What is needed for foundation formwork. How to make formwork for the foundation: types, materials, calculation, do-it-yourself installation work

The formwork for the strip foundation is a special form designed to be filled with concrete. Its installation is carried out immediately after the completion of the trench and the site for the foundation of the building. If desired, it is easy to do it yourself.

Basic information about formwork - why is it needed, and what is it?

During the construction of various structures and houses, it is impossible to do without formwork - a constructive form-building element in which the concrete mixture solidifies. With its competent design, you can minimize the cost of erecting a strip foundation and at the same time get a truly reliable and durable underground foundation for any building, from a fence to a residential building.

The formwork is manufactured in two types. It can be removable and non-removable. Removable is most often used in suburban construction for the construction of private houses on a strip foundation. It is easy to make it with your own hands from almost any wooden blocks and boards. The construction of more complex bored columnar foundations involves the use of permanent formwork. Such a structure, as its name implies, remains forever part of the base of the building; it is not removed after the concrete has set.

Nowadays, fixed-type formwork made of expanded polystyrene is in demand (including in private construction). It, firstly, provides the required form to the concrete solution poured into the foundation, and secondly, it performs the function of a high-quality and effective heat insulator.

Nowadays, ready-made formwork is sold in construction stores. They have a number of undoubted advantages:

high strength;
absence of errors and inconsistencies of individual parts;
the ability to choose the material from which they are made (wood, expanded polystyrene, metal).

But ready-made kits cost a lot of money. Therefore, private construction usually uses formwork, which can be done with your own hands at low cost. Such an event is quite laborious. In this case, you will only need to stock up on planks (plywood), ordinary nails and wooden planks in order to build a reliable form for pouring concrete.

Formwork materials - minimum required

For a strip foundation at home, it is recommended to make the shape of interest to us for the concrete composition from plywood or boards. It is made in the form of shields fixed on a base of wooden blocks. The resulting shields are assembled into one structure by means of clamps, slopes and simple ties, and then mounted in a trench for. Here it is important to ensure that the inside of the panel structure is as even and smooth as possible.

Outwardly, the "uneven" side is brought out with all the elements for fastening individual parts of the formwork. To make a collapsible form for concrete with their own hands, they use plywood sheets of birch or an edged board (it is allowed to work with second-grade material) with a thickness of 2.4 to 3.6 cm. , clamps and so on) - from the remnants of wood materials. It is only necessary to ensure that they are firmly fixed. After using the formwork, take it out.

Subsequently, you can use this form many more times. . To make the process of dismantling it quick and convenient, it is recommended to line the formwork that you made with your own hands with plastic wrap.

How to make a simple removable structure yourself?

In practice, the construction of a foundation mold is as follows. First, cut the bars into equal-sized pieces and sharpen one of their sides. Then you need to cut plywood or boards as accurately and correctly as possible - so that they correspond to the geometric parameters of the shields. It is important to tightly fit the elements of the panel structure, trying not to leave even the slightest gaps between them. With due diligence, this stage of do-it-yourself work is quite simple.

spread the bars on a flat surface, keeping a distance of about 100 cm between them;
align them carefully along the top edge;
put plywood (boards) on the bars and fix them with self-tapping screws (fasteners can also be made with ordinary nails).

Pay attention - the hats of the hardware must be inside the self-made panel structure for the strip foundation. If you do the opposite, the points of screws or nails will not allow you to easily remove the formwork after the concrete has hardened. If you need to make a foundation that has a certain expansion in its lower part, the shields must be resting against the board (it will be the supporting one), and the bars must be cut to the width of the frame. In this case, the latter is allowed not to deepen into the ground.

We continue to do the formwork with our own hands according to the following scheme:

we stretch a string of nylon between the bars driven into the ground in order to correctly mark the site;
we dig according to the marking of the ditch of the required depth (it is advisable to fill the trench with a mixture of gravel and sand);
we put, if necessary, a support board, and then a panel structure (at this stage it is imperative to use a level and a plumb line, which will allow the panels to be placed correctly and evenly).

With low stability of the shields for the strip foundation, they can be made more reliable. It is not difficult to strengthen the structure with special struts made from cuttings on the outside and bars on the inside. The cut is the same block cut at a 45-degree angle. It is mounted by a bulge between the shield frame and the ground. In fact, you have already managed to build the simplest formwork with your own hands. It is only necessary to put a dense polyethylene film on its walls and bottom (such protection will not allow the cement mixture to evaporate and eliminate the risk of the concrete solution seeping out).

Then the installation of the bar reinforcement for the strip foundation is carried out, the filling of the made form with concrete and the leveling of its surface. There is nothing else to do. It is required to wait for the moment when the concrete mix sets. Dismantling of the formwork is performed when a small gap appears between the concrete base and the boards. For strip foundations with a minimum of effort, tap with a rubber mallet on the outside of the panel frame.

First of all, you need to dismantle the clamps, slopes and screeds. And only after that, take out all the shields that make up the structure (this must be done in turn - one part of the frame, then the second, and so on). We hope that the installation of the formwork will take place at your place, thanks to our advice, simply and quickly. And you will get a really solid foundation "for centuries".

The house starts from the foundation. Making it with your own hands is not difficult, experts say and give their advice on the step-by-step installation of formwork - a key element of the future foundation of the house. An article, as well as photos and videos, will help you understand the recommendations.

How to choose formwork

In order for the concrete support of the building to become strong and monolithic, the builders came up with formwork.

It can be temporary or permanent, made of wood or polymers, but its main tasks remain unchanged:

create and maintain the shape of the above-ground part of the concrete strip foundation;
be as smooth as possible from the inside in order to minimize subsequent finishing work on the surface of the structure;
to cope with the loads when pouring and compacting concrete mortar;
quickly assemble and disassemble;
if necessary, isolate concrete from soil and other negative factors.

In order for the installation to go smoothly, and you do not have to solve unexpected problems, before starting work, you need to make sure that there are five main conditions:

The soil on which the base is poured must be completely free of debris and various impurities.
The panels on the inside should have as flat and clean surface as possible in order to reduce finishing work.
The formwork fasteners must withstand the pressure of the concrete and not deform.
Maximum contact between the shield components is required to prevent leakage. For this, the clarity of the geometry of the edges of the structure is important.
If the shuttering boards are reused, it is necessary to clean the entire working surface from the remnants of the previous mortar.

Attention! Modern formwork is classified into two categories: removable and non-removable. In addition, it differs in the type of material used: wood, plywood, metal, expanded polystyrene, etc.

Removable formwork: time-tested installation

Mount, pour, hold and remove - this is a short recipe for installing removable formwork. Its most popular variety - wooden - is as old as the concrete foundation. It is not difficult to make such a formwork. Shields are made outside the construction pit from boards and sawn timber of the required dimensions. The boards are edged, since it will be necessary to fit them tightly to each other.

Attention! Slots up to 3 mm in timber formwork are considered the norm. As a result of preliminary wetting, the boards will swell and the distance will decrease. If the slots are larger, up to 10 mm, they must be closed with tow, and the very large ones must be filled with slats.

