Building a house on soil with a high sand content is a rather complicated process. The foundation, which is the base of the building, must be selected and made technologically correct. We will consider further on the features of choosing a foundation for sandy soil and on the technology of its manufacture..
Table of contents:
To determine the type of foundation that is most suitable for building a house, you should examine the soil for sand content. There are several types of sand, which differ in the size of the fractions..
Coarse-grained sand is an excellent base for almost any foundation. Among its advantages, we note the excellent characteristics of moisture removal, the absence of frost heaving, and resistance to seasonal movements. If the sand particles in the soil are small enough, then in the process of exposure to moisture, they retain it without passing through themselves. In this case, the formation of dirt occurs, which, when solidified, increases its size. Therefore, the soil of takonia doenta, consider this moment.
In addition, the sandy soil of fine-grained composition is characterized by a sklgo type and is highly prone to heaving. In the course of work on the project, the fundam waters are quite high. In any case, before starting the erection to the formation of quicksand. This is especially true of areas on which the soil and the preparation of its design, it is necessary to conduct an examination of the soil for the location of groundwater.
In relation to the percentage composition of sandy soil, several types of it should be distinguished:
1. Soil containing silty sand. This foundation is the most unsuccessful in the construction of buildings on it. Since it is the moisture indicator that determines the bearing capacity of a given soil. If such sand is saturated with moisture, then it has properties similar to clay.
2. Construction of a house on shallow sandy soil is also characterized by a decrease in its bearing capacity when moistened. In this case, it is recommended to waterproof the pit with a polyethylene film. Approximately seventy-five percent of the composition of such soil contains sand, ranging in size from 0.1 mm.
3. Soil with medium to high grain size. More than half of its particle diameter consists of fractions of half a millimeter in size. Such soil has excellent bearing capacity. This soil is the ideal solution for the construction of any building..
4. Sandy soil of a gravel type – it contains more than twenty-four percent of parts, more than two millimeters in size. This type of soil also removes moisture well, is not prone to heaving and has excellent operational characteristics..
If we consider the features of sand post, then we should first of all note the level of its carrying capacity, which depends on the density of the soil. The denser the soil, the greater the load from the building it can withstand.
In the presence of too wet soil, the bearing capacity is reduced. If the size of the bedding of the rock increases with depth, then the sand is more resistant to compression. Therefore, the deeper the foundation is laid, the less the building is subject to shrinkage. In the process of performing work on the construction of the foundation, you should first of all perform high-quality waterproofing of the base. Irrespective of the type of sand, waterproofing is a must.
A sandy base is rarely characterized by heaving, since moisture passes through it. Therefore, almost any type of foundation is suitable for sandy soil. If the site is characterized by high humidity, then to eliminate this problem, you should equip the drainage system and insulate the house around the perimeter.
It is possible to change the structure of sandy soil in depth. Therefore, while examining it, one should also pay attention to deep soil samples. Due to the presence of a low moisture level on sandy soil, it rarely freezes.
Coarse sand implies the construction of almost any foundation on its basis. However, the most economical option would be the construction of a strip foundation with a shallow base. It is usually set up under buildings that do not have a basement or under wooden houses..
There are two options for a strip shallow foundation:
If there is a need for quick work, then it is better to dwell on the first version of the foundation. For its construction, special blocks of reinforced concrete are used. They are connected to each other with concrete mortar. The cost of work in this case is slightly reduced, however, compared with a monolithic foundation, the quality remains at the lowest level..
A monolithic foundation is built directly on the site. For its manufacture, formwork is mounted, a reinforcing cage is installed and the entire area of the foundation is poured with concrete mortar.
The recessed strip foundation is used in the process of building a house with a basement or basement floor. In this case, there is a need to manufacture an additional drainage system that removes moisture from the house. In addition, you should ensure reliable waterproofing of the walls and floor in the basement..
A more economical option would be the construction of a pile foundation. In this case, the total cost of work is significantly reduced. This version of the foundation is simpler and easier to perform..
The choice of this or that type of foundation is based on the type of soil and the level of occurrence of groundwater. The depth of the foundation is determined by the freezing depth of the sandy soil and the level of groundwater.
A technologically correct foundation is the key to the long-term operation of the house. Please note that you should not save on the foundation. A poorly equipped base will lead to a decrease in the performance of the house, the appearance of cracks in the foundation, the appearance of moisture and dampness in the house.
The site is preliminarily cleared of weeds, trees, debris and dirt. This is followed by the removal of the top fertile soil layer. In order to prevent flooding of the trench under the foundation with water, a moisture drainage system should be provided.
