The foundation, as it is known, is the basis of the whole structure, the strength and durability of the house depends on the quality of its laying. The most common is a strip foundation. For more than half a century, FBS blocks have been used for arranging such structures, they are used in both industrial and residential construction. Next, we analyze in detail what is the reason for such popularity.
What is a concrete block FBS
As the name implies, it is a monolithic structure made of concrete. Overwhelmingly, all the blocks come with internal reinforcement. These designs are made on special equipment using vibropresses and are characterized by increased strength characteristics.
As for marking, it consists of an alphabetic abbreviation and a number of numbers characterizing certain parameters of the product. FBS stands for wall block. The digital series consists of 3 numbers that indicate the length, width and height of the product. All data are in decimeters.
So, for example, a concrete block FBS 24 4 6, is a solid-cast, reinforced, monolithic block 2.4 m long, its width will be 400 mm and a height of 600 mm. Sometimes at the end of the marking there may be put a letter characterizing the type of composition that was used for manufacturing. As a rule, it is heavy concrete, for example, FBS 24 6 6 T, would mean a block of 2400x600x600 mm in size, cast from heavy concrete.
Plants manufacturers offer a fairly wide range of products. All of them are cast from concrete with strength from B7.5 to B15. Manufacturing techniques and parameters are regulated in accordance with GOST 13579-78.
Important: all similar products in the end parts have a special groove designed for fixing the blocks between themselves with cement mortar.
What are the advantages of designs
- If we compare the monolithic and block foundation, then when casting a monolithic structure it is difficult to achieve such a level of mortar quality as the concrete block has.
- Such a concrete foundation is a kind of masonry, where all sections are rigidly fastened and mutually support each other.
- As you know, concrete matures within 28 days. The block base can be mounted within several days.
- Structures cast from high-strength types of concrete have unique characteristics of frost resistance and water resistance, which allows their use everywhere, up to the regions of the Far North.
- The production technology does not require large capital investments, it has long been verified and debugged. Due to this, the price of most products is acceptable for a wide range of consumers.
What are the disadvantages
- Filling a monolithic structure with your own hands, although it will take much longer, will cost the owners about a third cheaper.
- Reinforced concrete products of this class have a lot of weight, which requires the involvement of special equipment for transportation and installation. And entails additional costs for the rental of this technology.
- Laying of blocks is carried out on cement-sand mortar, and even with an ideal quality of installation, the sealing of the foundation will be insufficient. As a result, most of these structures are necessarily equipped with an additional waterproofing layer.
Important: some experts blame the block foundation for insufficient strength. But the notorious Khrushchev on this basis have been reliably standing for more than half a century. From this we can conclude that a private house, built on blocks of FBS, has a multiple safety margin.
Subtleties of arrangement of the block foundation
It cannot be said that the installation manual is too complicated, but compared to the casting of a monolithic structure, some nuances do exist. Next, we analyze step by step, what should pay attention.
Building a house is quite complicated and responsible. Therefore, before the start of construction, everything should be carefully calculated and prepared.
In particular, you will need the following data:
- First you need to find out the level of soil freezing in the region. This value is not constant and depends on the climatic zone and the location of the structure, for example, on a hill, the ground freezes through more deeply than in the valley. In the central part of Russia, the average value is 1200 mm, and in the south it is about 600 mm.
- When calculating the trench depth, it is necessary to add at least 100-200 mm to the tabular data on the level of soil freezing, so that the frost heaving forces that occur during freezing and thawing do not squeeze or deform the structure.
- Of great importance is the level of occurrence of groundwater. If the house is built in the village, then the best option would be to interview the neighbors. If the terrain is unknown, deserted, then it may be necessary to drill hydrogeological wells, and here we cannot do without the help of specialists.
- You will also need information about the geology of the area, that is, on what soil you will have to build. How stable is it, is there any float in the area, and is the level of exposure of the soil to frost heaving.
- Depth of depth and thickness of the structure is calculated depending on the approximate weight of the future structure. Of course, it is better to entrust the calculation of serious buildings to specialists, but if you are planning to build a bath or garden house, then an online calculator is quite suitable for this.
- There are still data on the seismic activity of the area. But, fortunately, most of the territory of our vast country has stable indicators.
When all the data is known and the foundation drawing is ready, you can proceed directly to the tab.
- All such works begin with the marking of the territory.. The marking is done with the help of support posts (beacons) and fishing line or rope defining the boundary of the pit. It is worth measuring it several times, both the perimeter and the diagonal.
Tip: if you use an excavator to set up the excavation, then after you finish working on it, you need to trim the borders of the excavation manually. The base should be horizontal, and the walls should be smooth.
- If you do not take into account the very light construction type of wooden bath, then for all other buildings, experts advise to equip the pillow. This can be done in 2 ways.
- On stable soils, you will only need to make sand-crushed stone dumping about 100 mm thick, tamp it down and install a reinforced concrete cushion under the blocks. In documents, it is labeled as FL. And yet, the excavation is digging along the width of this particular structure, so that there is a place for arranging waterproofing.
- For complex types of soil, in addition to sand and crushed stone dumping, it will be necessary to equip a self-leveling belt.. The reliability of the belt will double if you initially pour a layer of “lean concrete” of 100 mm and already install a monolithic concrete pad on it. For massive buildings, it is desirable to reinforce it. Construction can be continued only after full maturation of concrete.
- After that, first on the supporting corners and further along the entire perimeter, concrete blocks of the pillow FL are installed. Then you can start laying FBS blocks.
- As mentioned earlier, the structures are laid according to the brickwork principle, that is, not strictly vertically, but with displacement between rows. In this regard, as a rule, products of different sizes are used. In the row can stand several full-size blocks FBS 24 6 6 and completes the laying of FBS 12 6 6.
Important: for the installation of complex connections, there is an additional concrete block FBS 6 4 3 and some dimensions close to it. According to GOST 13579-78, such elements are made without reinforcement, but they use high-strength types of concrete. Although customized can reinforce them.
- To crown masonry should monolithic concrete belt with mandatory reinforcement. For this, a formwork for a concrete product is mounted across the width of the block, after which the reinforcement cage is laid into it and the concrete is poured.
- If the deadlines are tight, and there is no time to wait until the concrete belt is fully strengthened, it can be folded out of brick, but the price of this design will be much higher..
- Construction of the foundation is completed with the installation of waterproofing.. If the house is on solid soils and the ground water does not bother you, then you can do with two layers of bitumen mastic. If you are in doubt, then you should additionally glue the design of roll waterproofing. In wetlands, a separate drainage drainage system should be installed.
The video in this article will complement the above instructions.
The use of concrete blocks in the construction of the foundation will significantly reduce the time to build a house. If simple rules are observed, such a construction will not yield to a solid monolithic one in anything, and using high-strength concrete FBS blocks will even surpass the self-leveling structure in quality.