The structure is fastened with the help of vertical posts (most often - from a bar). It is recommended to place them at intervals of about 1 m. Bars can be placed more often if the boards are thin. It is also important that the length allows them to hold tight.

It is better to sharpen the bars at one end, then they will easily enter the ground. To fix the formwork panels at the same distance, wire twists, struts, frames, wooden ties are taken.

Advice. Instead of nails during installation, it is better to use self-tapping screws. The structure assembled on them is easier to disassemble, because it will be enough to simply unscrew them, and not unbend, as is the case with nails. It is necessary to knock down the boards so that the heads of the nails (screws) are on the inside of the formwork.

The final step in the installation of wooden formwork is to secure the panels in the trench using spacers: wooden stakes or bars. After pouring and tamping, the concrete is cured in the formwork for up to two weeks, until it hardens and gains strength. After that, the structure is dismantled. Plywood formwork is installed according to a similar principle.

Attention! It is advisable to isolate the removable formwork from concrete with special compounds against the adhesion of materials.

Fixed formwork for foundations: a new word in construction

In recent years, the removable structure has been replaced by a structure using polymer formwork, which, after pouring concrete, becomes part of the future foundation. It gives it additional properties, protecting it from water and keeping it warm. Additional properties of permanent formwork made of such a material: ease of assembly (somewhat reminiscent of a constructor or a puzzle) and, as a result, geometric harmony of parts. Certain types of polymer formwork have a reinforcing mesh that reinforces the foundation.

Of the minuses, the cost of such a foundation is higher than that of a foundation built with the help of boards. However, the game is worth the candle when it comes to what is being built for decades and for yourself. Permanent formwork can also be made of galvanized profile sheet - in the finished foundation, it will protect the concrete surface, and its waves will serve as stiffeners. In addition to such a metal structure, a removable "belt" of stakes from a bar is required.

Formwork for the foundation: video

DIY foundation: photo

From an engineering point of view, no specialist will be able to calculate the formwork absolutely precisely: too many variable objective and subjective factors affect the structure.

How to make the right formwork for the foundation

Let's name just a few of them.

The quality of the lumber. In nature, there are no two completely identical boards. The strength of sawn timber depends on malformations, the number, nature and specific location of the knots, etc.
Indicators of concrete. Concrete can have a different consistency in terms of viscosity, it depends on the proportions and characteristics of the fractions used during preparation. In addition, the loads on the formwork vary depending on the concrete pouring speed, the ramming method and the availability of reinforcement.
Climatic conditions. At subzero temperatures, the boards have some indicators of physical strength, in summer others. Dry boards can withstand higher forces, while in rainy ones their strength decreases.

Formwork boards

There are building standards that regulate the maximum deflection of the formwork. For the aboveground part of the foundation, the deflection should not exceed 1/400 of the length; for the underground part, the standard is increased to 1/250 of the length. It is difficult for non-professionals to achieve such values. What should ordinary developers do? During the creation of the formwork, you need to be guided by the advice of experienced builders and your intuition. And remember the main rule - it is better to do any formwork with an obvious margin of safety, not to rely on "maybe it will withstand". It must be remembered that it is very difficult and expensive to correct violations of the linearity of concrete.

Any formwork is best done with a clear margin of safety

First, you should know for what purpose you need formwork. If you plan to use it repeatedly, then you should use a special laminated waterproof plywood or knock down standard shields from high-quality edged boards.

Film faced plywood formwork

If the formwork is for one-time use, then low-quality materials will be used; under certain conditions, you can use pieces of chipboard, ordinary plywood or even unedged boards. As a rule, for the construction of a bath, you can choose the cheapest formwork manufacturing option.

Plywood formwork

By design features, the formwork can be:

Manufacturing of removable formwork for a strip foundation

Initial data: the formwork will be made of a removable type along the entire height of the foundation, the material of manufacture - edged boards of the second grade with a thickness of 25 mm.

Edged board II grade

There is no one universal algorithm for the manufacture of formwork, each master makes his own changes, taking into account the specific material, characteristics of the foundation and personal preferences. We will only talk about one of the many options.

Scheme of formwork panels

Step 1. Preparing the shields. Measure the length and depth of the trench. Do not make the shields large - it will be very difficult to work with them, in length they should not exceed 3-4 meters, depending on the height. Knock off the boards from edged boards; the same boards or slats can be used as vertical racks. If your slats are thin, then nail them with an edge.

Wooden formwork for strip foundations

Practical advice. Never use self-tapping screws to assemble the formwork.

Firstly, it takes a long time and you need to have a special electric tool to screw them in.
Secondly, disassembling shields with self-tapping screws is one torment. The holes for the asterisk are clogged with earth or concrete, "picking out" them from there is a very thankless and "nervous" job. And self-tapping screws are much more expensive than nails, and for formwork they will need more than one kilogram.
Thirdly, not a single formwork element works in tensile, all have a load only in bending or compression. In this case, the nails will not be pulled out of the boards, use them calmly. By the way, it is not necessary to take long nails and then bend "by the meter" from the front side of the shield.

Step 2. Formwork installation.

Lower the shields carefully into the trench. Prepare ground pegs and corner posts. In our case, props need to be done on both sides approximately every 50 ÷ 70 cm.

Drive in wedges to the desired depth

To prevent the lower part of the shields from moving during fastening, fix it with small pegs or insert spacers of the appropriate length between opposite shields. Then you do not need to take them out, let them remain in the concrete.

Step 3. Drive in the pegs in the corners of the trench and pull the rope between them. The height of the rope must be greater than the height of the above-ground part of the foundation. The fact is that you will not be able to accurately align the formwork along the horizon at a given height; you will have to align the foundation strip manually after pouring.

Step 4. Drive the pegs into the bottom of the trench under the level or plumb line, the driving depth depends on the characteristics of the soil, but in any case it should exclude their horizontal movements.

Step 5. Expose one row of shields, temporarily grab them to the vertical pegs. Place the second row and grab it too. Check all markings.

Step 6. Install horizontal spacers between the boards. These can be pieces of metal rods, wooden slats, plastic tubes, etc. The distance between the spacers is about a meter, they are not affected by the expanding force of concrete, they only serve to facilitate the installation of the formwork.

Step 7. Measure the required width of the formwork in the upper part, connect the two rows of panels together with wooden slats to size. This connection will protect the formwork from deformation during the pouring of concrete. The distance between the slats is approximately 50 centimeters. If you have an above-ground part of more than 50 centimeters, then you need to tie the boards through two with a drag to prevent swelling of the boards under the weight of concrete. The wire from the outside is fixed to the vertical crossbars, twisted with a slight tension - the walls of the basement part of the foundation will turn out to be even. During the dismantling of the formwork, the wire is simply cut off and remains in the concrete.

