Houses made of permanent formwork - advantages and disadvantages

Combining insulation with durable wall material and making the wall construction process quick and simple - that's why permanent formwork was developed.

Expanded polystyrene is quite rigid and at the same time very warm material is optimal for this. If we take into account the economic factor - the low cost of this polymer, then the high popularity of the technology among developers becomes clear permanent formwork.

Standard permanent formwork made of expanded polystyrene consists of large-sized (1200x250x250 mm) lightweight blocks with through “windows”. Concrete is poured into these cavities and reinforcement is installed.

Round or rectangular protrusions and recesses are made on the upper and lower edges of the polystyrene foam blocks, with the help of which they fit tightly on top of each other. Anyone who has seen the “bricks” of a children’s Lego set will probably find a lot in common between them and permanent formwork.

There is another “collapsible” design of thermoblocks, when instead of one volumetric mold, two flat ones are used. Such a block consists of two sheets of foam plastic 50 mm thick, connected to each other by plastic jumpers.

The idea of permanent formwork technology is very simple: we assemble a warm wall row by row, filling it with concrete as it grows and inserting reinforcing bars to increase spatial rigidity. The result is a durable frame construction– reinforced concrete grating, the internal and external surfaces of which are reliably insulated with foam plastic.

Labor-intensive operations typical of conventional brickwork - laying out mortar, trimming and splitting bricks - are absent here. The blocks are quickly assembled into a single line, and workers can only fill them with fine-grained concrete in time.

The eternal problem of masons - masonry corners - has also been successfully solved. For this purpose, special corner foam blocks with perfectly precise geometry are used.

The main condition for high-quality construction of walls using permanent formwork technology is a level foundation. If it has differences in height, then accurately place the blocks on it without additional gravy cement mortar it will be very difficult.

Important note! Permanent formwork can be successfully used not only for the construction warm walls, but also for pouring strip foundations.

Features of the technology

At the stage of constructing the foundation, it is necessary to lay vertical rods in it to connect it with the wall made of permanent formwork.
Reinforcement outlets from the foundation must be long enough to install the first three rows of polystyrene foam blocks.
Waterproofing of the first row of formwork is necessary. Without it, moisture will flow freely into the concrete, reducing the thermal insulation of the wall. For this you need to use compounds that do not dissolve polystyrene foam.
Horizontal reinforcing bars are laid inside each row to provide longitudinal rigidity to the frame.
Pouring concrete is carried out after installing three rows of formwork blocks. After the concrete has set, the wall can be built up further.
For covering windows and doorways you need to buy special jumpers and plugs that lock the ends of the formwork to prevent concrete leakage. Above the opening, the formwork is reinforced with two rows of horizontal reinforcement and supported from below to avoid deflection.

The outside of polystyrene foam permanent formwork is finished with special adhesive mixtures that have a high coefficient of adhesion to polymer surfaces. To protect the plaster or putty from cracking, a fine-mesh fiberglass mesh is glued to the blocks, which is then covered with a finishing mortar.

Other types of permanent formwork cladding are not particularly problematic, provided you make a suitable base for them in advance. For example, for siding, at the installation and concreting stage, you need to attach bars or metallic profile. For finishing decorative bricks or with a stone, wire loops are placed in the concrete of the formwork to connect with the masonry.

For interior decoration For walls, sheet plasterboard or glass magnesite are optimally suited. It can be fixed with the usual starting putty. Ceramic tile It can also be easily attached to the surface of polystyrene foam using special adhesive.

Pros and cons of fixed formwork

Avoiding emotions and trusting laboratory tests and practice, let's say the following. The sanitary safety of this polymer is confirmed by hygienic certificates, which each manufacturer receives for fixed formwork. This is a fact that is hard to ignore. Owners of houses built using this technology, having lived in them for quite a long time (3-5 years or more), do not notice discomfort and growing health problems.

The fire safety of polystyrene foam blocks is within the framework of the current Russian norms and rules. They belong to the category of low-flammable and hardly flammable materials (G1 and V1). But their level of smoke formation is quite high - D3.

This is what we see in the hygienic certificate for polystyrene foam boards (analogous to blocks for permanent formwork).

But after studying the information on the scope, some questions arise.

The use of polystyrene foam as the middle layer of a wall structure is a requirement of Soviet GOST. Today, building facades are covered with this material everywhere.

But when internal use(the blocks face one side into the room) high-quality foam insulation is required. That is, it is not enough to simply putty it and paint it. It is necessary to line the wall with fire-resistant plasterboard or glass-magnesite sheets (SML) and then work on them finishing.

This polymer is not dangerous in operation, but in case of fire without proper protection it releases toxic gases. Fire-resistant drywall or plaster will allow people to leave the room before the gases from decomposing polystyrene foam fill it.

To be fair, it must be said that the use of polystyrene foam indoors, provided it is protected from direct contact with fire, is less dangerous than conventional household items - chipboard furniture and decoration (linoleum, curtains, wallpaper and other materials containing flammable polymers).

High-quality external finishing of permanent formwork is very important, since the direct action of ultraviolet radiation quickly destroys the polymer. Therefore, after finishing the construction of external walls, do not delay with plastering.

Approximate prices

When buying fixed formwork blocks, it is advisable to choose those made of denser polystyrene foam (25-35 kg / m3). They can better withstand the pressure of wet concrete.

