We make permanent formwork.

The construction of any house always begins with laying the foundation. The durability of the entire structure depends on how durable and warm it is. Typically, traditional removable formwork is used to construct the base. It is cheap, since any available materials are used during installation. But during the operation of the house, freezing is very soon discovered, which leads to rapid destruction. Solving this issue requires additional efforts and costs for insulation.

To avoid problems with thermal insulation, energy-saving technologies come to the rescue. An excellent method of insulation at the initial stage is the method of permanent formwork for the foundation.

Peculiarities

It is a modular form consisting of building blocks or slabs. It is mounted directly on the foundation site and filled with mortar. During the hardening process, the walls are reliably fused with the concrete and form a monolithic structure that cannot be dismantled. You can immediately lay the base plate on top of it.

The use of permanent formwork provides the developer with a double effect:

• reduces installation time;
• protects the monolithic base of the house from freezing and heat loss during operation.

The method is also used in the construction of plinths and walls. The finished surfaces are smooth, even, and easier to coat. Construction experts recommend laying foundations in permanent boxes when constructing low-rise buildings, country houses, cottages, industrial facilities, insulated swimming pools and sports complexes.

Basic materials

To build formwork, you can choose blocks of various shapes and sizes: for foundations, walls, corners or architectural elements.

1. Polystyrene foam (expanded polystyrene) is the most common type of construction base. The frame consists of two plates fastened with steel bridges. It is characterized by moderate strength, light weight, wide availability and low cost. This is an excellent heat insulator that does not interfere with air circulation. Finished surfaces need lining.
2. Polystyrene concrete is a durable composite material with the inclusion of porous aggregate. Compared to polystyrene foam, it weighs more and has a low level of thermal insulation.
3. Fibrolite is a mixture of wood shavings and a binder component (Portland cement or magnesite). It has excellent noise absorption, moisture resistance and vapor resistance, is not flammable, and retains heat well. Formwork is most suitable for reconstructing the base, as well as laying interior partitions. The use of wood limits its service life, so it is rarely used in practice.

In practice, one-piece formworks made of expanded clay concrete, wood concrete, glass magnesite, and glass fiber reinforced concrete are also found. During installation, one or a combination of several types of materials are used. The choice depends on the purpose of the foundation.

Advantages and disadvantages

In order to choose the right shape when constructing a foundation, it is necessary to make a comparative analysis of different types and really evaluate the technical and operational characteristics of permanent formwork.

Advantages:

• simple installation technology;
• high assembly speed;
• absence of additional parts (supports and struts);
• the ability to build a foundation of ideal geometric shapes with high load-bearing capacity;
• tightness of butt joints;
• the presence of technological holes for laying utilities;
• savings on heat-insulating materials;
• seasonal independence.

Flaws:

• the need to use a construction vibrator;
• installation of additional thermal and waterproofing of the foundation base;
• high price.

Installation technology for strip foundations made of polystyrene foam

The construction of the permanent part of the formwork begins with the preparation of the trench. To do this, you need to carefully level the soil surface around the entire perimeter of the base. A building level helps verify accuracy.

1. Lay a drainage layer of sand and gravel mixture 150 mm thick at the bottom of the trench. Compact thoroughly, pouring cement laitance. The bulk cushion can be additionally filled with a thin (no more than 50 mm) cement screed.

2. Spread a waterproofing material - a roll of geotextile or roofing felt.

3. Lay a layer of lower blocks with a closed bottom - this is the basis of the foundation. To connect the corners, use special rotating elements or polyurethane foam. You can also use ready-made plugs to make fitting easier.

4. Lay out the next 2-3 rows from box-shaped blocks that do not have a top or bottom. Laying should be carried out offset. The grooves at the ends provide a tight horizontal connection.

5. In each row of formwork, pull a reinforcing rod through the internal through holes.

6. After laying the third or fourth row, strengthen the base vertically. To do this, select steel bars with a length equal to the height of the formwork.

7. Fill the foam box with M150 concrete mortar. Turn on the vibrator, which will ensure the density and uniformity of the filling. If you do not have special equipment, you can compact the concrete manually. A wooden beam with a cross member is suitable for this.

