Foundation construction technology
The most common type of foundation is tape. It allows you to provide high strength for any type of building, if necessary, makes it possible to equip a basement or underground garage with a high level of waterproofing.
Of course, you can use foundation blocks. And although the lack of solidity and the presence of seams reduce the strength and waterproofing capabilities of the foundation, this does not play a big role in low-rise construction. The main disadvantage is the higher cost and the need to use a crane or beam crane on site, which further increases the price of the foundation.
Foundation construction Krasnogorsk reinforcement and earthworks.
Even at the project development stage, the necessary foundation parameters are determined, which depend on the presence of a basement or basement, terrain, groundwater depth, soil type and its features.
Even the simplest foundation for a small country house without a basement provides for a depth below the level of soil freezing.
Before marking the pit or trenches, it is necessary to remove the top fertile layer separately. They do this with a margin of 1.5–2 meters around the entire perimeter of the future structure.
The marking of the pit (trenches) is carried out using ordinary pegs and a cord. It is important that the distances are measured strictly horizontally, and not along the relief, for which a level is used.
The profile of the excavation largely depends on the type of soil. Even dense clay soil cannot provide a vertical wall more than a meter deep. Therefore, a pit or trenches are dug with a margin in width and with a bevel, which can be reinforced with retaining walls made of boards. This space is then used for formwork removal and waterproofing.
After excavation, the bottom must be leveled. In order to ensure the strength of the base and interrupt the rise of groundwater through the capillaries, a pillow of crushed stone of medium or fine fraction and a layer of sand is poured at the bottom. The thickness of each layer is 15-20 cm. The sand is moistened and rammed, the surface is leveled and markings are transferred to it for the construction of formwork for pouring the foundation.
Formwork, reinforcement, concrete pouring
The formwork is made of unedged boards and timber. The poured concrete exerts strong pressure on the walls of the formwork (the wider and higher the foundation, the greater the pressure), in order to prevent the destruction of the structure, it is reinforced with external stops and a wire tie of the timber at several levels of the formwork. A dense film is laid from the inside, it does not allow concrete to leak between the cracks and facilitates the simple removal of boards.
The reinforcement cage is mounted inside the formwork. If the foundation is high and powerful reinforcement is required, then it is better to reverse the operations - first tie the frame, and then mount the formwork.
Concrete is poured in layers with intermediate compaction of each portion. The use of a deep vibrator for concrete is not always possible due to the lack of electricity on the site, so you can use a rebar. The main thing is to “drive out” the air and compact the concrete mass so that it fills the entire volume of the formwork.
The final stage
Proper maturation of concrete is possible provided that the temperature regime is not lower than +5 ° C and the humidity level. During the first week (during which 70% of design strength is reached) it is important to maintain a high humidity level to ensure proper hydration. It is at an “early” age that concrete based on Portland cement must be watered, covered with wet matting or film - when it dries and shrinks quickly, microcracks form, reducing the strength of the foundation.
Maturation to 100% of design strength occurs in 4 weeks. After the expiration of this period, the formwork can be removed and waterproofing measures can be started.
The simplest, but quite effective waterproofing is two layers of roofing material on the outer walls of the foundation over a bituminous primer, which are applied by heating the inside of the roll with a blowtorch. To enhance the effect, with a high level of groundwater and perched water, waterproofing can be strengthened with a retaining wall or clay castle, and drainage can be laid along the perimeter of the foundation base.
After these works are completed, the soil is backfilled and compacted. The final stages of arranging the foundation are the blind area and finishing the basement. But these works are already carried out after the completion of the construction of the walls and the installation of the roof.
Source: www.stroi-alfa.ru Foundation Krasnogorsk