When choosing the type of foundation, the home owner must first take into account the peculiarities of the soil and the structure. An important criteria for choosing a particular base system is the price availability, a decrease in the complexity of installation, the possibility of maintaining work without attracting special equipment. The foundation on asbestos pipes is suitable for “problematic” soils, has a smaller cost compared to some other types of bases.
A few decades ago, asbetic pipes were practically not used in private housekeeping, which was due, firstly, which existed for that period by the myth of their environmental non-safeness, secondly, lack of knowledge and practical experience in the technology of applying this material.
Today, a columnar or pile foundation on asbestos reasons was quite widespread, especially on the soils where it is impossible to equip a belt base. Such soils are primarily clay and thin, water-saturated soils, as well as sections with a height drop.
Using piles of asbestos-cement pipes, you can raise a building by 30-40 cm, which is convenient for sites located in lowlands, river floats, as well as susceptible to seasonal flooding. Unlike metal piles, asbestos-cement is not inclined to the emergence of corrosion.
Asbestos pipes are building materials based on asbestos fiber and portland cement. They can be pressure and non-per-“. Only pressure modifications are suitable for construction, they are used in the organization of wells, wells.
Such pipes have a diameter in the range of 5 – 60 cm, withstand pressure up to 9 atmospheres, are characterized by durability and good hydraulic resistance coefficients.
In general, the technology of their installation is standard – the installation of most pile foundations is in the same way. For pipes, wells are prepared, the location and depth of which corresponds to the project documentation, after which they are lowered into prepared plugs and poured concrete. In more detail about the installation technology will be discussed in subsequent chapters.
Pros and cons
The popularity of the foundation of the type under consideration is primarily due to the possibility of making a plot with “problem” soil suitable for construction. Asbestos cement pipes can be installed with their own hands without attracting special equipment, which distinguishes them from metal piles. It is clear that this reduces the cost of the object.
The absence of a large amount of land, as well as the need to fill large areas with a solution of concrete, determine the smaller complexity of the installation process and its higher speed.
Asbestos cement pipes are at times cheaper than piles, while they demonstrate better moisture resistance. There are no corrosion on the surface, the material degradation does not occur and the loss of strength. This allows you to maintain in excessively implanted soils, as well as on flooded territories.
If we compare the cost of a column foundation on an asbestos-cement base with the cost of a belt analogue (even finely breed), then the first will be cheaper by 25-30%.
When using piles of this type, it is possible to raise the building on average to a height of 30-40 cm, and with proper load distribution – even up to 100 cm. Not any other type of foundation demonstrates such qualities.
The main disadvantage of asbestos-cement pipes is their low carrier capacity. This causes the impossibility of using them during construction on marsh localities and organic soils, and also imposes certain requirements for building. The object should be low-rise out of lightweight materials – wood, aerated concrete or frame-type design.
Due to a small bearing capacity, it has to increase the number of asbestos-cement pipes and, accordingly, wells for them.
In contrast to metal analogues, such supports are characterized by the absence of “anchor” properties, and therefore, in non-compliance with the installation technology or errors in the calculations when the soil begged, the support will be squeezed out of the ground.
Like most pile houses, objects with asbestos-cement base are built without basement. Of course, with a great desire, it can be equipped, but it will have to digging (on well-saturated soils to equip a powerful drainage system) that in most cases is irrational.
The construction of any type of foundation should begin with the preparation of project documentation and drawings. They, in turn, are based on data obtained during geological surveys. The latter suggests laboratory analysis of soil in different seasons.
To get information about the composition of soils and their features allows drilling of a test well, due to which the sublayer of soil, its composition, the presence and volume of groundwater becomes obvious.
The pledge of a durable foundation is the exact calculation of its bearing ability. Supports of pile foundations must reach solid soil layers, which lie below its level of freezing. Accordingly, to carry out such calculations you need to know the depth of the soil freezing. These are permanent values that depend on the region, they are freely access in specialized sources (Internet, official documentation of bodies regulating the rules of construction in a particular region, laboratories that produce soil analysis and so on).
Having learned the necessary coefficient of drainage depth, it should be added to it 0.3-0.5 m, since it is so asbestos-cement pipes protrude above the Earth. Usually, this is a height of 0.3 m, but if we are talking about flooded regions, the height of the above-ground part of the pipes increases.
The diameter of the pipes is calculated on the basis of the load indicators that will affect the foundation. To do this, learn the specific mass of the materials from which the house was built (they are set forth in SNUVE). At the same time, it is necessary to summarize not only the weight of the walls of the walls, but also the roof, facing and thermal insulation coatings, floors.