8. After filling three or four rows with reinforcement and concrete, continue laying the base.

Fixed polystyrene foam formwork cannot be left in the open air for a long time, especially in summer. Direct sunlight contributes to accelerated destruction of the material.

How to inexpensively make a non-demountable structure with your own hands?

The high cost of foam formwork often becomes an obstacle to budget projects. To save on building a foundation, you can build a mold with your own hands from available materials: chipboard, fiberboard, steel frame, pipe scraps. The main thing is that the structure can withstand the pressure of the solution and not leak.

• Prepare a mold for making blocks. It is most convenient to choose a steel box and line it with thin polystyrene foam pads.
• Fill the molds with sand-cement mortar prepared in a ratio of 1:4. You can also buy ready-made concrete grade M150.
• Place the filled elements on a vibrating table and compact the concrete mass, freeing it from voids and air bubbles.
• Place the curing molds under cover. Leave for 5-6 days.
• After the solution has set well and gained strength, shake the blocks out of the molds. The result is ready-made elements for mounting the base.

Review of prices for foam formwork

The blocks are not unified, so their cost can vary greatly among different manufacturers. Before you buy building materials, you need to decide on the type and standard sizes, as well as correctly calculate their quantity.

The price of blocks reinforced with additional thermal insulation is approximately 2 times higher.

The foundation is poured into pre-arranged formwork. This structure must be installed in compliance with a number of established rules and regulations. Familiarize yourself with the features of existing types of formwork, the procedure for their calculation, instructions for the construction of the most common structures and get to work.

Of course, before erecting the formwork, you need to decide on the type of foundation that you will build. We recommend reading the following materials on our portal:

— first of all, we invite you to familiarize yourself with the step-by-step technology for constructing a strip foundation. In which, among other things, it talks about the method of constructing wooden formwork.

Materials for the manufacture of formwork

Foundation formwork can be made from different materials.

Metal

Universal and most expensive formwork option. To assemble the structure, steel sheets with a thickness of 1-2 mm are used.

Metal formwork is perfect for arranging strip and monolithic foundation structures. it will be possible to weld directly to the formwork sheets, which will help increase the rigidity of the foundation.

The main advantage of the metal is the simplicity and convenience of its processing - the sheets can be bent to the required shape of the concrete base without any problems.

The main disadvantage of metal formwork is its very high cost when compared with other existing options.

Reinforced concrete

A relatively expensive type of formwork.

This formwork is constructed from concrete slabs. Depending on the thickness of the slabs used, when pouring the foundation it will be possible to slightly reduce the consumption of concrete mixture, which will save on the construction of the foundation without compromising the strength and other important characteristics of the structure.

Among the disadvantages, it is necessary to note the large weight of the slabs, which requires the use of special equipment for their installation.

Moreover, if the formwork is made from ready-made slabs and the dimensions of one element are not enough, you will have to install additional spacers, which will also not have the best effect on the final cost of the structure.

Expanded polystyrene

A very high quality and practical option. The formwork is assembled from ready-made individual polystyrene foam blocks. The formwork elements are extremely easy to install. They can be processed to the required shape without any problems.

The main disadvantages are difficulties at the stage of selecting certain structural elements (usually roundings and corners) and relatively high cost.

Available materials

During the process of arranging the formwork, make sure that its walls are installed exclusively vertically.

It is important that there are no large gaps in the structure. Seal gaps with suitable materials at hand. In this case, a gap with a width of more than 4-5 mm is considered large - such a gap will be quite enough for the leakage of concrete mortar.

Additionally, to prevent minor leaks of the solution, you can attach plastic film to the inner surface of the formwork walls.

It is recommended to dismantle removable formwork only after the foundation has reached the required strength. On average, this takes 3-5 weeks. The gaps left after dismantling the formwork are usually filled with soil. In some situations they are filled with concrete or cement

Good luck!

Prices for various types of construction boards

Construction boards

Video - DIY foundation formwork

The world does not stand still and new technologies created every year penetrate into all areas of construction. Work on the construction of the foundation was not left unattended. In this article we will talk about permanent formwork, which has recently become popular among developers, making their life easier.

