Bored piles with a grillage and a foundation with your own hands
A bored foundation is one of the foundation options that is perfect for difficult terrain with sharp elevation changes and difficult soil, in the presence of dense buildings in the settlement, in places with a risk of damage to neighboring buildings and communications.
Advantages of a bored foundation
- When it is not possible to install a traditional one, it can easily be replaced by a bored foundation, which, when installed correctly, has sufficient bearing properties.
- In addition to those already listed above, an important advantage of the bored foundation is that the technology of its construction allows you to work at any time of the year, low noise production, ease of installation.
- The very technology of erecting a bored foundation saves you from the need to purchase and deliver piles and other structural elements to the construction site.
Design features for a house with a grillage
The construction of this type of foundation, like a bored foundation, is the drilling of post holes in the soil, into which a metal frame is immersed, and all this is covered with a concrete mixture or a solution of cement with sand.
The bored foundation is mounted directly on the building site. When starting, it is necessary to take into account the nature of the soil (the level of its freezing) and the weight of the future structure. As a rule, the width of the future foundation should be 30-40 cm more than the expected width of the external and load-bearing walls of the house.
Stages of installation of a bored foundation
Stage 1. Calculation of the foundation for piles
- The first step is to calculate the building site. Do not worry, for a frame house, you do not need a powerful zero level. In frame houses, they are light, but if you are building a massive house, then the piles will have to be made 30-40 mm thicker so that the load on the foundation is commensurate. The calculation table will help you.
Stage 2. We mark the site
You can choose the location of the piles in different ways, usually this is done under the main load-bearing walls of the house, but you can also arrange the bored piles in a checkerboard pattern.
Stage 3. Drilling wells for the foundation of the house
Mark the building site, dig a trench, determine the location of the pillars and align the foundation line with a fishing line and level.
We provide drilling and insulation. Then, with the help of a motor drill or a special drilling machine, wells of a given diameter are drilled in the marked places.
Stage 4. Production of wooden formwork
Formwork is necessary where there is the possibility of shedding, for piles, formwork wrapped in a tube can play a role. For strip foundations, we produce wooden formwork.
Stage 5. Pile strength
In order for the piles to serve for a long time, choose piles of better quality, bored piles can be placed at a distance of a couple of meters from each other, depending on your home. If your piles are 50 cm in diameter, each pile can withstand up to 5 tons, which gives you the opportunity to build even from high reliability.
Stage 6. sand cushion
At the bottom of the well, a pillow of sand or gravel is arranged, which is manually compacted. After that, the prepared construction quick-hardening cement mixture (concrete) is poured into the pit, sometimes it is combined with stones. A prerequisite is the supply of concrete composition at a certain level of vibration and in small portions. This will eliminate the formation of air voids and provide the foundation with strength and durability.
Stage 7. Rebar knitting
It is better to use fittings with a diameter of 10-12 mm. They will provide sufficient structural strength.
At the next stage, we knit a reinforcing cage, the lower edge of which should remain immersed in the concrete mixture and not come into contact with the bottom of the pit. Otherwise, the metal will be susceptible to corrosion, and the bored foundation will lose its strength.
Stage 8. We waterproof wells
To ensure the strength of the future bored foundation, wells are drilled using a layer or two of roofing material. On soils with high humidity, casing pipes are used for protection.
Stage 9. Pouring the foundation with concrete
The reinforcement is installed in the formwork in the form of a grid, however, not in contact with it. For this, the reinforcing cage is connected to the pile frame. Then the formwork is poured with mortar, after it hardens, the bored foundation is considered ready.
At the final stage, installation takes place, which combines the parts of the bored foundation protruding above the ground. The most durable is considered a monolithic grillage made of reinforced concrete. To install it, you will need reinforced concrete mortar, reinforcement and wooden structures for formwork. After that, you need to let the foundation dry for up to one month.