Establishing a foundation is not complete without creating a form for laying a supporting structure. Whether it is a tape structure or a monolithic slab, the installation of retaining elements will be required. And if earlier wooden prefabricated structures were mainly used for this task, today non-removable formwork for the foundation is becoming more and more popular, which is a block masonry with wide possibilities for designing different configurations of the supporting base.
Technology Features
To understand the specifics and advantages of this method, you should become more familiar with the tasks of formwork as such. This is one of the basic structural elements of the house, responsible for the reliability of the foundation. Removable formwork structures only form the poured cement mortar, allowing it to be reinforced and given the desired contours - this is especially important in the case of strip structures. After the concrete has hardened, the elements of the mold shell are removed, and the foundation receives the necessary insulation with reinforcement.
What is the advantage of a load-bearing structure that does not require a demoulding operation? First, sheexcludes several technological operations. This also applies to the dismantling of the structure, and additional work on the insulation and waterproofing of the walls. Secondly, the fixed formwork for the foundation, in its left form, in itself performs the functions of strengthening the supporting base, providing its external protection. There are also structural advantages that allow a more accurate approach to modeling the configuration of the foundation without significant errors already during the implementation of the project.
Concrete block formwork
One of the most complex approaches to the implementation of technology, which involves the use of homemade rather than special factory components. The work involves cement mortar and barrier pins, which will ensure the formation of load-bearing walls. Even at the laying stage, a fixed concrete formwork for the foundation is arranged with the inclusion of heat-insulating material. To maintain external protection, special attention should be paid to joints, slots and technological gaps. They are sealed with polyurethane foam, and the resulting cavities can be reinforced with fiberglass or metal rods. The resulting design is reliable, durable and is more often used in the construction of large houses. This is a solid alternative to the classic monolithic foundation.
Screed-cement slabs for fixed formwork
A variety of materials ready for the construction of formwork, which are made using wood-shaving raw materials and a cement binder. As regards the first andthe main component, then it is represented by chips or lamellas of coniferous trees. Fiberboard can be called a typical representative of fibrous boards. Wood blanks for it are mixed with Portland cement, catalytic substances and liquid glass. The advantages of chip-cement fixed formwork for the foundation include the following qualities:
- Protection from biological negative processes. The material is not subject to decay and damage by fungi with mold.
- High insulating qualities. At least in practice, good heat-saving characteristics are noted.
- Structural strength. In the future, walls, exterior finishes, etc. can be mounted from the same plates.
- Environmental safety. Depends on the binder used, but most manufacturers strive to maintain the chemical purity of the same fiberboard.
Expanded polystyrene formwork
The material is characterized by high density and hardness, as well as low combustibility - in terms of structural value, this is the optimal set of performance qualities. At the same time, blocks ready for formwork are provided with a special design with grooves "thorn - groove" even in the factory. The presence of such additions makes it possible to conveniently join the blocks to each other in different configurations without the use of binding solutions. Subsequent pouring and reinforcement will strengthen the fixing nodes, while maintaining a reliable platform.
An important feature of the fixed formwork for the foundation of expanded polystyrene isthe possibility of laying communications in the niche of the block structure itself. Since the masonry elements have a hollow structure, even before pouring, it is possible to lay the necessary plumbing or electrical wiring, providing it with reliable insulation.
Reinforced formwork panels
A variety of thermal insulation liners based on the same polystyrene foam, but with significant structural differences. The peculiarity lies in the reinforcing reinforcement of block walls due to thin metal rods or steel mesh. Actually, the docking of the components of the fixed formwork for this type of foundation is carried out by connecting the rods embedded in the structure of the panels. Then, the external finishing of the structure is made with white concrete, which increases the structural integrity of the formwork. As a result, you can count on such advantages of the technology as high installation speed, good insulating functions, elimination of the need for additional decorative finishing and reliability.
Panel and block structures - what's the difference?
The design of the finished formwork determines a number of technical and operational qualities for the foundation bearing platform. Panel elements usually measure 2x3 m in length and height, respectively. For fastening, integrated locking units, metal staples or tie-down devices such as plastic or steel ties can be used. This formwork option is optimally suited in cases where a complex configuration of the tape is implemented.foundation.
The block structure is made of small-sized segments, which are connected by ties. The most convenient from the point of view of installation is considered to be a lamellar system for forming a carrier base due to perforated joints. The main advantage of fixed formwork blocks for foundations is their high density and durability. On such a base, you can build large two-story houses with a heavy roofing system.
Requirements for fixed formwork
The technological process of the device of this design is based on building codes. To date, the following requirements for fixed formwork apply:
- Mechanical strength. The design must comply with the static and dynamic loads that will be placed on it during operation.
- Insulation protection. The material used must protect the poured concrete and the ceiling with grillage from thermal and humidity effects from the environment.
- Tightness of joints. For many panel and block components of fixed formwork for the foundation, the instruction prohibits the use of joints that leave technological gaps. In some cases, the hitch mechanism itself provides tightness, while in others additional sealing is performed. The maximum size of allowable gaps is 2 mm.
- High adhesion. As a result, the formwork material should form a single strength structure with cement pouring. This requires sufficientadhesion function with a specific brand of concrete.
Instructions for fixed formwork installation
Installation begins on a previously cleared area with marked contours for the installation of formwork system elements. For example, polystyrene foam blocks are laid around the perimeter of the future foundation, after which the elements are assembled, reinforced in given directions and rods are knitted. Next comes the filling. How to make a fixed formwork with your own hands in several levels so that the structure is stronger? The first row can be poured with concrete at a height of 25 cm. Next, a floor is laid from a solid metal plate, and then the operation is repeated with the same rise up to 25 cm.
General recommendations for the installation process
Issues of strengthening the structure with reinforcement should be given the most attention. The most reliable formwork systems are made according to schemes that involve fixing the end of the rods directly in the lintels of the bearing blocks. Do not forget about timely communication. Experts often give advice on the installation of fixed formwork for the foundation, which notes the importance of laying pipes with wiring at the stage of installing reinforcement. You can combine their contours, but in such a way that the trace sensitive to damage has a separate protective shell. As for the recommendations for pouring concrete itself, the jet should be directed to the corners, and the final filling of hollow blocks should be carried out in straight sections.
How much does fixed formwork cost?
Despite the complexity of the construction of one-piece formwork elements, it is not much more expensive than the implementation of the classical technology with wooden structures. The cheapest concrete blocks cost an average of 150-300 rubles. As the size increases, the numbers can increase to 900-1000 rubles. The average prices of fixed formwork for a foundation made of expanded polystyrene are 600-900 rubles. For a module 1 m long, domestic enterprises ask for 1000-1200 rubles. And in any case, elements with the provided reinforcement add about 200-300 rubles to the price.
Conclusion
When thinking about building a private house, you should definitely consider the method and technical nuances of the foundation and its formwork. The technology under consideration has many advantages that attract ordinary consumers, but the disadvantages of this method should also be taken into account. These include low vapor and waterproofing properties of materials, the need for ventilation ducts, the addition of flame retardants to increase fire resistance, etc. And this is without taking into account financial investments in fixed formwork for the foundation, the price of which in the general estimate can reach 15,000 rubles. including consumables and mounting hardware.
Does the use of this technology justify itself in principle, taking into account the named weaknesses? If there are no barriers to use fixed formwork in terms of strength and complianceloads, it justifies. Problems with insulation and the need for additional refinement will in any case be faced by the project executor, and with the installation of a removable structure, their number will only increase.
