If there is marshy soil on your site that you plan to use to build your home, you should not be upset. Modern technology makes it easy to lay the foundation, even in difficult conditions. The main rule in this case will be the correct choice of the type of base. You can’t be mistaken, because the life of not only the foundation itself, but the entire building will depend on this.
What is swampy soil?
Before you begin to build a foundation in the swamp with your own hands, you should familiarize yourself with this type of soil. It is a heterogeneous multilayer structure, which provides for the presence of:
The swamp is always oversaturated with moisture and has fine particles in large quantities. They resist compression quite weakly. The soil is unstable, therefore, determining the ultimate load is quite difficult.
Swampy soil is one of the most difficult for construction. Before determining the depth of the foundation, the type of foundation and the area of the structure, it is necessary to study the geological situation.
Features of construction in the wetland: geological studies
If you decide to lay the foundation in the swamp under the house, then at the first stage you must carry out geological research. They are necessary for determining soil indicators. You will need to find out what is the volume of soil water, to what level freezing occurs, the type of soil, as well as the surface proximity of groundwater.
To select the soil, you must use a manual probe. Wells are drilled on the site, which are located at the corners of the future foundation. It is better to carry out research in the winter, when the soil is most saturated with moisture. Soil sampling provides the following information:
- formation thickness;
- physical properties of the soil;
- bedding depth;
- soil change in recent years.
For a wooden house, 5-meter wells are drilled, whereas if you plan to build a stone or brick house, then the depth of the well needs to be increased to 10 m.
Before starting construction on a wetland, the depth of soil freezing should be determined. If the foundation is laid to an insufficient depth, then subsequently this may cause its destruction. As a result of engineering and geological studies, you will receive information that will allow you to determine the type of soil.
Which foundation is better to choose?
The most labor-intensive and expensive process in building a house is the work on arranging the foundation. The cost of carrying out these manipulations will be 1/3 of the total cost estimate for the construction of the building. After a few years, any foundation in the swamp begins to collapse, but only if it does not reach the depth of seasonal freezing.
On the south side, the base begins to protrude if the work was carried out incorrectly. In order for the design to last as long as possible, it is necessary to make a drainage system. She will remove excess moisture from the site. On swampy soils, three types of foundation are used, one of them is pile.
This design is the most suitable, as it has the following advantages:
- relatively low cost;
- the possibility of construction in any terrain;
- increased durability;
- high stability and durability;
- excellent corrosion resistance.
Screw piles for the foundation can begin to be installed in any weather. The construction time is very short. You can complete the foundation device in 2 days. If you use supports of different heights, then you can smooth out surface irregularities.
The main part of the foundation is a pile, which can be installed in the ground vertically or with a slight slope. The supports are combined using a grillage, which is a pillow in the reinforcing cage.
Screw piles for the foundation are one of the varieties of supports used in marshland. These products are protected against corrosion by zinc coating or mastic. Screwing in is carried out using a special lever. Piles can be reinforced concrete, they are clogged with a hand head. As an alternative solution are complex combined piles that are placed in the casing. They are removed after mounting the supports and concreting the site.
Foundation construction on the basis of bored piles
The foundation in a swamp may consist of bored piles. It is being built according to one of several technologies, among them:
- with waterproofing;
- with fixed formwork;
- with removable formwork.
In drilled wells, covers are installed that are welded from a plastic film. The walls are laid out with roofing material, and concrete is poured inside. When creating piles, you can use removable formwork made of metal or plastic. 2 hours after pouring, the concrete strength will be sufficient to maintain the structure. The formwork is pulled out after solidification of the solution.
Such supports have one drawback, which is expressed in the fact that they do not have protection against moisture. But the effect of the frozen layer can be leveled by creating sand cushions.
The foundation on bored piles in a swamp can be created according to the third method, when the formwork is not removed. In this case, it will perform the function of waterproofing. The technology involves the use of pipes made of the following materials:
- special cardboard;
- asbestos cement;
- metal.
This method allows you to protect piles by eliminating elevation differences and creating a layer of sand between the supports and the walls of the well. Before installing the structure, water is pumped out of the well by a pump. The lower part of the pipe, which acts as a formwork, is filled with waterproofing concrete per meter of height.
Such a foundation in a swamp requires increased support strength. For this, frames made of metal 1.2-cm rods are used. You can use triangular designs.
Should I choose a slab foundation?
One of the most expensive, but reliable is the slab foundation. He is able to undergo heavy loads and sudden changes in temperature. The weight of the building will be evenly distributed over the entire area of the structure, which eliminates the possibility of subsidence. Under the slab is a sand and gravel cushion that allows groundwater to pass through, preventing damage to the foundation.
Conducting construction on a wetland site. Slab foundation - is it suitable?
If there is marshy soil on the territory, then you can equip the slab foundation. At the first stage, a shallow pit is dug, and after it is drained using pumps or drainage. Layers of sand and gravel are laid at the bottom, which are well compacted and covered with several layers of roofing material.
For concrete pouring, formwork is installed, as well as a reinforcing frame of 1.2 cm rods is being constructed. The prepared site is poured with a solution, and then left for several days to dry. After that, the formwork can be dismantled.
Such a foundation is poured in a swamp at a time, and a tape base can be installed on top. It is performed on its own, it is durable, and during shrinkage it protects the walls from cracking. This technology is relevant for those who want to have a basement in the house.
Alternative - shallow strip foundation
The strip foundation in the swamp is one of the cheapest, but relevant only for buildings made of metal frame or wooden beam. Such a foundation requires a good drainage system, as they lay the structure above freezing. The tape should be monolithic, this provides the ability to withstand heaving of the soil.
The structure will evenly rise and fall along with the soil. The tape will need a sand cushion, as well as thermal insulation of the base. Such a foundation in the swamp can be poured independently, observing the technology. The work is not too complicated.
Strip foundation construction
If you decide to build a strip foundation, then first you need to dig a trench of the desired shape. A sand cushion is laid at the bottom, and then a reinforcing cage is installed.
If water appeared at the bottom, then it should be disposed of by the method of constructing a drainage. Next, formwork is installed and the mixture is poured, which should be left until solidification. When everything dries, the surface is covered with waterproofing.
Finally
Peatlands and marshes are some of the most difficult soils for construction. Wet soils are oversaturated with moisture and prone to the formation of unstable quicksand. In winter, such soil is subjected to frost heaving, and in the spring - erosion. The hard layer lies at a considerable depth, which excludes the possibility of using some types of foundation.
For wetlands, it is best to use floating bases, which are also called monolithic slabs. The design will turn out to be integral, thanks to this there will not be a partial shift of the house, while distortions and destruction of the walls will be excluded.