The best foundation for sandy soil

The best foundation for sandy soil What foundation to choose on sandy soil

The most important thing when building a private at home is its foundation, that is, the foundation. With improper design, this can cause the house to sink, its distortion, the appearance of microscopic cracks and their further expansion, and as a result, this also leads to the destruction of the roof and walls. In order for a house building to be reliable, it is required to take into account all sorts of parameters, technical characteristics, including the variety of soil and its properties. For a foundation on sandy ground, there are certain differences in construction, in contrast to the standard cases.

Step-by-step algorithm for determining the type of soil

Before starting planning the foundation, it is imperative to perform an engineering-geological analysis of the soil, because certain types of foundation are suitable for each type of land.

You can determine what type of soil in your summer cottage by examining the percentage of clay, sand and silt, even through the tactile-visual method. You can conduct such a study yourself or with the involvement of specialists. During geological surveys, it is required to drill several wells with a great depth, up to 15 meters, and extract from there ground samples, as well as ground water for further laboratory analysis.

Surveyors' research makes it possible to avoid serious mistakes, in which spending on fixing is ways to exceed all the costs of building a foundation (and this is the most expensive part of building). In order to determine which type of base is preferable, specialist advice is required.

Properties and characteristics of sandy soil:

  1. The best foundation for sandy soil Bearing capacity - this is one of the main qualities of sandy soil. It will characterize the possible load that the soil can withstand without negative consequences. The high characteristic of the bearing type of earth does not allow subsidence of the base, and the earth will be kept intact to prevent displacement of layers. So, the first indicator is the compaction of the layers. The greatest pressure logically is ways to withstand high density soils.

    The second is moisture content. Soils with a low water content are less prone to displacement and changes.

  2. Soil compressibility is a characteristic that indicates how much the earth is able to compress under load pressure. The depth of the foundation will directly affect the compression resistance, and greater depth can even lead to a higher degree of resistance. Due to this, the degree of subsidence of the house decreases.

    Land with a predominance of sandy fractions has a low degree of compressibility, which means that subsidence will not last long.

  3. The degree of frost heaving - this parameter directly depends on the degree of soil moisture.Under the influence of the low temperature of the earth, which is surrounded by water, it expands and pushes soil particles to the surface. Depending on how saturated the soil is with water, swelling can be very strong (provided that there is a lot of moisture in the soil) and weak (if there is almost no water). To make frost heaving less, and this is not negatively reflected on the base, it is recommended to use the soil with non-heaving soil.

    On moist soil, it is better to build the foundation lower than the freezing line. The heaving indicator for sandy soil is much less than for other varieties. The water level in the ground is also able to affect the heaving indicator. When they are located close, the degree of frost heaving will increase, and the level of soil water can also change at different times of the year, eroding the ground and having aggressive additives in its composition - destroy the base. The rise in the water table in sandy soil can reach up to 5 meters.

Sandy soil is a loose rock, which contains loam and sand in a ratio of 1 to 3. Sand is a rather loose material, consisting of grains of sand, the size of which is from a couple of mm to the smallest particles more like dust. It is best to build the foundation foundation on coarse sand.


Varieties of sandy soil

Almost any type of foundation can be built on sandy soil. In order to know exactly which species to choose, you need to take into account the soil structure, the size of the particles and their percentage.

Gravel type of sandy soil meets the requirements for laying the foundation better than others, and it also consists of the largest particles and has high bearing parameters. Sandy soils made of coarse sand and medium ones are also perfect for building a country house, because they are in no way susceptible to frost heaving, they drain water perfectly, and are also resistant to seasonal displacement. In addition, they are almost free of quicksand and quicksand. Fine-grained sand cannot pass water, but on the contrary, retains it, absorbing it into itself.

What foundation will "take root" on the sandy ground? We will consider this further.

And in the fine type of sandy soil, it is more prone to frost heaving. When laying a foundation on such a soil, the trench must be laid out with plastic wrap in order to isolate the base from possible interaction with water. The dusty type of soil looks very much like dust, and it is also sometimes called loess-like. For installation work for the foundation, it is unsuitable, since it absorbs moisture strongly, retains it for a very long time, due to the formation of dirt and in appearance, when wet, resembles clay. It also has a very low bearing capacity.

