The foundation is the most important part of the building. It must withstand enormous loads. In order for the construction of the house to be reliable, its foundation must be solid and of high quality. In modern buildings, foundation blocks are often used.
They are made by special technology, resistant to heavy loads and various weather conditions.
This building material can be used for re-construction, if there is no visible damage.
What is a block?
Base blocks (FBS) are a rectangular concrete structure, which is used in construction. Most often they are used for the construction of walls, foundations, as well as basements.
The material for the manufacture is heavy concrete. It is worth noting that reinforced blocks are used to build tall buildings.
Mounting puzzles are located on the sides of the element, and mounting loops on the upper part.
It is extremely rare for construction to use FBV (fundamental blocks with a cut) and FBP (blocks with voids down). They are designed for laying hidden networks and communications.
Wall blocks can be made with a smooth or corrugated surface. Also, painted blocks are used for cladding (with a special color pigment that is resistant to weather conditions and climate).
Classification
According to the material of manufacture, they distinguish:
The latter have several advantages compared to the first:
- ease and speed of manufacture;
- high technical characteristics;
- simplicity in operation;
- small mass (due to this, the load on the foundation is significantly reduced);
- durability.
It is worth noting that for different purposes, you can choose the most suitable dimensions of the foundation blocks.
By appointment, these materials are divided into:
- Wall. This species, in turn, is divided into: draft, facial, facing (bilateral).
- Foundation. These products have a special design and are suitable for arranging all types of foundations: strip, columnar, solid and columned.
- Heat insulating. They are of two types: solid and hollow. The second are more practical, because they have less weight and thermal conductivity. Such blocks are ideal for supplying covert communications. A key disadvantage is reduced strength. The average level of thermal conductivity is 1.15 W / m 2 .
Application area
The main field of application is the construction of foundations in multi-storey buildings. For individual buildings, they are used less often (due to the large weight and high cost of renting special equipment).
The dimensions of the foundation blocks allow you to lay them on any soil - both wet and dry.
Reliability of the design allows their use in areas with increased seismic activity.
Depending on the characteristics of the block, the necessary solution and its quantity are selected.
Concrete foundation blocks: technical specifications
The main characteristics include:
- dimensions (LxWxH);
- density;
- special parameters.
Standard lengths are as follows: 900, 1200 and 2400 mm. Width varies from 300 to 500 mm, and heights are only 300 and 60 mm.
Density, as well as strength and frost resistance, refer to a whole batch of products. These parameters are selected depending on the terrain and the direct purpose of the blocks.
Additional characteristics of the fundamental blocks are indicated in Arabic letters. For instance:
- "P" - low permeability;
- “N” is normal;
- “O” is especially low.
Typical sizes
The weight of the block depends on its size. For example, the foundation blocks 20, which are used to build administrative, industrial and other large objects, weigh 31 kg 700 g.
Thanks to these characteristics, costs at the initial stage of construction are significantly reduced, and special equipment is not required for transportation.
One pallet of blocks with these parameters weighs no more than two tons. This allows you to use manipulators for unloading.
Reinforced blocks, the length of which is up to 240 cm, can weigh from 310 kg to 2 tons.
It is worth noting that for some types of buildings, metal forms for additional blocks are provided. The height of the latter is 300 mm.
Important! Before designing the building, you should contact the special services to check the soil for groundwater, acidity, sediment, etc. Depending on the results obtained, the most suitable materials are selected in terms of size and other characteristics.
Also, before buying a batch of materials, you should pay attention to the certificates and reputation of the company, because poor-quality blocks can lead to the destruction of the building or injury to workers.
What does block marking mean?
The labeling briefly indicates:
- type of block;
- geometric parameters;
- additional characteristics.
For example, the foundation block FBS 24 is deciphered as follows:
- FBS - the fundamental block is continuous;
- 24 - the length of the product (in dm).
If the letter T is indicated at the end of the marking, heavy concrete served as the material for the manufacture. In this case, for ordinary concrete, the density will be 220 kg / m 3 , and for silicate or expanded clay - at 2000 and 1800 kg / m 3, respectively.
