We make formwork with our own hands under the strip foundation. Do-it-yourself foundation: simple solutions for mounting formwork. Useful properties of polyethylene film

Absolutely exactly from an engineering point of view, no specialist can calculate the formwork: too many variable objective and subjective factors affect the design.

How to make formwork for the foundation

We will name just a few of them.

1. lumber quality. In nature, there are no two completely identical boards. The strength of lumber depends on malformations, quantity, nature and specific location of knots, etc.
2. 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 the preparation. In addition, the loads on the formwork vary depending on the speed of pouring concrete, the method of tamping and the presence of reinforcement.
3. Climatic conditions. At sub-zero temperatures, boards have one physical strength indicators, others in summer. Dry boards can withstand higher forces, while in rainy weather their strength decreases.

Formwork boards

There are building standards that regulate the maximum deflection of the formwork. For the above-ground part of the foundation, the deflection should not exceed 1/400 of the length; for the underground part, the standard has been increased to 1/250 of the length. It is difficult for non-professionals to achieve such values. What should ordinary developers do? When creating 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 a clear margin of safety, do not 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 purposes you need formwork. If it is planned to be used repeatedly, then you should use a special laminated waterproof plywood or knock down standard boards from high-quality edged boards.

Laminated plywood formwork

If the formwork is 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 option.

Plywood formwork

plywood formwork

According to the design features, the formwork can be:

Production of removable formwork for strip foundation

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

Edged board II grade

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

Scheme of formwork panels

Step 1. Prepare shields. Measure the trench in length and depth. Do not make shields large - it will be very difficult to work with them, they should not exceed 3-4 meters in length, depending on the height. Hammer shields from edged boards; you can use the same boards or slats 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 formwork.

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

Step 2. Formwork installation.

Carefully lower the shields into the trench. Prepare pegs for driving into the ground and corner supports. In our case, supports must be made on both sides approximately every 50–70 cm.

We 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 don’t need to take them out, let them remain in concrete.

Step 3 Drive in the pegs at 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 set the formwork along the horizon at a given height, you will have to manually align the foundation tape after pouring.

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

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

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

Step 7 Measure the desired width of the formwork in the upper part, connect the two rows of panels to each other with wooden slats in size. This connection will protect the formwork from deformation during concrete pouring. The distance between the rails is approximately 50 centimeters. If you have an above-ground part of more than 50 centimeters, then you need to tie the boards in two with a wire to prevent the shields from swelling under the weight of concrete. The wire from the outer sides 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 Place the supports of the shields in turn, 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 support. Constantly check the position of the shields on the rope. If you have correctly installed the internal formwork braces, then it will not change its position during installation and fixing. If you see errors, correct them immediately. It happens that some pegs stagger in the ground - you no longer need to rely on them. Drive in new ones nearby and fix inclined struts to them. At the junction of the shields, you need to put a board and be sure to support.

formwork

Step 9 In the upper part of the formwork, you need to insert pieces of plastic pipes for ventilation products 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 strength of fixation of the foundation formwork, problem areas should be corrected immediately. The formwork should stand firmly, should not stagger even under great effort.

Formwork for strip foundation

Everything, you can pour concrete. 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 abundantly daily. The fact is that the strength of cement depends on the humidity 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 decrease significantly.

As for the formwork for columnar foundations, the work on its manufacture is almost no different from those described above. It is only necessary to immediately make the dimensions of the shields according to the dimensions of the columns. Of course, the small width and height of the columns greatly simplifies the technology of fixing the formwork in the desired position.

Formwork for column foundations

Formwork for a monolithic slab

Formwork for a monolithic slab

Foundations made of reinforced monolithic slabs are made for baths built on waterlogged soils or soils with very low bearing characteristics. In most cases, the dimensions of the bath do not exceed 4 × 4 meters. It is rather 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 earth as much as possible, fill and compact a sand cushion with a thickness of at least 20 centimeters.

Compaction of a sand cushion with a vibrating plate

Step 2 Prepare 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 stakes firmly into the ground. Put the formwork with the letter “P”, so it will be much more convenient to feed and level the concrete, you won’t have to step over the formwork every time. During concreting, do not forget about reinforcement.

Step 4 When approximately one meter remains to the end of the concrete slab - install the last board, level it, fix its position and continue pouring concrete.

Formwork for a monolithic slab

Video - Box-shaped foundation

Video - Marking and formwork for a monolithic slab

Video - Formwork and reinforcement strapping of a monolithic slab

Now you can consider a few questions regarding the use of additional materials for the manufacture of formwork.

Polyethylene film

Polyethylene film

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

1. Boards after dismantling the formwork are not thrown away, they can be used during further construction. Of course, except for those cases when unnecessary waste was used for formwork, it is easier to immediately cover them with earth. Formwork lumber can be used during the construction of draft floors and ceilings, in these cases it is enough just to clean the surfaces from large concrete residues. If high-quality lumber was used for formwork, then their use is not limited to auxiliary structures. But there is one problem - not a single self-respecting master will pass such boards through a thicknesser - sand and dirt will instantly dull the cutting knives.

   Sheathing formwork with parchment or film

   The polyethylene film perfectly protects the formwork surfaces from contamination. And not only in direct 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 on the reverse side.

2. 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 case of premature disassembly.

   It is much easier to dismantle the formwork with a film

The film must be installed from the inside of the formwork. To prevent sagging or slipping, secure it with a stapler.

Metal tie studs

If you have them - use them to your health, if not - you should not buy a bathhouse especially for the foundation. 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; be sure to place large-diameter washers and pieces of boards under the nuts.

Fixed formwork

Fixed formwork filled with concrete, photo

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

The design of fixed formwork for the foundation

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

1. From the made foam especially strong expanded polystyrene. Represents flat plates or blocks, angular 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 spikes, all dimensions must be checked with a level. Depending on the height of the formwork, concrete is poured in several layers around 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

2. Concrete permanent 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 by jumpers. Such formwork can be used both for pouring foundations and for erecting monolithic reinforced buildings. The fittings do not fit, vertical rods are inserted into the holes, and horizontal ones lie on special stops.

   Fixed concrete formwork

3. Wood concrete. It can take 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, there may be reinforcement inside. The panels are assembled on ties installed inside the concrete. The front surfaces of the screeds look like large flat washers, the surfaces of the panels are characterized by high adhesion to all building finishing materials.

   Wood-concrete fixed formwork

It is not economically feasible to use such expensive formwork on strip foundations of a bath. For baths, an insulated foundation is not needed, and the basement visible part will be finished with ordinary decorative materials.

Scheme of fixed formwork

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 during the construction of formwork.