Step 8. In turn, put the supports of the shields, in the lower part they should rest against the pegs, in the upper part a small piece of board should be nailed to the shield for an emphasis. Check the position of the shields on the rope at all times. If you have correctly installed the internal spacers of the formwork, then it will not change its position during installation and fixation. If you see mistakes, correct them immediately. It happens that some pegs are loose in the ground - you no longer need to rely on them. Drive in new ones next to them and fix the inclined spacers to them. At the junction of the shields, you need to put a board and always a support.

Formwork

Step 9. In the upper part of the formwork, you need to insert pieces of plastic pipes for ventilation ducts and technological holes in the strip foundation. There are no pipes at hand - make ordinary wooden boxes, then they will be removed, and the holes will get better.

Step 10. Once again, check the correct position and firmness of fixing the formwork of the foundation, problem areas must be corrected immediately. The formwork must stand firmly, must not stagger even under great effort.

Formwork for strip foundations

Everything, concrete can be poured. It is recommended to remove the formwork no earlier than two weeks after pouring the concrete. If the weather is hot and dry, the concrete should be watered daily with plenty of water. The fact is that the strength of cement depends on the moisture content and drying time of the concrete. If the water evaporates quickly, then the chemical reactions will not have time to end, the reliability of the foundation tape will significantly decrease.

As for the formwork for columnar foundations, the work on its manufacture is almost the same as those described above. It is only necessary to make the size of the shields immediately according to the size of the columns. Of course, the small width and height of the posts greatly simplifies the technology of fixing the formwork in the desired position.

Formwork for columnar foundations

Monolithic slab formwork

Formwork for a monolithic slab

Foundations of reinforced monolithic slabs are made for baths built on waterlogged soils or soils with very low bearing characteristics. In most cases, the size of the bath does not exceed 4x4 meters. It is quite difficult to pour a large monolithic slab on your own; it is unlikely that you will be able to achieve its ideal horizontal performance.

Step 1. Level the surface of the ground as much as possible, fill in and compact a sand cushion with a thickness of at least 20 centimeters.

Tamping a sand cushion with a vibrating plate

Step 2. Prepare the lumber, you will need edged boards and slats. The height of the formwork depends on the thickness of the monolithic foundation, in most cases it is no more than ten centimeters. This means that it is quite enough to have boards 20 cm wide and 20 ÷ 30 mm thick.

Step 3. Drive pegs into the corners of the future monolithic slab, pull the rope. Place boards under the rope, secure them with pegs. Drive the pegs into the ground firmly. Place the formwork with the letter "P", so it will be much more convenient to feed and level the concrete, you will not have to step over the formwork every time. When concreting, do not forget about reinforcement.

Step 4. When about one meter is left to the end of the concrete slab, install the last plank, level it, fix its position and continue pouring with concrete.

Formwork for a monolithic slab

Video - Box slab foundation

Video - Layout and formwork for a monolithic slab

Video - Formwork and reinforcement strapping of a monolithic slab

Now you can consider several issues regarding the use of additional materials for the manufacture of formwork.

Polyethylene film

Instead, you can take roofing material, roofing felt, thick waxed paper or other materials. The use of these materials for upholstering formwork panels is encouraged. Why?

After dismantling the formwork, the boards are not thrown away, they can be used during further construction. Of course, except for those cases when unnecessary waste was used for the formwork, it is easier to immediately fill it with earth. Lumber from formwork can be used during the construction of sub-floors and ceilings, in these cases it is enough only to clean the surfaces of large concrete residues. If high-quality sawn timber was used for formwork, then their use is not limited only to auxiliary structures. But there is one problem - not a single self-respecting master will pass such boards through a thickness gauge - sand and dirt will instantly blunt the cutting knives.
Formwork cladding with parchment or foil

The polyethylene film perfectly protects the formwork surfaces from dirt. And not only directly in contact with concrete, but also from the opposite side. It will not be possible to knock down the shields perfectly tightly (and it is not necessary), and the liquid fraction of concrete will always seep through small cracks and stain the boards from the back side.
The presence of polyethylene greatly facilitates and accelerates the dismantling of the formwork, minimizes the risks of violating the integrity of the foundation surfaces in the event of premature dismantling.
It is much easier to dismantle the formwork with the film

The film must be installed from the inside of the formwork. Secure it with a stapler to prevent sagging or slipping.

Metal tie rods

If you have them, use them for health, if not, you should not buy specifically for the foundation of the bath. It is advisable to use metal studs on high foundations, they cannot be strengthened with side stops. The studs must be inserted into plastic tubes of the appropriate size; under the nuts, be sure to place large diameter washers and pieces of boards.

Fixed formwork

Permanent formwork is filled with concrete, photo

The new technology of pouring foundations and erecting walls is characterized by excellent operational characteristics and, unfortunately, the same high price indicators. Significantly speeds up the construction process, plays the role of not only formwork, but also insulation. It is often used for the construction of monolithic earthquake-resistant reinforced concrete buildings. Bearing walls are not only durable, but also insulated.

Construction of permanent formwork for the foundation

Construction companies produce fixed formwork from various materials and with different linear parameters. The specific type of formwork should be selected taking into account the place of its use. There are several types of permanent formwork.

Made of highly durable expanded polystyrene foam. Represents flat plates or blocks, corner turns, spacers, reinforcement clamps, etc. The thickness of the sidewalls can be from 40 to 100 mm. The process of assembling formwork blocks is carried out in tenons, all dimensions must be checked with a level. Depending on the height of the formwork, concrete is poured in several layers along the entire perimeter of the foundation or wall. After pouring the previous layer, several rows of formwork are again assembled and the next one is poured.
Fixed formwork made of expanded polystyrene foam
Permanent concrete formwork. It is made of durable concrete, the side surfaces of the blocks have spikes and grooves for a strong connection to each other. The walls are held in place by bridges. Such formwork can be used both for pouring foundations and for erecting monolithic reinforced buildings. The reinforcement does not fit, the vertical rods are inserted into the holes, and the horizontal ones rest on special stops.
Permanent formwork made of concrete
Wood concrete. It can be in the form of hollow blocks or flat panels, the front surfaces must be finished, it is used only for the above-ground part of the foundation or walls. The blocks are installed using the dry masonry method; fittings may be inside. The panels are assembled on screeds installed inside the concrete. The front surfaces of the screeds are in the form of large flat washers, the surfaces of the panels are characterized by high adhesion to all building finishing materials.
Timber-concrete fixed formwork

It is not economically feasible to use such expensive formwork on the strip foundations of the bath. Baths do not need an insulated foundation, and the basement visible part will get off with ordinary decorative materials.

Permanent formwork scheme

Possible consequences of poor-quality formwork

Let's say right away - all the consequences of an incorrectly made, installed or fixed formwork are very sad, their elimination requires a lot of effort and money. In the most serious cases, pouring the foundation will have to start from scratch. Consider three possible options for the consequences of marriage in the construction of formwork.

