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What is needed for foundation formwork. Self-production of formwork for strip foundations. Video: requirements for boards for formwork installation

Formwork is a kind of form for cement-sand mixture, which allows you to form the correct geometry of the walls. Builders use both removable/temporary and permanent/permanent formwork for the foundation. The second option allows you to save effort and time on dismantling works, as well as insulate and/or strengthen walls, so it is increasingly used not only in industrial, but also in private construction.

Basic requirements for permanent formwork for foundations

Let's consider what properties permanent formwork should have.

• Moisture-proof material and tight seams. In the absence of this characteristic, the formwork will allow concrete to pass through, which will lead to excessive consumption of the mixture and make it impossible to construct the wall.
• Structural strength. This is necessary so that the formwork can withstand the pressure of the concrete mixture from the inside and the earth from the outside (at the foundation level) without deformation or cracking.
• Correct element geometry. It would be impossible to build straight walls and 90-degree joints between them using blocks of different thicknesses or with irregular angles.
• Long period of operation. The longer the formwork can potentially last, the higher the likelihood of a long life for the entire house. If the formwork collapses quickly, the unsupported walls may not be able to withstand structural loads. In cases where the formwork does not have load-bearing properties, its destruction will lead to deterioration appearance due to delamination decorative finishing facade.

Fixed formwork is an important element of an energy-efficient house

Table: advantages and disadvantages of permanent formwork

Fixed metal formwork

To ensure uniform wall thickness, sheets of metal formwork are connected with metal studs

Metal formwork is one of the most expensive, therefore it is used mainly in industrial construction. It is made from sheets of aluminum or steel 1–2 mm thick on a metal frame and connected with anchors, plates or locks. The type and number of fasteners are calculated in such a way that when concrete is poured and hardened, the sheets do not bend either inward or outward.

When the formwork is made to order for a specific building, the manufacturer’s craftsmen themselves carry out a test assembly of the structure and only after confirming the suitability and completeness of all parts, the order is sent to the buyer.

Metal formwork has the most accurate geometry. The permissible deviation in the parallelism of the sheet edges is no more than 2 mm over 1 m of product length.

To prevent premature oxidation and destruction of metal due to contact with concrete and groundwater, in production, sheets of future formwork are carefully coated with paint and lubricant. Often galvanized steel is also used, or a powder coating method is used, which forms a dense polymer film on the sheet. But if welding is used during installation (welding sheets to a frame or reinforcement to sheets), areas damaged by temperature will need to be re-applied. protective composition(lubricant, mastic, paint).

Powder coating of metal sheets is one of the most effective methods of protecting them from corrosion

Metal is well suited for buildings with complex geometries, since thin sheets can be easily bent at any desired angle, made into a curve or an arch. Finished walls They turn out very neat and smooth; if desired, they can be left without decorative finishing. Architects recommend using metal formwork in areas with complex loose soils.

To prevent concrete from leaking, the joints of metal formwork are connected especially carefully.

But experts also note some disadvantages of metal formwork:

• significant weight steel sheets, which requires the use of special equipment;
• the need for additional thermal insulation of walls and foundations;
• The grease on the sheets wears off easily and stains workers.

Installation of aluminum sheets for wall formwork can be done by a couple of workers

Aluminum sheets with the addition of silicon, which weigh much less than steel sheets and do not require protection from the external environment, will help minimize labor costs for transportation and installation of metal formwork.

Permanent formwork made of reinforced concrete blocks

Reinforced concrete formwork blocks are recommended for large construction projects, at least a three-story private house. Since they have increased strength characteristics, in smaller buildings such a safety margin will be unnecessary. Thin-walled blocks are excellent for arranging the foundation of a permanent fence.

Reinforced concrete formwork blocks are installed offset

Reinforced concrete formwork blocks have the following advantages:

• allow you to save cement-sand mortar due to the significant wall thickness;
• suitable for the construction of basements of any depth, as well as interfloor ceilings;
• mounted with a minimum joint width;
• provide a building service life of several hundred years.

The best formwork is made from reinforced concrete blocks with indicators F75 (frost resistance), W4 (water permeability), 6% (water absorption), 350 kg/cm 2 (mechanical strength).

An example of the arrangement of reinforcement in formwork made of reinforced concrete blocks designed for two rods

The disadvantages of reinforced concrete blocks include:

• heavy weight (a 510x400x235 mm block weighs 30 kg), due to which it can only be transported by trucks and installed only by workers with a crane;
• high price - about 500 rubles per unit.

Expanded clay concrete blocks do not have such disadvantages. Providing high strength of the walls, these analogues of reinforced concrete blocks do not require insulation of the house, since they already contain insulation - expanded clay.

Fixed plywood formwork

For formwork, moisture-resistant plywood is most often used, but even then, this material is usually used to create a temporary form. After all, the service life and weather resistance of laminated plywood sheet an order of magnitude lower than the same parameters of a concrete wall.

