Pier foundation raft with their own hands

When private construction it comes to choosing the type of foundation, preference is often given to columnar a raft.Why?Mainly because of the cheapness of a base.Concrete it goes several times less than in the tape, and an order of magnitude less than in the pouring of the foundation plate.But on the reliability and durability should not be forgotten, so we choose the reinforced concrete pillars.

important stage of work is the calculation of the pier foundation, when it is determined how many poles need and how they will be located.

should start with conducting geological surveys in order to calculate the bearing capacity of soil whether he will be able to withstand the weight of the structure.Next, we determine the weight depending on the material used, as well as on what is wind and snow load.

basement area - the result of dividing the resulting figure by the weight, which is able to withstand the 1 square centimeter of soil.To eliminate the potential for miscalculation resulting figure should be added to 20-30 percent.

To calculate the number of pillars divide the support area on the base of the column area.

to correctly mark a pier foundation raft, it is important to take into account three factors.First, the support must necessarily be under each of the four corners of the building.Secondly, the columns must be installed at the intersection of walls.Thirdly, on the straights recommend bars placed at a distance of 2.5-3.5 meters.

Earthworks

First you need to remove on the perimeter of the foundation topsoil.Then dig a hole under the poles to a depth equal to the figure of the soil freezing, with the addition of 20 centimeters, it is necessary to put a pillow.

opening width should be the thickness of the wall plus 20 cm on both sides of the installation of the formwork and spacers.

laid on the bottom of each pit pillow of crushed stone and sand, so that it is performed at 10-20 cm per post basis.Sheds plenty of water, rammed.Top laid polyethylene or roofing material, in order to not leave the ground, about pouring a foundation with his own hands, read here while pouring concrete the moisture out of it.

shuttering device for the foundation

pillars Formwork is advisable to use the board thickness of not less than 20 millimeters.They are easy to install because it is easy.In addition, it is much cheaper than metal and wood-base materials.Applied also iron, ceramic or iron pipes.If the walls of the holes are dry and not prone to collapse, it is permissible to do without formwork - enough to pave the pit polyethylene.

If you choose to boards, bring down their shields, and then in the box.Set in the hole.Damp to prevent the formwork of concrete to absorb moisture and facilitate further extraction of soil after casting.

reinforcement supports columnar foundation

Used armature diameter 10-14 mm.

longitudinal reinforcement bars are choosing such a length that after the setting of concrete, they towered above the ground by 30-40 centimeters.Surplus after you install the reinforced frame grillage can be cut.

rods welded or tie (which is better) with a round or rectangular horizontal bridges, which have a distance of 30-40 cm from each other.Reinforced carcass was collected on the ground, and lowered into the pit.

Pouring concrete and filling of soil

Concrete is poured layer of 20-30 cm, leveled with a bayonet or a vibrator so as not to form air pockets.

To avoid seams, which will weaken the carrying capacity of the structure, the concrete should be laid entirely, without interruption.

days later, three or four, you can remove the removable formwork.It is necessary to treat the surface of the pillars waterproofing material (bituminous resin gidrostekloizol) and back fill soil.If he was heaving, the filling should be done with sand.It is possible to insulate this foundation using extruded polystyrene foam boards.

device columnar grillage foundation

For its production are commonly used modular or monolithic concrete.Builders argue whether the raft foundation should be laid on the ground or climbing over its surface.The main argument in favor of hanging - that it does not apply heave force.

Install solid formwork for the foundation perimeter.On its bottom pour a layer of sand and close cellophane.From d 12-14 mm rods tie the frame, install it.Calculating the number of required reinforcement is made similarly to strip foundations.The frame can be connected or welded to the reinforcement rods sticking out of the ground.It is necessary that the bars form walls defended by at least 5 centimeters.

Pour grillage also need to simultaneously, so that no seams.Remove air vibrator or a piece of rebar.After setting the concrete formwork and remove the sand from under the raft foundation.

Instead of sand suitable plank formwork in the form of an inverted letter P. It is set between the supports several brick columns, put it in the reinforcing cage and pour concrete.After three to four days with the removed bricks.

Video - fukndament with columnar grillage