In the photo - permanent concrete formwork for the foundation

The first installation stage of construction work is preparing the foundation for the future building. In most cases, such foundations are made of wooden formwork, which is dismantled after they have completely dried.

However, currently there are methods that allow the use of non-removable elements. Read below about what they are and how to make a foundation with your own hands.

General information

The first tests of such a technique began at the beginning of this century (in 2000-2001). At the same time, the main stages of laying the foundation were no different; the differences were only in the assembly and installation of the formwork. Let's remember the main stages of constructing a strip foundation:

Advantages and disadvantages of the design

And it is precisely from this place that significant differences begin in the installation of a foundation with removable and permanent formwork:

1. The first one includes a large number of elements and its correct creation, as well as subsequent installation, requires certain knowledge and skills.
2. In the second case, anyone can do the job. It does not require further dismantling, and besides, it performs another role - thermal insulation. As you know, when installing classical formwork, thermal insulation materials are laid separately.

Its advantages:

1. If you decide to make permanent formwork, then this gives two advantages at once:

• good limiter for concrete mixture;
• excellent thermal insulation layer.

1. Use allows you to avoid installing an additional reinforcing belt. To make it, you will have to buy metal fittings and make a frame out of them. The intersection points are welded or simply tied with special wire. Agree that these are additional costs for construction.
2. Another significant advantage of permanent formwork is its water-repellent ability. As a result, you don’t have to worry about the constant proportions of the concrete mixture.
3. Most types of permanent formwork have excellent fire resistance and do not lose stability in a humid environment.

Of the design shortcomings, only one can be highlighted - the high price of the product. However, there is also a nuance here; do not forget that when using it you can save on installing a heat-insulating layer.

Types of permanent formwork

Currently, there are several varieties of this material. Let's take a closer look at each of them:

Technologies in construction

In addition to the foundation, this type of formwork can also be used during the installation of walls. However, there are cases when it is used as their basis.

Wherein:

1. The walls must be mounted on a pre-waterproofed foundation.
2. To fix them, use metal reinforcement, which must first be installed and brought out from the base. In addition, with its help, new rows of reinforcing mesh will be formed, which must be overlapped.

Tip: before you begin installing the first row of permanent formwork, you should decide where the doorways will be located, as well as the places to which the internal walls will adjoin.

1. After this, you can continue to increase the reinforcing mesh and apply permanent formwork. By and large, this process is reminiscent of creating a sandwich, where a concrete casting, supported by a metal frame, will be protected on both sides by heat-insulating material.

Tip: if you then need to dismantle, cutting reinforced concrete with diamond wheels is used for this.

The instructions for pouring concrete into permanent formwork do not differ from the basic technologies used during the formation of a conventional concrete casting:

• It is recommended to fill in one stage, but if this is not possible, layers of concrete should be used;
• be sure to use a deep vibrator (the best option) or a tamper to remove air bubbles from the mass. If they are not available, you can simply take any sharp object and pierce the entire volume of the solution.

Advice: it is very important during such processes not to forget to leave space for utilities.

Otherwise, only diamond drilling of holes in concrete with special crowns will help you. In addition, do not ignore the formation of the structural elements of the room.

Conclusion

Purchasing really high-quality blocks of permanent formwork, as well as a competent process of preparing fasteners and tools, together with reliable fastening of the entire structure, can have a significant effect.

In this case, the house will be reliably heat and sound insulated, and the process itself will not seem so complicated. The video in this article will help you find additional information on this topic.

Formwork is an auxiliary prefabricated structure designed to form the correct geometry of concrete walls. For its construction, materials are used that do not absorb moisture and can withstand the pressure of liquid concrete during pouring and compaction. Once the concrete mixture has hardened, the formwork can be dismantled for reuse or left in place. In the second case, the formwork structure is called permanent.

The decision to leave the formwork without dismantling it after finishing concreting can be justified:

• impossibility of carrying out dismantling work;
• inappropriateness of dismantling;
• using enclosing material as a thermal insulation layer and waterproofing;
• the need to strengthen the concrete structure.