Option 1. The swelling of the formwork became noticeable during the pouring of the concrete. Stop work immediately and call all assistants for help. Use a shovel to push back the concrete where the formwork swells. To prevent the concrete from floating back, nail at some distance the transverse boards along the entire width inside the formwork. Keep in mind that the concrete will gradually fill the depression and work must be done quickly. Throw concrete more than 1.5 meters from the emergency location.

The pressure on the formwork has noticeably weakened - try to level it. It is very good if you can adjust the jack and use the beams to slowly level the formwork. You can stretch a wire in a place free from concrete and use it to level the bulge. It is very important: do not knock on the formwork with a sledgehammer, in this way you will make it even worse. The vibration will cause the concrete to float downward and further disrupt the straightness of the formwork. Level up the shield gradually, without excessive fanaticism. Excessive force can completely break the shield or individual fasteners. The consequences will be very sad. As soon as it was possible to align the shield, immediately fix its position. This time, check the reliability of the props with extreme care.

This is the easiest case, all the others are much more troublesome.

Option 2. The displacement of the formwork was noticed only on the second day.

What to do if the formwork has shifted

Important. Not everything that is written on the construction forums, however, think with your own head before believing the first advice of the "expert" that catches your eye. Many such "experts" advise to remove the formwork, and while the concrete has not yet gained strength, cut down the hillock with a shovel. This is not advice, but a mockery. Never remove the formwork! It is very likely that the entire foundation will crack. It may not crumble before our eyes, but give almost imperceptible cracks, which will reduce the strength of the structure to almost zero. We noticed the trouble the next day - that's it, the train left. Wait until the concrete has completely hardened, disassemble the formwork, pick up the hammer drill and work "in the sweat of your brow."

Option 3. The formwork or part of it fell during the pouring of the concrete. The most unpleasant situation. What to do? Scratch your smart head "silently and with a smile", remove the concrete, clear the site and start all over again.

Has the shield fallen? Start over again

We hope that from the second time you will understand how the formwork is correctly installed. And to prevent this from happening - read the article carefully again. It is possible and necessary to make your own improvements, but only if you have experience in the construction of at least three different formwork.

Video - Possible consequences of poor-quality formwork. The gap

Conclusion

Many articles on the Internet begin with the words "the foundation has a great influence on the strength of the building." This is true. But then you can read that “everyone can do it”, that “there is nothing complicated here,” etc. This is not true. Don't waste time reading these tips. Consider why the earnings of professional experienced builders are several times higher than the earnings of engineers? Because a professional builder has not only theoretical knowledge, he has tried all the "scientific" recommendations with his own hands.

When starting the manufacture of formwork, you need to adhere to two rules.

First, you need to know the job. Do not think that everything is very simple, you can "somehow blind" and it "will somehow stand".
Second. There is no need to be afraid of any work, but it must be respected. You should always have a vision of operations several steps ahead in your head, you should be able to choose the most optimal from several possible options.

Video - Reinforcement and formwork of a shallow strip foundation

Video - Installation of formwork braces

How to choose formwork

In order for the concrete support of the building to become strong and monolithic, the builders came up with formwork.

It can be temporary or permanent, made of wood or polymers, but its main tasks remain unchanged:

create and maintain the shape of the above-ground part of the concrete strip foundation;
be as smooth as possible from the inside in order to minimize subsequent finishing work on the surface of the structure;
to cope with the loads when pouring and compacting concrete mortar;
quickly assemble and disassemble;
if necessary, isolate concrete from soil and other negative factors.

Construction of wooden formwork

In order for the installation to go smoothly, and you do not have to solve unexpected problems, before starting work, you need to make sure that there are five main conditions:

The soil on which the base is poured must be completely free of debris and various impurities.
The panels on the inside should have as flat and clean surface as possible in order to reduce finishing work.
The formwork fasteners must withstand the pressure of the concrete and not deform.
Maximum contact between the shield components is required to prevent leakage. For this, the clarity of the geometry of the edges of the structure is important.
If the shuttering boards are reused, it is necessary to clean the entire working surface from the remnants of the previous mortar.

Attention! Modern formwork is classified into two categories: removable and non-removable. In addition, it differs in the type of material used: wood, plywood, metal, expanded polystyrene, etc.

Removable formwork: time-tested installation

Pouring solution

It is better to sharpen the bars at one end, then they will easily enter the ground. To fix the formwork panels at the same distance, wire twists, struts, frames, wooden ties are taken.

Advice. Instead of nails during installation, it is better to use self-tapping screws. The structure assembled on them is easier to disassemble, because it will be enough to simply unscrew them, and not unbend, as is the case with nails. It is necessary to knock down the boards so that the heads of the nails (screws) are on the inside of the formwork.

Attention! It is advisable to isolate the removable formwork from concrete with special compounds against the adhesion of materials.

Fixed formwork for foundations: a new word in construction

Fixed formwork

Formwork for the foundation: video

DIY foundation: photo

Formwork is a structure of shields, spacers and stops, which serves to shape concrete and reinforced concrete products. If we talk about construction, then this system is necessary when pouring any type of foundation, but the largest structures are needed when installing a strip monolithic foundation. Formwork is also used when creating reinforcing belts in the masonry of walls from building blocks. In the same buildings, a reinforced belt is often needed at the top to create a solid foundation for fastening the roofing system. It is also formed using formwork. This design will also be needed when pouring concrete paths or concreting a blind area, for some other types of work.

Removable and non-removable

According to the principle of use, the formwork is removable (collapsible) and non-removable. As the name implies, the removable one is disassembled after the concrete gains strength above the critical one (about 50%). Therefore, it can be used several times. Depending on the material, one and the same set can withstand from 3 to 8 fillings, industrial versions can be used several dozen, and some hundreds of times.

Removable formwork is dismantled after the concrete has reached 50% strength

Permanent formwork becomes an inseparable part of the foundation. Such systems began to be used relatively recently. They are made mainly from extruded polystyrene foam. Blocks of different configurations are produced, which are interconnected with locks and metal pins. From blocks, as from a constructor, the required form is typed.

Fixed formwork becomes part of the foundation - it is also a heat insulator

Fixed formwork made of expanded polystyrene not only gives shape, but also at the same time is heat and hydro insulation, also has soundproofing properties. It costs a lot, but it immediately solves many problems, and the time spent on the foundation is significantly reduced.

There is another type of permanent formwork - hollow concrete blocks. They also have different configurations - wall, corner, radius, etc. They consist of two or three walls and several bridges that hold the walls in a certain position. They are connected to each other with locks, reinforced with rods.

Formwork requirements

Since this entire system is created in order to shape concrete and reinforced concrete products, it must be strong and resilient enough to withstand the pressure of a mass of liquid concrete. Therefore, quite serious requirements are imposed on the materials for the formwork in terms of strength. In addition, the assembled panels should have a smooth and even inner surface: it forms the walls of the foundation, and then hydro- and / or heat-insulating materials are fixed on them. It is easier to attach them to even (at least relatively) surfaces.

