The foundation is the most important part of a building. It must withstand enormous loads. In order for the construction of the house to be reliable, its foundation must be strong and of high quality. Foundation blocks are often used in modern buildings.
They are made using special technology, resistant to heavy loads and various weather conditions.
This building material can be used for re-building if there is no visible damage.
What is a block
Foundation blocks (FBS) are a rectangular concrete structure 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 for the construction of tall buildings.
On the sides of the element there are fastening puzzles, and on the upper part there are mountingloops.
FBV (foundation blocks with a cutout) and FBP (blocks with voids down) are rarely used in construction. They are designed for laying hidden networks and communications.
Wall blocks can be made with a smooth or corrugated surface. Also, colored 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:
- brick;
- concrete cellular.
The latter have a number of advantages over the former:
- easy and fast manufacturing;
- high specification;
- easy to operate;
- with a 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 sizes of foundation blocks.
By purpose, these materials are divided into:
- Wall. This view, in turn, is divided into: draft, front, facing (double-sided).
- Fundamental. 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 latter are more practical, because they have less weight and thermal conductivity. Such blocks are ideal for supplying hidden communications. Key disadvantageis reduced strength. The average thermal conductivity is 1.15 W/m2.
Scope of application
The main area of application is the construction of foundations in multi-storey buildings. For individual buildings, they are used less frequently (due to the large weight and high cost of renting special equipment).
The dimensions of the foundation blocks allow them to be laid on any soil - both wet and dry.
The reliability of the design allows them to be used in areas with increased seismic activity.
Depending on the characteristics of the block, the required solution and its quantity are selected.
Concrete foundation blocks: specifications
The main characteristics include:
- dimensions (LxHxW);
- density;
- special options.
Standard length dimensions are as follows: 900, 1200 and 2400 mm. The width varies from 300 to 500 mm, while the height is only 300 and 60 mm.
Density, as well as strength and frost resistance refer to the whole batch of products. These parameters are selected depending on the terrain and the direct purpose of the blocks.
Additional characteristics of fundamental blocks are indicated by Arabic letters. For example:
- "P" - reduced permeability;
- "N" - normal;
- "O" - especially low.
Typical sizes
The weight of a block directly depends on its size. For example, 20 foundation blocks that are used to buildadministrative, industrial and other large facilities, weigh 31 kg 700 g.
Thanks to these characteristics, costs at the initial stage of construction are significantly reduced, and special equipment does not have to be used 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, which are up to 240 cm long, can weigh from 310 kg to 2 tons.
It is worth noting that for some types of buildings there are metal molds for additional blocks. The height of the latter is 300 mm.
Important! Before drawing up a building project, you should contact special services to check the soil for groundwater, acidity, sediment, etc. Depending on the results obtained, the most suitable materials in terms of size and other characteristics are selected.
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 marking briefly states:
- block view;
- geometric parameters;
- additional features.
For example, the foundation block FBS 24 is deciphered as follows:
- FBS is a solid fundamental block;
- 24 - product length (in dm).
If the letter T is indicated at the end of the marking, heavy concrete served as the material for the manufacture. At the same time, for ordinary concrete, the density will be 220 kg/m3, and for silicate or expanded clay concrete - 2000 and 1800 kg/m3 respectively.
The last digit indicates the group of the maximum bearing capacity of the product. The following groups are distinguished:
- first - up to 1.5 kgf/cm2;
- second - up to 2.5 kgf/cm2;
- third - up to 3.5 kgf/cm2;
- fourth - up to 4.5 kgf/cm2.
FBS benefits
Among the advantages of using concrete foundation blocks in construction are:
- Quick erection. On a block base, you can continue construction immediately after it is laid out. For comparison, after pouring a 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. FBS can be used in a variety of conditions - during the manufacturing process, impurities are added to the main composition, which provide resistance to adverse weather conditions. There are also acid resistant blocks.
- Ease of installation. Absolutely identical materials, as well as the presence of end grooves and loops, greatly facilitate the laying process.
- Versatility. 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 service life (at least 50 years);
- fire resistant;
- high strength (about 100–110 kg/cm) and density (about 2400 kg/m3);
- resistance to negative external factors and frost resistance;
- water resistant.
Important! Blocks do not collapse when subjected to compression force B 12.5.
Disadvantages of foundations from the FSB
The disadvantages are:
- The need for insulation of individual seams. For this, polystyrene foam is most often used.
- Expensive. The high cost of materials and the rental of special equipment can limit the buyer's options.
- Need for masonry waterproofing.
Installation of foundation blocks
To create a strip foundation you will need:
- waterproofing;
- concrete mix;
- sand for foundation cushion;
- blocks;
- tools: shovel, crowbar, trowel, etc;
- level and level;
- steel wire;
- roulette;
- equipment: concrete mixer, construction crane (in special cases).
Installation is made in a special order:
- First, they prepare the axles and the trench.
- Next, start creating a pillow. To do this, sand is poured (in small layers) and compacted well. In this case, the thickness of the layer should be from 5 to 10 cm, and the width should be about 30 cm more than the base. Costsnote that sand, crushed stone and bitumen are used for the columnar foundation.
- After the bottom is ready, the necessary (pre-calculated) dimensions are set aside. At the control points, pins are installed, which are interconnected by a cord. It should be placed 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 building. The quality of the whole building depends on the correct placement of such blocks.
- After laying out the first row, the mooring line is raised to the upper ribs, and work continues.
Important! Dimensional tolerances are 10mm.
The fundamental blocks are laid out on an even layer of mortar. At the same time, the crane slings are not lifted until the block is in the correct position. Gaps for summing up communications are left in accordance with the project.
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.
Please wait 2-3 days (depending on weather conditions) before proceeding with wall construction.
How to build walls with blocks
Walls may be laid out only after a thorough check of the foundation. A leveling layer of mortar is spread on it.
Wall materials are also marked with letters and numbers. For example, the foundation block FBS 4 means that it is a wall block, and the nominal width is 4 dm.
Before laying out, mark the axes, boundaries and fixthem on the foundation. Marking is carried out using various instruments: geodesic and wire.
The installation itself begins with the installation of beacons on the solution. It is worth noting that an incorrectly laid block is lifted, cleaned, and then reinstalled.
The brand of a suitable solution must be specified in the project.
If there are no hinges on the block, it is mounted using a grip. A protective net must be attached to it from below.
The process of laying brick foundation blocks is the same as above.
Safety when working with blocks
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 carrying out construction work and operating equipment.
The crane is installed on a secure area and ground that is not subject to subsidence. Crane legs must not be installed in collapsed areas or near the edge of the excavation.
The whole team is instructed by the chief foreman in advance of the start of work. Specialists who have not mastered the rules are not allowed to work.
When planning the construction, weather conditions and the season should also be taken into account. Depending on these parameters, the number of standard working hours is selected.
