The foundation device is not complete without creating a form for laying the 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, then today, fixed formwork for the foundation, which is a block masonry with wide design capabilities for different configurations of the bearing base, is becoming increasingly popular.
Technology features
To understand the specifics and advantages of this method, you should familiarize yourself 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, making it possible to reinforce it and give the necessary contours - this is especially important in the case of tape structures. After hardening the concrete, the elements of the molding shell are removed, and the foundation receives the necessary insulation with reinforcement.
What is the advantage of the supporting structure, which does not imply a formwork operation? Firstly, it excludes 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, by 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 during the project.
Concrete block formwork
One of the most difficult approaches to the implementation of technology, which involves the use of not special factory, namely home-made components. The work involves cement mortar and barrier pins, which will ensure the formation of the bearing walls. Even at the stage of laying, fixed concrete formwork for the foundation is arranged with the inclusion of thermal insulation material. To maintain external protection, special attention should be given to joints, crevices and technological gaps. They are sealed with polyurethane foam, and the resulting cavity can be reinforced with fiberglass or metal rods. The resulting design is reliable, durable and more often used in the construction of large houses. This is a solid alternative to the classic monolithic foundation.
Cement-cement slabs for fixed formwork
A variety of materials ready for the construction of formwork, which are made using wood-particle materials and cement binder. As for the first and main component, it is represented by wood chips or lamellas of conifers. A typical representative of fibrous boards can be called fiberboard. Wood billets for it are mixed with Portland cement, catalytic substances and liquid glass. The advantages of chip cement permanent formwork for the foundation include the following qualities:
- Security from biological negative processes. The material is not exposed to rot and mold damage.
- High insulating qualities. At least in practice, good heat-saving characteristics are noted.
- Structural strength. In the future, walls, exterior decoration, etc. can be mounted from the same plates.
- Environmental Safety. It depends on the binder used, but the majority of manufacturers strive to maintain the chemical purity of the same fiberboard.
Polystyrene formwork
The material is characterized by high density and hardness, as well as low combustibility - from the point of view of structural value, this is the optimal set of performance. At the same time, the blocks ready for formwork, even in the factory conditions, are provided with a special design with "tongue - groove" recesses. The presence of such additions makes it possible to conveniently join the blocks together in different configurations without the use of binding solutions. Subsequent pouring and reinforcing will strengthen the fixing nodes, while maintaining a reliable platform.
An important feature of fixed formwork for polystyrene foam foundation is the ability to lay communications in the niche of the block structure itself. Since the masonry elements have a hollow structure, even before pouring, you can lay the necessary plumbing or electrical wiring, providing it with reliable insulation.
Reinforced formwork panels
A kind of thermal insulation liners based on the same polystyrene foam, but with significant structural differences. A feature is the reinforcing reinforcement of block walls due to thin metal rods or steel mesh. Actually, the docking of fixed formwork components for this type of foundation is done by connecting rods embedded in the panel structure. Then, the exterior is finished 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, eliminating the need for additional decorative finishes and reliability.
Panel and block designs - what is the difference?
The design of the finished formwork determines a number of technical and operational qualities for the foundation bearing platform. Panel elements usually have a size of 2x3 m in length and height, respectively. For fastening, integrated lock knots, metal staples or knitting devices, such as plastic or steel ties, can be used. This formwork option is ideal in cases where a complex configuration of the strip foundation is implemented.
The block design is made of small segments that are connected by couplers. The most convenient from the installation point of view is the lamellar system for forming the supporting base due to perforated joints. The main advantage of fixed formwork blocks for the foundation is its high density and durability. On such a base, you can build large two-story houses with a heavy roofing system.
Non-removable formwork device requirements
The technological process of the device of this design is based on construction standards. To date, the following requirements for fixed formwork apply:
- Mechanical strength. The design must comply with the static and dynamic loads that will be assigned to it during operation.
- Insulation protection. The material used should protect the poured concrete and the ceiling with a grill from thermal and humidity influences from the environment.
- Joint tightness. 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 coupling mechanism itself ensures tightness, while in others additional sealing is performed. The maximum size of allowable clearances is 2 mm.
- High adhesion. As a result, the formwork material should form a structure of uniform strength with cement casting. This requires a sufficient adhesive function with a particular concrete brand.
Instructions for the design of fixed formwork
Installation begins on a previously cleared site with marked outlines for installing elements of the formwork system. For example, polystyrene blocks are laid around the perimeter of the future foundation, after which the elements are assembled, reinforced in predetermined directions, and the rods are knitted. Fill follows. How to make 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 ceiling of a strong metal plate is laid, and then the operation is repeated with the same rise to 25 cm.
General recommendations for the installation process
The issues of strengthening the design of reinforcement should be given the greatest attention. The most reliable formwork systems are carried out according to schemes involving fixation to the end of the rods directly in the bridges of the bearing blocks. Do not forget about the timely conduct of communications. Specialists often give advice on installing fixed formwork for the foundation, which emphasizes the importance of laying pipes with wiring at the stage of installation of the reinforcement. You can combine their contours, but so that the damage-sensitive path has a separate protective shell. As for the recommendations on concrete pouring, the stream 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 device elements of integral formwork, it is slightly more expensive than the implementation of 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 the base of polystyrene foam are 600-900 rubles. For a module 1 meter long, domestic enterprises ask for 1000-1200 rubles. And in any case, elements with the provided reinforcement add about 200-300 rubles in price.
Conclusion
When planning the construction of a private house, you should definitely consider the method and technical nuances of the foundation device 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 in order to increase refractoriness, etc. And this is without taking into account financial investments in fixed formwork for a foundation, the price of which in the total estimate can reach 15,000 rubles . taking into account consumables and mounting hardware.
Is the use of this technology justified in principle, taking into account the identified weaknesses? If there are no barriers to the use of fixed formwork in terms of strength and load tolerance, then it is justified. In any case, problems with insulation and the need for additional refinement will confront the project executor, and when the removable structure is installed, their number will only increase.