Permanent plywood formwork is acceptable in the following cases:

• when making a temporary structure (for example, small house, in which the owner lives during the construction of the main house);
• during the construction of non-residential buildings (chicken coop, barn, wood storage);
• when it is necessary to save as much as possible on construction;
• if the walls and foundation are insulated along the outer contour and the plywood is completely protected from external influences.

In addition to questionable durability and strength, plywood formwork will require a lot of labor and careful handling. Since the sheets do not have a tongue-and-groove system and special joints, you will have to assemble the structure using self-tapping screws, additionally seal each joint and make an external sheathing with supports (so that the plywood does not bend). In addition, non-waterproof plywood swells and flakes from water, while laminated plywood repels the concrete mixture and never forms with it. monolithic wall, so it is very important to find a waterproof material with good adhesion.

Technoblock - an example of the successful use of plywood in formwork

Designation in the picture:

• 1 - decorative facing layer;
• 2 - layer of insulation;
• 3 - plastic supports for reinforcement;
• 4 - concrete pouring(there is a cavity for it in the block);
• 5 - plywood sheet.

As a result, despite the cheapness and environmental friendliness of plywood, experts recommend using it only for temporary formwork. For permanent applications, it is better to use a technoblock - a composite product with an inner plywood layer.

Fixed wood concrete formwork

Arbolite is a relatively new, but time-tested material. Formwork blocks from concrete and wood chips began to be made recently, but this mixture was used for floor insulation back in Soviet times. Arbolite blocks are much cheaper and lighter than reinforced concrete, so they are actively used in individual low-rise construction.

Some models of wood concrete blocks have a layer of insulation - stone wool or polyurethane foam

Compared to other types permanent formwork wood concrete blocks:

• are easily cut with tools for working with wood, which allows you to adjust them on site to the required parameters: cut corners, make arched curves, cut out fragments for better adhesion of walls at the corners of the building, reduce height/length;
• can be installed quickly and without special equipment (1 m2 of wall is only 8 blocks);
• provide high strength, sound absorption and thermal insulation with a smaller wall thickness (compared to brick and expanded polystyrene);
• safe for the health of others, waste can be industrially recycled;
• strong enough to secure downspout clamps and loaded elements facade systems(guides for hanging siding, etc.);
• are not afraid of fires (withstands up to 90 minutes of open fire);
• frost-resistant, suitable for regions with harsh climates.

The disadvantage of wood concrete is its water permeability, so it is recommended to use it for the construction of walls on a ready-made waterproofed strip or slab foundation. The use of wood concrete for arranging the foundation is undesirable, since it will need to be very carefully protected from moisture.

An example of arranging formwork made of wood concrete and brick

Arbolite is produced in the form of hollow blocks and panels. In the second case, the panel serves only as the inner contour of the wall, and the outer one must be made of brick. The cavity between the materials is filled with concrete and reinforced, as when using other types of formwork. This option is more difficult to install, but the finished house is warm (arbolite), beautiful (brick) and durable (merging the strength characteristics of three materials).

When purchasing wood concrete blocks and slabs, pay attention to the eco-label, as some manufacturers use binders that are harmful to health (phenol, naphthalene). Be careful, plasticizer toxins can be released from the material even at room temperature.

Manufacturers of wood concrete blocks for formwork offer options for both high-rise buildings and small buildings. Be sure to consult with a consultant so as not to spend extra money on concrete for pouring thin-walled blocks or not to mistakenly take blocks with too small voids.

Fixed formwork made of CBPB

CSP (cement particle board) or sawdust concrete is another variation of a mixture of cement and crushed wood. It differs from wood concrete in the type of binder component and the addition of sand. Therefore, DSP is a denser, stronger and heavier material, and its thermal insulation is worse than that of wood concrete.

Cement particle boards can serve as a finishing material when covered with decorative mineral chips

Among the advantages of wood concrete formwork:

• the material breathes, so there is no need to equip the house with forced ventilation and fight the greenhouse effect in other ways;
• DSP is able to withstand fires, its fire resistance is confirmed by laboratory tests;
• the plate consists of natural materials, therefore does not harm nature and health;
• gives the house high strength: with a thickness of 25 cm, the wall can withstand three times greater loads than a brick wall of the same thickness;
• DSP is resistant to sudden temperature changes, therefore suitable for regions with a sharply continental climate;
• the material is sufficiently stable and geometrically stable so that the distance between the floors can be 2.8–3 m;
• it is possible to build houses using cement particle boards even in winter, as long as the temperature does not drop below -20 o C;
• DSP requires minimal finishing, inside the house it can be painted or wallpapered without putty.

An example of creating reinforced formwork for a foundation made of cement bonded particle boards

European builders have been using permanent DSP formwork for more than 25 years, so there are many houses that confirm the durability and reliability of this material. Cement particle boards are well suited for both individual and multi-storey buildings, even in the harsh northern climate.

