Installation of formwork: technology, instruction

One of the first stages of erection of structuresfor various purposes is the installation of formwork. Often this process is left without due attention. But already at the stage of preparation for the casting it becomes clear that not everything is as simple as it was thought at first. The assembly of the formwork will help to assemble the frame.

Types of formwork

There are three types of construction:

• Removable, which is dismantled after a fulldrying solution. There is such formwork from separate parts. As a result, a collapsible construction is obtained, which is dismantled and can be re-used. Among the advantages of this type of formwork are the simplicity of installation, the possibility of reuse, which significantly reduces the financial costs of construction.

• A non-removable, respectively, one that is notdismantled. Installation of the formwork of this type is made mainly of expanded polystyrene or foam. It remains part of the erected building. And at the same time it acts as a heater.

• "Floating" formwork is typical for the erectionA monolithic foundation that is immersed in the ground. It is a board assembled from boards, which is slightly higher in height than the planned concrete structure. The shield descends to the pit and is attached to its walls. Over it rolled cardboard or roofing paper.

There are also several types depending on the purpose:

• Wall formwork. Its installation is carried out for the erection of vertical structures and walls.

• Horizontal, which is used to install the foundation and floors.

• Curved, which allows you to fill in details of unusual shapes.

Installation and dismantling of the formwork of each type has its own characteristics. They need to be known for quality work.

Advantages of non-removable formwork

Installation of non-removable formwork involvesthe acquisition of a ready-made kit for the performance of work. It remains only to assemble the structure and perform its installation. Hence, there are a number of advantages that formwork of this type possesses:

• short terms of work execution;

• simplicity of installation;

• light construction weight;

• resistance to the appearance of fungus and mold;

• fire safety;

• low cost.

Also, a fixed formwork is bothlayer insulation and is a block of foam, which are easily connected to each other. In this case, the inner wall is thinner than the outer one. Thanks to this, a high level of thermal insulation is achieved.

Construction of non-removable formwork

The installation of the formwork of walls with the help of fixed blocks is much easier than the traditional method.

Work begins with site preparation,laying a layer of waterproofing. On the foundation simply put on the blocks on the principle of brickwork (with a shift of seams). This allows to increase the strength (rigidity) of the structure.

First, only one row of blocks is laid,further reinforcement (overlap). For this, there are special grooves. The reinforcement is connected with each other by a vertical wire. In the same way, the following series are laid out.

Blocks are fastened together by simple joining of special grooves by easy pressing. Begin to pour concrete solution already on the third row of blocks.

In the process of work there is one small secret. The walls will be more reliable if the joints of the mortar layers remain in the middle of the block. To do this, fill the top row with half.

Features of the execution of a removable formwork

The basic moments of installation of the formwork will be considered with the example of a removable collapsible structure. This species is often carried out by landowners without the assistance of professional builders.

Installation of the formwork is made of boards, bars,plywood and other sheets of wood. The main thing is that these plates should be flat. All work begins with the preparation of the site. The site must be completely cleaned of foreign objects, garbage and so on. Further, with the help of bars marks the corners of the erected building. They will be the basis from which the remaining measurements will be performed. In accordance with the dimensions between the bars, a formwork panel is assembled.

Ready-made shields are attached to corner bars with the help ofscrews or nails. Mounting must be reliable. With the expansion of concrete, the pressure on the shield will increase, which can lead to cracking of the boards. The main thing is that the bar itself is left from the outside. Parallel to the assembled structure, another row is assembled at a distance from the future wall. As a result, you should get a frame around the perimeter.

A layer of crushed stone is poured into the completed formwork boxor sand. This will protect the solution from loss of moisture, which will go to the ground. The technology of mounting the formwork provides for the protection of the wooden shield from the leakage of the solution through the available openings. For this, the shields are covered with a film or roofing paper, which are fastened with screws or staples using a stapler.

All work must be done taking into account the level. It is very important. At each stage, the evenness of the structure is checked for height, length and vertical (especially important). Two rows of shields must go strictly parallel to each other.

Basic elements of formwork

The demountable formwork, which is assembled independently, consists of the following elements:

• The deck, which is a flat shield,which is the fence of the whole form. The structure should be strong enough to withstand the pressure of the solution. Therefore, it is made of plywood or edging boards 4-5 cm thick.