In the last two cases, the material for formwork is selected in advance and used as a building structure, performing certain design functions.

Eps formwork.

Advantages and disadvantages of permanent formwork systems

The main advantages of using concrete permanent formwork for the foundation when constructing reinforced concrete monolithic structures include:

1. the ability to provide good thermal and hydraulic insulation;
2. simple assembly technology;
3. absence of a dismantling stage;
4. obtaining a smooth outer surface;
5. minimizing the amount of construction waste;
6. increase in service life;
7. versatility of use for various structures.

Experts include the following disadvantages of using non-removable technology:

1. increased costs due to the use of additional materials;
2. reduced vapor permeability of the building structure;
3. the need for gradual pouring of concrete mixture;
4. complicating repairs or reconstruction in the future.

Comparing the pros and cons, we can say that the main controversial issue of this technology is the increase in construction costs. But a concrete strip foundation during its construction still requires the installation of an external waterproofing layer, and if there is a basement or semi-basement, insulation of the wall and blind area is very often done. Both of these issues can be easily resolved by using moisture-resistant, durable insulation materials to assemble the formwork structure.

Basic system requirements

Materials for formwork systems of this type must meet the following requirements:

• mechanical strength to withstand the pressure of the concrete mixture and loads from the soil during operation;
• moisture resistance of the layer and tightness of joints;
• precise geometry of individual elements with a flat surface;
• long service life without changing technical characteristics;
• simple installation technology;
• relatively low cost.

It is also worth mentioning the necessary availability for purchase in regular market sales.

Materials used for permanent formwork

The choice of the main formwork material depends on the technical purpose, cost and complexity of the foundation structure. In practice, for permanent formwork systems the following is used:

• extruded polystyrene foam;
• cement particle boards (CSB);
• wood concrete;
• glass magnesite;
• sheet metal.

In addition, moisture-resistant plywood and fiberboard are used, but due to the fragility of these materials when used in the ground for foundation structures, they are used extremely rarely, and only to speed up installation.

Expanded polystyrene formwork

Dense extruded foam plastic is the most popular material for permanent formwork when constructing monolithic strip foundations. The high level of demand is explained by:

• sufficient strength and moisture resistance;
• light weight and ease of processing;
• the presence of a tongue-and-groove system for connecting individual elements;
• low labor costs during installation;
• excellent heat, sound and waterproofing properties;
• the presence of reinforced and coated slabs;
• biological inertness, preventing the formation of mold and mildew;
• durability.

Opponents of the use of permanent formwork for polystyrene foam foundations point to its instability and danger in case of fire, as well as the low level of environmental friendliness. However, for the underground part of the foundation, exposure to flame during a fire is practically not dangerous, and for the same reason no environmental damage can be caused, especially if the outer surface is covered with a protective layer.

The only important drawback is the lack of corner and rounded elements on sale. This limits the use of the material in the case of installation of formwork of complex configuration.

Cement particle boards

DSP is produced by mixing crushed wood with cement-sand mortar and pouring the mixture into flat molds. This is a fairly dense, durable and heavy material. The presence of wood chips in its composition increases the thermal insulation properties, but there is no great efficiency in this matter. Among the main advantages of using cement bonded particle boards, we can point out that this material:

• has good vapor permeability and does not create a greenhouse effect;
• fireproof and has a high level of fire resistance;
• has high strength, which helps strengthen the foundation structure;
• made from environmentally friendly raw materials;
• resistant to sudden temperature changes over a wide range;
• affordable for most developers;
• requires minimal finishing, consisting of additional sealing of joints.

The main disadvantage of cement particle boards is their moisture permeability. Therefore, when constructing strip foundations, the underground part of the formwork must be covered with coating or roll materials on a bitumen basis to enhance the waterproofing properties.

The practice of using DSP as permanent formwork has a 25-year history. And we can say with confidence that this material is durable and reliable.

Arbolite blocks

Arbolite is a relatively new option for using cement-bonded particle board mixtures. From them I make hollow blocks from which the formwork structure is assembled. When making wood concrete, in addition to cement and wood shavings, crushed straw, sawdust and plasticizers can be added to its composition.