Fixed formwork made of corrugated sheets

Profiled sheets, corrugated sheets or corrugated sheets have also found their use as permanent formwork, although much more often they are used for the manufacture of fences, roofs, and outbuildings. Important: profiled sheeting is only suitable for arranging composite slabs of interfloor floors and for large spans (from 5 m) it requires additional temporary supports. This material is not used for the construction of walls due to its small thickness, which reduces its resistance to mechanical loads in a vertical position.

An example of a floor design with a base made of profiled sheets

Builders are attracted to formwork made from this material with the following features:

• the metal is completely protected by galvanization and/or polymer layer, therefore does not rust;
• in industrial buildings the material can be left without decorative finishing, the ceiling is visually pleasing and practical;
• The corrugated sheet not only serves as a form for concrete, but also serves as sheet reinforcement;
• corrugated sheeting transfers the load to the metal frame of the building, so the internal walls do not bear heavy loads and it becomes possible to save money by constructing them from lightweight materials (aerated concrete, sandwich panels);
• sheets of small thickness are simply cut with metal scissors; formwork of any shape can be created from them.

To ensure good adhesion to concrete, choose special corrugated sheets with teeth for the formwork.

This is what it looks like interfloor covering based on corrugated sheeting from inside the building

Permanent formwork made from corrugated sheets is used mainly in industrial construction, as it requires construction metal frame buildings and metal beams ceilings For individual house it will not be suitable, as it will be unreasonably expensive.

Fixed polystyrene foam formwork

Expanded polystyrene/foam is the most popular material for permanent formwork. Its demand is explained by factors such as:

• light weight, making it easy to transport;
• tongue-and-groove connection system for the simplest possible installation;
• speed of installation (foam blocks of permanent formwork are larger than concrete ones, so work progresses faster);
• variety of types (reinforced, with protective impregnations);
• thermal insulation properties, thanks to which the house does not require additional insulation;
• soundproofing;
• biological inertness, preventing the development of mold, moss, etc.

Examples of polyurethane foam formwork blocks of different configurations

Opponents of polystyrene foam formwork point to its danger in case of fire and low degree of environmental friendliness. Even if you buy materials labeled eco, this does not guarantee that the formwork will not harm your health or the environment.

It is also important to keep in mind that foam formwork will be a good choice for buildings of simple shape, since the range of corner and rounded blocks does not yet allow satisfying all consumer needs.

Fixed formwork made of glass-magnesite

Glass-magnesite sheets or FMS have been used as permanent formwork since the mid-20th century for the purpose of constructing thermally insulated houses. The material consists of a mixture of magnesium oxide and chloride, perlite, sawdust, fiberglass and polypropylene fabric. Not all components of glass magnesite are natural, but the finished composition is completely safe for people.

Different options for glass-magnesite sheets with decorative finishing

LSU - great option for the construction or reconstruction of a house with a weak foundation. Since the sheets themselves and those used for filling are lightweight concrete mixtures weigh much less bricks, reinforced concrete blocks and others traditional materials, they do not load the structure of the building so much.

Among the advantages of glass magnesite:

• multifunctionality: it is suitable for creating foundations, walls, ceilings, fences, etc.;
• high thermal insulation, which is associated not only with the properties of the formwork itself, but also with the advantages of the filler (fiber foam concrete grade D250-D320, concrete with polystyrene foam balls M300);
• fire resistance;
• complete moisture resistance, which makes the material suitable for the construction of baths and saunas, use in areas with a humid climate and in wetlands;
• the small thickness of walls with SML formwork will save space inside the house;
• the rough surface of the sheets can be easily covered with clinker tiles, decorative plaster or any other finishing material;
• the sheet can be slightly curved if necessary for the construction of a half-turret or other home decoration (radius of curvature - 3 m).

If you plan to cut LSU boards on site, purchase spare jigsaw blades. This material wears out nail files several times faster than wood concrete and plywood.

Glass-magnesite sheets will be suitable for use at all stages of house construction

Glass-magnesite sheets, like arbolite sheets, often form only the internal contour of the formwork, while the external one is most often built from decorative bricks. As a result external finishing turns out to be unnecessary, and a thin layer of putty will be enough inside. The technology is suitable for the construction of houses up to 5 floors on a ready-made strip/slab foundation. In addition, it requires more time and effort than using polystyrene foam or DSP formwork (excluding decorative finishing).

Glass-magnesite sheets are currently produced only in China and Korea, and LSU quality control is also carried out there. There are no domestic analogues for this material.

Instructions for installing permanent formwork from prefabricated blocks

We will consider the technology of constructing a foundation from ready-made hollow blocks using the example of lightweight concrete products. Unlike reinforced concrete blocks for high-rise buildings, these “bricks” can be installed by hand without a crane or manipulator.