Removable materials

In construction organizations, there are metal structures assembled on pins and bolts. In private construction, formwork panels are made from boards, moisture-resistant plywood and OSB. Wooden blocks are used as stops and spacers. No one bothers to make a metal structure, but it is very expensive and unprofitable for one-time use.

When building a cottage or a country house, boards from boards are most often used. You can use any species, both coniferous and deciduous. It is better to take an edged one: the solution should not ooze through the formwork, and it is unrealistic to achieve this with an unedged board.

What does the formwork for a strip foundation look like in a section?

With a foundation height of up to 1.5 meters, the formwork board must have a thickness of at least 40 mm. Shields are fastened using bars with a section of 60 * 40 mm or 80 * 40 mm. If the height of the foundation is large - it is deep - such bars will not be enough to hold the mass of concrete. At a height of more than a meter, you need to use a bar of 50 * 100 mm or more. For assembly, use nails or screws. Their length is 3/4 of the total thickness of the board and bar (for the above dimensions 60-70 mm).

Formwork is also made of plywood. There is even a special formwork laminated with synthetic paper. The coating has increased resistance to aggressive environments, which is liquid concrete. This material is marked with FSF (using formaldehyde glue).

The thickness of plywood for formwork is 18-21 mm. Shields are assembled on a metal or wooden frame. The wooden frame is made from a bar of 40 * 40 mm, you need to use a shorter fastener - 50-55 mm. When using plywood, it will be easier to work with self-tapping screws: nails are hard to hammer.

Construction of formwork panels made of plywood and OSB

OSB is rarely used for this purpose, but this option also takes place. The thickness is about the same: 18-21 mm. Structurally, it is no different from plywood boards.

Select the dimensions of the sheets of these sheet materials based on the dimensions of the required formwork panels - so that there is as little waste as possible. A special surface quality is not required, therefore you can take low-grade materials, which are usually called "building".

From what to make the formwork for the foundation, decide for yourself: it depends on the prices of these materials in your region. The usual approach is economic: what is cheaper is used.

Diy formwork for strip foundation

The most voluminous is the formwork for the strip foundation. It follows the contours of the house and all load-bearing walls on both sides of the tape. When building a more or less large building with a large number of partitions, the consumption of materials for the foundation formwork will be very significant. Especially with deep foundation.

The design of the panels and their connection

When assembling the formwork with your own hands, it is important to make the shields strong: they will need to hold the mass of concrete until hardening occurs.

The dimensions of the formwork panels vary and depend on the geometry of the foundation. The height is slightly higher than the height of the foundation, you determine the length of each shield yourself, but usually it is from 1.2 to 3 m.It is inconvenient to work with very long structures, so the optimal length is about 2 m.The total length of the entire formwork should be such that they became exactly according to the marking of the foundation (do not forget to take into account the thickness of the shield).

How can the formwork for the strip foundation be installed: in the trench dug by the dimensions of the tape and in the pit in the braces

When making formwork from boards, cut several pieces of the same length, fasten them with bars and nails or self-tapping screws. When using nails, they are hammered from the inside of the shield, bent over on a bar. It is easier to work with self-tapping screws: they do not need to be bent, since due to the thread they provide a snug fit of the elements. They are twisted from the inside of the shield (the one that will face the foundation wall).

The first and last bar are fixed from the edge at a distance of 15-20 cm. Between them, at a distance of 80-100 cm, additional ones are placed. To install the formwork panels it was convenient, two or three bars (at the edges and in the middle) are made 20-30 cm longer. They are sharpened and driven into the ground during installation.

Approximate dimensions of edged board formwork panels

Plywood or OSB boards are assembled on a bar frame. When assembling, it is important to reinforce the corners well. In this design, they are the weakest point. You can strengthen them with metal corners.

Do-it-yourself formwork installation

If the shields were made with several elongated bars, they must be placed along the cords of the stretched markings. The difficulty lies in the fact that at the same time it is necessary to exhibit in a vertical plane. For fixing, you can use bars hammered along the mark and set vertically. When installing, the plane of the shields should be set close to these bars. They will be both support and guides.

Shields with elongated cross bars are easier to install

Since the bottom of the trench or foundation pit must be flat (it is compacted and leveled under the level), it should be easy to place the shields horizontally. Try not to hammer them too much: it will be easier to align later. Lower one of the corners to the level of the bedding. There should not be a gap, the solution should not flow out. Having achieved a snug fit, take a building level, apply it along the shield and hammer in the second edge with a hammer until the upper edge is set horizontally. You are already exposing the next shield relative to the established one: they must be on the same level and in the same plane.

If the shields are made without long bars, a bar is fixed at the bottom of the pit, along the line marking the tape, which will serve as an emphasis. The shields are placed close to it, then they are fixed with the help of bevels and spacers.

Strengthening - braces and stops

In order for the formwork not to fall apart under the mass of concrete, it must be fixed from the outside and from the inside.

Braces are installed outside. The supports should be at least every meter. Particular attention should be paid to the corners: here they put stops on both sides. If the height of the backboard is more than 2 meters, then one stop belt is not enough. In this case, at least two tiers of spacers are made: an upper and a lower one.

Outside the formwork, stops and braces are placed. At high altitudes, they are made in several tiers. Pay attention to the thickness of the support bar

It is also necessary to stabilize the distance between two opposite shields. To do this, use studs made of reinforcement with a diameter of 8-12 mm, metal gaskets and nuts of the corresponding diameter. Hairpins are installed in two tiers: above and below, at a distance of 15-20 cm from the edge.

The length of the pins is about 10-15 cm larger than the width of the tape. There are two options:

Threads are cut at both ends of the reinforcement. Then for each stud you will need two metal sealing plates and nuts.
On one side, the hairpin is bent and flattened, a thread is cut with an arc. In this case, one nut is needed (there are still two plates).

The inner distance between the panels, equal to the design width of the tape, is fixed using pieces of plastic pipes. Their inner clearance should be slightly larger than the thickness of the studs.

How to make spacer pins in the formwork

The assembly takes place as follows:

Holes are drilled in both shields with a long drill.
A piece of pipe is installed between them.
A hairpin is threaded.
Metal plates are installed (they will not allow the hairpin to break the shield material).
The nuts are tightened and tightened.

You need to work together, or better - three. One installs tubes inside between the shields, and one person for installing studs and tightening nuts.

When removing the formwork, first unscrew the nuts and remove the pins, then dismantle the slopes and stops. The released shields are removed. They can be used further.

How to spend less

It takes a lot of material to make the formwork for the strip foundation: the shields form the entire strip on both sides. At great depths, the consumption is very high. Let's say right away: there is an opportunity to save money. To make only a part of the formwork and fill not all in one day, but in parts. Despite the popular belief, this will hardly affect the strength of the foundation (if you know the secrets), and you can save a lot. You can divide the foundation either horizontally or vertically.

Fill with layers

When the depth is large, it is more profitable to fill in parts horizontally (in layers). For example, the required depth is 1.4 m. You can split the fill into two or three stages. At two stages, it will be necessary to make boards with a height of 0.8-0.85 m, at three - 50-55 cm.