• Woods which are a support of a design. They hold the walls, not allowing the solution to squeeze out the deck. Produce forests from pine bars or planks (2.5-5 cm).

• Fasteners are all parts with which all the elements of the construction are twisted: wire, clamps, ties, hardware and so on.

The deck is most often assembled from boards with a width of 15cm, which are joined in several rows by means of nails (driven from inside, curled from the outside) or self-tapping screws (they are screwed from the inside). The distance between the boards should not exceed 3 mm. Shields are fastened together with additional slats.

A simpler version of the manufacture of the deck is the use of moisture resistant plywood with a thickness of 1.8-2.1 cm.

Installation of formwork

The frame will be set exactly and level ifin advance correctly prepared area. It is marked using cords tied between pegs. The sand cushion is filled and compacted. If necessary, a foundation pit is prepared.

The formwork is installed in the following order:

• The perimeter should be marked with vertical guides (wooden blocks, metal corners or pipes).

• On the guides it is required to place the finished boards, keeping the necessary distance between them (it is equal to the necessary thickness of the basement).

• Secure the deck firmly. Support it from the outside with inclined beams (1 scaffold per meter of deck).

• Connect the boards to each other with brusks 5x5 cm.

• The inner side of the formwork is covered with a film (roofing material).

Foundations up to 20 cm high do not require a serious design. For them, enough bribed into the ground.

Installation of wall formwork

More difficult is the process of erection of wall formwork. At the same time, small-piece and large-panel formwork is selected.

The first option is suitable for the erection of small buildings (cottages, buildings of economic purpose) and partitions between the rooms. In this case, small plywood panels are used.

The installation of large-panel formwork is typical for the construction of buildings with high altitude. For work use sheets of metal or large sheets of plywood.

For the installation of walls prepare the foundation, inwhich stick in the reinforcement. Around it are assembled a two-row frame formwork. When using conventional plywood, joints are smeared with glue or sealant. Currently, the market has a special plywood for formwork. Individual sheets of it are connected on the principle of "spike-groove", which does not require additional sealing.

Types of overlapping

Installation of the formwork of the ceiling depends on the type of overlap. Allocate the following types of structures:

• On the large bowls. It is used for structures with high altitude. In this case, use vertical stands, jacks, inserts, crossbars and other elements to connect the individual parts.

• On the wedge forests, which are used for multi-storey buildings. Instead of plywood panels, scaffolds are installed.

• In the forests of the cup type. This type provides for the installation of the frame. Stands are connected by a cup method.

• On telescopic bowls. Suitable in cases where the height of the ceiling is less than 4.6 m. It is based on tripods that support the entire structure. On top are shields made of moisture-proof plywood.

Formwork for overlapping

Currently, monolithic overlap is most often used. On his example, we will analyze the process of mounting the formwork.

Vertical racks are used for formwork,connected by bolts. They are attached at right angles to the bars going in the transverse direction. On these cross bars there is a plywood board, which is the bottom of the formwork.

The following materials are used for these works:

• stand - a beam with a section of 12-15 cm;

• crossbar and cross bar - edged board with a width of 16-18 cm and a thickness of 5 cm;

• slats - board thickness 3 cm;

• flooring - waterproof (laminated) plywood with a thickness of 1.8 cm.

Before the work begins, accurate calculations must be made. It is important to determine the necessary number of racks, the step of their placement and other indicators.

Installation instructions for the formwork of floors

The work instruction includes the following steps:

• To the top of the racks are attached longitudinal bars, the second end of which is fixed on the wall.

• In the same way, the second row is collected. For this, a board thickness of 5 cm is laid under the supports.

• Cross strips are laid in 60 cm steps.

• Install the support posts (strictly vertically).

• The posts are connected with each other by braces.

• On the cross bars are laid plywood sheets, leaving no cracks.

• The ends of the overlap are protected by a brick or brickwork.

• Is going to the frame of the armature. If necessary, leave space for communications.

When all the work is done, you can pour concrete. Remove formwork in 3 weeks.

Conclusion

Installation of formwork of each type providesuse of certain materials. If boards are used, they must be new. Rotten old boards can not withstand the load and break. Plywood must be moisture resistant or laminated.

All work must be performed in accordance with the calculations made. This is especially important for the installation of formwork of ceilings and walls.

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