According to the project of the house, the base is marked on the sand under the foundation. First, the external walls of the house are marked, and then the internal ones. The type and method of marking depends on the type of foundation chosen for the construction of the building..
If it is planned to erect a strip foundation, then the marking is carried out in relation to the perimeter of the building and the location of the load-bearing walls. When constructing a columnar foundation, it is necessary to mark the places of installation of pillars or supports on which it is based. If a slab-type foundation is made, for example, for houses with a basement, then in this case, only the perimeter of the building is marked out, and a trench is dug.
Please note that before starting work, geodetic studies should be carried out to determine the type of soil and the level of groundwater. If the work is carried out on the soil, which is characterized by fine granularity, then the heaving of the soil should be prevented and its frost resistance should be increased. In this case, the bottom of the foundation should be larger than its top. It is preferable if the foundation is in the shape of a trapezoid. In order to prevent deformation of the base, it should be waterproofed. For these purposes, it is optimal to use roll materials. With their help, the sliding of the frozen soil is ensured. In addition, in order to reduce the heaving of the soil, you should take care of its insulation..
The next stage of work on the foundation involves digging a pit. For these purposes, specialized equipment is most often used. The type and size of the pit is determined by the type of foundation that is chosen for the construction of the house. To calculate the depth of the sand trench under the foundation, use the following guidelines:
1. When building a foundation on solid ground, a depth of 100 cm is sufficient.
2. If the work is carried out on sandy loam, then the optimal foundation will be 120 cm deep.
3. For clay soil or for sandy soil with a high content of fine particles, a trench should be equipped with a depth of about 150 cm..
If you plan to arrange a columnar foundation, then we will make depressions of a round or square configuration. More sturdiness against shedding, round corner trenches.
The trench must be isolated from running water entering it. For these purposes, a system should be built from ditches or dumps. The base of the foundation is laid immediately after digging the pit, thus it will be possible to increase its strength.
Tip: Never fill soil back into the trench. This will lead to uneven shrinkage of the building and its cracking..
If you overdid it and dug a trench a little more than required, then you should fill it with carefully compacted sand, gravel or crushed stone. The best option, pouring the base with concrete mortar.
We suggest that you familiarize yourself with the option of manufacturing a strip-pile type of foundation on a soil of a fine-grained type. In this case, piles installed on the supporting parts of the house are used to strengthen the strip foundation..
Foundation – proportions of sand and filling the foundation with sand:
1. First, the foundation is prepared before marking. To do this, remove debris, plants from the site and remove the top layer of soil. Most often, the foundation pit is set up at a slope of forty-five degrees. In this case, the formwork is erected in height. For its manufacture, wooden boards are used, and for strengthening – a screed and struts. At the corners and intersections of the foundation strips, wells should be drilled under the foundation.
2. If quicksand was found on the site, then asbestos-cement-based pipes should be used for the manufacture of the pile foundation. First, pipes are installed inside the well, followed by their fixation with spacers. Note that the pipes must be high enough to completely fill the trench. In the presence of not very moist soil, the piles are made of concrete, with their preliminary reinforcement.
3. Pile pouring is carried out using concrete mortar, while the first stage of pouring involves filling only one third of the pipe. The concrete slurry must fill the bottom of the well. Thus, it is possible to thicken the pile.
4. For the manufacture of fittings, rods are connected with wire. The reinforcement must be high enough to tie it to the top of the strip foundation.
5. Next, fill the foundation with sand or gravel. If the question is about which sand for the foundation is the most optimal, then coarse-grained sand should be used on the foundation cushion.
6. The reinforcement for the foundation must have a corrugated surface. Thus, it provides a tighter adhesion to concrete. Use wire to tie the reinforcement horizontally. Welding is an unreliable means of connecting reinforcing rods, since under the influence of concrete, it corrodes.
7. Pouring with concrete is carried out simultaneously on the entire part of the foundation. Vertical joints on the tape are unacceptable, as they contribute to a decrease in the bearing capacity of the foundation. Pouring with concrete is completed by leveling the base and covering the foundation with a polyethylene film.
8. After the foundation is dry, it is waterproofed vertically. For these purposes, roll materials are used, which protect the foundation from the load. If the soil is humid, then the drainage system must be equipped. If necessary, the foundation is insulated with polyurethane foam or other alternative material.
Steel piles will help to equip the foundation directly on the surface of quicksand, if any. At the same time, the main guarantee of the construction of a high-quality foundation is the correct determination of its type, depth, width and method of laying. Remember that it is impossible to save on the basis of the building in any case, since the durability of the building directly depends on the quality of its execution..