Weight per 1 asbestos cement pipe should not exceed 800 kg. Their installation is required to the perimeter of the building, at the points of high load, as well as in the places of crossing the bearing walls. Installation Step – 1 m.
Having obtained information about the specific grade of the material, it is usually added to this value another 30% to obtain the overall pressure coefficient of the house operated on the foundation. Knowing this number, you can calculate the amount of pipes, suitable diameter, as well as the number of reinforcement (at the rate of 2-3 rods on the support).
On average for framework buildings, as well as non-residential objects (arbor, summer kitchens), pipes with a diameter of 100 mm are used. For aerated concrete or log houses – products with a diameter of at least 200 -250 mm.
Concrete consumption depends on the diameter of the support. So, about 0.1 cubic meters of solution is required to fill 10 m pipe with a diameter of 100 mm. For similar pouring pipe with a diameter of 200 mm, 0.5 cubic meters of concrete.
Installation must be preceded by soil analysis and project preparation, which contains all the necessary calculations.
Next, you can proceed to the preparation of the site under the foundation. First of all it is necessary to remove from the trash. Then remove the top floral layer of the soil, align and tumble the surface.
The next step will be the markup – according to the drawings in the corners, as well as in the points of intersection of the supporting structures, pegs are driven, between which the rope is stretched. Upon completion of work, you should make sure in accordance with the resulting “drawing” of the project, as well as to double-check the perpendicularity of the parties formed.
After the markup is completed, proceed to drilling pipes. For work, the drill is used, and in the absence of its deepening manually. Their diameter of 10-20 cm is superior to the diameter of the supports. Depth – 20 cm greater than the height of the underground pipe.
This “stock” is required to fall asleep the layer of sand. It is embanked to the bottom of the recess of about 20 cm, after the taper, wetted with water and reappeared. The next stage is the primary waterproofing of the pipes, which involves the lining of the bottom of the well (on top of the rammed sand “pillow”) rubberoid.
Now the recesses are lowered pipes that are aligned by level and fix temporary supports, usually wooden. When pipes are immersed in soil with elevated moisture level along the entire length of the underground breakage, they are covered with bitumen waterproofing mastic.
Concrete solution can be ordered or cook with your own hands. Mixed cement and sand in proportions 1: 2. This composition adds water. Must with a solution, a consistency resembling fluid dough. Then 2 pieces of gravel are introduced into it, everything is still well mixed.
Concrete is poured into a pipe at a height of 40-50 cm, and then the pipe is lifted by 15-20 cm and leave until the solution is freezing. This technology allows you to create a “base” under the pipe, thereby increasing its stability to be ground.
When a concrete solution completely freezes, the pipe walls are waterproofing rubberoid. Between the walls of the deepening and the lateral surfaces of the pipe fall asleep with river sand, which is well tumped (the principle is the same as during the arrangement of the “pillows” – the sand is poured, the trambet, water, repeat the actions).
Between the pipes stretch the twine, once again are convinced of the accuracy of the level and proceed to the reinforcement of the pipe. For these purposes, several rods associated with transverse wire jumpers, which are lowered into the pipe.
Now it remains to fill a concrete solution into the pipe. Eliminate the preservation of air bubbles in the thickness of the air allowance allows. If it is not, you should pierce the solution in several places by reinforcement, after which it is necessary to close the resulting holes on the surface of the solution.
When the solution types strength (about 3 weeks), you can start aligning the above-ground part of the bases, their waterproofing. One of the positive features of these supports is the ability to speed up the process of preparing the foundation. As you know, for a complete set of strength concrete, you need 28 days. However, pipes, bonding concrete, play the role of non-removable formwork. Due to this, it is possible to proceed to further execute work after 14-16 days after the fill.
Between each other can be born or united by a monolithic slab. The choice of specific technology is usually carried out on the basis of the materials used.
The beams are used mainly under frame and paving houses, as well as small buildings of economic purposes. For houses from aerated concrete or arbolit, scarlet is usually poured, which additionally reinforced. Regardless of the selected technology, it is necessary to link the reinforcement of the pillars with a power element of the base (beams or wipers).
Consumers using foundation on asbestos-cement pipes leave most positive reviews. Homeowners note the availability and lower cost of the house, as well as the ability to fulfill all the work with your own hands. As in the case of the fill of the monolithic or slab base, you do not need to order concrete mixer.
For clay soils in the northern regions, where much ground swelling, residents of the built houses are recommended to increase the step of the support, be sure to make them with expansion at the bottom and increase the number of reinforcement. Otherwise the soil pushes pipes.
From the video below you will learn about the benefits of the foundation from PVC pipes, asbestos or metal.