Option 1. Swelling of the formwork became noticeable during the pouring of concrete. Stop work immediately and call all helpers for help. With shovels, recline the concrete at the place of swelling of the formwork. To prevent the concrete from floating back, nail the transverse boards at some distance across the entire width inside the formwork. Keep in mind that the concrete will gradually fill the recess, the work must be done quickly. Throw concrete more than 1.5 meters from the emergency site.

The pressure on the formwork has noticeably weakened - try to level it. It is very good if you manage to adjust the jack and use the beams to slowly level the formwork. It is possible to stretch the wire in a place free from concrete and use it to level the bulge. Very important: do not knock on the formwork with a sledgehammer, in this way you will make it even worse. Concrete from vibration will float down and further violate the straightness of the formwork. Align 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 you managed to align the shield - immediately fix its position. This time, check the reliability of the props with particular care.

This case is the easiest, all the others cause much more trouble.

Option 2. Formwork displacement was noticed only on the second day.

What to do if the formwork has shifted

Important. Not everything that is written on construction forums, however, think with your own head before believing the first advice of an “expert” that caught your eye. Many of these "specialists" 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 mockery. Do not under any circumstances 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 that will reduce the strength of the structure to almost zero. We noticed trouble the next day - that's it, the train left. Wait until the concrete has completely hardened, disassemble the formwork, pick up a hammer drill and work "by the sweat of your brow."

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

Shield dropped? Start work again

We hope that from the second time you will understand how the formwork is installed correctly. And to prevent this from happening, read the article again carefully. You can and should make your own improvements, but only if you have experience in building at least three different formworks.

Video - Possible consequences of poor-quality formwork. 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", etc. This is not true. Don't waste your time reading these tips. Think about 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.

Starting the manufacture of formwork, you need to follow two rules.

1. First, you need to know the job. You should not think that everything is very simple, you can “blind somehow” and it will “somehow stand”.
2. Second. Any work should not be feared, but it must be respected. You must constantly have a vision of operations several steps ahead in your head, you must be able to choose the most optimal from several possible options.

Video - Reinforcement and formwork of a shallow strip foundation

Video - Installation of braces for formwork

A house starts with a foundation. It is not difficult to make it with your own hands, experts say and give their advice on the step-by-step installation of formwork - a key element of the future foundation of the house. The article, as well as photos and videos, will help to 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 the same:

• 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 ground part of the structure;
• cope with the loads when pouring and compacting the concrete solution;
• quickly mounted and disassembled;
• if necessary, isolate the concrete from the ground and other negative factors.

Construction of wooden formwork

To ensure that the installation runs smoothly and you do not have to deal with unexpected problems, before starting work, you need to make sure that five main conditions are met:

1. The soil on which the base is poured must be completely cleaned of debris and various impurities.
2. Boards on the inside should have as flat and clean a surface as possible in order to reduce finishing work.
3. The formwork fastening must withstand the pressure of concrete and not be deformed.
4. Maximum contact of the components of the shield is necessary to prevent leakage. For this, the clarity of the geometry of the edges of the structure is important.
5. If the formwork panels are reused, the entire working surface must be cleaned from the residues of the previous mortar.

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

Removable formwork: time-tested installation

Mount, pour, withstand 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 easy to make such a formwork. Shields are made outside the construction pit from boards and lumber of the required dimensions. The boards are edged, as 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 pre-wetting, the boards will swell and the distance will decrease. If the gaps are larger, up to 10 mm, they must be closed with tow, and very large ones should be hammered with slats.

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

Pouring solution

It is better to sharpen the bars from one end, then they will easily enter the ground. To fix the formwork panels at the same distance, twists of wire, 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 just to unscrew them, and not unbend them, as is the case with nails. It is necessary to knock down the boards so that the heads of the nails (self-tapping 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 with spacers: wooden stakes or bars. After pouring and tamping, the concrete is kept in the formwork for up to two weeks, until it hardens and gains strength. After the structure is dismantled. Plywood formwork is installed according to a similar principle.

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

Fixed formwork for the foundation: a new word in construction

In recent years, a 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 retaining heat. Additional properties of fixed formwork made of such material: ease of assembly (somewhat reminiscent of a designer or a puzzle) and, as a result, the geometric harmony of parts. Certain types of polymer formwork have a reinforcing mesh that reinforces the foundation.

Fixed formwork

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

Foundation formwork: video

Do-it-yourself foundation: photo

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

Removable and non-removable

According to the principle of use, the formwork can be removable (collapsible) and fixed. 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, the same kit can withstand from 3 to 8 pours, industrial options can be used several dozen, and some hundreds of times.

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

Fixed 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 using locks and metal studs. From the blocks, as from the constructor, the necessary form is typed.

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

The non-removable formwork made of expanded polystyrene not only gives shape, but also simultaneously serves as thermal and hydro insulation, and also has soundproofing properties. It costs a lot, but immediately solves many problems, and the time spent on building the foundation is significantly reduced.

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

formwork requirements

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

Removable construction materials

In construction organizations, there are metal structures assembled on studs and bolts. In private construction, formwork panels are made of boards, moisture-resistant plywood and OSB. Wooden blocks are used as stops and spacers. Nobody bothers to make a metal structure, but it is very expensive and unprofitable for a one-time use.

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

What does the formwork for strip foundation look like in 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 with bars of section 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 from plywood. There is even a special formwork, laminated with paper with synthetic impregnations. 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 40 * 40 mm, fasteners need to be used shorter - 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 used for this purpose infrequently, but this option also takes place. The thickness is about the same: 18-21 mm. Structurally, it is no different from plywood shields.

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. Special surface quality is not required, so you can take low-grade materials, which are usually called "building".

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

Do-it-yourself formwork for a 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 constructing a more or less large building with a large number of partitions, the cost of foundation formwork materials will be very significant. Especially with deep foundations.

Shield design and 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 formwork for a strip foundation be installed: in a trench dug according to the dimensions of the tape and in a pit in braces

When making formwork from boards, cut several pieces of the same length, fasten with bars and nails or self-tapping screws. When using nails, they are hammered from the inside of the shield, bent on a bar. It is easier to work with self-tapping screws: they do not need to be bent, because 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 be facing the foundation wall).

The first and last bars are fastened from the edge at a distance of 15-20 cm. Between them, at a distance of 80-100 cm, additional ones are placed. To make it convenient to install formwork panels, two or three bars (along 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 formwork boards from edged boards

Plywood or OSB boards are assembled on a bar frame. When assembling, it is important to strengthen 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 stretched marking cords. The difficulty lies in the fact that at the same time you need to expose in a vertical plane. For fixing, you can use bars clogged at the mark and set vertically. When installing, set the plane of the shields close to these bars. They will be both support and guides.