1. Prepare a cushion for the block foundation by filling and compacting layers of sand and small crushed stone. A thin screed should be poured over the cushion to simplify further laying of the blocks, and also to avoid concrete leakage when pouring the foundation.
   

   Sandy- gravel bed Before installation, a thin layer of concrete must be poured

2. Stretch a thread along the trench and place the first layer of blocks on the cushion, being careful not to deviate from this guide. It must be mounted so that the gap between the elements is minimal. If the gap increases significantly along the trench, the reason may lie in the unevenness of the cushion. In this case, the row needs to be disassembled and a more even base made.
   

   Thanks to the correct geometry of the blocks, the foundation strip is smooth and clear

3. Connections between walls should be provided with special blocks of slightly longer length. If there are none, a recess should be made in the universal blocks, as in the picture. This will ensure reliable adhesion of the perpendicular foundation strips.
   

   At the junctions of internal and external walls you need to put special corner blocks

4. Place metal or fiberglass reinforcement. For low-rise construction, two parallel rods are sufficient, but if necessary, three can be arranged.
   

   The blocks have special grooves for reinforcing rods

5. At the junction of the walls, the rods must overlap so that the length of the free end is at least 2 cm.
   

   Pay attention to the location of the upper and lower rods in relation to each other, they should form a regular square

6. When the length of the rod is not enough, it can be increased by tying a new rod with a special thin wire. It is advisable to make 2-3 dressings per different areas overlap.
   

   The reinforcement should be tied with an overlap of 15–20 cm

7. Place the second row of concrete blocks exactly on top of the first. Do not allow even small deviations; if necessary, adjust the position of the block with a mallet.
   

   Install the second row of hollow blocks on top of the first

8. Fill the prepared formwork with liquid cement-sand mortar so that the concrete level does not reach the grooves for the reinforcement.
   

   The concrete level should be slightly higher than the middle of the top row of blocks

9. Before the concrete begins to dry, try to expel excess air by poking the space inside the formwork reinforcing rod movements from top to bottom. After this, place the reinforcement vertically, especially carefully strengthening external corners and wall joints.
   

   Vertical reinforcing bars can be installed individually at a distance of 1.5 m from each other

10. After the concrete has dried, begin building the foundation. Install and tie the reinforcement, install two new rows of blocks and fill the formwork with concrete. Continue this until the foundation reaches the height you want.
    

    New reinforcement is installed on top of the concrete screed

11. The last row of foundation blocks is poured until a smooth horizontal surface is formed. While the concrete is still wet, you can level it with a small board or a long plaster trowel.
    

    The foundation is ready for the construction of the walls of the future house

A foundation made of concrete hollow blocks for a private house using the described technology is installed by two workers in 2–3 days, taking into account the time for the first layers of concrete to set.

Comparison of costs for creating a foundation from full and hollow reinforced concrete blocks and monolithic with temporary formwork

A comparison shows that a foundation made of hollow concrete blocks is 18% cheaper than a foundation made of solid ones and 36% cheaper than a strip monolith poured using temporary wooden formwork. This is achieved by saving on the amount of reinforcement, reducing labor costs, the amount of concrete, etc. But constructing walls from reinforced concrete blocks will be too expensive (compared to polyurethane foam, wood concrete), it is better to use it only for the foundation.

Making permanent formwork with your own hands

Let's consider the process of creating permanent formwork from sheet materials with independent cutting using the example of EPS (extruded polystyrene foam).

1. Unfold the sheets into fragments corresponding to the width and length of the compacted trench. From the remnants, cut out strips for sides 20–25 cm high. The total length of the sides should correspond to the double perimeter of the trench + 20% for overlap at corner points.
   

   You can cut sheets of polystyrene foam not only with power tools, but also with a hand saw

2. Place the sheets in the trench so that the sides rest on the EPS layer and do not touch the ground. Secure the sheets at the corners by piercing the material plastic ties SVT systems.
   

   When laying EPS sheets in a trench, try to minimize the gaps

3. Place the halves of plastic ties between the vertical sheets and secure them together. If the system does not click tightly enough, tighten the connections with pliers.
   

   Plastic ties are easy to install by hand

4. Install reinforcing bars above and below the horizontal ties. To ensure that the metal is embedded in the thickness of the concrete, place pieces of polystyrene foam under the rods. Special grooves on plastic ties will help maintain the same distance between the reinforcement bars throughout the entire foundation.
   

   Both metal and fiberglass reinforcing bars are suitable for reinforcement

5. Tie the rods together with thin wire, folded 2-3 times. In the same way, the reinforcement can be tied to plastic ties.
   

   Installed reinforcing rods must be tied with thin wire; welding is not allowed

6. Build up the foundation with whole sheets of EPS, having previously attached narrow strips of the same material to them using plastic clips. Place the prepared sheets as shown in the figure. When installing, pay attention to the location of the grooves and ridges on the sheet.
   