The last digit indicates the group of the maximum load-bearing capacity of the product. The following groups are distinguished:
- the first - up to 1.5 kgf / cm 2 ;
- the second - up to 2.5 kgf / cm 2 ;
- the third - up to 3.5 kgf / cm 2;
- the fourth - up to 4.5 kgf / cm 2 .
FBS Benefits
Among the advantages of using concrete foundation blocks in construction are:
- Quick erection. On a block basis, construction can continue immediately after it is laid out. For comparison, after pouring the monoblock, you should wait about 30 days until it solidifies completely.
- High reliability. The production of this building material is fully automated. Therefore, marriage among the blocks is very rare.
- Sustainability. PBS can be used in a variety of conditions - during the manufacturing process, impurities are added to the basic composition, which provide resistance to adverse weather conditions. There are also acid resistant blocks.
- Convenience of installation. Materials that are absolutely identical in size, as well as the presence of end grooves and loops, greatly simplify the masonry process.
- Universality. These materials are suitable for the construction of both small structures and multi-storey buildings.
According to GOST, foundation blocks must have the following characteristics:
- long term of operation (not less than 50 years);
- fire resistance;
- high strength (about 100-110 kg / cm) and density (about 2400 kg / m 3 );
- resistance to negative external factors and frost resistance;
- water resistant.
Important! Blocks do not collapse when exposed to compressive forces B 12.5.
Deficiencies of foundations from the FSB
The disadvantages are:
- The need for insulation of individual seams. For this, polystyrene foam is most often used.
- High cost. The high cost of materials and rental of special equipment may limit the capabilities of the buyer.
- The need for masonry waterproofing.
Installation of foundation blocks
To create a strip foundation you will need:
- waterproofing;
- mix for concrete;
- sand for a fundamental pillow;
- Blocks
- tools: shovel, crowbar, trowel, etc;
- level and level;
- steel wire;
- roulette;
- equipment: concrete mixer, construction crane (in special cases).
Installation is carried out in a special order:
- First, prepare the axis and the trench.
- Next, proceed to create a pillow. To do this, fill the sand (in small layers) and compact it well. The thickness of the layer should be from 5 to 10 cm, and the width should be approximately 30 cm more than the base. It is worth noting that sand, gravel and bitumen are used for the column foundation.
- After the bottom is ready, the necessary (pre-calculated) sizes are postponed. At the control points, pins are installed that are interconnected by a cord. It should be located at a distance of 2-3 mm from the foundation blocks (FBS).
- The next step is to install beacon blocks. They are placed in the corners of the future structure. The quality of the entire building depends on the correct placement of such blocks.
- After laying the first row, the mooring cord is raised to the upper ribs, and continue to work.
Important! Size tolerances are 10 mm.
The calculation of the fundamental blocks is carried out on an even layer of the solution. In this case, the slings of the crane are not lifted until the moment the unit occupies the correct position. Gaps for summing up communications are left according to the design.
The finished foundation should be covered with a double layer of waterproofing. The final stage is the creation of a drainage system and slopes of the building.
Before continuing the construction of the walls, it is necessary to wait 2-3 days (depending on weather conditions).
How to build walls from blocks
Walls are allowed to be laid out only after a thorough check of the foundation. A leveling layer of the solution is spread on it.
Wall materials are also marked with letters and numbers. For example, the FBS 4 foundation block means that it is wall-mounted, and the nominal width is 4 dm.
Before starting the calculation, the axes and boundaries are marked and fixed on the foundation. Marking is carried out using various instruments: geodetic and wire.
Installation itself begins with the installation of beacons on the solution. It is worth noting that an improperly placed unit is lifted, cleaned, and then reinstalled.
The brand of the suitable solution should be indicated in the design.
If there are no loops on the unit, it is mounted using a grip. Be sure to attach a protective net to it from below.
The process of laying brick foundation blocks does not differ from the above.
Block Safety
According to GOST, foundation blocks are made in various sizes and have a large weight. Given these factors, it is important to carefully observe safety precautions when conducting construction work and operating equipment.
The crane is installed on a reliable area and soil, which is not exposed to subsidence. Crane supports cannot be installed in caving zones or near the edge of the pit.
The whole team is instructed by the chief foreman before the start of work. Specialists who have not learned the rules are not allowed to work.
When planning construction, you should also take into account weather conditions and the season. Depending on these parameters, the number of standard working hours is selected.