Please note that the construction process for foundations on this type of soil is an expensive and time-consuming process that will be complicated by the likelihood of quicksand.

Varieties of bases

All the load from the built house will go to the foundation. Its degree of reliability will determine the safe use of the building. The depth of the base will be equal to the length from the top soil layer to the bottom of the base. In order to choose the most suitable type of foundation, it is imperative to take into account not just the properties and type of soil, but also the height of the building, operational features, building materials used for the construction of walls.

All kinds of bases and their properties make it possible to determine which one is ideal for construction.

Strip base

The strip base is the most popular. It is a tape that is concreted deep into the soil along the general perimeter of the planned building and under the walls. They can be shallow in the ground or have a great depth of burial. If we talk about the first type of strip base, then it is quite simple to build it if it is possible to use foundation blocks.

It is ideal for constructing wooden structures due to the potential for subsidence. The deepened tape type of base is usually used for building a house in which there is a basement. In addition, it is extremely important to insulate the walls and floor in the basement from the influence of moisture. With non-rocky soil, the base can be made of expanded clay concrete or concrete blocks with free laying.

If the ground has a high degree of frost heaving, then ideally it is worth using monolithic reinforced concrete, and for a greater effect, a reinforcing belt, on which floor slabs are usually held.

But not in all cases, the strip base can provide the required degree of house strength. On sandy soil with fine particles, this type of foundation can lead to skewing and subsidence of the building as a whole. The strip foundation requires a lot of time and money.

Columnar base

The best foundation for sandy soil is columnar. Such a base consists of small pillars that need to be buried in specially prepared holes.

When laying the foundation between the ground and the beams, it is imperative to leave a gap. This type of warp can be used to build a large house on sand. When building a columnar base, much less physical and material costs are needed, and the process is simple. But it should be borne in mind that the depth of the pillars must be sufficient so that the earth does not push them to the surface. otherwise, especially if the soil consists only of dusty particles, the pillars can be repainted, begin to disperse, and the building will quickly collapse.

Pile foundation

The best foundation for sandy soil Pile foundation it is installed from metal hollow pipes that have screws at the end and slabs or reinforced concrete beams combined from above. This type of foundation is distinguished by a high degree of reliability, because the depth of pile installation is located lower than the soil freezing line. The pile foundation is used in areas where loess-like weak soil (up to 50% of dust particles), mostly on slopes and under buildings of several floors. The piles are strong enough and do not deteriorate even with large ground movements. In certain cases, the pile foundation is even able to replace the strip base.

But here it all depends on the degree of deepening, and the pile base can be reinforced concrete, driven and concrete rammed, screw and drilling reinforced concrete.

The placement of piles at the base can be single, in the form of piles and a tape, as well as pile bushes. Reinforcement with pile bushes is usually done in order to anchor the weak area. Most piles are installed vertically, but you can place them at an angle. Installation of this type of foundations is usually carried out using specialized equipment and requires little material costs.

We do not recommend using it for the construction of large houses.

Slab base

This is the most reliable option to build a large cottage on sandy ground.

The base in the form of a slab is a monolithic base, which consists of a lattice or solid slab of reinforced concrete, as well as a prefabricated slab with a monolithic coating, and it is deepened into the ground to a depth of 1/2 meters. In this case, the thickness of the slab can be from 0.2 to 0.

5 meters. The slab can be both on the ground surface and deepened. It is poured over the total area of ​​the building and has a rigid frame.

At the bottom of the prepared pit, pour crushed stone, sand, and then insulate from water. For a private residential building with a basement, the slab foundation should be in depth as prescribed in the project documentation.

A deeply buried foundation is often made in such buildings, and this type of foundation can be used for rough floors. When sandy-type soil is displaced, the slab seems to "float on the waves" with the house, and the structure will not collapse due to the strong and rigid frame. The slab base is more suitable for small buildings. Installing this type of foundation is extremely expensive and requires a lot of concrete and reinforcement.


In general, the construction process on sandy soil has only slight differences from construction on other types of soil.