   We begin to increase the height of the foundation

7. Attach the vertical sheets to each other with ties, install and tie the reinforcement using the technology described above. You should get at least two plastic reinforcement belts, approximately at a distance of 10 cm from the top and bottom edges of the sheet.
   

   Plastic spacers between the plates are installed in the same way

8. Attach locking plates to the sharp ends of the plastic ties and trim off the ends that remain free.
   

   Protruding tails of ties can be easily trimmed with pliers

9. Fill in reinforced formwork cement-sand mortar. To prepare concrete, you can use your own concrete mixer, but you will need a lot of solution. If you doubt that you can pour the entire foundation in a day, it is better to use the services of an industrial concrete mixer tank.
   

   Filling the finished foundation with concrete

10. Remove air bubbles with a construction vibrator and level the concrete surface. In this case, it is impossible to expel the air with a reinforcing rod, since the metal will damage the formwork, easily piercing the EPS sheet.
    

    The upper plane of the concrete layer should be at the level of the outer layer of the formwork

After the foundation concrete has completely hardened, you can continue pouring the walls using the same technology, but such a foundation can also be used with other materials.

Video: technology for building a house with permanent formwork from particle blocks

When giving preference to one of the options for permanent formwork, consider not only your financial capabilities and labor costs, but also its purpose. For example, in areas with swampy soil you should not use blocks based on wood chips, and in cold regions you should pay attention to a material with a minimum thermal conductivity coefficient. In this case, you can quickly build a warm house without extra financial costs.

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

How to choose formwork

To make the concrete support of the building strong and monolithic, the builders came up with formwork.

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

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

To ensure the installation goes smoothly and you don’t have to deal with unexpected problems, you need to make sure that there are five main conditions before starting work:

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

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

Removable formwork: time-tested installation

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

Attention! Gaps of up to 3 mm in wood formwork are considered normal. 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 covered with tow, and very large ones must be clogged with slats.

The structure is fastened with vertical racks(most often made of timber). It is recommended to place them at intervals of approximately 1 m. The bars can be placed more often if the boards are thin. It is also important that the length allows them to hold tightly.

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

Advice. Instead of nails, it is better to use self-tapping screws during installation. The structure assembled on them is easier to disassemble, because it will be enough to simply 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 (screws) are on the inside of the formwork.

The final step in installing wooden formwork is securing the panels in the trench using spacers: wooden stakes or bars. After pouring and compacting, the concrete is kept in the formwork for up to two weeks until it hardens and gains strength. Afterwards the structure is dismantled. Plywood formwork is installed according to a similar principle.

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

Permanent formwork for the foundation: a new word in construction

IN recent years The removable one is 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 permanent formwork made from this material: ease of assembly (somewhat reminiscent of a construction set or a puzzle) and, as a result, geometric harmony of the parts. Selected species polymer formwork has a reinforcing mesh that strengthens the foundation.

The downside is that the cost of such a foundation is higher than that of one built using boards. However, the game is worth the candle when it comes to something that is being built for decades and for oneself. Permanent formwork can also be made from galvanized profile sheet - in the finished foundation it will protect the surface of the concrete, and its waves will serve as stiffeners. To such metal structure Additionally, a removable “belt” of timber stakes is required.

Formwork for the foundation: video

DIY foundation: photo

This is explained by its high reliability and ease of construction. Even a person who does not have much construction experience can easily fill an area for a garage or a fence. Knowledge about formwork installation will never be superfluous and will allow you to correctly calculate the required amount of material for pouring. Therefore, today we’ll talk about how to make formwork for a strip foundation with your own hands.

The term “formwork” refers to a special construction barrier with the help of which concrete is poured into molds. In progress liquid solution poured into the prepared form, vibrated with special devices to compact and remove air bubbles, leading to internal destruction, and left until hardened.

At the same time, the formwork allows you to give the future foundation various shapes and configuration, and also, when performed with a certain accuracy, allows you to obtain a flat horizontal surface of the strip foundation, ready for masonry work.

Types of formwork

According to classification, formwork can be divided into several groups: according to material, manufacturing method, removable or non-removable.

Metal formwork fencing is highly reliable, can withstand large volumes of poured concrete, and can be assembled in the shortest possible time. The assembly of any necessary figure, be it a square or a rectangle, is carried out in a few simple operations. Special mounts Allows you to move and expand metal sheets, giving required volume for filling. The disadvantages of this type include high cost. This equipment is mainly used on large construction sites and in specialized construction teams whose profile is pouring foundations.

For people who need formwork for a single use, it is perfect wooden version. The assembly process takes longer compared to a metal counterpart, but the cost of the raw materials used is several times lower.

There is also the option of permanent formwork, which consists of polystyrene foam blocks into which concrete is poured. This type of formwork is also insulation for the foundation. This product is installed in the required location, poured into the cavity, after which the entire system remains in place. A foundation of this kind is one of the smoothest and confidently holds the palm in the budget rank.