Shields with extended transverse bars are easier to install

Since the bottom of the trench or pit must be flat (compact it and level it to the level), it should be easy to set the shields horizontally. Try not to hammer them too much: it will be easier to level them 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 the building level, apply along the shield and hammer the second edge with a hammer until the upper edge is set horizontally. You are already setting up the next shield relative to the installed one: they must be at the same level and in the same plane.

If the shields are made without long bars, at the bottom of the pit, along the marking line of the tape, a bar is fixed, which will serve as a stop. The shields are attached close to it, then fixed with the help of slopes and struts.

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. Supports should be at least a meter apart. Particular attention should be paid to the corners: they put stops in both directions. If the height of the shield is more than 2 meters, then one belt of stops is not enough. In this case, at least two tiers of spacers are made: upper and lower.

Outside the formwork put stops and braces. With a high height, they are made in several tiers. Pay attention to the thickness of the support beam

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 appropriate diameter. Studs are installed in two tiers: above and below, at a distance of 15-20 cm from the edge.

The length of the studs is approximately 10-15 cm longer than the width of the tape. There are two options:

• Both ends of the reinforcement are threaded. Then each stud will require two metal sealing plates and nuts.
• On the one hand, 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 internal distance between the shields, 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 studs in formwork

The assembly goes like this:

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

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

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

How to spend less

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

Filling with layers

With a large depth of laying, it is more profitable to fill in parts horizontally (in layers). For example, the required depth is 1.4 m. You can break the pour into two or three stages. With two stages, it will be necessary to make shields 0.8-0.85 m high, with three - 50-55 cm.

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

The order of work is as follows:

• The formwork is set up from the short panels made, the reinforcement is knitted for the entire required volume.
• Concrete is poured according to the height of the formwork.
• After 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 vibrating concrete, cement milk rises. As it hardens, it becomes brittle and brittle. It is this layer that will need to be removed. As a result, the surface will be uneven and rough, and this will improve adhesion (adhesion) with the next layer of concrete.
• At a temperature of +20°C, after three days the formwork can be removed, the boards cleaned and fixed higher. When removing the shields, take out the studs. Tubes can be left in concrete. They have already become part of the monolith. Sometimes they are taken out, and the holes are filled with mortar.
• Raise the formwork higher and pour it again.

  The shield is simply installed on the already "grabbed" 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 find a little on the already filled area, covering the tape from the sides. In this case, the lower row of studs usually serves as a stopper and emphasis. Therefore, when installing them, put them all on the same level from the bottom edge of the shields.

The fittings are already connected, the internal studs are cut. It remains only to put the other tubes, put the studs back in place and put the outer stops and braces. It does not take much 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 in the calculation. She goes to reserve. In addition, the load in strip foundations is distributed along the long side. And there are no gaps in length. So the foundation will stand for a long time.

vertical division

The second way is to split 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 space the joints a certain distance.

In the part of the building selected for installation, install the formwork with "plugs" in those places where the part to be installed ends. Inside the installed part, knit a reinforcing cage. In this case, the bars of 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 outlet 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 to these 60 cm.

One important detail: when breaking the plan of the house into parts, make sure 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 (they are marked in different colors in the figure)

Fill the assembled area with concrete. As in the previous method, after 7 * 8 hours it will be necessary to beat the solution, but already on vertical surfaces. Take a hammer and remove the sidewall plug, beat the cement-sand mortar down to gravel (near the formwork there will most likely be a layer of mortar without aggregate). As a result, the surface will be chipped, which is good for adhesion with 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 another trick. Everyone says that boards or plywood can then be used in auxiliary work. In practice, it turns out differently: it is impossible to cut wood or plywood soaked with cement. In addition, it becomes dirty and rough, and it is also unrealistic to clean and polish it: it does not “take” any grain. So, in order for the wood (and plywood, if not laminated) to remain usable, the front of the shields is covered with a dense film. It is fixed with a construction stapler and staples. If it is damaged, replacement takes very little time. 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 takes the load from the weight of the constructed object. The period of operation of the entire building depends on the durability of this product, so it is important to follow the correct technology in its manufacture.

A tape-type foundation has good performance characteristics, which is equipped around the perimeter of the object being built 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 a formwork into which the concrete mixture is poured.

The strip foundation has matured - the formwork can be removed

The purpose of the formwork for the foundation

The formwork for the foundation is a box-shaped structure consisting of shield railings and fasteners 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 its largest dimensions when arranging strip foundations. The structure must have sufficient elasticity and strength to withstand the pressure of the concrete solution poured into it. For this reason, building materials for its assembly are selected taking into account the indicated characteristics.

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

Choosing the type of formwork: removable or fixed?

The currently existing huge variety of formwork types can be divided into two large groups: removable and non-removable type. Removable formwork can be used repeatedly, fixed - 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 saving characteristics. They are caused by polystyrene blocks remaining on the outer surface after curing of the concrete mixture poured into the cavity of the blocks. This technology can be used both in the construction of private houses and in the construction of buildings up to nine floors 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 formwork for a fixed type foundation in a special article.

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

Formwork materials

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 this formwork are its heavy weight and significant cost.

Beam, edged board, plywood or OSB - running 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 the ease of installation without the use of special tools and their affordable cost. The disadvantages include the need to perform work to strengthen the stops and spacers. Formwork made of boards and plywood sheets are 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 you assemble a fence for concrete? Instead of OSB, it is possible, of course, 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 improvised means, such as old doors, slate sheets and other materials that can actually be connected without gaps in their side surfaces. The only advantage of this solution is its low cost. Several options for arranging removable formwork

There are many more negatives. These include:

• increased complexity of installation work;
• the possibility of leakage of the concrete mixture;
• low characteristics of the bearing capacity of the structure;
• the need for additional fasteners.

Such structures can only be used in the construction of small buildings. During capital construction, formwork made from such materials is not used.

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

Do-it-yourself installation of a removable formwork for a strip foundation involves a large amount of work. The concrete base tape 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 cost 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. To work with these materials, you do not need to use special tools.

Assembly and connection of shields

When performing installation work on your own, it is important to make panel 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 shield is about two meters, with a longer length it is difficult to work with shields.

Edged board panels ready for formwork installation

When assembling the formwork, the bars into which nails are hammered are located at a distance of fifteen to twenty centimeters from the edges of the shield and every meter of its length. Longer and pointed bottom slats are vertically stuffed in the middle and along the edges in order to bury them into the soil during installation.

