Prefabricated reinforced concrete foundation is a rather practical and high-quality design, which began to be used in construction not so long ago. It is a monolith in which iron blocks are mounted. Using a similar technology in construction, you will noticeably save not only installation time, but also money. In our article we will try to tell everything about what a reinforced concrete structure is, what types it is, where it is used, and so on.
General information about monoliths
Before you start installing prefabricated reinforced concrete foundations, it is recommended that you familiarize yourself with this design, since the quality of the constructed building may depend on this knowledge. For example, among monoliths there are lightweight blocks with air voids. Their use is justified only if the height of the building will be no more than one floor.
As for the laying of monoliths, it is performed on ordinary cement mortar - this helps to eliminate drafts inside the room, as well as moisture in the basement floors. In addition, strip foundations are also recommended to be protected with special waterproofing, which prevents the penetration of moisture into the room.
A significant drawback of reinforced concrete structures is their large weight. As a rule, prefabricated reinforced concrete foundations can only be installed using special equipment, such as a crane. However, for the manufacture of some modern monoliths, lightweight materials and modern technologies are used that facilitate the weight of the structure up to 30 kg.
Conditions for the use of reinforced concrete construction
Precast monolithic reinforced concrete foundations are massive structures that can be used for the construction of multi-story buildings or private houses. However, every builder knows that the foundation is the most important element of any construction, so it must be performed with the highest quality. Installing reinforced concrete structures is allowed only if the soil on the site and the future structure will meet the following characteristics:
- as a material for the construction of walls, brick, concrete, stone is used, the density of which does not exceed 1300 kilograms per cubic meter;
- in the process of building construction it is planned to use heavy reinforced concrete floors, which will give the structure strength;
- the soil along the perimeter of the site has a heterogeneous structure (it is desirable that gravel, gravel, sifting and other hard rocks be present in it);
- foundation construction will continue to support the basement or basement.
It is strongly recommended not to install a precast concrete foundation under the column in places with peaty or silty soil, as the structure will sooner or later push the soil layer and the building slopes down. In addition, groundwater should be at a depth of not less than three meters, especially when it comes to the construction of a basement. Otherwise, excessive moisture will eventually penetrate the walls of the structure, which is fraught with moldy walls or even their collapse.
Technology of prefabricated strip foundation
As a rule, a prefabricated strip reinforced concrete foundation is used for the construction of the basement floor, which is planned to be commissioned. This design consists of blocks and prefabricated plates that form a full floor. Since pouring such a foundation on its own will be quite difficult, most experienced builders recommend using monoliths from reinforced concrete and cement-sand mortar with vertical joints.
As for the iron element, the monolith does not consist entirely of metal - it just uses fittings, which gives the structure additional strength and simplifies the assembly process. In addition, the strip foundations also have good enough mobility, and the stabilization of the monoliths is due to a special reinforced belt consisting of a movement and several shock-absorbing elements. Such plates are suitable for the construction of cottages and multi-storey buildings.
Foundation properties and block selection
We decided to purchase prefabricated reinforced concrete foundations of the glass type? Are you sure that this type of construction is suitable for your region? For example, for the construction of buildings in cold areas, it is strongly recommended to purchase blocks with increased frost resistance. This quality is achieved through the use of special additives during manufacture. Well, if you plan to build a building on soil with high acidity, it is best to use a foundation wall block, which includes granite crushed stone that is resistant to acidic conditions.
Also, the foundations of factory production are distinguished by a huge variety of sizes and shapes. For large buildings, large-sized structures are used that can withstand a weight of several hundred tons. Of course, for their installation will have to use special equipment. Well, for a private house blocks of rather small sizes are provided, which can be installed manually.
In the introduction, we mentioned that the use of reinforced concrete foundations can save a lot of money, but it’s worth clarifying that they save not on the cost of structures, but on labor. As a rule, one monolith will cost about 30 percent more than purchasing building materials separately. But installation is several times faster than construction work. Although you should not forget that the blocks will also require an additional layer of waterproofing, which is quite expensive.
When choosing a precast concrete foundation, GOST is very important. If you acquire material of dubious quality, then the building can completely collapse over time. To prevent this from happening, you need to purchase only certified products with a quality guarantee. It is best to buy monoliths at construction bases, since in ordinary stores their prices are usually overpriced by 40 or even 50 percent.
Preparatory work
Before installing prefabricated reinforced concrete blocks of the foundation, it is necessary to clear the area. In addition, it is necessary to mark the area using a construction cord and metal stakes. As a rule, the length of each side of the construction site is two meters larger than the required size. Marking is a very important stage of construction, since even the slightest mistake can lead to the fact that the parts simply do not fit together.
