Because of how correctly the formwork for the strip foundation is equipped, the strength of the erected structure depends. When creating it, it is very important to comply with all construction standards and rules, which we will tell you today.
Formwork for the strip foundation — the process of preparation
Video pouring tape foundation
The first stage of the construction of the foundation is the marking of the territory. At this stage, it is very important to ensure that all calculations are made as accurately as possible, otherwise there is a risk that the foundation will turn out, to put it mildly, not very even. If you are not confident in your abilities, we recommend inviting workers with experience of such measurements — especially if your site is uneven. To designate the marking, the nylon cord stretched between the stakes. Particular attention must be paid to the exhibition of corners — they should be strictly 90 degrees.
After the place under the foundation is marked, you can start digging the trench. This can be done both manually and resorting to the help of an excavator. The first method, of course, is preferable, since the edges and bottom of the trench are more even. If you still have chosen a mechanized method, then the edges of the resulting “channel” are aligned with a shovel, and the excess soil is removed.
Further, the bottom of the trench is lined with a “pillow” from gravel or crushed stone, thoroughly tamped and covered with waterproofing material. This is necessary so that when pouring concrete, some part of the water from the solution does not leak out the soil, thereby worsening the properties of the solution. As waterproofing, you can also use a cement-sand mixture.
How is the formwork device for a strip foundation is carried out?
Video — knitting reinforcement for a strip foundation
To arrange formwork, rubberized boards are 0.15 with a thickness with a thickness of 0.04-0.05 m. They should be strictly strict on the one hand (the one that will subsequently come into contact with concrete). The boards are installed from both sides of the pit strictly vertically, believing the correct installation using a plumb line. To fix the boards use spacers.
Over the surface of the earth, the formwork boards are taken to the height of the basement. The gaps between horizontal boards should not be more than two millimeters, so non -inferior lumber for formwork cannot be used. To fix the boards, use wooden bars that are attached to them from the outside using self -tapping screws. Install such fixers at a distance of no more than one meter from each other. In addition, at the same stage it is necessary to make holes for various communications and lay the “sleeves” from asbestos -cement pipes in them. Otherwise, you will have to make holes in a hardened concrete monolith.
Additional fixation of the formwork is made using diagonal spacers, which are installed from the outer walls of the structure to wedges specially driven into the ground. The design should turn out as strong as possible, otherwise the concrete flooded into it can dilute the boards in different directions, and the foundation will turn out to be uneven. In addition, in the corners of the foundation for additional reinforcement of the structure, you can fasten metal corners.
The walls of the formwork are lined with waterproofing material (it is best to use PVC film), which will also prevent the “leaving” of water from concrete. So that the film does not crumble and not shift in the process of pouring concrete, it is fixed with the help of a construction stapler. After that, a reinforcing “skeleton” consisting of rods cooked or interconnected by a metal knitting wire is installed in concrete formwork.
The calculation of the number of necessary reinforcement and its thickness should be calculated at the design stage of the building.
Formwork for the foundation — proceed to pouring concrete
A concrete solution can be poured into the prepared formwork. It is poured gradually, in layers, the thickness of which does not exceed 200 mm, while each of them should be compacted. If a concrete pump is used to fill the solution, then it is necessary to use the gutter by which it will go from the car to the foundation. The fact is that if the concrete is poured from a height of more than one and a half meters, it can simply break the formwork.
After the fill is finished, concrete must be left for at least two weeks. This is necessary so that it gains at least half of the design strength (it is completely achieved in 28 days). In this case, it is necessary to ensure that it dries evenly, so in hot sunny weather the top of the foundation should be wetted with water, and covered with a film during the rain. If pouring occurs at minus temperature, concrete must be provided to heating. After removing the formwork, additional waterproofing of the foundation is made. To do this, it is coated with bitumen mastic, on which they are «planted» by roofing material. Then, in accordance with the construction standards, the foundation is backfilling.