After installing the blocks, their internal cavities are half filled with concrete, reinforcing bars are laid and concrete is added to the upper level. Arbolite blocks are much cheaper than high-quality reinforced concrete and therefore this type of permanent formwork is widely used in private low-rise construction for the construction of foundations and walls of buildings. The advantages of wood concrete include:

• possibility of simple mechanical processing during installation;
• performing work without the use of special equipment and special tools;
• high strength and improved thermal insulation properties compared to concrete;
• environmental safety and recyclability;
• resistance to flame and high temperatures;
• good frost resistance.

The disadvantage of arbolite blocks, like those of DSP, is moisture permeability and the need to install a waterproofing layer.

1. Pillow lightly poured with concrete mixture.

2. First row.

3. Reinforcement.

4. Second row.

5. Filling.

Fibrolite

This is another option for making blocks based on a cement-sand mixture. But in this case, long strips of wood, cut along the fibers using special equipment, are used as filler. The material has the same properties as arbolite blocks, but is much stronger. This allows it to be used as permanent formwork when constructing foundations for two- and three-story buildings.

The need to use special equipment for producing wood fiber and increased requirements for raw materials make fiberboard a more expensive material compared to wood concrete and fiberboard. However, its use still makes it possible to reduce the overall costs of constructing strip foundations.

Glass magnesite

Glass magnesite sheets or FMS are made from a mixture of magnesium compounds, perlite, fiberglass, polypropylene and sawdust. Despite the fact that not all components are of natural origin, finished materials are environmentally friendly. These slabs were developed and manufactured in Asian countries. Domestic enterprises do not produce glass-magnesite boards.

LSU is an excellent option if you need to strengthen the foundation structure. The increased strength of the slabs allows them to withstand quite significant loads, both in the longitudinal and transverse directions. Moisture resistance is good, but additional waterproofing is still recommended.

Among the advantages of glass magnesite it should be noted:

• good thermal insulation properties;
• versatility of use;
• fire-resistant properties and non-flammability;
• relatively small thickness;
• the ability to bend sheets, making radius formwork;
• high surface adhesion.

The main disadvantage is considered to be the complexity of installation work due to the need to process the material. When cutting it, jigsaw files and wheels wear out 3-5 times faster. It will take more time for installation.

A metal sheet

Permanent metal formwork is used when there is a need to strengthen the foundation structure and obtain a perfectly flat surface of any, even the most complex, configuration. Mainly used in industrial construction. Private developers practically do not use this technology.

The number of connections is calculated in such a way that when pouring the concrete mixture, possible deflection of the sheet is completely eliminated. As a result, metal formwork provides the most accurate foundation geometry. Maximum deviations from dimensions do not exceed 2 mm.

To protect steel sheets from corrosion, their surface is coated with powder paint or a thin layer of zinc. If welding is used, the damaged protective layer is cleaned and repainted.

Among the disadvantages of using metals for installing permanent formwork, one should note the high cost, significant weight and the need for additional thermal insulation.

Strip foundation with permanent formwork using the example of polystyrene foam boards

Work on the construction of the foundation structure begins with marking and digging trenches to the designed depth. The width of the trench should be 0.5 meters greater than the width of the foundation on each side of it. After completing the excavation work, it is necessary to fill it with a thickness of 20-25 cm and compact it well. To provide the bottom layer of waterproofing, 2 layers of roofing material or waterproofing are spread at the bottom of the trench.

Opposing walls can be connected to each other using special clamps, standard coupling bolts installed in polypropylene tubes, or ordinary wire along the internal wooden spacers. During assembly, it is necessary to strictly adhere to the design geometry of the foundation.

To ensure that the integrity of the formwork is maintained, the concrete mixture should be poured in layers.

