How to fill a strip foundation correctly

Tape foundation is most often used in private buildings when erecting cottages, garages, baths. It is cheaper than the foundation of a solid structure, yet functional than a pile foundation, and is ideal for buildings with a basement used.

Required materials

The filling strip foundation is made of concrete grade 200. It can be ordered or prepared independently. Take into account that this is a very laborious work, and the foundation, filled with small portions, will be heterogeneous. The composition of concrete for pouring the foundation: cement, coarse-grained sand, gravel in a ratio of 1: 2: 2.5.

In addition to concrete for the foundation, you will need:

• A 20 mm thick board for formwork;
• Steel rod 8-12 mm and wire for reinforcing the foundation;
• River sand for a sand cushion.

Preparatory work for

Before correctly pouring a strip foundation, it is necessary to order a geodetic survey of the site in the design and construction company to determine the type of soil and the depth of its freezing during the winter months, as well as the depth of groundwater. After the research the firm will make calculations and execute the project of the foundation device. For the construction of the cottage, these works are not recommended for their own use, the foundation for a small house, bath or garage can be calculated independently, taking into account the recommendations of SNiP II-B.1-62 or use the table.

Layout of the site

Marking - the most important stage of the foundation. Before beginning the marking, the site must be cleaned of debris and foreign objects, and also cut the soil to a depth of 15 cm to avoid biological decomposition processes inside the basement of the building.

Markup technology:

1. Define the axis of the building and the location of the first corner. Install the peg using a plumb line. As a peg, you can use trimming fixtures.
2. Pull the twine from the first peg, forming a perpendicular, and at the design distance mark the second and third angle, set pegs.
3. From the second and third angle pull the string toward the fourth, put the angle on the corner, put the peg.
4. The diagonal is checked at the resulting rectangle that depicts the outer contour of the building. If all angles are correctly constructed, the diagonals must be equal.
5. The internal contour of the foundation is also marked in a similar way, as well as the outline of the foundation for its individual elements: bearing walls, porch, terrace, pillar supports.
6. To align the horizontal marking, set the wooden strips at the desired height, through which the string is stretched.

Land works

To fill the foundation, you need to prepare a trench with the depth specified in the project. Begin to dig a trench from the lowest angle, so that the depth of the excavation is not less than the calculated one. The walls of the trench should be made as vertical as possible if the ground is crumbling - you can set up temporary supports. The bottom of the trench must be leveled and periodically check the level of slope.

A layer of river sand is poured into the finished trench, forming a pillow of at least 15 cm. It is necessary to redistribute the load on the foundation, especially in the subsoil soils. Sand fall asleep layer by layer, each layer is spilled with water and compacted.

Installation of formwork

Formwork is performed on a contour marked with a twine.

1. Install the corner supports from the bar 50 mm. Once again check the diagonals of the foundation.
2. From the edging board you collect the formwork, fixing the boards together with the help of bars or a metal corner and screws. The hat of the screws must remain inside the formwork, and the bars and corners - outside.
3. On the outside, the supports are installed to avoid deforming the formwork when pouring concrete.
4. The height of the formwork above the ground must be such that it provides a foundation height of at least 30 cm.
5. Inside the foundation, the level at which concrete is poured is indicated.

Laying of the armature

The metal bars with a diameter of 8-12 mm, cut into lengths of the required length and laid along and across the foundation axis, are used as the reinforcement, and at a base depth of more than 0.4 meters - also vertically. The reinforcement is fastened to the formwork walls and fastened together with steel wire. Welding is not recommended because of a reduction in the corrosion resistance of metal at welding points and a reduction in its flexural strength.

reinforcement. Filling the foundation

The casting is made concurrently in case of ordering ready-mixed concrete or layer-by-layer if the concrete is prepared independently.

1. Preparation of concrete: the cement is mixed with sieved river sand in a ratio of 1: 2 - 1: 2.5 and diluted with water to the consistency of liquid sour cream, and then poured them with prepared crushed stone. Crushed stone is taken as much as sand. Stir so that the entire rubble is a moistened solution.
2. Pour concrete into the prepared formwork. For better filling pierce the concrete in several places with a metal rod and compact it with a wooden bar, removing the remaining air from the voids. It is possible to use for these purposes a perforator with a special nozzle or a construction mixer.
3. Pour concrete to the level indicated on the formwork. At the same time, the formwork is taped from the outside for a better draft of concrete.
4. The top layer is aligned with the rule or trowel.
5. Sprinkle a concrete mirror with dry sifted cement, you can do this through a sieve. This technique allows you to quickly grab the top layer of concrete, prevent it from blurring or cracking.
6. Cover the concrete with burlap or cover material and leave to ripen for 3-4 weeks. In dry weather, it is necessary to wet the top layer of concrete to prevent it from drying out.

It is possible to start the erection of walls only after full maturation of concrete. After removal of the formwork it is necessary to perform waterproofing of the foundation to increase its service life and heat and moisture insulation characteristics.

Also be sure to read about: columnar foundation with grillage, and also your next step will be the lower frame of the frame house.