Shield construction based on plywood or OSB

Boards made of plywood sheets and OSB boards are mounted on a prefabricated frame made of wooden beams. The illustration shows the design of a shield made of plywood. At the same time, it is convenient to use sheets with dimensions of 1525x1525 mm, which are sawn in half. Finished shields are interconnected with bolts and nuts through holes in the side bars.

Installation of formwork in the excavation

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

• vertically arranged pegs indicate the perimeter of the formwork installation;
• panel fences are aligned along them, the distance between them must correspond to the width of the foundation strip;
• through each meter of length, shield fences 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 with considerable effort.

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

The easiest way is to install shield fences with slats vertically pointed at the bottom located on them. They sink into the ground, and the shields are leveled using the building level.

Fixing shields

The formwork must withstand the pressure of the concrete mass poured into it, therefore, the structural elements are reinforced 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 shield fence exceeds two meters, the supports are installed in two tiers, with a significant height of the shields, the reinforcement is carried out in several rows.

Options for strengthening the formwork depending on the height of the foundation

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

• a piece of plastic pipe is placed between the opposite 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;
• nuts are screwed onto the thread from the outside.

Spacer sleeves and liners for service holes

When dismantling the formwork, the nuts are first 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, they are very difficult to unscrew.

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

Features of the arrangement of round formwork

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

Do-it-yourself round formwork is conveniently installed from a metal profiled sheet. Such material easily takes the desired shape in one direction and well withstands the load of the mass of concrete when pouring the foundation.

After the concrete has hardened and the profiled sheet has been dismantled, a surface of the corresponding shape will be obtained. It can be treated with coating waterproofing, but rolled waterproofing cannot be used.

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 the round section of the foundation and drive a support bar with a cross section of at least 50x50 mm into the ground. Options for mounting round formwork from various materials

Support bars are installed on the inner and outer parts of the round 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 fastened to the supports with self-tapping screws.

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

The formwork is strengthened with the help of stops and braces, as described above. Examples of a device of a round 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 making a sketch of the formwork to scale. The construction of shields is stronger than that of bent plywood, and is preferable for arranging a large foundation. Let's calculate the amount of materials needed

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 project documentation must be divided by the length and width of the boards intended for use, respectively. By multiplying the obtained numbers, their number is determined, which is necessary for the construction of a particular formwork. In addition to the boards, you need to purchase wooden bars and spacers. Their cost can reach up to half the cost of purchasing boards. It is necessary to take into account the additional costs for studs and fasteners.

Useful properties of polyethylene film

It is not possible to make a shield fence without slotted gaps at all, and the concrete mixture seeps out, soiling the formwork elements. A polyethylene film or roofing material fixed on the inside of the formwork perfectly protects the surface of the boards from contamination by the concrete mixture, not only from the inside, but also from the outside of the structure.

The use of polyethylene film or roofing felt 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 prematurely remove the formwork panels, the concrete surface of the foundation is not damaged. Shields made of wood are not exposed to moisture and can be reused.

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

We rearrange the shields and fill the foundation in parts

The pouring of the foundation in parts provides for a vertical or horizontal arrangement of the butt joints. With their vertical arrangement, the concrete base is separated by partitions. After curing of the concrete mixture 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 in parts with vertical division

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

Scheme of pouring the foundation in parts with horizontal division

The pouring of the foundation in parts can be carried out by waiting for the complete curing of a fragment of the concrete base, only after that proceeding to the manufacture of the next one or taking short breaks in work. In the latter case, in order for the concrete not to seize, its surface is covered with plastic wrap or roofing material. After removing the shelter, you can continue the process of pouring the foundation.

The method of building a foundation in parts allows you to rearrange removable formwork panels from an already finished section to the next one. Thus, materials and time of production of protections are saved.

Regardless of the type of foundation and formwork material, someone else's specific experience is useful for arranging it. Let the video answer all your questions.

The formwork serves as an element of the fence when pouring concrete, preventing it from flowing out of the future structure and thus giving it the necessary shape. This device is used for the manufacture of foundations of various types. The most common application is the formation of formwork for strip foundations. With the help of formwork, reinforced belts are made for floor slabs or the roof frame of the building, as well as many other structures that involve pouring the form with concrete or cement mortar. The material for the foundation formwork can be used differently, and in our article we will consider several options.

Wooden formwork with waterproofing coating

Types and materials for the manufacture of formwork

Depending on the desired quality of the concrete structure, the speed of its construction and the possibility of reusing the enclosing material, the following types of formwork are distinguished:

• Removable (collapsible). It implies the repeated use of functional parts of the device. It is dismantled after hardening of reinforced concrete.
• Fixed. It remains in the foundation, while serving as an additional protective or decorative element of the structure.
• Wooden. It is used in collapsible structures. As the main enclosing material, edged wooden boards of various sections, plywood, OSB boards, and in rare cases chipboard are used.
• metal. Enclosing elements in such formwork are made of sheet metal. The nodes that provide rigidity and prevent deformation of the planes can be made of wood or a metal profile.
• Polymer. It can be either removable or non-removable. In the first case, it implies the use of special plastic sheets as a fence. In the second, concrete is poured into polystyrene molds, assembled by means of locks into a one-piece structure.

Formwork for reusable use - often these are rented

Overview of standard formwork: types and conditions for the use of formwork structures

Depending on the requirements for the reinforced concrete structure, the type of formwork is selected. The dimensions of the foundation, namely its height and width, are of paramount importance. The higher the structure, the stronger the enclosing material should be.

Collapsible formwork

This is the most common version of the formwork for strip foundations and not only. Its popularity is due to ease of manufacture, availability of material and low cost compared to other options.

Most often, such formwork is built from OSB, boards from wooden boards, plywood, and sometimes chipboard. As a material for the frame, a wooden beam of a suitable section or a metal profile is used. All material after dismantling the formwork can be used in further construction work. Naturally, this is possible with a careful attitude to it.

Even disposable formwork can be collapsible, and the boards are quite suitable for a subfloor or similar work.

From the boards

For the construction of formwork, you will need a board with a thickness of 25 mm or more, if the width of the foundation is up to 300 mm. A larger design with a tape width of 400 mm and above will require the use of a 40-50 mm board. Lumber of any breed, both hardwood and softwood, is suitable. It is most economically feasible to use spruce or pine. In addition, these rocks have sufficient strength and resistance to moisture changes.

Flaws: a long time for the assembly of panels and the subsequent installation / dismantling of building elements; The structure needs additional reinforcement.

Advantages: low cost.