The average cost of one block of fixed formwork (1500x250x250 mm, wall 25 mm) made of expanded polystyrene with a density of 30 kg / m3 (M25) ranges from 150 to 170 rubles.

The cost of a one and a half meter collapsible block (wall thickness 25 mm) starts at 170 rubles. Its main advantage is the ability to adjust the width by installing jumpers of different lengths (150-250 mm).

For harsh climatic conditions, manufacturers produce permanent formwork with increased wall thickness (75 mm). The price of such blocks ranges from 190 to 210 rubles per 1 piece.

In addition to the standard length of 1.5 meters, ordinary meter blocks (1000x250x250 mm) are sold on the market. Their cost starts from 130 rubles per piece.

Wooden or brick houses rightfully have an army of fans. But despite all their advantages, they have one very significant disadvantage - their construction cannot be called quick. For those who are thinking about building own home, but at the same time does not have enough time in reserve and cannot boast of great knowledge in construction, it remains to choose a monolithic method of building housing. The article will focus on houses made of fixed formwork.

In order to fill the foundation and walls of such a house, formwork is used. It can be removable (that is, dismantled after completion of work) or non-removable. The second option remains in place after the mortar is poured and hardened, and all external finishing work is carried out directly on top of the formwork.

House using fixed formwork technology

Formwork is nothing more than a form. You can remember your childhood games in the sandbox or imagine the housewife pouring dough for cakes into special baking containers. Only unlike the examples given, the form will remain in place, becoming part of the walls or foundation.

Houses from fixed formwork photo

Permanent formwork is assembled according to the principle of a children's construction set from blocks having different composition. The principle of installation resembles brickwork. Structural elements have grooves or special lock-type connections.
If necessary, fasten opposite blocks using screeds. Vertical reinforcement must be used, and in order for the structure to withstand the pressure exerted on it from the inside by the solution, pouring is carried out in series. In each of the passes, a height equal to three or four rows of blocks is filled with cement.
Elements for formwork are made from polystyrene foam or some other materials that promote thermal insulation.

Advantages of using fixed formwork

Monolithic structures are strong in themselves. Abandoned formwork creates additional frame, reinforcing the walls of the future house.
Monolithic walls puts less pressure on the base, therefore, when developing projects for houses made of permanent formwork, it is possible to calculate the option of increasing the number of storeys of the house.
Sound and heat insulation of the home. Foamed polystyrene is an excellent material for insulating residential premises, and its characteristics are complemented by the fact that it perfectly dampens sounds. The construction of permanent formwork is, in its own way, the simultaneous carrying out of insulation and sound insulation work.
Less time - less labor costs. When building your own home, you need to save wisely. Renting expensive construction equipment will be excluded from the estimate for a monolithic house. And you won’t need many voluntary or hired workers. The filling process is fast. This means that workers won’t have to overpay for extra time spent on site either.

Space saving. There is never a lot of free space, even inside private houses designed according to personal projects. Monolithic walls are thinner than brick ones, but they protect their owners from the cold no worse, and they save a lot of space inside.
Continuing the conversation about savings, it must be said that permanent formwork will allow you not to overpay for heating during further operation of the house.
Durability. If you adhere to technology to the smallest detail, then walls formed by polystyrene blocks and concrete will last at least a century.
Simplicity of finishing. Blocks create good flat surface walls, which allows you to effortlessly and extra costs To level the bases, finish them both from the street and inside the house.

What type of permanent formwork is there?

Expanded polystyrene blocks for installation of permanent formwork

These are hollow elements with walls of varying thickness. The outer side of the material is much larger than the inner side - it will be responsible for maintaining heat in the house. The blocks themselves are strong enough to hold the solution being poured, are non-hygroscopic and affordable.
Assembly in the form of brickwork adds strength to the structure, and reinforcement will give additional rigidity to the wall. Reinforcement rods located vertically are overlapped. It is important to choose the right diameter, as well as the grade of concrete.

Communications, including electrical wiring, are laid through pre-cut holes in the blocks. All work must be completed before pouring begins. The result is a kind of sandwich, where the “filling” of reinforced concrete is enclosed between layers of insulation.
Opponents of polystyrene foam emphasize that this material is not environmentally friendly. But this is rather a matter of choice of manufacturer. Foamed polystyrene manufactured in accordance with all standards and rules does not pose a threat to health. It is enough to note that picky European commissions and examinations have allowed the use of this synthetic material in conjunction with food. Therefore, when purchasing material, you should familiarize yourself with quality certificates and not pursue dubious monetary benefits.
But with the vapor permeability of expanded polystyrene, things are really bad. But problems will not arise if you think through the ventilation system well.

Polystyrene concrete - it is a “breathable” material

It is vapor permeable because it is based on cement. The blocks will have to be laid with special glue, tied with reinforcement and then poured. They are stronger than foamed polystyrene formwork.
Cement-based blocks are also very diverse. Thus, there are masonry blocks for load-bearing walls, produced in several sizes and modifications; you can separately purchase elements for the formwork of columns, vertical or load-bearing floor beams, lintels or strapping belts.

