require serious financial investments. In many ways, the type of foundation depends on the characteristics of the soil of the base, but the influence of the material of the walls and floors should not be ruled out. Next, what foundation is needed for building a house from expanded clay concrete blocks.
Material Features
Only two characteristics of the material from which the walls are made have a significant impact on the foundations:
- weight;
- resistance to deformation.
According to these characteristics, a house made of expanded clay concrete blocks is better than a brick one, but still inferior to a tree. Further discussed in more detail.
Resistance to deformation
Blocks are piece building materials, therefore they are very unstable to deformations of the base. Uneven shrinkage is a danger when one side or corner sags or rises more than the others.
In this case, a distortion of the foundations occurs, and inclined cracks go along the walls.
To prevent the occurrence of such unpleasant phenomena, you need to correctly select the type of foundation, perform its calculation and strictly comply with the do-it-yourself erection technology at the construction site.
A careful attitude to each stage will guarantee the reliability of the supporting part of the house from expanded clay concrete blocks.
Mass and density
The density of the material is in the range of 500-1800 kg per m3. This is a fairly small mass, which is an undoubted advantage of wall structures. The fact is that the less the walls weigh, the lesser the load on the foundation. At the same time, its required bearing capacity, financial costs for construction and labor intensity are reduced.
The blocks have holes that, without compromising thermal conductivity, reduce the final mass of the product. Due to the ability to retain heat, the wall thickness of the material in question is needed less than for less heat-efficient products, which again reduces the load on the supporting part of the building.
For comparison, we consider below the masses of walls made of various materials. The values are given for the running meter of the wall of the house within one floor (3 m high) for the optimal thickness according to the heat engineering indicators (on average). The normalized heat transfer resistance is multiplied by a factor of 0.63, which is permitted by regulatory documents.
- reinforced concrete without insulation with a thickness of 400 cm - 30 tons;
- ceramic brick 64 cm thick - 3.5 tons;
- expanded clay concrete blocks with a density of 1000 kg / m3 and a thickness of 65 cm - 1.95 tons;
- expanded clay concrete blocks with a density of 700 kg / m3 and a thickness of 40 cm - 0.85 tons;
- 30 cm thick pine - 0.5 tons.
The list above shows that the load depends on the density of the blocks. Compared to brick or reinforced concrete, expanded clay concrete clearly wins in terms of reducing the required bearing capacity of the foundation, which allows you to have more choice in the design and construction of your own hands.
To make a more accurate collection of the load, it will be necessary to perform a thermotechnical calculation of the wall thickness for the climatic conditions of a particular section and the selected grade of wall material.
Base type selection
Before choosing what to lean on a building, it is necessary to consider the following characteristics:
- foundation load from overlying structures;
- soil strength at the site;
- the tendency of the soil to frost heaving;
- groundwater level location.
Load
The load depends not only on the material of the walls, but also on the number of floors being erected. So for a one-story building, it will be enough to provide for one type of foundation, and for a two-story building, a more powerful foundation is required.
If we take into account only the load, then we should consider options for the construction of one and two floors with our own hands for different density of expanded clay concrete blocks. For convenience, the data are tabulated.
Block density | Storeys of the house | |
Single storey | Double decker | |
1000 kg / m3 | Depending on the geological conditions, a tape shallow, slab, pile foundation is suitable. The cross section of the tape can be either t-shaped or rectangular. Piles to save money can be used screw. Also, for this type of structure, columnar supports of shallow or deep laying can be used. Unfinished foundations (poles and tape) can be used on soils with good characteristics. Slab-free slabs can be used for DIY construction without concern. | The mass of walls in this case makes the use of piles economically unprofitable, since their frequent step, large cross section and powerful grillage will be required. It is better to dwell on such options as:
It is highly not recommended to use columnar foundations because of their small bearing capacity. |
700 kg / m3 | Under these conditions, construction on piles is possible, but it is worthwhile to perform a preliminary calculation, to collect the load from all the building structures on the foundation. As an indicative value, you can use the fact that one pile (both screw and bored) can withstand 4-6 tons on average. It is also worth considering options for strip and slab foundations. |
It is also important to consider the need for a basement in the house. If you need it, then you should choose a plate or tape with sufficient depth.
Before construction it is important to carry out the calculation of the bearing capacity. It differs for different types, but it necessarily includes the following steps:
- study of geological conditions and determination of soil types;
- load collection;
- carrying out calculations (calculating the thickness or width of the foundation, calculating the reinforcement, determining the penetration of piles).
Base soil characteristics
Strength, water saturation and heaving of the soil have a joint effect on the choice of the type of foundation with your own hands for a house of blocks. The following recommendations can be made:
- Construction on coarse soil or sand of medium and large fractions. In this case, you need to control that the soil is not too saturated (otherwise it is better to stop on piles). These bases are conditionally non-porous and have a sufficiently high bearing capacity.
- Construction on clay, loam, sandy loam and fine sand. Such soil has a lower bearing capacity and is prone to heaving. For a home with your own hands, it is important to pay attention to ensuring that the supports are laid at least not less than the depth of freezing of the soil. The groundwater level should be located at least 50 cm below the base of the building, otherwise water reduction and drainage will be required.
Construction technology
It all depends on the type of construction for the house made of expanded clay concrete blocks. Brief recommendations can be made for each type of substrate.
Tape type
It can be made in two ways:
- made;
- monolithic.
Monolithic has more advantages in the construction of a private building, since it avoids the attraction of heavy and lifting equipment. The width of the tape is selected based on the thickness of the walls. It should ensure the normal support of building envelopes, if possible without overhangs and displacement of the axes of walls and foundations.
The following requirements can be cited for materials:
- concrete B20 - B25;
- А400 fittings;
- sand for adding medium or large fractions.
- if it is planned to install a shallow tape, it is necessary to provide for insulation with extruded polystyrene foam or expanded clay.
Column type
As well as a tape, it can be made of monolithic and precast concrete. By trimming, a grillage is provided, which will ensure the joint operation of separate elements. This type of support is rarely used for massive structures.
Plate type
It is made of monolithic reinforced concrete. For private construction, the thickness of the slab (excluding concrete preparation) will be 200-300 mm. DFor manufacturing, concrete of classes B20-B25 and reinforcement of class A400 are used. Reinforcement is performed by frames. Filling must be carried out in one step, which will ensure compliance with the technology and reliability of the design.
Pile type
Here you can choose from two technologies:
- screw;
- bored.
The second ones allow you to do all the work yourself. To make them you need to dig wells, install reinforcing cages in them and pour concrete. Screw foundations can reduce construction time, labor and cost of work.
To trim supports of any type to ensure collaboration, a grillage is provided, which can be:
- reinforced concrete;
- metal;
- wooden.
Under walls made of expanded clay concrete blocks, it is better not to use a wooden harness.
In the general case, we can say that for the considered wall material, a tape or plate base is best suited.