From plywood, chipboard, OSB

In order for the OSB formwork for the foundation, or from plywood and chipboard, to be strong, you cannot do without a wooden beam, which will be necessary when assembling the frame and stops with braces. The recommended plate thickness is 18 mm or more. The thicker the plate, the less timber for rigidity will have to be added. Sheets size:

• waterproof plywood - 1200 * 2400;
• construction plywood - 1500 * 1500;
• OSB: 2500*1250;
• Chipboard - 3750 * 1750.

For a single use, you can use ordinary plywood, OSB boards or even chipboard (then you will have to throw it away). If many pouring cycles are planned, you should pay attention to laminated waterproof plywood.

On our website you can find contacts of construction companies that offer foundation repair and design services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Positive traits: simplicity and speed of assembly compared to all other collapsible options. When using cheap varieties of slabs, the cost of such formwork for the foundation will be lower than that of wood.

Flaws: high cost of waterproof laminated plywood; one-time use of inexpensive board materials.

Metal formwork

An expensive but practical option that can provide a high quality surface, which reduces the cost of its subsequent grinding (if any). Such designs are more often factory-made, therefore, they are most adapted for quick assembly. They have significant rigidity and the same significant mass, which implies the involvement of a team of builders for installation and, possibly, lifting equipment. There are lightweight options made of aluminum or its alloys, but it is not practical to use them to save on the wages of workers and cranes.

The metal formwork for the foundation (photo below) is designed for reusable use and has significant potential in this regard, which partly justifies its high cost.

Reusable metal formwork

The quality of the foundation made using iron formwork is an order of magnitude higher than the wooden options. This is due to the properties of the metal, which, unlike wood, does not absorb moisture and thus provides favorable conditions for the curing of concrete.

Polymer boards

The meaning is the same as with plywood, OSB or chipboard, with the only difference being that a polymer board is used as the fencing material, the size and thickness of which depends on the required rigidity. To ensure proper rigidity of the structure, a frame made of timber or a metal profile is required.

Polymer formwork is an expensive pleasure, but they are indispensable in the construction of standard structures.

Fixed design

When choosing a material for non-separable formwork, one should choose one that will give the monolithic structure the necessary properties. For example, if insulation is subsequently required, it is better to use expanded polystyrene than concrete blocks or metal sheets.

Styrofoam blocks

A very simple and quick option, in addition, the finished concrete structure is already insulated. The production of strip foundation formwork from blocks evokes an association with a constructor: lightweight high-density polystyrene blocks are assembled using locks located on the adjoining sides of the product. The technology provides for the presence of linear, angular, radius and other elements for the implementation of any geometric shapes and solutions.

There is also an option where dense polystyrene sheets are used as a bounding material. The joining of the sheets to each other is implemented using a simple tongue/groove connection. Opposite walls are connected by special metal brackets, which in parallel determine the width of the foundation tape.

The material has a small mass and is easy to handle, so the structures made of it are mounted quickly, do not require special equipment and skills.

Fixed formwork also works as a heater

Reinforced concrete foundation blocks

The name speaks for itself. Structurally, it resembles a formwork made of expanded polystyrene. The difference is in the absence of insulation, significant mass and greater rigidity of the finished monolithic structure. In the case of work with large-sized blocks, a team of builders and lifting equipment will be needed for mounting.

Auxiliary materials and necessary tools

In the process of mounting the formwork for the strip foundation, you have to use various devices. Most often they are needed in the case of the manufacture of wooden structures, especially when scrap sheet material is used. Factory products are usually equipped with everything you need.

metal studs

Needed for tall buildings. It is not possible to provide high-quality fixation of the thickness of the tape over the entire area of ​​​​the fence in other ways. Studs are not needed for structures less than half a meter high, especially if sufficiently rigid sheet materials or boards are used.

The purpose of this element is to prevent bursting of the formwork walls. For proper functioning, the stud is installed in a plastic pipe. This is done in such a way that when tightening, the walls of the fence from the inside rest against the pipe. From the outside, it is recommended to wear washers on the stud.

Braces

Designed to prevent the walls of the fence from bending outward. They are made from wooden blocks of different lengths. The entrance is all suitable material, including trimmings.

Polyethylene film

Prevents the concrete mix from flowing out of the formwork. It is mainly used for structures made of boards, including unedged ones. Helps prevent excessive contamination of wood with cement mortar, which gives more opportunities for their subsequent use.

Production of removable formwork for strip foundation

There are a lot of options for the construction of such structures and the choice of the most suitable one depends on the situation and the preferences of specialists. Consider how formwork is made for a strip foundation using wooden shields and timber.

Technology for the manufacture of wooden shields

The thickness of the board is selected depending on the width of the tape and the height of the structure. With a width of up to 300 mm and a height of up to 1 m, a board of 25-30 mm can be used. The length of the shields also depends on the dimensions of the fence and the geometry of the structure. Considering the standard length of the board (4.5 - 6 m), the shield length of 2 - 2.5 m can be considered optimal.

In the manufacture of fasteners, it is better to use nails. This will greatly facilitate dismantling, save money and speed up the process.

For shields up to 1 meter high, the assembly represents the following sequence of actions:

• It is necessary to prepare boards for a set of one shield, for example, 10 boards 2 m long, 100 mm wide;
• To ensure rigidity and bonding of boards, you can use a beam with a section of 50 * 50, - 4 pieces per shield;
• The board is nailed to the beam, which is located at regular intervals, while there should be a distance of about 200 mm along the edges of the ends (in order to tie the shields together during installation). The bars should be made somewhat longer so that they can be driven into the ground, if this is provided for by the design.
• For tall structures with a tape width of 400 mm or more, a board with a thickness of 40 - 50 mm should be used, a bar for the frame - at least 100 * 50 mm.

Installation work

First you need to make a markup. After that, the shields are located along the foundation tape. From the outside, the tapes are fixed with braces, from the inside, stops or studs are installed. During work, it is necessary to control the level in all planes and the geometric accuracy of the structure.

Video description

Visually about the formwork for the foundation, see the video:

Assembly of fixed formwork

The construction of polystyrene blocks is assembled gradually - as the height of the foundation or walls increases. The first row is laid out on a prepared base - a pillow, having previously laid waterproofing with entry to the walls of the trench (in the case of a trench option). The assembly is made in locks on the faces of the blocks.

The height is gained, at which it is possible to tie the reinforcement without significant difficulties. In the case of using polymer sheets, the walls are fixed together with brackets that come with the kit. Having typed several rows and unleashed the reinforcement, concrete is poured, after which the following rows are assembled, and so on until the structure is completely ready.

For non-separable concrete block formwork, the process is the same. The difference is in the design of the material and the method of decoupling the reinforcement, which fits into specially provided recesses on the upper and lower surfaces of the blocks. The installation process also occurs gradually - after pouring one or two rows, the following are mounted.