Chip-cement blocks

This is an invention of Dutch developers. They have been known since the 30s of the 20th century. Large wood chips are used for their production. coniferous species(it makes up approximately 80-90% of the total composition of the material). The chips are treated with special additives and held together with a mixture of gypsum, cement clinker and some other additives (Portland cement).
The advantages, in addition to environmental friendliness, are obvious:
- high strength against low weight;
- vapor permeability;
- heat and sound insulation properties;
- weather resistance;
- frost resistance.
Fire safety is achieved through special processing, and such blocks are also not afraid of rot, mold and pests. They are easy to cut and process. When constructing the formwork, the slabs are placed opposite each other and secured with wire ties. They not only connect structural elements, but also do not allow the wall to deviate from the vertical. Standard material dimensions: 2000 × 500 × 35 mm.
They have also found other uses: often chipped cement slabs are used to insulate facades or to build small panel houses at the dacha, designed for living in the summer.
The structure will have to be reinforced less. Strengthening will require lintels of window and door openings, columns. And the walls themselves are reinforced with a significant gap of 2.5 or 3 meters (for formwork made of polystyrene foam blocks, the interval is 1 meter). In one approach, pour the mixture, moving around the perimeter, to a height of a meter (two rows). The poured concrete is compacted using the bayonet method.
Since the first version of the material for permanent formwork is much more common, it is worth considering the construction technology from polystyrene foam blocks as an example.

Do-it-yourself construction of houses from permanent formwork

So, there is a foundation made in the most suitable way for the given soil. Most often it is a strip base. In any case, it is first covered with a layer of waterproofing material, and reinforcing rods are driven in.

Laying the first row

The blocks are carefully strung onto the reinforcement and fastened to each other in accordance with the manufacturer’s recommendations (wire ties). Start with the corner elements. It is convenient to stretch a cord between them in order to refer to it when laying out the remaining blocks in the row. There are ridges and grooves at the ends of the material. This type of connection will hold all of the formwork pieces in place. The first layer is the basis of the future building. At this stage, the installation of branches of internal partitions and openings takes place entrance groups. All engineering Communication are formed immediately. Design feature blocks (internal voids) allow you to hide all the necessary wiring inside the walls. We must not forget about ventilation.

Laying the second row

The second row of blocks is laid offset, like bricks. This dressing will ensure the strength and rigidity of the structure. It is important to ensure that the sides of the stacked blocks match. Be sure to check the level so as not to move the wall away from the vertical. Fixing the blocks of the first and second row is easy. The grooves on the surface of the elements close after light pressure.
The laying of the third row of polystyrene foam blocks is carried out similarly to the installation of the second level.

Pouring the solution.

Concrete is poured around the perimeter of the area with the erected formwork. It is important to compact the poured mixture well. The shallow depth of filling with the solution allows you to use a piece of reinforcement for these purposes: they act like a bayonet - they intensively pierce the concrete to get rid of voids, destroying air bubbles. The optimal length is calculated as follows: the height of the block must be multiplied by 3. But purchasing (or renting) a deep-well vibrator will facilitate the speedy completion of work. It will cope much more effectively with the task of compacting the solution. To do this, the diameter of its working part should not exceed 4 cm.
Experts advise not to fill with cement upper layer blocks until the very end. If you fill half the outer row, the seam will be hidden inside the polystyrene foam formwork elements. This means the wall will be stronger. Per m² you will need to pour from 0.075 to 0.125 m³ of solution.

Laying the fourth and subsequent rows

The laying of blocks in subsequent rows has the same algorithm that was described. After the sixth row takes its place, the operation of pouring concrete is repeated. Formwork of floors is best done with the support of specialists. The technology is like this. A recess is made in the row of blocks where it is planned to lay floor beams (or floor joists) the right sizes. The cut fragment should not exceed ¼ of the formwork element. Now the beams are installed in their places, and pouring is carried out.

Final stage

Finishing a house using permanent formwork is quite simple. Thanks to the high adhesion of the blocks to the plaster mixture, it will lie smoothly and easily. Roofing in monolithic houses are no different from erecting a roof in buildings built using a different technology.

House made from permanent formwork video

What can you use to make permanent formwork for your foundation yourself?

If home handyman If he has the strength to be precise, accurate and consistent in his actions, he will be able to make a permanent form for the foundation himself. You will need to choose from several options for suitable material:

moisture resistant plywood,
cement particle board,
flat slate.

All of them are quite durable, resistant to moisture, and elastic. The only indicator that these materials do not possess is thermal insulation. Therefore, you additionally need to purchase something to provide heat (for example, mineral wool). Still needed waterproofing material, fittings, components for the cement-sand mixture, a set of coupling screws and nuts for fixing the structural elements together.

Cost of building a house from permanent formwork

The cost of a monolithic house made of permanent formwork is much lower than a brick or wooden version housing.
The price of materials varies depending on the region and manufacturer, but on average you will have to pay from 800 to 1000 rubles for m² of formwork made from polystyrene foam blocks.
All manufacturers and sellers calculate the total cost of formwork for free, and the official websites have calculators for making accurate calculations.

Fixed formwork not only reduces the cost of construction, but also serves as insulation. In this article we will talk about:

various types of permanent formwork;
their cost;
application features;
the advantages and disadvantages of each type of formwork;
technologies for building houses using permanent formwork;
approximate construction costs compared to the construction of monolithic, brick and block houses.

What type of permanent formwork is there?

Many types of permanent formwork are ready-made blocks, from which a wall is assembled and then concrete is poured into it. From these blocks the perimeter of the house is formed and interior walls. The blocks are connected to each other using grooves and ridges or metal plates and corners. The height of the blocks is 10–50 cm, length 40–200 cm. Fixed formwork is distinguished by the material from which it is made:

expanded polystyrene;
polystyrene concrete;
wood chips (wood concrete);
sandwich (combination of various materials).

