Recently, the construction of small buildings and structures is considered popular. Increasingly, for their construction, the installation of a pile-screw foundation is used. Thanks to the achievements of scientific and technological progress, literally everyone who is more or less familiar with the basics of construction will be able to build a pile-screw foundation on their own. This technology is not new and has long been used as a low-cost type of construction of the foundation of a future building. In the article, we will take a closer look at the pros and cons of a pile-screw foundation, as well as step-by-step pipe installation technology.
What is a pile-screw base
The device of a pile-screw foundation is a certain number of screw piles that are screwed into the ground manually or with the help of special equipment. On top of the piles, a so-called grillage is formed, which isconnecting frame of all free-standing screw piles. A grillage can usually be made of wood or metal.
What one pile looks like
Looking at one single pile, you can see that it is made in the form of a thickened metal pipe, the wall thickness of which is 0.4-1.2 cm. At one end of the pipe there is a blade in the form of a large thread. Due to this structure, the piles are easily screwed into the ground. The tip in the form of a blade at the same time will be the support of the entire structure. For the convenience of installing a pile-screw foundation, most often on sale you can find piles with a length of 0.25-2.5 m.
Design Advantages
The use of screw piles allows you to create a strong, high-quality and durable foundation for a summer house, cottage, country house, bathhouse, gazebo or other building in the shortest possible time and at the best price.
Advantages of installing a pile-screw foundation:
- Economy: the cost of such a design is significantly lower than the cost of erecting a strip foundation or foundation slab. Significant savings are achieved through the use of a fundamentally different technology, the use of cheaper materials, and most importantly, simpler and faster installation methods.
- Quick installation and ready to use: most often the construction of a reliable foundation takes half a day, and the foundation can be operated immediately after installation.
- High environmental friendliness: installation of a pile-screw foundationcompletely harmless to the landscape - there are no mountains of construction debris, dust, traces of overall special equipment.
- All-season: piles are fastened both in the warm and cold seasons, and without increasing the cost of work.
- Versatility: this type of foundation is great for building low-rise buildings of any type on different soils (except rocky and rocky), as well as building houses on a site with a height difference.
- No dampness and low heat loss: during the operation of screw piles, an air cushion is formed under the building, which prevents dampness and retains heat.
Disadvantages of pile-screw foundation
Today, screw piles are made from different metals and their alloys, mainly from steel or stainless steel. These products are susceptible to corrosion. The structure is destroyed over time under the influence of alkaline soil compounds. The durability of literally the entire structure directly depends on the quality of anti-corrosion treatment of piles. Anti-corrosion coating is applied after sandblasting. This process is carried out only in industrial production. It is not possible to apply an anti-corrosion coating on your own. The cost of anti-corrosion treatment significantly increases the cost of building a house.
The maximum service life of screw piles today is up to 85-90 years. It is important to buy piles made of high-quality metal, which will guarantee a long service life of the entire structure.
Mounting Options
Installation of a turnkey pile-screw foundation can be carried out by two main methods:
- The manual method involves screwing metal piles into the ground manually. To do this, they use the well-known scrap or an ordinary steel bar, which are inserted into a special hole in the upper part of the pile. To build a pile-screw foundation with your own hands, you only need two specialists who screw up to 15 piles in one shift. Foundation construction should only be carried out during the warm season.
- The mechanical method of building a turnkey pile-screw foundation is to hammer metal pipes using special hydraulic equipment. The use of this method allows you to build in the winter, as well as build houses near the water. Thanks to the automation of almost the entire process, a team of three people drives up to 30 piles per shift.
Basic installation steps
In order to properly install the pile-screw foundation, you will need to follow the installation technology, which includes several steps:
- Calculation and markup. The first step is to determine the type of soil and the amount of work to drive piles. Also, experts calculate the structure of soil layers and the level of their freezing in winter. Based on the calculations obtained, the places for installing metal piles and their required number are marked.
- Pipes are installed vertically on pre-markedlocations.
- Since construction is most often carried out in non-standard landscape conditions, pipes are almost always cut at the same level. This procedure is essential for building a solid foundation.
- Additionally strengthen the pile-screw foundation, to ensure the protection of the structure from internal corrosion and external negative factors will allow concreting. Pipes are poured with concrete at the last stage of foundation creation.
How to lay a deep pile-screw foundation
The depth to which screw piles must be screwed in is determined before they are purchased and installed, because their overall characteristics directly depend on this.
The basic rule when determining the installation depth of a pile-screw foundation is that it must be below the freezing level of the soil. This will avoid heaving of the soil in winter and pushing the pile to the soil surface. If this type of soil is observed on the site, then the piles are screwed in not just below the freezing depth, but to the so-called good soil.
It is recommended to focus not only on the level of freezing of the earth in a certain area. This applies to soils of swampy, sandy, peaty types, where more or less solid ground is located at great depths.
It is important to remember: it happens that dense layers of soil lie at a depth greater than the length of the purchased pile. In this case, experts recommend building up metal pipes. Sometimes a pile-screw foundation has to be installed to a depth of more than 5meters.
Soil preparation
First of all, before screwing the screw piles, to facilitate construction work at the pipe installation sites, the top layer with the vegetation on it is removed. This is done with a drill of a smaller diameter than the diameter of the pile blade, or the soil is cleaned with a conventional bayonet shovel. It is desirable to do these works during the laying of piles.
How to choose piles
When choosing consumables, please pay attention to the following:
- Before driving the screw piles, it is required to conduct a detailed analysis of soil indicators on the land plot. In this situation, the type of soil, the depth of groundwater, the period and level of soil freezing are determined.
- Before buying material, the mass and design of the future building, as well as the subsequent load of the snow cover, must be taken into account. It is important to remember that the larger the diameter of the piles, the stronger the entire structure will be. Today, the recognized optimal option for the construction of a low-rise country house is the diameter of metal piles of 108-120 mm.
- Pipe wall thickness must be at least 4mm.
- Piles for the foundation should be selected only from new steel. The use of sandblasting and anti-corrosion treatment of pipes is considered mandatory.
- It is recommended to select piles without welding seams with a correct and geometrically adjusted blade without defects in the form of dents.
Prices of screw piles
The cost of screw piles may vary, depending on the material from which the pipes are made, and dimensional characteristics. Please note that piles may vary in length, diameter and wall thickness. Also, the cost of screw piles may vary. The reason for this is the use of high-strength materials, the price of which is much higher.
Before erecting a pile-screw foundation, the pros and cons should be assessed not only by the owner of the future building, but also by specialists. With the right approach, it is possible to build a durable and strong building. It is quite possible to form a pile-screw foundation with your own hands, the main thing is to adhere to the technology and the sequence of work.