Video description

See more about fixed formwork in the video:

Results

The use of this or that formwork largely depends on the costs that the developer is ready to go to, as well as the requirements for the quality of the foundation. For budget options, wood formwork using improvised means is quite suitable (there are examples using cardboard boxes). If speed is important, and quality will have to consider other options that will require a lot of money.

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 happens?

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

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

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

Today, ready-made formwork is sold in hardware 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, polystyrene foam, metal).

But ready-made kits cost a lot of money. Therefore, private construction usually uses formwork, which can be made by hand at low cost. Such an event is quite laborious. In this case, you will only need to stock up on boards (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 form of interest to us for the concrete composition of plywood or boards. It is made in the form of shields, fixed on the basis of wooden bars. 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 surface of the panel structure is as even and smooth as possible.

The “uneven” side with all the elements for fastening individual parts of the formwork is displayed outside. To make a collapsible form for concrete with your own hands, use birch plywood sheets 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 remains of wood materials. It is only necessary to ensure that they are firmly fixed. After using the formwork, it is removed.

You can use this form many more times later. . In order for the process of its dismantling to be 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 the form for the foundation is as follows. First, cut the bars into segments of the same size 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 work with your own hands is quite simple.

• lay the bars on a flat surface, maintaining a distance of about 100 cm between them;
• to make their careful alignment along the upper edge;
• put plywood (boards) on the bars and fix them with self-tapping screws (fasteners can also be made with ordinary nails).

Please note that the hats of the hardware must be inside the do-it-yourself shield structure for the strip foundation. If you do the opposite, the tips of self-tapping 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 rested against the board (it will be the support), and the bars should be cut to the width of the frame. The latter is allowed not to deepen into the ground.

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

• we stretch between the bars driven into the ground a nylon twine in order to correctly mark the site;
• we dig according to the marking of the ditch of the required depth (it is advisable to sprinkle the trench with a mixture of gravel and sand);
• we put, if necessary, a support board, and then a shield structure (at this stage, it is necessary to use a level and a plumb line, which will allow you to correctly and evenly place the shields).

With low stability of the strip foundation shields, they can be made more reliable. It is not difficult to strengthen the structure with special spacers made of cuts on the outside and bars on the inside. The cut is the same bar, but cut at a 45-degree angle. It is mounted at a distance 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 concrete mortar seepage).

Then the installation of 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 mixture seizes. The formwork is dismantled when a small gap appears between the concrete base and the boards. In order for a strip foundation with a minimum of effort, tap with a rubber mallet on the outside of the shield frame.

First of all, you need to dismantle the clamps, slopes and ties. And only after that, remove 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 be easy and fast for you, thanks to our advice. And you will get a really solid foundation "for centuries."

The construction of the formwork, which is a constructive and significant element, is an important stage in the construction of the foundation.

- This is the form into which the concrete solution is poured. It is installed after earthworks have been completed, when the trench has been dug and the platform for the foundation has been prepared. Purpose - giving the structure a certain shape and strength.

How to make a formwork for the foundation with your own hands, so that it contributes to the construction of a solid foundation for the house, while reducing labor and money costs to a minimum. These tasks excite every person who independently decides to build a cottage, garage and other buildings that must have a solid foundation.

Construction technology

1. Equip a trench for the base of the foundation; determine the dimensions of the reinforcement, its density, depth and width. These values ​​​​depend on the number of floors of the house being built and on the type of building material used.
2. Clear area from debris around the trench.
3. Level the area along the dug trenches so that there are no holes, depressions in the place where the structure will be built. Otherwise, cement will leak out through the cracks due to poor formwork construction.
4. Make shields from beams and boards, and drive them around the trench. It is necessary to take three-meter boards and knock them together, placing small boards across them, at a distance of 40 mm from each other. Therefore, a three-meter shield will have about three joints of transverse boards, the length of which is greater than its width. In the future, the difference in their length will help to drive shields around the trenches. The front side must necessarily be even, which qualitatively affects the reliability and strength of the base. Boards are connected with self-tapping screws (faster, stronger, more expensive) or nails (slower, cheaper). The head of the fastener should be located on the front side, which will interact with concrete in the future.
5. Production and use of wooden clamps, the length of the vertical elements of which should not be less than half the height of the shield. This will increase the rigidity of the structure, so when pouring concrete, maximum pressure is exerted on the walls of the mold. The system must be able to handle such loads. Otherwise, its deformation will occur: bursting, cracking, punching. In the middle between the struts are wooden clamps.
6. At a distance of at least 1 meter place struts (additional support elements) at the junction of the boards and the shield. Together with clamps, they serve to strengthen the formwork, giving it good strength so that it does not deform under high concrete pressure. Shields must be installed, observing all the necessary dimensions horizontally and vertically. This is checked by a level in the horizontal plane, and a plumb line in the vertical plane. Two opposite shields are fixed with the help of spacers made of timber and fixing elements located on top, in line with the struts.
7. With the formation of cracks in the structure, they must be sealed with a composition for waterproofing or tow. It can be lined with roofing felt inside and around the trench.
8. Then carried out.
9. If there is a need, the part of the foundation that is in the ground, from the outside. Insulation is laid under the waterproofing layer, after which other construction work is carried out.

Advice! For formwork, boards of the second grade can be used. It must be borne in mind that after that they can no longer be reused.

Kinds

Formwork happens:

• removable;

Removable formwork is usually used in the construction of cottages. It is usually made from steel panels, plywood sheets and boards.

The non-removable type is characterized by simple and quick assembly and installation. In the future, after the concrete has hardened, it does not need to be removed. For its construction, it will not be necessary to perform a large amount of land work, and after use, install additional parts: struts and supports.

The material is a variety of improvised building items, depending on the method and type of foundation being built:

• metal frame;
• polystyrene boards;
• asbestos or metal pipes, 150-200 mm in diameter.

The main advantage of a fixed structure is the strengthening and insulation of the base through the use of building materials.

Basic requirements for formwork

1. Sufficient level of rigidity.
2. When poured, concrete should not deform.
3. Easy installation.
4. Ensuring isolation from earth preventing concrete leakage.
5. The design must be without gaps to prevent concrete leakage.
6. High strength to withstand the pressure of the entire mass of concrete on the walls.
7. Dimensions- accurate and sustained.
8. Elements must be fastened so that after the concrete mixture has hardened, they can be disassembled and removed.

Formwork materials

Depending on the type of material, there are several types of formwork:

Metal formwork

Metal formwork is the most expensive, but at the same time, a versatile type of construction, made from 1-2 mm steel sheets.