Expanded polystyrene (foam)

Most cheap material for the manufacture of formwork, its cost is from 400 rubles per m 2. This formwork is made in the form of cells 20–25 cm high and up to 100 cm long. The thickness of the walls depends on the model of the formwork, so the customer can choose either the thickest one, which provides the greatest thermal insulation, or the one with the minimum wall thickness. Blocks of such formwork are assembled like children's designer, because there are grooves cut on the long sides of each block, as well as on one of the ends, and ridges are cut on the other end. When choosing such a formwork material, you cannot pour more than three rows (60–65 cm) at a time, otherwise the mass of concrete will squeeze out the foam and the formwork will not be able to shape the wall the required form. Another serious drawback is that such formwork does not allow steam to pass through, so the rooms will always be damp. When building houses with such formwork, it is very important to provide in advance in each room proper ventilation, which compensates for this negative effect.

Polystyrene concrete

Polystyrene concrete is a mixture of concrete and expanded polystyrene balls, which reduce the thermal conductivity of the material. In terms of thermal insulation properties, such a material, with equal wall thickness, is inferior to foam plastic, but it does not have its main drawback, because polystyrene concrete allows steam to pass through well, and therefore removes excess moisture from rooms. There is no single size of blocks, but on average the height is 30–50 cm and the length is up to 200 cm. To fasten the formwork cells, grooves and ridges are used, as well as additional elements (corner, end, etc.). The average cost of such formwork is from 600 rubles per 1 m2 of wall. The advantage compared to foam formwork is the high height of pouring concrete at a time - up to 150 cm, if there is a vibrator of suitable length.

Chip concrete

Chip concrete (arbalite) are slabs made from a mixture of concrete and sawdust or shavings. Unlike previous forms, they are supplied in the form of individual slabs rather than pre-fabricated cells, so traditional formwork is made from chipped concrete, which is then left on the concrete as insulation. The cost of one m 2 of formwork (two slabs measuring 200x50 cm and thickness 25–45 mm) is 750–900 rubles. In terms of thermal insulation, these slabs are comparable to polystyrene concrete formwork, but they are much more convenient in terms of finishing, because you can screw screws or drive nails into them. As with conventional formwork, it is necessary to provide ties that will keep the slabs from being squeezed out by concrete.

Sandwich

A sandwich is a combination of various materials, most often wood concrete and foam plastic. In this case, the foam is placed on the concrete side, because it is sensitive to ultraviolet radiation and oxygen. Arbolite is not afraid of the sun, water or air. Walls in such formwork do not need insulation even in the regions of the far north, however, the presence of polystyrene foam or expanded polystyrene blocks the release of excess moisture through the walls of the house, so high-quality ventilation is necessary. Sandwich slabs are installed in the same way as chipped concrete formwork. The cost of one slab measuring 200x50 cm starts from 750 rubles.

Technology of building houses with permanent formwork

Site planning and ground work are carried out in the same way as for any brick houses. First, the area is marked and a trench or pit is dug, then the bottom is compacted and a sand and crushed stone cushion is poured. After this, a base slab is poured, the width of which is 3–5 times greater than the width of the foundation. Typically, the width of this pillow is 80–120 cm. The pillow is reinforced, both horizontally and vertically, releasing reinforcement from it 2–4 meters along the wall line. This is necessary in order to connect the foundation wall and the pillow. During pouring, it is very important to check the surface of the pillow using a level; if it turns out to be uneven, you will have to pour a screed, which will level the surface of the pillow and increase the construction time of the house.

Pouring foundation walls

Having filled the cushion, it is allowed to stand for 25–28 days, after which the first rows of permanent formwork are installed. This formwork is preferable because the foundation must be insulated, otherwise the heat loss of the house will increase, followed by an increase in heating costs. For the foundation, it is advisable to use polystyrene foam or polystyrene concrete formwork, because wood concrete in conditions of high humidity will begin to collapse in 10–20 years. If you use polystyrene foam formwork, be sure to reinforce it with plastic ties. They will prevent the foam from being pressed through the concrete during compaction with a vibrator. If you use wood concrete or sandwich formwork, tie the outer and inner sheets together with ties and secure with spacers. This will save the formwork from being crushed by concrete and ensure verticality of the walls.

Fill no more than three rows of any formwork at a time, and fill the third row of formwork only to the middle. This is necessary to prevent cold bridges from appearing in the foundation. Use the same filling method for walls. The next day, install the next 3 rows of formwork and pour the concrete. The maximum interval between fillings is 30 hours, if it is exceeded, the strength of the wall will decrease. With a step of 1-2 meters, create a belt from reinforcement horizontally laid around the entire perimeter - it will tie the wall and keep it from shifting and deformation.

Concrete composition

It is very important to use correct concrete, because the traditional composition of this mixture does not have the necessary fluidity, and the addition of water reduces its strength. Therefore, here are the correct components and proportions for pouring one m 3 of foundation from the walls into permanent formwork:

cement 305 kg;
sand 825 kg;
crushed stone 1170 kg;
water 125 liters;
plasticizer 1–2 liters.

Plasticizers are sold in any construction stores and they are inexpensive. Therefore, do not skimp on plasticizers, because with their help you will get more durable and flowable concrete, which will more easily fill the entire internal space of the formwork and create a monolithic wall.