Budget formwork

If at a construction site there is an acute question of what to make formwork for the foundation from as cheaply as possible, then the cheapest way to create such a structure is to use old doors. This method is ideal for small volumes of pouring and allows you to reduce manufacturing costs significantly. Assembly and fitting has some difficulties, since the bulges of the doors do not allow pouring a completely flat foundation right away, but this problem is easily resolved. A huge advantage of door formwork is the solidity of the structure, which reduces the cost of spacer material.

Making formwork with your own hands

The first step, before starting work on the formwork itself, is to prepare the land. After digging the trench, you can calculate the required material. Using sheets of laminated wood of medium thickness will allow you to quickly assemble a structure to the required dimensions. Using boards is possible, but this method has several disadvantages:

• low accuracy of the side surface of the foundation with the final result;
• high probability of solution breakthrough due to excessive pressure on one area;
• long assembly.

If you decide to build formwork from boards, then to carry out the work you need to use edged board with a thickness of 40 mm. Boards with a smaller thickness can easily sag under the pressure of concrete, which will negate all efforts and costs. Boards with too much thickness will lead to unnecessary costs, although this will not affect the load-bearing capacity of the formwork. Therefore, each builder decides for himself which board to use for formwork, based on the budget and technical specifications future foundation.

As a rule, the internal cavity of the formwork, made of boards, is covered with a layer of greenhouse film, which prevents concrete from flowing out through the cracks between the boards.

When using sheets, the load is distributed evenly, which avoids excess pressure in specific areas. An important component is a sufficient amount of spacer material. Let's talk more about it.

Special devices and stops, which will support the formwork from the outside and tighten it from the inside, will avoid the destruction of the structure. As a rule, to strengthen the formwork of a strip foundation, studs are used, which are installed inside the formwork, secured from the outside with nuts and serve to hold the structure against concrete pressure from the inside.

The second element for strengthening the formwork is the jibs, which are installed externally in increments of 1-1.5 meters along the entire length of the formwork on both sides. These supports provide additional stability to the entire formwork.

Formwork for non-standard shapes

Columns, curves and other structures or their individual elements require a special approach. For these areas, it is recommended to use plastic or metal inserts that will retain the intended shape and aesthetic appearance with maximum accuracy. Strengthening with additional spacers will never be superfluous - you completely eliminate the risk of leakage.

Separately, it is worth mentioning the provision of technological holes in the foundation. Such openings include vents and outlets for communication pipes. For this purpose, special insert sleeves are made in the formwork from plastic pipes, which then make it possible to obtain through holes in the foundation.

Conclusion

The foundation is the basis of any structure and its key long term service, so you should take the most responsible approach to its preparation and filling. Careless attitude and the use of improper materials automatically reduces the service life several times. At the beginning of the construction process, every owner wants to end up with a strong and beautiful structure that will serve him and his children.

Do not neglect information from professionals when building on your own. Availability experienced craftsman in the team will help you correctly distribute available resources and make solid foundation for your future home. An important detail when pouring, reinforcement is used - creating a mesh of metal rods that create a powerful frame for strengthening. Taking into account all the nuances from the selection of raw materials to the process of filling the box with concrete is mandatory to obtain the required result.

Finally, we invite you to visually look at the independent construction of formwork for a strip foundation:

Creating a strip foundation for a house is almost never complete without formwork. It gives shape to the concrete structure, prevents water from flowing out of the concrete, and makes the surface of the tape smooth so that waterproofing and thermal insulation can be easily done. How to make formwork for a strip foundation with your own hands?

Requirements

The formwork must create an optimal temperature and humidity regime at which the concrete hardens well and gains maximum strength. An important requirement is the chemical neutrality of the materials used. They should not react with concrete.

If the formwork is removable, it should be easy to remove without damaging the concrete structure.

Types of formwork

The formwork for a strip foundation can be

• removable,
• non-removable,
• combined.

It is also sometimes possible to pour concrete directly into a trench without a mold.

Removable

Removable formwork is made of boards or plywood and other panel materials: chipboard or fiberboard. Most cheap material- tree. You can also use a slab, but it must be edged (edged) so that the boards fit tightly together. You can also buy or rent a ready-made set of prefabricated metal, plastic or wooden panels. Plastic or metal panels can make the concrete surface very smooth or, conversely, textured.

Fixed

Permanent formwork is most often made from extruded polystyrene foam (EPS). She looks like in the photo.

For a more durable connection, the sheets are fastened with plastic ties. At the same time, this form acts as insulation.

Important! EPS is afraid of ultraviolet radiation, so the foundation must be shaded while the concrete hardens.

You can assemble it yourself from sheets of polystyrene foam, or you can buy ready set. It can be standard or collapsible for non-standard buildings. The advantages of the non-removable option are precise adherence to geometry and high speed of operation. Disadvantage - it is difficult to concrete the foundation evenly

Removable-fixed (combined)

This is a combination of removable and permanent formwork. This design is used on loose soils. It consists of two layers: an inner one made of extruded polystyrene foam and an outer one - a regular removable deck made of boards.