Advantages:

1. This type quickly and easily takes the desired shape., since the steel sheet bends well at a certain angle.
2. Attaches high waterproofing structure.
3. Does it is possible to attach the formwork to the reinforcement frame by welding, which is ideal when erecting a strip or monolithic base.
4. P with a strong protrusion of the base above ground level, the metal structure is easy to process from the outside.

Flaws: great cost.

Reinforced concrete formwork

Reinforced concrete formwork is an expensive type.

Advantages:

Using thick concrete slabs, it is possible to significantly reduce the consumption of concrete mortar, without reducing the strength of the foundation.

Flaws:

Since the slabs are quite heavy, with insufficient height, it will be necessary to install spacers, in addition to those erected.

Styrofoam formwork

Expanded polystyrene formwork is the most practical formwork, which is constructed from blocks of expanded polystyrene, securely fixed to each other.

Advantages:

1. Ease of installation.
2. The ability to give the desired shape.
3. High waterproofing.
4. Insulation functions.

Flaws:

1. Difficult to find some items(corners and roundings).
2. High price.

wooden formwork

wooden formwork – a view in which boards and plywood sheets are used.

Advantages:

1. Affordable price.
2. Easy to find material.
3. Ease of installation.
4. No special equipment required for installation.

Flaws:

To ensure the strength of the connections of the elements, additional means are used. Reason: different sizes of materials.

Formwork from improvised materials

Formwork from improvised materials - various building materials are used for its construction: boards, slate, pipes, corrugated board, etc., providing the desired shape to the base and preventing the concrete solution from flowing out.

Advantages: availability and low cost.

Flaws:

1. Difficulty of installation, as usually a variety of building materials.
2. Danger concrete leaks.
3. Small Power: therefore, it is better not to build large structures, but to limit yourself to small sizes.
4. The need to use additional wedges and supports.

To correctly determine the type of formwork required, you must first select the type of construction that corresponds to a specific foundation or structure. Metal or wooden removable formwork is well suited for the construction of a basement that does not require insulation.

Fixed - for a building whose basement needs protection from water and cold.

The choice of a certain type is also influenced by the type of soil of the construction site, the features of the foundation, what materials it is made of.

Film formwork- a new economical type, in which the container, where the building mixture is poured, is enveloped in a material (film), which improves the quality of the reinforced concrete structure. In this case, the material used for the construction remains in its original state.

Regardless of the type of equipment and material used for, all types are similar to each other with a simple design device and installation principles.

Having decided to build something, we are wondering how to make the formwork for the foundation with our own hands? After all, it is the foundation for a wooden house that will be the basis of the future structure. So, what types of formwork exist and how to choose the right and more suitable option for us.

Types of formwork structures

The main purpose of the formwork is to give the future structure strength and its structural appearance. The tasks that the formwork needs to cope with are quite simple:

• It must withstand the pressure of the concrete mortar on its foundations.
• Do not change the given shape in the process of forming the foundation for the log house.
• It is easy and affordable to erect, and be hermetically isolated from the ground (to prevent leakage of the concrete mix).

The material from which the formwork is erected is different, it can be a reusable wooden or steel frame or a single-use structure that increases the overall stability of the foundation and, being its direct basis (a striking example of a fixed formwork is a columnar foundation made of metal pipes).

This type of formwork is advantageous for ease of installation and speed of erection, and after pouring with concrete, it remains an integral part of the foundation. For fixed formwork, improvised material is usually used, and depending on the variant of the foundation being built, this can be fiberboard, chipboard, metal frame or polystyrene foam. Another option is a columnar foundation made of pipes, in which pipes (asbestos, metal) with a diameter of 150-200 mm act as formwork.

An obvious advantage of such a formwork is the ability to strengthen the foundation due to the material used (especially for a columnar foundation and in the case of reinforced concrete slabs).

Such formwork is easier to install and requires less earthwork (because you do not have to remove it later). Additional supports and spacers will not be needed when collecting the formwork.

Types and features of the construction of fixed formwork:

metal

The most expensive, but rather versatile type is formwork made of steel sheets with a thickness of 1 to 2 mm. Pros:

• Such formwork easily takes the desired shape of the foundation due to the ability to bend the steel sheet at the angle you need.
• Good foundation waterproofing.
• 3. For metal formwork, a monolithic foundation and strip foundation will be an ideal option (the reinforcing cage can be welded directly to the formwork).
• If the foundation protrudes strongly above the ground level, ease of processing the outside.

Minus - the cost and again the cost.

Reinforced concrete

Relatively expensive option. Pros: depending on the thickness of the concrete slabs, it can significantly reduce the consumption of concrete without losing its strength.

Minus: the severity of the plates, and if the plates are not monolithic and the height of one plate is not enough, then additional spacers will be required.

Figure #1

Styrofoam

The bottom option is one of the most practical. The formwork is assembled from separate blocks (Fig. 1), which are clearly fixed to each other. Pros:

• Ease of installation
• The ability to betray the desired shape (rounding, corner)
• Waterproofing and insulation

The disadvantages include the difficulty of selecting some elements (the very corners and roundings) and not the lowest price.

Wooden

Figure #2

It can be either a board or plywood sheets. Pros: price and availability of material, ease of installation and no need to purchase additional equipment for installation. Cons: perhaps due to the different dimensions of the material used, it will be necessary to use additional means of connecting and reinforcing the formwork (Fig. 2).

From improvised materials

This can be slate, corrugated board, pipes (for column foundations) or any suitable material that can provide the desired shape and prevent leakage of cement from the formwork. Pros: The main and probably the only plus is the cheapness of construction. Cons: Difficult to assemble, especially if different materials are used. Concrete leaks. Weak bearing capacity, it is unlikely that you will be able to build a sufficiently high and strong case for formwork, and therefore it is worth limiting yourself to only small buildings. You may also need additional supports and wedges.

How to make formwork for the foundation? Do-it-yourself fixed formwork is constructed in the following several stages.

Stage one. Land works.

Having calculated (this stage will be described in detail below) the required power of the future formwork, trenches are dug (do not forget to take into account the thickness of the formwork). Tip: you can leave a margin of 1-2.5 cm between the formwork and the ground (this will simplify installation and after the formwork is split, this space will be covered with soil).

Figure #4

Next, the bottom of the trench is covered with gravel or sand (Figure 3) and rammed or concrete preparation is applied (foundation screed). This is done to reduce the loss of concrete when pouring the foundation. If the foundation foundation is reinforced with reinforced rods, then they must be driven into the ground at this stage.

Second phase. Erection of formwork elements

For fixed formwork, it comes down to fitting its elements and erecting a structure in accordance with the selected material. At this stage, a reinforcing cage is formed (if provided).