If the slabs do not have a factory protective coating, it is recommended to treat the outer surface after pouring and hardening of concrete

Monolithic reinforced concrete cannot be built without formwork. In the traditional sense, formwork is an enclosing structure, most often made of wooden structures, which serves to impart precise geometric parameters and spatial position to concrete products. After the concrete solution has cured, the formwork is removed. However, there is an alternative method that allows the formwork to remain as an integral part of the building structure.
This technology is called permanent formwork PENOPLEX®. This method allows you to reduce the volume of construction and installation work by one stage - eliminate stripping, and most importantly - there is no need for wooden formwork, which makes up a significant part of the work and is further disposed of during the work.
The unique technology with PENOPLEX® insulation helps improve many characteristics of the building structure. Permanent formwork PENOPLEX® also serves as thermal insulation for the foundation and basement parts of the future house. The method of installing permanent formwork has been actively used in Europe for a long time and this is due, first of all, to the energy efficiency of the building structures being erected.

Permanent formwork for private housing construction

The use of strip foundations in private housing construction is due to its versatility, reliability and affordable price. One of the most expensive stages of creating a shallow and recessed strip foundation is the installation of formwork for the foundation. Permanent formwork PENOPLEX® can significantly reduce the cost and speed up the technological process. The part of the strip foundation protruding above the ground becomes the base of the future house, which is already insulated with high-quality PENOPLEX® thermal insulation. Thus, this technology allows you to combine the creation of formwork and insulation of the foundation with the plinth into a single process.

Fastening permanent formwork PENOPLEX®

The permanent PENOPLEX® formwork is fastened using a universal screed. Thanks to the extension element of the screed, you can adjust the thickness of the concrete screed. Such a screed will be universally used both when constructing foundations and when constructing walls.

Type of assembled universal screed:

The construction of permanent PENOPLEX® formwork using a universal screed usually looks like this:

1. Outer layer: PENOPLEX®

2. Inner layer: PENOPLEX®

3. Universal screed for permanent formwork

4. Reinforcement frame

• Acceleration of construction work. Construction is accelerated and simplified by combining several operations in one. Load-bearing structures and thermal insulation are installed in one technological cycle.
• Financial savings. There will be no need for high costs for formwork, which is disposed of after dismantling. PENOPLEX® insulation also allows you to obtain a smooth surface of the foundation walls, which reduces the consumption of concrete mixture.
• Increased design reliability. The main element of permanent formwork, the reliable PENOPLEX® insulation, subsequently becomes part of the wall structure.
• High structural strength. Due to its high compressive strength (more than 20 tons per 1 m2), PENOPLEX® does not sag or press under the influence of the concrete mixture.
• Tightness of the structure. Zero water absorption and a stepped edge along the perimeter of PENOPLEX® allows you to mount the slabs as tightly as possible to each other and eliminate leaks of water and concrete mixture.
• Protection against biodamage. By protecting load-bearing structural elements from the adverse effects of the external environment, biostable and environmentally friendly thermal insulation PENOPLEX® extends their service life.
• Elimination of heat loss at home. The use of high-quality thermal insulation PENOPLEX® helps prevent soil freezing and cold penetration into the foundation. The constant low thermal conductivity coefficient of 0.032 W/m∙ºK PENOPLEX® eliminates heat loss from the house through the foundation, and accordingly the interior remains warm.

An important factor that distinguishes permanent formwork technology from the traditional strip foundation device is that with this technology the thermal contour of the concrete core of the foundation will be completely closed. (this will save up to 11% of thermal energy)

The cost of installing permanent formwork will be approximately 20% cheaper compared to conventional technology. In the calculation, it is assumed that the strip foundation will be thermally insulated in both cases.

Let's consider the monolithic construction of a strip foundation for a house 12m by 12m with a load-bearing wall in the middle using PENOPLEX as thermal insulation panels

Using a universal screed together with PENOPLEX FOUNDATION® slabs as permanent formwork allows you to:

• Set exact dimensions and minimize excess consumption of concrete mixture.
• Minimize labor costs. Installation using universal ties is convenient and simple.
• Attach the reinforcement directly to the ties, which will greatly simplify installation.
• Thermally insulate the foundation both from the outside and from the inside, which will significantly reduce heat losses. When heating there is no need to warm up the entire volume of the foundation.
• Implement the design of a complex foundation (for example, a T-shaped strip foundation)
• Reduce production time and material costs.