Increasingly, in the construction of a private house, technology of monolithic reinforced concrete is used. One of the main problems in this case is the formwork. It allows the concrete mix to maintain shape until the required strength is achieved. Formwork for the foundation has several varieties and some installation requirements, which must be familiar with before starting work.
Types of construction
The main division of the structure occurs depending on whether or not it is necessary to remove the structure after the concrete has hardened. If you need to remove the formwork, it is called removable. The opposite is fixed formwork. Fixed design greatly simplifies installation and increases the speed of work.
Material for making
Formwork for foundations can be made of various materials, such as:
- metal;
- reinforced concrete;
- wood;
- polystyrene foam;
- improvised materials.
As a universal material, metal can be used. A device of this design is suitable for both strip and column foundations.
In this case, the fittings are welded directly to the formwork, which ensures their joint work and additional reliability of the design. Installation in this case is quite simple, it is easy to give the metal sheets the necessary shape. The main obstacle to mass use of this type is the very high cost.
Assembling from concrete slabs is also quite an expensive event. Pouring the mixture into such a structure can reduce its consumption, but the slabs are heavy and require special equipment, which is undesirable when building a building with your own hands.
The most common types of formwork for individual construction are foam and wood. Foam elements have a very light weight and provide the fastest and easiest installation. In addition, the material provides additional insulation of the structure.
A device made of wood involves the use of plywood or boards. Do-it-yourself formwork for the foundation in this case does not require high financial costs and complex fixtures. This option is most preferred if there is not much experience in construction.
When it is not possible to use the above materials to reduce the cost of foundation work, you can use improvised materials. As formwork can be applied:
- professional sheet;
- slate;
- old wooden structures.
The disadvantages of such an event are an increase in the complexity of work, low bearing capacity, the likelihood of leaks in the concrete mixture, a limited scope. Such formwork can only be used when the construction of small buildings is planned.
Manufacture and installation
Before making the formwork for the foundation, it is necessary to calculate its quantity. The initial data for the calculation will be:
- foundation perimeter;
- his high;
- formwork element size.
For example, when using wood, it is necessary to find out the total length of the boards and the volume of all necessary wood. To carry out the installation correctly and quickly, it is best to provide a small supply of material 3-5% when buying.
Before starting work, it is required to level the base under the foundations and perform marking on the ground.
A device made of boards requires their tight connection with each other. It is permissible to have gaps of no more than 3 mm; with wider openings, the space between the boards must be caulked or hammered with slats depending on the size. It is important that the inner surface of the formwork is sufficiently smooth, and the distance between its shields does not deviate strongly from the drawings.
The formwork for the strip foundation is fixed using horizontal boards installed between small racks (pegs). The frame device starts from the corners of the building. It is important to remember that when the pouring is completed, the structure will need to withstand severe pressure from the concrete mix. To absorb this load with a foundation height of not more than 200 mm, installation of pegs is sufficient;
After installing the frame, check its position using a simple plumb or a more complex building level. If everything is correct, proceed to securing the shields. The fastening is carried out so that the heads of the nails are located inside the formwork. The device also requires the installation of spacers, to ensure the collaboration of opposing shields. For the manufacture of spacers, a bar with a section of 50 by 50 mm or metal studs is most often used.
To prevent leakage of the solution into the structure, a plastic film is sometimes laid. This will greatly simplify installation.
From polystyrene foam, the design is sold in the form of completely ready-to-use elements. The boards are already fixed to each other and have struts, it remains only to install the elements in the design position. After pouring, there is no need to remove such a formwork. It does not give a load to the foundation and remains as a heat-insulating layer.
Foundation pouring
To answer the question of how to make formwork for the foundation, it is also necessary to consider the process of pouring concrete mixture. Filling is carried out when panels are already mounted and fittings are laid. After laying concrete, perform its compaction. Particular attention should be paid to places of contact with the formwork. If the work is not carried out correctly, the formation of pores is possible, which will reduce the bearing capacity.
One of the most important issues when installing monolithic foundations is the question of when to remove formwork. In order to answer it correctly, it is necessary to pay attention to the terms of concrete strength hardening. It gains full strength four 4 weeks after pouring, and sufficient to remove the formwork after 2. From here we can formulate the answer: to remove the formwork from any materials for any type of monolithic foundation can be done no earlier than 14 days. But if possible, it is better to wait until the concrete has hardened completely.
The installation of a monolithic foundation is able to save the future owner of the house from solving issues such as transportation and storage of prefabricated elements, the need to use complex special equipment.
When the formwork for the foundation is selected competently, the construction of foundations is possible in the shortest possible time and at minimal cost. It is only important to securely fasten the formwork panels and remove it no earlier than the concrete has gained the necessary strength.