Floor installation

In houses made of permanent formwork, 3 types of floors are used:

reinforced concrete slabs;
monolithic slab;
wooden.

Reinforced concrete slabs are produced at factories of reinforced concrete products (RCP), therefore, with a relatively low weight, they are distinguished by great strength. After all, they are not monolithic, but with voids inside, due to which their mass is reduced. However, a crane is required to install such slabs, so they are rarely used.

The monolithic slab has a huge mass, so it is used only in houses standing on dense or rocky soil. To fill such a slab, removable formwork is installed and supports are installed. Then they are reinforced with two layers of mesh made of steel, fiberglass or carbon fiber reinforcement and filled with the same concrete that was used for the foundation walls. After 10 days, the formwork can be removed, but the construction of walls must continue the next day. Only in this case will the floor be monolithic with the wall.

Important: Concrete floor must pass through the joint between the rows of blocks, only in this case you can reduce the likelihood of the formation of cold bridges. Therefore, the inner side of the formwork is cut to the level of the removable formwork, and the outer side is left intact.

Wooden floors are the most popular because they are lighter than concrete, cheaper and easier to install. They must also pass through the joint of the rows of removable formwork, otherwise the appearance of cold bridges cannot be avoided. For installing joists in outdoor and inside formwork cut holes according to their size, then insert logs and support them from below so that they do not push through the formwork. After a day, the joist supports are removed, and after 25–28 days a subfloor is laid on them.

Pouring the walls of the house

The same technology is used to fill the walls as for the foundation. The difference is that reinforcing belts are installed around the openings for installing windows and doors, that is, they are ringed with reinforcement. Also, a reinforcing belt is necessary under the roof; it will bind the wall and increase its strength. When pouring walls, do not forget about ventilation holes which must be done in accordance with the ventilation plan. After pouring the last row, the box is left at home for 28 days, then installed rafter system and lay the roof. Only after this do they begin the internal and exterior decoration, as well as installation of windows and doors.

Exterior and interior decoration

Formwork made of wood concrete and polystyrene concrete can stand for 1–3 years without finishing, but finishing should not be delayed. Expanded polystyrene formwork must be covered with finishing in the first year. This is due to the high sensitivity of the material to oxygen and ultraviolet radiation. Wood concrete and polystyrene concrete are finished in the same way as any brick or concrete walls, that is:

plastering;
covered with siding;
install a ventilated façade.

Expanded polystyrene formwork is finished in the same way as a foam-insulated wall:

plastered with a reinforcing mesh sticker;
mount siding or a ventilated facade with fastening to concrete.

The inside of a house built using permanent formwork is finished in any way you like.

The cost of building a house with fixed formwork

The construction of such a house is cheaper and takes less time than the construction of buildings from:

bricks;
cinder blocks;
arbolite blocks;
foam blocks;
monolithic concrete.

Despite the high cost of formwork, savings come from:

reducing the cost of construction equipment;
reducing the time of erection of walls and foundations;
reducing heating costs.

Where to buy fixed formwork

It is possible to order fixed formwork directly from the factory that produces it. In this case, you can choose between standard offers and custom-made formwork. The latter option will cost a little more, but custom-made formwork will better suit your conditions. For example, you can order blocks made of thicker polystyrene foam, which will keep your house warm even in the most severe frosts. Or you can change the thickness of the wall - this is especially important for permanent formwork of the foundation, because it is desirable that the foundation be 1.5–2 times wider than the wall of the house. After your order is completed, the formwork will be delivered to the site where the house is being built and you can begin construction.

If for some reason you cannot or do not want to order formwork at the factory, then it can be purchased at construction markets and sites where building materials are sold wholesale. However, the cost of the formwork will be slightly higher than the factory price, even taking into account delivery, because intermediaries take a percentage for storing and selling the goods.

Conclusion

Fixed formwork - inexpensive modern material, which reduces the cost of constructing a monolithic house. After reading the article you learned:

what types of permanent formwork are there;
what is the price of permanent formwork;
how to build a house from permanent formwork;
why building such a house is cheaper than houses made of brick, concrete and other similar materials;

House made of permanent polystyrene foam formwork

What could be more reliable than a monolithic reinforced concrete house? And if such a house is also warm, then this is generally the ultimate dream for a thorough owner. Moreover, such a house can also be relatively inexpensive, and you can build it yourself during your vacation.

There are several types of permanent formwork structures, each of which has its own advantages and features, but despite the differences in technology, the principle of construction itself is the same in all cases. From blocks made at the factory with through cavities, like from a construction set, the frame of the house is assembled, which is laid with reinforcement and filled with cement.

We will tell you how this is done using the example of building a house using permanent polystyrene foam formwork. This type of permanent formwork has earned popularity due to its low price and high consumer qualities that a house built using it acquires. As is immediately clear from the name, it is made of polystyrene foam, the same in appearance as we can see when unpacking a box with a TV or other large household appliances.

The difference is that polystyrene foam for permanent formwork has special additives, thanks to which it becomes completely inedible for rodents and unfavorable for the appearance of mold and other microorganisms on it. With all this, polystyrene foam remains absolutely harmless to humans.

In addition, it is not subject to rotting, does not absorb moisture and does not allow water vapor to pass through, and practically does not burn. The only thing is that polystyrene foam does not particularly like straight lines. Sun rays, under which it turns yellow, however, without losing any other properties. Its last feature is determined by the fact that you will not see houses built using polystyrene foam formwork without external and internal cladding.

