Sometimes it becomes necessary to build a small object in a country house or garden plot. Something like a garden gazebo or utility room. Of course, they can be built without foundation just on the ground. But then they will be unstable and quickly collapse.
According to building codes, there must be a foundation under any stationary structure. Moreover, before choosing its type and size, you should consult your local construction organization and find out what requirements are presented to a typical foundation.
First of all, it is important to know the depth of soil freezing in winter. So you can set the depth of the foundation, and its base should be below the freezing depth.
Other properties of the soil are also important: its type, what is the bearing capacity, how deep the underground waters are, etc. Only after these indicators are clarified can one reasonably choose the type and size of the foundation.
The most simple in the execution of the strip foundation, but it will require a lot of concrete. He is also afraid of frost heaving and in some places in winter he can sag or rise, which will lead to cracking and subsequent destruction.
For small, but permanent buildings, financially, in terms of labor costs and in resisting frost heaving, the columnar foundation of a circular cross section - supports, is preferable.
Making a foundation on concrete supports
In principle, without even knowing everything that has been noted above, it is possible to establish the depth of the columnar foundation. Look at the grounds in nearby houses or cottages, choose the one in good condition and find out the depth of its foundation from the owners.
It turned out to be equal to 61 cm. There is a special formwork of circular cross section, made, say, of dense pressed cardboard. Its standard length is 120 cm, and the diameter is 15, 20, 25 and 30 cm.
We cut off a piece with a length of 61 cm using a hacksaw. By the way, the formwork for the column foundation can be made from many sheet building materials, for example, from roofing material.
We drill a hole using a mechanized or manual drill according to the diameter of the tube and a depth of 70-75 cm. Pour fine gravel to the bottom and ram it with a wooden beam with a section of 5 by 10 cm. The thickness of the compacted gravel pillow is 10-15 cm.
We put in a hole on a gravel pillow, a previously cut tube, and check the verticality of its installation using the building level.
This is important for a reliable perception by the columnar foundation of the weight of the structure.
We mix the solution manually or in a concrete mixer and after mixing it is completed, fill it with a mold, regularly piercing the concrete mass with a reinforcement pin and a trowel to prevent air bubbles from remaining in the mix, which will adversely affect the bearing capacity of the columnar support.
Having filled the mold with the concrete mixture to the very top, we level the surface and set the mortgage exactly in the center.
It must not be loaded for at least 24 hours after pouring until the concrete has set.
Construction can begin only after 3 weeks. It takes so long for the cement-based concrete mix to fully harden and gain maximum strength.