Upon completion of all preparations, the formwork is poured with concrete, and if your calculations turned out to be correct, then in 25-30 days you will be ready to proceed with further construction.

Removable wooden formwork

Consider one of the available and practical types of formwork (Figure 4). Removable timber formwork has a number of advantages, and although more modern materials have emerged, it is wood that most people prefer.

Reasons why you should choose it:

Although the cost of the material can sometimes be high, the reuse of the formwork, as well as the ability to use the board, for example, for laying the floor and building other wooden structures, completely pays for it. In order to save money, such formwork can be simply rented and then returned.

• If wooden material of the same type is used for the construction of the formwork (only board, plywood, etc.), it is easy to fit it (you can always saw off the excess).
• Ease of construction (you or your neighbors probably have all the necessary tools). In fact, in its simplest form, it can only be done with a hammer and a saw.

Minuses:

• Difficulty in constructing curves.
• With a large amount of mortar to be poured, the formwork will need to be reinforced with spacers.
• Difficulties may arise when giving the formwork a strictly vertical position (for example, if the board was not nailed quite evenly).

So, how to make the formwork for the foundation with your own hands, without making mistakes and miscalculations.

After marking and preparing the construction site. Wooden bars are driven into the corners of the future formwork (the structure will be attached to them), so that during the construction of the formwork they remain on its outer side. Further, according to the measurements, wooden shields are prepared and gradually connected to the bars with the help of screws or nails, thereby forming a frame.

If the volume of the poured solution is large, then to strengthen the structure, it is worth driving in additional spacers from the outside at a distance of 70-90 cm from each other. Another way is to pull the formwork walls together with studs (but it is worth remembering that then, after disassembling the structure, holes will remain in it, which may limit its further use).

During installation, make sure that the formwork is in a strictly vertical position! Do not allow large gaps in the structure and, if necessary, close them with improvised means (if the distance between the formwork segments is 4 mm or more, this is already a solution leakage in the future).

Tip: in order for the inner side of the formwork to be smooth, as well as to eliminate small mortar leaks, you can use a stapler to nail building oilcloth or cellophane to it.

Relatively new type of formwork and very versatile and easy to handle.

Due to the short time of use and a considerable price, it is still not widely used in private construction.

Advantages:

• The material holds heat well and does not allow moisture to pass through (you will not have damp corners)
• The ability to order any form of blocks will allow you to give free rein to your imagination when building a foundation.

Drawing No. 5

Very simple assembly. The blocks are attached to the reinforcement (installed in the main nodes of the future building, Fig. 5) and the blocks are connected to each other with metal brackets (Fig. 6). Sometimes a connection with special foam is acceptable.

• With the help of such formwork, it is possible to completely build the entire building, gradually laying on existing blocks, new ones and pouring them with concrete.
• Due to the design features, there are no concrete leaks, and the formwork is perfectly flat (with proper assembly, of course).

Flaws:

This formwork is non-removable and one person (due to the large investment of time and lack of experience) should limit himself to pouring the foundation on its basis.

Surely this question torments many enthusiasts and experimenters - how to make the formwork for the foundation with your own hands, while giving it a round shape?

The main preparatory work for the foundation will be the same as for other types of formwork, but the choice of material should be taken more seriously.

• Plastic

If the design is not impressive, and you decide to build, for example, a gazebo, then plastic is quite suitable. It has sufficient flexibility and, if necessary, it can be bent with a little heat, but the strength of such formwork is low.

• Boards

Drawing No. 7

Such formwork will be assembled according to the barrel principle (Fig. 7) and, if necessary, can be reinforced on both sides with pegs driven in at a short distance from each other (10-20 cm). If this is a fixed formwork, then it can be formed gradually - make a small part of the formwork and fix it with a small screed, and so on (tip: you can just dig in the boards, below the level of the “foundation cushion”, this will take longer, but will make the formwork more even). And after assembly, if there is a gap between the lower outer part of the formwork and the ground, fill it with gravel or sand. This type can withstand heavy loads.

• Plywood

Like plastic, it is a very weak type of material, and besides, it is not always possible to give plywood the necessary shape.

• Styrofoam

You can order the block parameters you need, so you save money and effort, but it will cost your wallet dearly.

• Metal

Steel sheets 1mm thick can also be used for this formwork. But without the help of additional tools, you alone are unlikely to be able to give it the desired shape.

Tip: you can look for ready-made frames for removable round formwork and, if you're lucky, find the right diameter.

The strip foundation is still one of the most common ways to fill the foundation for a future building. The principle is quite simple, a screed is poured onto a sand cushion, after which a reinforcing cage is formed and poured with a concrete mixture. But which formwork is preferable to choose for him?

Oddly enough, but if the soil is strong enough and the foundation is sunk into the ground, you can do without formwork at all, just dig a trench - of course, this is rare.

In other cases, any of the formwork methods presented above will do, it all depends on your imagination, the available materials and available funds, and most importantly, the “right hands”.

And yet, when building formwork, most prefer a wooden frame. Perhaps the point is the price and ease of construction, each has its own advantages, but the fact remains (probably not without reason). Perhaps this article will allow you to more accurately determine what you like.

Video:

Foundation formwork calculation

Everything depends on the chosen material.

So, let's give an example of a "classic" wooden formwork. The standard for the length of a purchased board is considered to be 6 meters, the width of the litter is 100-150 mm, and the thickness is at least 25 mm. Now we divide the perimeter of the foundation by the length of the board (6), and divide the height by the width of the board (0.10-0.15), multiply the results obtained and find out the number of boards needed. For reference, on average, 1m.cube can contain from 42 (width 100mm) to 64 (at 150mm) boards. The price for 1 cube is 5300-6500 rubles. To the price of the formwork itself, it is worth adding the cost of a beam for its fastening and spacers for reinforcement, which in various cases can be an additional 3000-4000 rubles.

• Metal. It is calculated according to the same principle as the wooden one, based on the parameters of the sheet 1 * 1500 * 2500 mm. Sold by weight at a price of 36,000-38,000 rubles / ton.
• Expanded polystyrene formwork should be calculated by a specialist based on the foundation plan. With complex nodes, the price will not be much lower than the metal one. And if the project is very intricate, then during the installation process you may need the help of a professional.
• Do not forget that it is worth adding the cost of consumables to any type of formwork: nails and staples, reinforcement and spacers. You also need to consider the use of additional tools that you may have to purchase.

Advice: The most economical (contrary to popular belief and if the foundation design allows) is not to wonder how to make the formwork for the foundation with your own hands, but simply rent it at the nearest construction site. This will save you time and effort and help you avoid some mistakes.