EPPS is attached to the ground with nails 20 cm long, and to wood - with self-tapping screws. This option has its advantages:

• there is immediately thermal insulation on the sides and on the base of the foundation,
• This results in a smooth surface on which the soil will slide when moving.

Such formwork can be made with insulation only in the underground part or to the entire depth.

If EPS blocks are installed to the full depth, they are placed directly in the trench, before which dowels are inserted into them so that the EPS is securely attached to the concrete. In the upper part, protruding from the trench, formwork is installed from plywood panels, which are secured with braces and stakes. Before installing the EPS blocks, the trench is lined with film. EPS is attached to the walls of the trench and wooden shields using nails 20 cm long.

If EPS is installed only in the underground part, they are made in the upper part wooden formwork, into which metal or plastic sheets to get smooth surface base

Concrete preparation

Concrete preparation (footing) is a thin layer of concrete that forms the bottom of the formwork. It has a waterproofing function and prevents cement laitance from going into the ground. However, the construction of a concrete footing is not necessary. They also make formwork without concrete preparation, especially in private construction. In this case, it is necessary to pour a sand cushion and compact it well. Polyethylene or roofing felt is laid inside the formwork. Waterproofing must be laid on the bottom in several layers, and it is attached to the wall with a stapler.

To make formwork with concrete preparation, the trench is widened, and its walls are made in the form of slopes. In this case, boards or plywood panels are installed to the entire depth of the trench and attached to a timber frame.

The shields are tightened with a metal pin inserted into the tube so that it can be removed. Studs are installed at the ends wooden blocks and nuts. Such ties are made at a distance of 0.5 m. The formwork is also strengthened with struts and stakes. If the formwork is placed on a concrete preparation, then anchors are made in the latter. Also, such formwork can be done without concrete preparation, for example, on loose soil.

Preparatory work

Before making the formwork for the strip foundation, it is necessary to prepare the area. To do this, it is cleared of debris and trees, the fertile layer is removed, and leveled. After this, the dimensions of the future building are transferred to the site. Carefully marking is very important.

Next, trenches are dug for the strip foundation, the depth of which depends on the type of foundation: 50-70 cm for a shallow foundation and below the freezing depth for a buried foundation. There is also a non-buried type of strip foundation. Typically, a trench is dug 10 cm wider than the foundation strip. The bottom of the trench must be level; this point is controlled by the level or by the ropes stretched during marking.

A sand or sand-gravel cushion is made in the trench. To do this, pour a layer of sand onto the bottom, wet it and compact it thoroughly. If the soil is dusty, geotextiles are placed at the bottom of the trench before filling with sand. The pillow is also made in two layers: 20 cm of sand and 20 cm of fine crushed stone. After these preparatory works, you can assemble the form for the foundation.

Manufacturing of removable formwork

The load, that is, the pressure of concrete on the formwork, depends primarily on the height of the tape. The larger it is, the greater the load on the formwork and the stronger it should be.

Most often, boards with a thickness of 25-50 mm and a width of 10 cm or more are taken; the wider the board, the easier it is to assemble the structure. Shields assembled from boards are installed in a trench using pegs and reinforced with struts. The struts are made from a bar at least 5 cm thick and placed at a distance of 0.5 m. You can also use panel materials:

• plywood.

Connect boards or panels with self-tapping screws or nails.

Plywood sheets are installed on the edges of the trench, reinforced with braces to stakes installed at a distance of 1 m from the edge of the trench. There should be no more than a meter between the braces. In the upper part, the deck is fastened with wooden jumpers at a distance of 0.5-1 m. The inside of the form is lined with polyethylene or other waterproofing, which should completely cover the panels and bend outward. Polyethylene is fixed with a furniture stapler.

You can use both new and used boards. It is important that they are free of cracks; it is also necessary to remove all nails from them. It is advisable to use boards from coniferous species wood, they must be sufficiently moist (not less than 22%).

Important! After assembling the formwork, it is necessary to check its strength. She must withstand pushes and kicks. Don't be afraid to break the boards: it's better if you find a weak spot during the inspection stage than if it reveals itself while pouring concrete.

It is immediately necessary to provide channels for pipes and other communications. To do this, holes are drilled in the shields required diameter and insert pipes into them.

The formwork should be slightly higher than the concrete level, which is marked on the boards using a cord. It is possible to make formwork flush with concrete, but this is more difficult for non-professionals.

It is important to control how evenly the shields are installed. This is especially true for the above-ground (basement) part of the foundation. The walls must be strictly vertical, and the upper edges must be aligned in the same horizontal plane.

Dismantling

An important question that worries builders is when to remove the formwork? If you do this too early, the foundation may be damaged, if it is too late, the adhesion of the boards to the concrete will be too strong, in addition, when drying, the wood will shrink and create stress.