If the foundation has a great depth, it can be poured in two or three parts, dividing vertically into approximately equal shares

The order of work is as follows:

The formwork is exposed from the made short panels, the reinforcement is knitted for the entire required volume.
Concrete is poured along the height of the made formwork.
7-8 hours after pouring, it will be necessary to remove the top layer from the entire surface of the tape with a trowel. When the concrete vibrates, the cement milk rises. As it freezes, it becomes brittle and brittle. It is this layer that will need to be removed. As a result, the surface will turn out to be uneven and rough, and this will improve adhesion (adhesion) to the next layer of concrete.
At a temperature of + 20 ° C, after three days, the formwork can be removed, the panels can be cleaned and fixed higher. Removing the shields, take out the studs. The tubes can be left in the concrete. They have already become part of the monolith. Sometimes they are taken out and the holes are filled with mortar.
Expose the formwork higher and fill it again.
The shield is simply installed on the already "set" concrete, and rests against the edges of the trench, but at a different level

When installing the second (and third, if necessary) tier, the shields are slightly located on the already filled area, covering the tape from the sides. In this case, the lower row of pins usually serves as a stop and an emphasis. Therefore, when installing them, put them all at the same level from the lower edge of the shields.

The armature is already tied, the inner studs are cut. It remains only to put other tubes back into place the pins and put the outer stops and braces. It takes less time to install the next layer of formwork.

Why does this method not affect the strength of the foundation? Because the strength of concrete is not taken into account when calculating the strength of concrete. She goes to the "reserve". In addition, the load in strip foundations is distributed along the long side. And we have no gaps in length. So the foundation will last for a long time.

Vertical division

The second way is to break the plan vertically. The foundation can be divided into two or three parts. Only you need to divide not exactly "along the line", but to spread the joints to some distance.

In the part of the building chosen for installation, install the formwork with "plugs" in those places where the part to be installed ends. Knit a reinforcing cage inside the installed part. In this case, the bars of the longitudinal reinforcement must extend beyond the formwork by at least 50 diameters of the reinforcement used. For example, a 12 mm bar is used. Then the minimum release outside the formwork will be 12 mm * 50 = 600 mm. The next rod is tied to this release, and one by one they will go on these 60 cm.

One important detail: breaking the plan of the house in parts, do so that the "pieces" poured during this period end at different levels (see the picture).

The second way is to divide the plan into several sections (in the figure they are marked with different colors)

Fill the assembled area with concrete. As in the previous method, after 7 * 8 hours it will be necessary to beat off the solution, but already on vertical surfaces. Take a hammer and, having removed the cover-sidewall, beat the cement-sand mortar to gravel (there will most likely be a layer of mortar without filler near the formwork). As a result, the surface will be chipped, which is good for adhesion to the next portion of the mortar.

These methods can be safely used in private construction: they are practiced in the construction of monolithic multi-storey buildings, and there the workloads on concrete walls and foundations are incomparably greater.

There is one more trick. Everyone says that boards or plywood can then be used in auxiliary work. In practice, it turns out differently: it is impossible to saw wood or plywood soaked in cement. In addition, it becomes dirty and rough, and it is also unrealistic to clean and polish it: no grain "takes". So, in order for the wood (and plywood, if unlaminated) to remain usable, the front part of the shields is covered with a dense film. It is secured with a construction stapler and staples. If it gets damaged, it takes very little time to replace it. The formwork improved in this way gives an almost perfectly flat foundation surface, which facilitates subsequent work on hydro and thermal insulation.

One of the most important stages in the construction of any building with your own hands is the arrangement of the foundation. It is a concrete base that accepts the load from the weight of the constructed object. The service life of the entire building depends on the durability of this product, therefore it is important to observe the correct technology in its manufacture.

A tape-type foundation has good performance characteristics, which is equipped around the perimeter of the building being erected from heavy building materials, such as brick and monolith. The required geometric shape of the strip foundation, which serves as a support for the load-bearing walls, is given with the help of formwork, into which the concrete mixture is poured.

The strip foundation is ripe - the formwork can be removed

Purpose of formwork for the foundation

The foundation formwork is a box-type structure consisting of shield rails and fastenings in the form of longitudinal and transverse struts and corner stops. Its main purpose is to give the concrete base the form provided for by the construction project.

Formwork is necessary in order to build a foundation of any type, but it reaches the largest dimensions when arranging tape bases. The structure must have sufficient elasticity and strength to withstand the pressure of the concrete solution poured into it. For this reason, the building materials for its assembly are selected taking into account the indicated characteristics.

Regardless of what type of formwork we use, the base for the house should be reinforced. Read in a separate article "What reinforcement is needed for arranging the strip foundation of the house: types, brand and diameter."

Choosing the type of formwork: removable or non-removable?

The huge variety of formwork types that exist today can be divided into two large groups: removable and non-removable types. Removable formwork can be used multiple times, non-removable - once. The choice is made depending on the operational requirements.

Fixed formwork has its advantages, but foundation waterproofing will not work

Building structures erected using fixed foam formwork have excellent sound absorption and heat conservation characteristics. They are caused by polystyrene foam blocks remaining on the outer surface after the concrete mixture poured into the cavity of the blocks has hardened. This technology can be used both in the construction of private houses and in the construction of buildings up to nine storeys high.

The fixed option is not used for buildings with a basement, since in this case it is impossible to perform a full waterproofing of the foundation. Read about how to make a formwork for a non-removable foundation in a special article.

The elements of the removable formwork, after the concrete mixture poured into it has hardened, are dismantled and can be reused. In this case, the surfaces of the foundation become available for waterproofing. Wood formwork, used in the arrangement of the foundations of small houses, has a limited number of applications, but its cost is also low. Metal formwork, which is most commonly used in industrial production, has a much longer service life.

Materials for removable formwork

The most expensive formwork material is sheets made of metal with a thickness of one to two millimeters. They are easy to bend at any angle, creating a structure of the most complex geometric shape. To increase its rigidity, reinforcing bars can be welded to metal sheets. The disadvantages of such formwork are its heavy weight and significant cost.

Beams, edged boards, plywood or OSB are common materials for creating formwork

The most popular formwork material is wood in the form of boards, plywood or OSB boards. The advantages of wooden structures include ease of installation without the use of special tools and their affordable cost. The disadvantages include the need to perform work on reinforcement with stops and struts. Formwork from boards and plywood sheets is often used in the construction of private houses.

At the same time, OSB formwork is distinguished by its durability due to the good moisture resistance of the material.

What else can a concrete fence be made of? Instead of OSB, it is, of course, possible to use ordinary chipboard, but it swells from moisture and will serve only once. Do-it-yourself formwork for a house can also be built from available tools at hand, such as old doors, sheets of slate and other materials that can really be connected without gaps in their side surfaces. The only advantage of this solution is its low cost.

