Design features of the foundation on the pipes.
If you start price comparison of the columnar foundation of plastic pipes with ribbon structures, of course it will be cheaper. Plus, materials for installation also cost much less, and the cost of transportation is ridiculous. 
The column foundation is easy to install( which reduces the earthwork front to a minimum) and has good strength( withstands low-rise buildings).Plus, it can be installed at a certain level above the ground. You will not worry about the fact that your foundation will be washed away by melt water. Also, it is perfectly installed on the topsoil. The order of the rig is cheaper than using an excavator. If the structure is designed for a small load, and its foundation is not laid deep - you can use even hand-held drills that run on gasoline or electricity.
Installed plastic pipes form a permanent formwork. They create a suitable geometry of the pillars both in diameter and in depth.
However, not everything is so wonderful. In addition to low strength, there are a few more minuses. First, the columnar foundation of plastic pipes has low stability. This means that you will not be able to apply it on the ground, which is characterized by horizontal mobility. Such grounds can not be used for houses where there are observed differences in altitude of 2 meters. If you want to build a basement, then with this foundation, such an event will fly you into a good penny.
The construction of a columnar foundation made of PVC consists of: a pipe body, a fittings, a so-called expansion shoe, a waterproofing and a concrete mix( in a pipe).
The installation of poles is done at the corners of the house, as well as in the places where the walls are adjoining. Approximate step: 1.5m. .. 2.5m.
This type of foundation is combined with a grill that gives stability to the structure.
Climatic conditions play an important role in choosing the type of foundation. The pipe base of plastic pipes is classified as follows:
- First type: not recessed. Pipes are at a height of 40-50cm.from the earth.
- Second type: shallow. Pipes are at a height of 50%. .. 70% of the depth of freezing.
- The third type: a deep foundation. Plastic pipes are slightly below the freezing level of the earth.
Briefly about the stages of the construction of the column foundation of plastic pipes.
The process of construction is laborious, but entertaining. To begin with, you will have to clear your site using the theodolite to perform markup, to establish exactly where the poles will be located and to sketch out data on their alignment. Once this is done, prepare to dig trenches, trenches and boring pits. Next, proceed to install the pipe in the pit, on the prepared waterproofing material. 
After installation, go to the concrete mix, which is poured into the pipe until the diameter of the hole is filled with concrete( approximate height 20-30cm).Once the level is reached, it is fixed until the mixture has solidified. And until then, the armature is placed in it( naturally, if it is a plastic pipe).
Do not forget to leave part of the armature in order to further connect it to the grillage. Its installation depends on its own material.
Fame has won the foundation, which includes asbestos-cement pipes. This is not surprising, because they do not have high cost and good corrosion resistance. They are characterized by simple machining and a small coefficient of thermal expansion.