When the construction of the Foundation of the country house as a series of concrete columns are usually used wooden formwork. However, it is much easier to use for concrete formwork is not expensive in these times of boards, and the cylindrical form of roofing material.
Take a flat beam with a diameter slightly less than the diameter of the drill that you did in the soil hole under the bars, wrap it in two layers of roofing material and tie a soft wire. Then remove the beam, and the resulting tube down the designated hole in the ground, the bottom of which are lined with successively compacted layers of sand and gravel.
When all pipes are installed, fill them with liquid concrete and insert the four cut the reinforcing iron. After the concrete has hardened, excess reinforcement can be cut.