The external cladding can be almost anything, from brick to... As interior decoration, they usually use sheets of plasterboard - gypsum board, lining or the same plaster.

The main advantage of expanded polystyrene is its high thermal insulation properties. Thus, a wall built using polystyrene foam permanent formwork, according to this parameter, is equivalent to one and a half meters brick wall or a wall made of timber half a meter thick. Thus, the house turns out to be very, very warm, which allows its owner to reduce heating costs by three times. After some time, these savings on heating will exceed the initial costs of building a house, which makes it possible to talk about such a house as a very profitable investment.

The concrete frame of the building makes it very durable, and the protection of the concrete with polystyrene foam on the inside and outside ensures minimal temperature fluctuations load-bearing wall. In turn, protection from temperature expansion and moisture (the material has high water and frost resistance) prevents cracks and chips from appearing in concrete.

How are polystyrene foam blocks made?

Polystyrene granules are poured into the storage hopper of the foaming agent, from which they are fed into the foaming agent by a screw feeder, where, with continuous stirring, they are foamed by a stream of steam at a certain temperature and pressure. During the foaming process, the volume of the granules increases. From the foaming agent, the sub-foamed polystyrene is fed by a fan through a pneumatic line into the storage bunker, where it is kept for 24 to 48 hours to equalize the internal pressure and finally stabilize the shape of the granules. From the aging hopper, polystyrene is fed by a fan through a pneumatic line into the storage hopper of the mold, from where it is fed into the mold by injectors fixed in the mold lid until it is completely filled. Inside the mold, during heat treatment with steam, the polystyrene granules once again increase in volume. Since the form has a closed volume, the granules mutually deform each other, filling the voids, and “weld”: the process of molding the finished product - a polystyrene foam building block - occurs. After cooling the mold with water ready product is automatically removed from it and stored by the operator.

The polystyrene foam blocks themselves for the walls are cast at the factory. Their production consists of three stages: foaming, drying and intermediate curing, block molding by secondary foaming

intermediate blocks for the wall;
wall blocks with a cap at the end, which are installed in the places of window and door openings;
wall blocks with thin walls for internal partitions or utility rooms;
corner blocks;
small plugs for unusual places;
blocks for walls with oblique angles.

The blocks are actually very Lego-like in that they have special locks on the top and bottom. In the upper part there are convex squares, and in the lower part there are depressions of exactly the same size.

As in the case with brickwork, the blocks are installed on top of each other in a checkerboard pattern, so that each block of the next row fastens two blocks of the previous row. Laying is carried out with an offset multiple of 250 mm, which ensures that the vertical voids (niches) in the blocks coincide.

Technology of building a house using permanent polystyrene foam formwork

Now let's move on directly to the description of how a house is built using permanent polystyrene foam formwork.

	As with building any home, it all starts with the foundation. The optimal type of foundation for this type of structure is a monolithic slab on a gravel-sand cushion. It is also possible to have a shallow, tape, monolithic foundation. In any case, reinforcement outlets for fastening to the walls are removed from the foundation monolith.
	The laying of polystyrene foam blocks begins on a foundation carefully leveled horizontally, directly on a layer of waterproofing made of two-layer roofing felt on mastic or waterproofing cement mixtures. Expanded polystyrene blocks are placed along the foundation, placed on the reinforcement terminals from the foundation in those places where the wall is supposed to be erected.
	The installation of blocks begins from the corners that determine the configuration of the building or structure in plan. For oblique angles Special corner blocks with a hinge are designed, but you can simply cut polystyrene foam blocks with a regular hacksaw at the desired angle. All that remains is to connect them later.
	Between all rows, in special grooves of polystyrene foam blocks, horizontal reinforcement rods are laid, which will then give the reinforced concrete wall the maximum possible strength. In addition to horizontal rods, vertical reinforcement is also laid into the wall. The connection of the rods is carried out using a knitting wire.
	After the first three rows are assembled, the geometry of the corners and the vertical of the wall are checked by a plumb line. After that, it's time to pour concrete into the cavity, resulting from the polystyrene foam blocks of the wall. It is not recommended to pour more than four rows at a time, as there is a possibility that there will be voids in the bottom layer where the concrete cannot flow.
	Concrete can be poured either using a special concrete pump with a low-pressure nozzle that delivers it to the right place, or simply with a bucket, fortunately there is more than enough time to pour several crowns before the concrete sets.
	A wall made of polystyrene foam blocks is quite airtight and has no gaps through which concrete could leak. While the concrete is liquid, it is vibrated (compacted) using the vertical bayonet method (for example, with a reinforcing rod). This is done in order to make sure that there are no air pockets left inside.
	All pipes and cable channels can be immured directly into the wall so as not to spoil the appearance in the future.
	In door and window openings special blocks with plugs at the end are used, and to form the top of the opening, a temporary formwork is installed, which allows you to lay polystyrene blocks on it and pour them with concrete.
	After the concrete has hardened, the temporary formwork is removed.
	In this way, all the walls of the first floor are assembled. Blocks after filling with concrete are monolithic reinforced concrete wall 150 mm thick, covered on both sides with insulation 50 or 100 mm thick on each side.
	Interfloor ceilings can be either wooden or concrete.
	In the case of concrete interfloor slabs, special formwork is built.
	Monolithic reinforced concrete is made on top of the formwork interfloor covering. To ensure that the ceiling is integral with the walls, a cutout is made in the inner wall of the polystyrene foam formwork of the walls along the entire perimeter, into which the reinforcement is inserted and through which cement is poured. The cut is made horizontally, in the center of the block, so that the top layer remains, which will be necessary for connection with the next row of wall blocks.
	Next, according to the scheme described above, the second floor is assembled, reinforced and poured with concrete.
	The finished walls are sheathed on the outside with siding or blockhouse.
	The inside of the walls is usually sheathed with plasterboard (gypsum board) panels.
	The walls can also be covered with plaster. The plaster is placed on a special reinforcing mesh, directly along polystyrene foam wall. Both external and internal walls can be plastered.
	Upon completion of all finishing works construction of the house is completed.

