When building a foundation, builders are faced with a situation when it is necessary to strengthen the soil. These works can be done in several ways, but the simplest is the use of geotextiles. It is a special material used in the construction of buildings and structures, as well as the strengthening of road surfaces.
With the help of geotextiles, it is possible to strengthen the slopes and slopes. It is made on the basis of polyester and polypropylene fibers, and the basis of production methods is needle piercing and hydraulic bonding. The technology provides for heat setting and calendaring, which ensures water resistance and increased strength.
Basic properties
Geotextiles for the foundation have certain properties, among them it should be highlighted:
- moisture resistance;
- mold immobility;
- high strength;
- ability to maintain initial weight.
During operation, the material is resistant to aggressive chemicals, it is not exposed to fungus, it is not afraid of insects and rodents, which simply do not show interest in lining webs. Geotextile is resistant to punctures, tearing and stretching, which is very convenient when it is necessary to protect the building from the roots of plants, which can seriously damage the base without adequate protection. The material does not absorb moisture, therefore, even under appropriate conditions, the rolls retain their original mass, as well as all specified properties.
Key Specifications
The geotextile for the foundation is selected according to several parameters, for example, the thickness and width of the web, the filtration coefficient, the tensile load, and also the surface density. The geo-cloth can be non-woven and woven, the first is quite widely used in construction. Thickness is not such an important characteristic, because it depends on the density. This parameter can vary from 0.8 to 1.8 and from 2.4 to 3.8 mm.
If you want to choose a geotextile for the foundation, then you should pay attention to one of its main characteristics - surface density. It is measured in g / m 2 and can be equal to the limit from 80 to 1000, as for needle-punched geo-cloth. If you have thermally bonded material in front of you, then its maximum surface density can reach a value of 600 g / m 2 , while the minimum value is 100. A larger digital value indicates a more impressive strength.
The need to use geotextiles
Quite often, novice home masters ask themselves whether geotextiles are needed for the foundation. The answer to this question will be a definite yes. The soil under the foundation must be strengthened. There are many ways to do this today, but using geotextiles is the most effective and easiest. Materials in the base of the foundation require protection against negative factors in the form of moisture and exposure to chemicals.
Canvases are able to strengthen soft soils when there is a need to redistribute the load at the base of the embankment. If the material is correctly laid under a sand cushion, this will prevent sand from mixing with the ground. Once you have decided which geotextile to use for the foundation, it is important to consider another function of it - drainage.
Even the foundation that does not go too deep into the ground is constantly exposed to groundwater, which negatively affects the strength of the structure. The use of geotextiles allows you to install a drainage system that prevents the formation of a water hoses and removes water from the building.
How to choose geotextiles according to density
When choosing geotextiles, you need to determine the type of material in the base. If it is a needle-punched lining, then its density should vary from 350 to 600 g / m 2 , which will depend on the parameters of the soil and the mass of the building.
Heat-bonded geotextiles are made by heat treatment and fiber soldering, which results in improved tensile elongation and deformation modulus. This fabric is stronger than needle-punched and has a longer service life. In order to protect the base, it is necessary to purchase a thermofixed geotextile, whose density is 200 g / m 2 . This is true for a residential building.
Geotextile selection by other parameters
Choosing a geotextile for the foundation, you can pay attention to the hydro-punched material made of polypropylene monofilament. It is great for building technology. Less commonly used today is polyester needle-punched geotextile made of endless thread. Woven staple modifications do not have sufficient strength, so it is better not to use them in construction.
If the territory is prone to swelling, it is better to choose a geotextile designed for non-metallic soil. In this case, the density should not be higher than 300 g / m 2 , therefore it is recommended to use in this case cloths made of propylene monofilament.
When it is planned to lay geotextiles under the foundation cushion, which should be protected from freezing and getting wet, medium-density material should be purchased, which varies from 100 to 150 g / m 2 . This option is budgetary and contributes to an increase in the resource of the structure.
Laying technology: foundation preparation
In order to achieve maximum efficiency during the operation of the geo-cloth, the installation technology should be followed. It provides for surface preparation. Roughnesses in the soil must be eliminated, the cracks must be repaired, and the soil layers must be well leveled to form a drainage. If this is problematic, it is necessary to add sand and compact it well.
Laying the web and joining layers
Laying geotextiles under the foundation involves rolling the rolls and spreading it on the surface of the material so that the sheets come on top of each other with an overlap of 30 cm. If it was not possible to achieve an even base under the flooring, then the overlap width should be increased to 50 cm. Each new layer is placed on aligned previous. Otherwise, you will encounter the problem of material displacement, which will make it difficult to fasten the segments together.
Geotextiles, the properties and characteristics of which were presented above, should be fastened at the joints with metal or plastic staples by the method of sewing. However, it is economically more expedient to connect the layers by welding, because the overlap in this case can be equal to only 10 cm. In this case, the seam is more durable. The edges for this are heated by the burner, and the second segment is superimposed on top. The seam is pressed down for a while. Under the influence of thermal force, the material will not lose its properties.
Backfill and seal
At the next stage, it will be necessary to cover the geotextiles with soil or sand. If it is planned to form the bulk layer using special equipment, it is important to control that the canvases do not catch on the wheels. Material must not be biased. The final step will be surface leveling and tamping to fix the geotextile and prepare it for further construction work.
Geotextile cost
The price of geotextiles will vary depending on its characteristics and the size of the canvas. By purchasing Dornit nonwoven fabric with a density of 300 g / m 2 , you will pay 35.4 rubles. per square meter. In this case, we are talking about a canvas with dimensions equal to 3x50 m.
If the parameters increase to 3x100 m, and the density decreases to 200 g / m 2 , then you will have to pay 24.2 rubles for the material. per square meter. Non-woven geotextiles Technohaut Geo, whose density is 60 g / m 2 , costs 756 rubles. for one roll, the dimensions of which are 1.6x43.75 m. You may also be interested in the price of geotextiles, whose density is 130 g / m 2 , and the dimensions of the roll are 1.6x43.75 m. Cost - 1554 rubles. a piece.
Conclusion
Geotextiles today are widely used in laying the foundation. This material has many positive features, among them must be distinguished moisture resistance and immunity to mold and mildew. The material is resistant to aggressive environments, does not absorb moisture, and if necessary allows you to strengthen weak soils.
The canvases laid under the foundation perform a reinforcing function, retain large fractions that could damage the waterproofing, and also do not allow water to accumulate in those places where it could damage the structure. As a result of the use of geotissue, it is possible to lay the foundation, which is characterized by high reliability and special density.