In order for the angles in the marking to be as even as possible (90 °), it is necessary to use the building level, attaching it to two hammered pegs. Once you are sure that the marking is as even as possible, drive the stakes as deep as possible so that they do not budge even after rain. The accuracy of the calculations can be checked using the diagonal, drawing it from the upper corner to the opposite lower. Thus, we obtain two right-angled triangles that must obey the Pythagorean theorem.
Trench work
As soon as the marking is ready, you can begin construction work. If your choice is a prefabricated reinforced concrete foundation for the column, then during the preparation of the trench you need to dig a hole of suitable depth. All work can be done with your own hands or using special earthmoving equipment. Be sure to check from time to time the depth of the trench, which should always remain at the initial level. With excessive deepening, it is possible to add a layer of crushed stone (up to 10 centimeters) into the pit and compact it thoroughly.
As soon as the pit for the foundation is ready, you can begin to lay the sand cushion, the layer of which should not exceed 15 centimeters, and the width is 20-30 centimeters more than the width of the reinforced concrete block. As soon as the material is poured, pour it with water and ram well. After that, it will be necessary to install a waterproofing layer. To do this, you can use a special plastic film, which can be purchased at any hardware store. In some cases, waterproofing is also laid on top of a reinforced concrete foundation.
Tools and materials for work
In order to install a precast concrete foundation, it is necessary to prepare all the necessary materials and tools in advance. Otherwise, in the process of work you will have to constantly be distracted by something. To install the foundation you will need:
- material for waterproofing;
- blocks of design size;
- plate pillows made of reinforced concrete;
- reinforcing bars;
- mortar for masonry.
Depending on individual preferences, this list of materials can be significantly expanded. For example, if you decide to use crushed stone bedding, you will have to take this into account at the planning stage. In addition, you will also need to acquire many tools, the list of which is approximately as follows:
- a concrete mixer or some kind of container for the preparation of a solution;
- metal pegs, nylon cord and tape measure for marking;
- rail with a flat base for leveling the solution;
- construction level (level) and plumb;
- welding machine, grinder with a disk;
- scrap, trowel, trowel, shovel.
It is easy to guess that the list of tools directly depends on the materials that are planned to be used during the construction process. Therefore, if you decide to add some element to the foundation, be sure to consider this at the planning stage, so that later you do not have to look for precious tools for working with the material.
Installation of block pillows
In order to improve the bearing characteristics of a precast reinforced concrete foundation strip, it is necessary to install a layer of block pillows under it. They are laid out on the waterproofing layer, which goes after the sand cushion. The design is designed to increase the footprint and stability of the foundation. Installation is carried out using a conventional solution, which is laid out on the waterproofing layer.
Do not forget that an even foundation is the key to the reliability of any design. If the layer of block pillows is installed crookedly, then the entire foundation and the building will also be skewed on one side. The horizontalness of the surface can be controlled using a level or the usual building level. If the installation was not carried out correctly, do not be afraid to dismantle the unit and reinstall it.
Metal reinforcement with a cross-sectional area of at least 30 millimeters is laid on the upper plane of the pillows. Sawing parts occurs using a conventional grinder with a disk, and a conventional welding machine will be indispensable for installation. As for the docking, it should be overlapped. In this case, the length of the weld should be approximately 10 rod diameters - 30 centimeters. The reinforcement is covered with a layer of mortar on top.
Reinforced concrete block assembly
Installation of any series of prefabricated reinforced concrete foundations is necessary in a checkerboard pattern, otherwise the structure will simply collapse as a result of a strong blow to the corner. When laying blocks, a cement-sand mortar is used, with a thickness of about 20 millimeters, which should be constantly leveled using the building level. As you install, the seams should also be densely filled with mortar.
Do not forget about the need to leave special openings between the blocks in order to then carry out communications or sewage systems. As soon as the sleeves are mounted in the wall, it is necessary to seal all the seams and holes with a mortar. Otherwise, drafts and moisture inside the house can not be avoided.
Also, when installing blocks, it is strongly recommended to use dressing in rows. especially at the point of contact of internal and external walls. Well, high-quality waterproofing is one of the most important values, since contact with a humid environment can be detrimental to the foundation. That is why in the ground part of the foundation it is worth hammering all the grooves of the blocks with dense soil. It is best to use clay or the same earth for this purpose, which will remain on the site after digging a pit.
Video and conclusion
We hope that now you better understand what constitutes a device of prefabricated reinforced concrete foundations. If you have any questions about this matter or you don’t fully understand the installation process of reinforced concrete structures, we recommend watching a short video in which the author talks about the construction technology based on reinforced concrete blocks. This information will be relevant for the most part to beginners, although it is quite possible that professionals will also learn something useful from the video.
We hope our article helped you understand all the features of working with a precast foundation. Of course, such a technology will cost much more than building a conventional structure, but there is no doubt about the quality and reliability of reinforced concrete blocks. Be sure that the cost of buying building materials will more than pay off on the salaries of builders.