If you have at least once been involved in the construction of a private house or any other structure, then surely, like many future homeowners, you tried to save even at the stage of planning the estimates and construction. When people pursue such a goal, they try to reduce costs at the most expensive stages of construction. Perhaps you are one of them, then the information below will be useful for you.
An effective and reasonable solution in this matter is to use the most affordable and simple supporting columnar foundation, which replaces an expensive point-screw or shallow base. A positive result can be achieved if building technologies and norms are observed.
Key Features
The supporting columnar foundation may seem weak at first glance, but in reality it is reliable. If you follow the rules of construction, the design will be ready to serve even longer than the building itself. In addition to durability, several distinguishing features can be distinguished, among which:
- impressive construction speed;
- low cost;
- minimum waterproofing of supports;
- the possibility of using supports on any type of soil;
- the ideality of such a foundation for wooden buildings.
Why choose a pillar support
The support-columnar foundation allows you to install supports in a short time, which is especially important when comparing with monolithic bases. In the first case, the construction time is reduced several times. Comparing such foundations with strip foundations, we can understand that the former win when it comes to price. After all, the construction of supports costs 2 times cheaper.
Such a base can be built on all varieties of soil, as an exception wetlands and rock formations. Such soils do not allow to dig holes for the installation of supports. When it comes to building a wooden house, the pillar-foundation is the best solution, because it provides ventilation to the building and eliminates the dampening of the wooden floor.
Main advantages
The supporting columnar foundation is so popular also for the reason that it has many advantages. Among others, the possibility of using this type of foundation for small frame houses and baths should be highlighted. The use of a column support base during the construction of a house reduces the probability of soil expansion to an acceptable minimum, which does not affect the resource of the structure.
To do this, along the perimeter of the foundation, it will be necessary to arrange the drains at the level of the sole. In this case, the grillage falls 30 cm below the ground, and the blind area is insulated 30 cm in depth. This condition can be used for foundations with any design, but piles are installed with a lower construction budget and low labor costs.
Additional benefits
The supporting-columnar foundation, the pros and cons of which should be considered before starting work, can be erected not only on heaving soils, but also on loose soil, the latter will be deposited minimally during the operation of the building, which is explained by the small weight of the columns compared to the shallow foundation. For a brick cottage, the described construction technology will be ideal, which is especially true when the base should be deepened below the freezing line of the soil. This saves up to 50% of the budget.
Key Cons
Before you begin the construction of the support-columnar foundation, you should also consider the disadvantages, among them are:
- unsuitability for complex terrain;
- the impossibility of construction on soft soils.
As for the first factor, when the height difference is within 1.5 m, impressive horizontal loads from heaving will be observed, which will cause the pillars to tip over. The described construction should not be used in the case when weak soils prevail in the territory, this is true for silty and peaty soils, as well as water-saturated clay, which is notable for insignificant design resistance. Using a sufficiently powerful grillage, you can compensate for horizontal movements of the soil. But in this case, the economic effect will decrease, so it will be easier to prefer a floating monolithic slab, for the arrangement of which an impressive amount of earthwork will not be needed.
Technology Feature Reviews
The support-column foundation, the reviews of which are very positive, is built using a special technology. For this, columnar supports are prepared, which are located on a gravel pillow. Next, formwork is made, where concrete is poured. According to the owners of private houses, the laying of supports can be made of rubble stone or brick. Column supports are made of concrete blocks. The platforms are cast in the form of pyramids, each element is tied to the ground.
The supporting-columnar foundation of concrete blocks, according to developers, is stable, half of which depends on the state of the pillow. If we compare the shallowly columned pillars with other bases, then the first ones allow qualitatively and thoroughly waterproofing, warming and draining the bottom.
The nuances of the work
Home craftsmen argue that the bearing capacity of the soil and its density affect the depth of the pit, where poles are installed that serve as supports. When construction is carried out on a stone base or fine sand, only crushed stone can be laid on the ground with a layer of 15 cm. The support will be more stable if the ratio of the height of the support to the cross section is less. A layer of sand and gravel is covered with gravel screenings, which are sometimes replaced by dense geotextiles.
According to experts, such a sole perfectly copes with the removal of water and allows for the stability of supports on flooded soil. The power and depth of the pillow, according to home masters, are selected taking into account the magnitude of the lateral load and the rigidity of the lower rim of the building. For thin and elongated columns of asbestos-cement pipes, the depth is made greater. If concrete supports are installed , then surface sanding will suffice.
Foundation reinforcement
If you decide to thoroughly study how to strengthen the support-column foundation, then know: for this you can use several techniques. This is especially true when the pillars are made of red brick. It will be necessary to prepare a pit, the depth of which will be 25 cm. Its bottom is covered with a pillow and concreted to install a brick column.
It is important for this to prepare a support platform with a thickness within 15 cm. Its size should be greater than the support section by 40%. For reinforcement in the thickness of concrete, a reinforcing cage should be laid, which can consist of three or four bars. To do this, use 8 mm steel. The support frame should be laid out on a design height of brick. For extra strength, high-quality or granite concrete should be used, to which basalt or fine granite screenings are added. The support and column foundation of concrete blocks, reviews of which are much better than those of brick structures, are assembled in a similar way. The only difference is that the mortar for masonry blocks is prepared using the same technology as for concrete.
Features of the foundation of the blocks
The pillar-base foundation, the price of which will be 200,000 rubles, if the design provides for the presence of 16 pillars, can be deformed if the technology is not followed. It is necessary to arrange the load-bearing elements every three meters, they should be at corners and in those places where the walls intersect with each other.
Do not make the posts too frequent, because this will increase the cost of building materials and forces. Depending on the roughness of the area, the recesses for the supports may be equal to the limit of 150 to 300 mm. With a slight slope in the area, one support can consist of 5 blocks, while the other - from one or two. If the construction is carried out on an even area, then the posts should not have more than 3 blocks in height, while the recess for them will be 200 mm. The support-column foundation of blocks can support the greater weight of the building, if the support platforms for installing the pillars are correctly made. This will increase the bearing capacity of the soil.
Support pads can be performed in different ways. Some place square blocks under the blocks with a side of 400 mm or 500 mm. But this approach cannot be called correct, because the tile is not designed for increased load and almost always cracks, losing its purpose.
It is better to fill the site with reinforcement in one row, to strengthen the road grid should be used. However, it is better to use reinforcement with a diameter of 10 to 12 mm. Such monolithic platforms in cross section will have a square with a side of 400 mm or 600 mm. Their thickness will be equal to a number in the range from 50 to 70 mm. This option is considered more time-consuming, but the most reliable.
Recommendations of specialists
Do not neglect the stage of installation of reference sites. Some builders immediately begin installing blocks on a sand cushion. If the supports do not have a solid foundation, then after a while they will begin to “walk” at the first serious load. If you still decide to resort to such a technology, then the blocks in the front row should consist of two products, and laying should be done with overlap. In cross section, the foundation post must have the following dimensions: 400 x 400 mm. Saving time on the construction of the reference site, you will spend money on the purchase of additional blocks.
Conclusion
If the territory for the construction is quite flat, the construction of the support-column foundation will cost much cheaper compared to laying a shallow tape or a monolithic slab. The main disadvantage of such a solution is only a slight resistance to rollover. In this regard, measures are being taken to reduce heaving forces. But this disadvantage is offset by the advantages of a high resource, as well as the possibility of installation on freezing soils. For a columnar foundation, a prefabricated or monolithic grillage is a prerequisite.