And finally, a few video reports straight from the construction site. Construction is carried out using permanent polystyrene foam formwork.

Features of wall reinforcement during construction using permanent polystyrene foam formwork:

Abundance construction technologies allows each developer to choose the best way erection of a structure that suits it in all respects. IN last years permanent formwork has been added to the traditionally popular brick, block and frame housing construction - a technology that causes a lot of controversy and has both supporters and opponents. This topic is also relevant among users of the FORUMHOUSE portal; it makes sense to consider it in more detail.

Warm form

Permanent formwork technology allows you to simultaneously build and insulate a structure, and is used for the construction of both the foundation and the frame. This is a universal method used in private and multi-storey construction. It is based on the principle of monolithic reinforced concrete structures: the reinforcement frame is poured with concrete, but the formwork is not dismantled after the mortar has set, but remains an element of the “pie”. In essence, formwork is a form that allows the reinforced concrete “filling” to take on a given geometric shape. But in the case of the fixed type, this is insulation, the use of which significantly reduces the heat loss of the building. The use of non-removable ones began, continued with rectangular walls, today radial blocks are also produced: if you want, fill in a bay window, if you want, fill in a fantasy pool.

Monolith or permanent formwork consists of hollow blocks or slabs with jumpers; additional interconnection of the rows is provided by the tongue-and-groove system.

The necessary additional elements are also produced - corner blocks, crown blocks, caps and the like. Initially, three types of raw materials were used for the production of fixed formwork.

Polystyrene - based on it, foam plastic (PSB) and expanded polystyrene (PPS) blocks and plates are made.

Polystyrene concrete - formwork made of mineral binder (cement) and granular (polystyrene) filler.

Wood cement - in the composition of blocks and slabs - up to 90% of organic filler and cement as a binder. Usually, organic matter is represented by large fraction wood chips, but some manufacturers can add other plant materials (reed, reed, straw) to the mixture. Both in blocks and in slabs for external walls inside - a layer of insulation - expanded polystyrene (half of the internal volume), blocks for internal partitions are empty.

Now on sale in stores in Moscow and all regions of our country there are also combined options, when the outer wall is made of PPS or PSB, and the inner wall is made of sheet materials type OSB or DSP. Since the thermal conductivity of such an internal layer is higher than that of EPS (PSB), the thickness of the outer layer is much greater than in solid polystyrene foam blocks. The starting thickness of the block wall is 50 mm, but such a layer inside and out is sufficient for warm climates; for cold regions, the outer layer should be from 100 mm. Other popular ways to insulate a home are described in the article

The formwork of the house is insulated.

The most environmentally friendly formwork is made from woodchip cement, since it consists of natural raw materials and a mineral binder and has good vapor permeability, but is much more expensive than pure polystyrene. The bulk of houses built using permanent formwork technology are built from polystyrene foam blocks - they are more affordable than wood chips and stronger than foam blocks. The strength and durability of the formwork will depend on the density of the blocks. Unscrupulous manufacturers pass off loose blocks as dense ones, and put the required numbers on the certificate of conformity.

In order not to be deceived, a user of our portal a991ru, who is professionally involved in construction, advises paying attention to the weight - according to him, 1 mᶟ of high-quality, dense formwork should weigh at least 15 - 16 kg.

The main advantages of an insulated monolith include not only the speed of the construction process and financial accessibility, but also the possibility self-construction even without the appropriate qualifications. Also, ideally smooth (with correct installation) surfaces that do not require a thick layer of plaster. There's enough outside decorative plaster or a hanging screen, and the inside is most often treated with plasterboard.

Opponents of the technology say the main disadvantage is the harmfulness of PPS and low vapor permeability - the walls can release aggressive chemicals into the air, and the house becomes a thermos.

kubarik FORUMHOUSE Member

We built a house for a friend using permanent formwork technology - yes, the house is warm, but absolutely breathless - in winter the windows fog up, the humidity in the house is crazy. I contacted a customer who was also built using this technology - the same problem.

The hypothetical aggressiveness of the material is on the conscience of block manufacturers - high-quality raw materials and adherence to formwork manufacturing technology minimize the possibility of releasing volatile compounds. If in doubt, the material you like can be taken to the local SES laboratory for testing. And in order to protect yourself from poison, you should carefully choose a supplier and not be fooled by too low prices, as an option - use a chip-cement or combined formwork. The correct way to avoid the thermos effect organized system ventilation that solves the problem high humidity, and if there are violations, mold can appear on both brick and block walls. Although some FORUMHOUSE members did not notice problems with humidity in the room even without additional ventilation.

Kamzhenya FORUMHOUSE Member

Regarding ventilation - in our region the climate is, you know, humid, even very - no extras. There are no ventilation in these houses. Well, there is no such problem, this is in practice.

