Formwork structures are indispensable at almost all stages of the construction of reinforced concrete structures. Today there are removable, non-removable, adjustable and floating formwork. The first type is the most popular. This is due to the ease of installation of such structures and their low cost. In addition, these frames are reusable.
Shield formwork device and its functions
The formwork structure is necessary for the liquid concrete to harden in position to form a foundation or wall. As a rule, non-removable frames are dismantled 10-15 days after pouring the building sand-cement mixture. Removable formwork is mounted immediately before laying the concrete base and is not removed before the cement-sand mortar gains brand strength. This option is convenient in that you do not have to spend energy on dismantling the frame, however, in this case, you will need a lot of money for building material.
Shield formwork can bemade from:
- metal sheets;
- wooden shields;
- foam blocks.
Small-panel and large-panel boards
To decide which type of frame is more suitable for a particular project, it is necessary to take into account the design features of these "forms":
- Large-panel formwork. Such a formwork system is suitable for the construction of wall openings of great length. The height of one shuttering board can reach up to 0.3 m (and if you take into account the locks and leveling rails, then 1 m). Such panel formwork is characterized by the greatest strength, which allows pouring concrete continuously. This significantly reduces construction time. However, it requires specialized lifting equipment to use.
- Small-panel formwork. This type of system allows you to form a frame for structures with complex geometry. The height of one shield in this case is about 200 cm. This is quite enough for the construction of both low-rise and more serious structures. At the same time, the shields are easily installed in a horizontal and vertical position.
For the construction of foundations or walls with the correct geometry, it is more convenient to use large-panel formwork, and when erecting complex architectural objects, it is better to give preference to small-panel systems.
You also need to decide on the material from which the frame will be made.
Plastic formwork
Removable frames made of synthetic materialsare gaining popularity due to their light weight and ease of use. Plastic panel formwork is a lightweight construction, which consists of small sheets measuring 1210 x 605 mm. You can even handle their installation alone.
In addition, such systems have the following advantages:
- equipped with special latches;
- UV and corrosion resistant plastic;
- the turnover of such products is 100 times;
- easy to remove as concrete does not stick to the smooth surface of the boards;
- does not require additional lubrication before use.
If you plan to build a house up to 3 m high, then such panel formwork for walls will be the best option.
Wooden formwork
This is the cheapest formwork structure that you can easily make yourself. It is allowed to use improvised materials, but it is better to listen to the advice of specialists. For wooden panel formwork, it is recommended to use softwood lumber. However, it is much cheaper not to prepare panels from several boards, but to purchase ready-made sheets of plywood (preferably varnished).
The turnover of wooden formwork is no more than 30 times. However, if we are talking about private construction, then this will be more than enough.
Steel formwork
Steel panel formwork has many advantages. It is the strongest and most durable design. Metal sheets are either made from galvanized steel or galvanized.
Steel sheets are not deformed and well move away from the concrete mass during the dismantling of the formwork.
However, such shields have some drawbacks. For example, they weigh quite a lot, which greatly complicates the process of building a frame without the use of specialized equipment. In addition, steel is susceptible to corrosion.
Aluminum Formwork
Aluminum weighs a lot less than steel. In addition, the shield formwork for the foundation, made from such sheets, will not rust.
Of the minuses of this material, it is worth highlighting its low strength and loss of geometric shape under the pressure of liquid concrete mortar. Therefore, such structures are used only for small-sized buildings and foundations. For the construction of high walls, it is better to choose a more reliable material.
