Installation of formwork: technology, instruction

One of the first stages of the erection of structures for various purposes is the installation of formwork. Often this process remains 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 the solution dries completely. There is such formwork from separate parts. As a result, a collapsible construction is obtained, which is dismantled and can be reused. Among the advantages of this type of formwork are easy installation, the possibility of reuse, which significantly reduces the financial costs of construction.

• Fixed, respectively, one that is not dismantled. Installation of the formwork of this type is mainly made 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 erection of a monolithic foundation, which 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 into 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.

• The horizontal, which is used to install the foundation and overlapping.

• 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 involves the acquisition of a ready-made kit for the execution of works. 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 work execution time;

• Simplicity of installation;

• Light construction weight;

• Resistance to the appearance of fungus and mold;

• Fire safety;

• Low cost.

Also, a non-removable formwork is simultaneously a layer of insulation and is a block of foam that easily connects with 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

Mounting the formwork of walls with non-removable blocks is much easier than the traditional method.

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

For start lay only one row of blocks, then the 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 the concrete solution 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 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 help of professional builders.

Installation of the formwork is made of boards, blocks, 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 platform must be completely cleaned of foreign objects, debris 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 sizes between the bars, a formwork panel is assembled .

Ready-made shields are attached to the corner bars with the help of screws 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 rubble or sand is poured into the finished formwork box. 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 flow of 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 the support of the structure. 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 elements of the structure are twisted: wire, clamps, ties, hardware and so on.

The deck is most often assembled from boards measuring 15 cm wide, which are joined in several rows by means of nails (driven from inside, curled from the outside) or self-tapping screws (they are twisted 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 if the site is prepared in advance. It is marked using cords stretched 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 bars, 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 5x5 cm brusks.

• Cover the inside of the formwork with a film (roofing paper).

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 construction of small buildings (cottages, buildings of economic purpose) and partitions between the rooms. In this case, small plywood boards are used.

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

For the installation of walls prepare the foundation, in which the reinforcement is stuck. 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 by 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.

• On the forests of the cup type. This type provides for the installation of the frame. Stands are connected together 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 the formwork, connected together 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;

• Slants - board thickness of 3 cm;

• Flooring - moisture resistant (laminated) plywood with a thickness of 1.8 cm.

Before work begins, it is necessary to make accurate calculations. 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 purpose, a board thickness of 5 cm is laid under the supports.

• Folding bars are stacked in 60 cm increments.

• Install the support posts (strictly vertically).

• Racks connect with each other with braces.

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

• The ceilings of the floor are protected by a brick or block.

• Is going to the frame of the armature. At the same time leave space for communications if necessary.

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

Conclusion

The installation of the formwork of each type involves the use 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.