Considering that the region of residence of the portal participant is Far East, fixed formwork is especially relevant due to its high seismic resistance: a monolithic structure is less susceptible to deformation.

Installation technology

The optimal foundation for permanent formwork is a strip foundation. If concrete blocks are used, it is advisable to pour monolithic belt 30 cm thick. In the process of pouring the foundation, vertical reinforcing pins (diameter - from 10 mm) are mounted in it, which in the future will help to combine the base and the box into a single spatial structure. As in any construction process, waterproofing is performed between the foundation and the first row. Rolled membranes or film are pinned onto pins. Welded bitumen mastics it is not recommended to use it under polystyrene foam blocks, polyethylene or roofing felt with asphalt dressing is preferable. Under certain circumstances, they do without waterproofing.

Kamfish FORUMHOUSE Member

I made the tape, released the reinforcement, but did not lay the waterproofing. But then the walls ground floor sheathed it with DSP and waterproofed it with weld-on material. The base is approximately 1.8 meters.

When assembling the first row, strict adherence to the level is mandatory. The distortion is leveled with adhesive or cement mortar. The blocks begin to be laid out from the corners, stringing them onto the reinforcement. After assembling the first row, horizontal overlapping reinforcement is installed in the grooves and tied with wire twists to the vertical one; some use plastic ties. The second row is assembled in the same way. The masonry imitates brick - the displacement of adjacent rows in order to increase the strength of the monolith. The groove system additionally fixes and seals the seams and joints; divergence of the grooves is not allowed, otherwise cold bridges will result. Depending on the type of blocks or slabs and the manufacturer’s recommendations, the segments can be additionally fastened together with wire or staples. Dmitriy Kov, who built his house using permanent formwork technology from polystyrene foam blocks, created the following reinforcement frame.

Dmitriy Kov FORUMHOUSE Member

The vertical reinforcement was placed approximately sixty centimeters apart, the horizontal reinforcement every two rows. Naturally, I reinforced all the window and door openings: there were two reinforcements on the sides, four pieces on top, and four pieces in all corners and intersections. Where the opening for the garage is - there are six pieces on top, I tied the reinforcement together as expected, with approximately an overlap. All the reinforcement in the walls is 10 mm in diameter, in the grillage - six pieces, 12 mm each. The house stands on 43 pillars made with a TISE drill with a 0.5 m extension at the bottom.

According to the project, when laying out the first rows, bends are formed for internal partitions and door groups, utility lines are laid: grooves are cut out in the blocks, the necessary ones are laid on at this stage pipes. As the blocks are installed, a reinforcement frame is formed from vertical and longitudinal rods connected to each other. The strength of the monolith and its resistance to deformation will largely depend on the diameter of the reinforcement; most often the frame is knitted from rods with a diameter of 10 - 12 mm.

For a monolith, a standard cement-sand mortar with the addition of fine gravel, mixed mechanically or manually.

Considering that from two to four rows are poured at a time (depending on the brand and type of formwork), the use of pumping equipment is justified on construction sites with large square footage, when several cubes of mortar are placed in these several rows. If the technology is violated and a larger number of rows are poured at the same time, it is possible that the blocks will bulge - “belly”, as well as the formation of voids and gaps. To compact the solution, both vibrators and the “poke method” are used - using a long reinforcement bar or a wooden handle.

Since when pouring mortar, partial filling of the grooves is possible, which will interfere with the installation of the next row, one of the portal participants, Lord Kyron, made metal U-shaped frames, equal in width to the walls of the blocks, and covered the surface while filling the section of the wall. To assemble the rows, mix the mortar, install the reinforcement frame and pour the monolith, he used the most popular “Tajik construction” among private owners as labor. And in order to minimize the possibility of defects, he carefully controlled the laying of the first row and the further process. If you notice the protruding segment in time, before the solution has set, it is quite easy to level it.

Considering that the mortar is poured into the formwork in layers, in order to avoid the formation of cold bridges, the outer row is filled not to the top, but to the middle - the seam is completely closed in the block.

And taking into account the fact that each subsequent layer is poured not after complete setting, but after a short interval, in the process of final maturation of the concrete a full-fledged, insulated monolith is formed.

The formwork itself is not load-bearing, so all floor slabs and joists are laid directly on the concrete filling, for which appropriate grooves are cut out in the polystyrene foam layer. To increase the heat capacity of the building, which will be “lame” due to the insulation, internal partitions are sometimes made from other wall materials– bricks, blocks, plasterboard structures. One of possible options– pouring the monolith into the formwork, and after the structure hardens, removing the polystyrene walls.

Finishing

Facing fixed formwork is needed to increase the decorative effect and protect the material from external influences, this also applies to most block varieties and skeletons. Given that there is no need to level the walls, they do without a thick plaster layer. A reinforcing layer of fiberglass or stainless steel mesh with an adhesive solution and subsequent application of a decorative plaster or putty is sufficient.

The margin of safety of the walls is also enough for heavier materials - tiles or stone, siding is no less popular. The siding is mounted on a subsystem that is fixed either directly into the concrete or, when the lintels in the blocks are plastic, into the lintels. Today on sale you can find a variety of decorative formwork - it already has a facing layer that imitates a stone facade. But due to the rather high cost, this option is not in high demand. Portal member AlexIll22 turned a standard building into an exclusive one with an interesting finish.