There are much more negative sides. These include:

increased complexity of installation work;
the possibility of a leakage of concrete mix;
low characteristics of the bearing capacity of the structure;
the need to equip additional fasteners.

This kind of structure can only be used in the construction of small buildings. In capital construction, formwork made of such materials is not used.

We mount the formwork for the strip foundation with our own hands

Do-it-yourself installation of removable formwork for a strip foundation involves a large amount of work. The tape of the concrete base is located along the perimeter of the constructed building, repeating the contours of its load-bearing walls on both sides.

If the structure is large enough, the financial costs of arranging the foundation will be very significant, especially if it is significantly buried in the ground. For the manufacture of removable formwork in private housing construction, boards, plywood and OSB boards are most often used. You do not need to use special tools to work with these materials.

Assembly and connection of shields

When performing installation work on your own, it is important to make shield fences with good strength, they must withstand the pressure of the concrete mass. Several edged boards of the same length are fastened with threaded fasteners or nails. The optimal length of the assembled board is about two meters, with a longer length, it is difficult to work with the boards.

Edged boards are ready for formwork installation

When assembling the formwork, the bars into which the nails are driven are located at a distance of fifteen to twenty centimeters from the edges of the shield and every meter of its length. In the middle and at the edges, vertically longer and sharpened slats are packed vertically in order to bury them in the soil during installation.

Panel construction based on plywood or OSB

Plywood and OSB panels are mounted on a prefabricated timber frame. The illustration shows the construction of a panel made of plywood. In this case, it is convenient to use sheets with dimensions of 1525x1525 mm, which are sawn in half. The finished shields are connected to each other using bolts and nuts through the holes in the side bars.

Installation of formwork in the pit

Before installing the formwork in the pit, the site is marked with the help of pegs and a rope stretched between them. The bottom of the pit is covered with compacted sand. The work is done as follows:

vertically positioned pegs indicate the perimeter of the formwork installation;
shield fences are aligned along them, the distance between them must correspond to the width of the foundation strip;
through each meter of length, panel boards are supported from the outside by inclined stops;
the joints of the shields, if necessary, are additionally reinforced with wooden bars;
pipes are installed in the upper part of the fence to create technological holes in the foundation;
all parts of the structure are carefully strengthened, they should not stagger even when significant efforts are applied.

The higher the foundation and the formwork, the more fasteners will be required

The easiest way is to install shield fences with rails, which are vertically sharpened from below, located on them. They sink into the ground, and the shields are leveled using a building level.

Fixing shields

The formwork must withstand the pressure of the concrete mass poured into it, therefore, the structural elements are strengthened with supports every meter of its length. The braces in the corners look in two directions, so they need to be given special attention and work carefully at this stage. If the height of the backboard fence exceeds two meters, the props are installed in two tiers, with a significant height of the backboards, the reinforcement is performed in several rows.

Formwork reinforcement options depending on the height of the foundation

The internal distance between the opposing structural elements, equal to the width of the foundation strip, is stabilized by means of studs made from a rod and pieces of plastic pipes. Spacer rods, which are threaded rods at the ends, are installed in the formwork as follows:

a piece of plastic pipe is placed between the opposing formwork panels;
a hairpin is threaded into it through the drilled holes;
on the inside, metal washers are installed to protect the formwork from damage;
from the outside, nuts are screwed onto the thread.

Spacer sleeves and sleeves of holes for communications

When dismantling the formwork, first of all, the nuts are unscrewed, then the studs are pulled out and the stops and braces are removed. Shield boards can be reused. It is difficult to disassemble the formwork if self-tapping screws were used to fasten its elements. Their heads are clogged with dirt and it is very difficult to unscrew them.

As soon as the structure is ready, concrete can be poured into it. Read about "How to knead concrete for a foundation with your own hands: the composition and proportions of the mixture" in a special article.

Features of arrangement of round formwork

In the case of a rounded building facade, the question arises of how to make a round formwork for its base. The easiest way is to put a formwork for a round-shaped foundation made of factory-made metal elements. However, this possibility is not always present.

It is convenient to install a round formwork with your own hands from a metal profiled sheet. Such material easily takes the desired shape in one direction and withstands well the load of the mass of concrete when pouring the foundation.

After the concrete has hardened and the profiled sheet is dismantled, a surface of the corresponding shape will be obtained. It can be treated with coating waterproofing, but roll-up will not work.

Most often, round-shaped removable formwork is made using bending sheets of plywood or metal. In this case, it is important to correctly mark the round part of the foundation. To do this, a metal pin is hammered into the center of the corresponding circle and twine is tied to it. Two knots are tied on the twine in accordance with the outer and inner radii of the future formwork. Now you can set any point on a round section of the foundation and drive a support bar with a cross section of at least 50x50 mm into the ground.

Support beams are installed on the inside and outside of the circular formwork, taking into account the thickness of the plywood. The distance between them along the perimeter is the smaller, the smaller the bending radius and the lower the strength of the sheet material, but not less than 50 cm. On the inside of the formwork, plywood sheets bent in place are attached to the supports with self-tapping screws.

It is better not to use nails, as they are difficult to hammer through the plywood into loose support bars.

The reinforcement of the formwork is carried out using stops and braces, as described above. Examples of a circular design are shown in the photo. In order to equip the foundation for round walls, it is possible to use a large number of small-sized fencing elements. In this case, the inner shields are made shorter than the outer ones. It is convenient to determine their size by performing a sketch of the formwork on a scale. The construction of panels is stronger than that of bent plywood, and is preferable for arranging a large foundation.

The required amount of material for arranging the formwork with your own hands is determined as follows. The length and height of the concrete base known from the design documentation must be divided accordingly by the length and width of the boards to be used. By multiplying the numbers obtained, their number is determined, which is necessary for the construction of a particular formwork. In addition to the planks, you need to purchase wooden beams and spacers. Their cost can be up to half the cost of purchasing boards. It is necessary to take into account the additional spending on studs and fasteners.

Useful properties of plastic wrap

It is not possible to make a shield fence without slot gaps at all, and the concrete mixture seeps out, dirtying the formwork elements. Polyethylene film or roofing felt, fixed on the inner side of the formwork, perfectly protect the surface of the boards from contamination with the concrete mixture, not only from the inside, but also from the outside of the structure.

The use of polyethylene film or roofing material preserves the formwork and simplifies its dismantling

The use of these protective materials greatly facilitates and speeds up the dismantling work. If it is necessary to remove the formwork panels prematurely, the concrete surface of the foundation is not damaged. Wood panels are not exposed to moisture and can be reused.

Also, the surface of concrete is covered with plastic wrap or roofing felt if it is necessary to take a short break from work or upon completion of casting. They prevent the formation of a hard crust on the surface of the material and retain the moisture necessary for the curing of concrete.

We rearrange the shields and fill the foundation in parts

Pouring the foundation in parts provides for a vertical or horizontal arrangement of butt joints. With their vertical arrangement, the concrete base is separated by partitions. After the concrete mixture has hardened in the first section, the partition is removed and rearranged to the length of the next section. Thus, the entire perimeter of the base is filled.

Pouring the foundation piece by piece with vertical division

With a horizontal arrangement of butt joints, partitions are not installed. Most often, this method is used when arranging tape-type foundations. The concrete strip is divided in height into several parts and sequentially poured with layers of concrete mixture until it reaches the ground level. Docking seams cannot be placed on the reinforcement belts, they must be above or below their level.

Foundation pouring scheme in parts with horizontal division

Pouring the foundation in parts can be carried out after waiting for the complete curing of the fragment of the concrete base, only then proceeding to the manufacture of the next one or taking short-term breaks in work. In the latter case, in order to prevent the concrete from seizing, its surface is covered with plastic wrap or roofing felt. Having removed the shelter, you can continue the process of pouring the foundation.

The method of constructing the foundation in parts allows you to rearrange removable formwork panels from an already finished site to the next. This saves material and time in fencing.

Regardless of the type of foundation and formwork material, someone else's certain experience is useful for its arrangement. Let the video resolve all your remaining questions.

The main requirement for the formwork for the strip foundation is that it must be rigid and strong so that the shape of the zero level is ideal. That is why the deviations of the formwork geometry cannot be more than 2 mm and there can be no more than 2 mm gaps in the joints between the boards and panels - all this can be easily controlled with a two-meter rail. So, the device of the formwork for the foundation and its types - this article will tell about all the subtleties and nuances.

Traditional simple technology

For the strip foundation, the installation of the formwork is as follows: guide boards are placed and fixed with pegs, which are driven into the ground. Then, on one side of the foundation, shields are placed - so that their plane completely coincides with the edge of the board.

Shields are fastened with braces, in a strictly vertical position. And then shields are placed on the other side of the foundation, and here it is extremely important to observe its internal dimensions.

Further, the shields are fastened with spacers and additional clamps every half a meter, which will not allow the formwork to open when pouring concrete. Outside, they can be fixed with the same struts, struts or pegs. All this is a removable formwork for the foundation.

The formwork for the strip foundation is traditionally built from boards and boards of deciduous and coniferous species, the humidity of which does not exceed 22%. That is, it is the same moisture resistant plywood, chipboard and fiberboard. And in order for the temperature and humidity regime to be optimal, the entire inner surface of the formwork is often lined with plastic wrap - it is easy to attach it to the boards with an ordinary furniture stapler. So the solution will not leave through the cracks, and the whole mixture will solidify quickly and efficiently.

The most affordable formwork option - and more than once

How to make a formwork for a foundation from scrap materials? Easily! It can even be made of plywood - cheap and cheerful. You need to fasten its sheets together with self-tapping screws and steel corners. But the joints should be covered with strips of thinner plywood, on self-tapping screws. Holes for screeds in it need to be done horizontally with a pitch of 550 mm, 50 mm vertically and 250 mm from the top.

Supports here only need to be placed in places - to align the formwork vertically. But for the longest sections of the foundation, in order to achieve straightness at the very top of the plywood, a rectangular steel pipe 25x60 mm is screwed with an edge.

Today, plastic formwork for the foundation is also popular - and it is not expensive.

Fixed formwork option

Permanent formwork is much easier to install than traditional formwork - everyone who could see it. But, in addition to this advantage, such a formwork also has a number of indisputable advantages - and the most important of them is that the fixed formwork itself also creates a heat-insulating layer for the foundation. And yes, you don't need to take it off later.

So what is a permanent foundation formwork? These are slabs or blocks made of expanded polystyrene. They are distinguished by increased density, and are fastened to each other with special jumpers, while the perimeter part has locking grooves. The weight of one such element reaches only one and a half kilograms. And the concrete mixture will not leak anywhere during the pouring process - the tightness of such joints is high.

No supporting elements are needed here - this is another rather significant plus. In addition, such formwork makes it easy to ensure the correctness of the geometric shapes of any foundation - even a complex structure with steps. But from the inside of the formwork slabs, special grooves are placed - it is they who help the concrete mixture to effectively adhere to the wall surfaces. In total, such a protective structure consists of three layers - and it is installed in one production cycle. The base materials are well protected, heat-insulated and cannot be destroyed either by external atmospheric phenomena or by water. This is both waterproofing and protection against fungus - after all, such blocks perfectly cope with any destructive organisms, due to which there can be no rot or mold on such a foundation. And such a foundation has been serving for more than 80 years - and this is not the limit.

As a result, the entire production of the tape turns out to be extremely simple - concrete is poured between the formwork plates and, if necessary, reinforced in advance. And after the concrete mixture hardens, the formwork for the foundation made of expanded polystyrene is no longer removed - they will protect the foundation from heat loss for many decades to come. And most importantly, even the most remote person from construction can easily build such a foundation - everything is so simple that it reminds many of an ordinary children's designer.

The only thing that needs to be done is to create a good drainage system in the bath. And without any problems, a ventilation system is created inside such a foundation, and pipelines and electrical wiring are laid.

As a result, the foundation for the bath is warm, protected and economical - special studies have shown that polystyrene foam formwork speeds up construction work by one and a half times, its labor intensity is reduced by 40%, and 25% is less than the estimated cost of building a zero level. For a beloved bath, this option is ideal.

How to choose formwork

In order for the concrete support of the building to become strong and monolithic, the builders came up with formwork.

It can be temporary or permanent, made of wood or polymers, but its main tasks remain unchanged:

create and maintain the shape of the above-ground part of the concrete strip foundation;
be as smooth as possible from the inside in order to minimize subsequent finishing work on the surface of the structure;
to cope with the loads when pouring and compacting concrete mortar;
quickly assemble and disassemble;
if necessary, isolate concrete from soil and other negative factors.

In order for the installation to go smoothly, and you do not have to solve unexpected problems, before starting work, you need to make sure that there are five main conditions:

The soil on which the base is poured must be completely free of debris and various impurities.
The panels on the inside should have as flat and clean surface as possible in order to reduce finishing work.
The formwork fasteners must withstand the pressure of the concrete and not deform.
Maximum contact between the shield components is required to prevent leakage. For this, the clarity of the geometry of the edges of the structure is important.
If the shuttering boards are reused, it is necessary to clean the entire working surface from the remnants of the previous mortar.

Attention! Modern formwork is classified into two categories: removable and non-removable. In addition, it differs in the type of material used: wood, plywood, metal, expanded polystyrene, etc.

Removable formwork: time-tested installation

It is better to sharpen the bars at one end, then they will easily enter the ground. To fix the formwork panels at the same distance, wire twists, struts, frames, wooden ties are taken.

Advice. Instead of nails during installation, it is better to use self-tapping screws. The structure assembled on them is easier to disassemble, because it will be enough to simply unscrew them, and not unbend, as is the case with nails. It is necessary to knock down the boards so that the heads of the nails (screws) are on the inside of the formwork.

Attention! It is advisable to isolate the removable formwork from concrete with special compounds against the adhesion of materials.