Depending on the air temperature and time of year, the formwork is removed after 2-15 days, when the concrete has hardened. The lower the temperature, the longer you need to wait. The formwork can be removed when gaps appear between it and the concrete. The boards can be reused; for this, the formwork is lined with polyethylene or treated with oil or lime milk. Remove the boards from the strip foundation carefully, avoiding hitting it.

Correctly made formwork prevents many problems during pouring and further exploitation strip foundation. Therefore, it is necessary to approach this task responsibly and follow technology.

The construction of a foundation is a labor-intensive and expensive process; in individual construction, the only way to save money is to carry out all the work (or its individual stages) on your own. In particular, this applies to the installation of formwork when pouring strip-type foundations; with the right approach and studying the video instructions, even a non-specialist can install, secure and remove it. The material of the panels and supports can be any: plastic, metal, moisture-resistant plywood, boards. Wood is used most often for reasons of economy, ease of assembly and adjustment to the required dimensions.

On preparatory stage The foundation is marked and its perimeter is calculated. The formwork is placed on flat and compacted layers of drainage cushion made of sand and crushed stone. The panels and supports are assembled in advance; the gap between digging the trench and their installation should be minimal, otherwise the walls will begin to crumble and rain moisture will accumulate at the bottom. It is easy to calculate the required number of boards or plywood for formwork under a strip foundation; you just need to know its area. Up to 90% of supporting structures in private construction are made of wood; their thickness depends on the mass of concrete being poured and the purpose of the building. The minimum for timber is 50x50 mm, plywood - 10 (subject to its support), boards - from 22.

Construction technology step by step

Let's look at the standard instructions for building formwork with your own hands step by step (you will find more recommendations in):

1. Drawing up a foundation diagram, selection and calculation of material.

2. Knocking down shields. The boards are sawn into pieces of the same size, attached to the timber with nails or self-tapping screws, with the heads facing inward. Deviations in level are inevitable (there are none except when using plywood), but it is important that they do not exceed 2-3 cm. Gaps and cracks are unacceptable: large ones are clogged with thin slats, small ones with tow. This stage is easy to carry out yourself; the help of another person is required only with limited lines.

3. Lowering and fastening the formwork panels together. The method of fixation depends on the type: removable ones are twisted from the outside, non-removable ones (made of polystyrene foam, fiberboard or other DSP) - whichever is more convenient. Corners require special attention.

4. Installation of spacers (wooden blocks or pieces of plastic pipes in reusable formwork between panels with a length equal to the width of the strip foundation) and securing the structure from the outside with supports sawed at an angle of 45 °, the second end of which is buried in the ground.

5. Checking strength and deviations from markings. Final fixation, adding sand to the lower section. Line marking the border of the upper edge of the base.

6. Flooring inside the waterproofing film. This step is optional, but it is recommended to carry it out if there are gaps between the boards and for the convenience of removing the formwork. When working with panels made of plywood, plastic or metal, the inner surface should be lubricated with oil.

7. Pouring and spreading concrete inside the foundation formwork: layer by layer, but without significant breaks, compacting every 20 cm and leveling the top edge with a trowel. With correctly selected boards and reliable fixation, the structure does not bend under the weight of the solution and remains motionless when air is expelled. It is this condition that allows you to obtain a stable foundation.

8. Dismantling of formwork - depending on the brand and time of concrete hardening, but not earlier than 3 days. Private developers remove it after 70% hardening - that is, after 2 weeks. The main sign that such an operation is permissible is the appearance of a gap between the concrete base and the formwork. You should not carry out the work yourself, especially when removing large supports.

After this, they proceed to the next stage of constructing a strip foundation with their own hands: waterproofing, if necessary, insulation, backfilling with soil. A slightly different (simpler) step-by-step scheme of actions is observed when installing and operating permanent types of formwork, recommended for construction in areas with heavily frozen soils in winter. Structures with walls made of expanded polystyrene or DSP reduce the load on the foundation and give it stability. They are easy to assemble yourself, but unlike ordinary wooden ones, they remain in the ground (points 8 and 9 of the instructions given are skipped).

If the height of the strip foundation exceeds 2 m, it is recommended to make formwork panels from solid materials, and not knock down from the boards. In this case, square structures are considered the most durable; when installing too long ones, the requirements for the number and reliability of stops and internal struts increase. When laying a deep foundation, due to increasing costs, it is worth considering the option of renting formwork.

Contacting specialists (at a minimum, consultation) is required when conducting construction on loose soils. In addition to increasing the number of supports (with a standard step of 0.9-1 m), it is recommended to combine materials, for example, covering formwork boards from the inside with plywood. The opinion of professionals is also important when organizing vertical and lateral supports when the tape rises significantly above the zero mark; in some cases, the latter variety is even screwed to the walls. The standard maximum is 15 cm above the ground level; if it is exceeded, the formwork for the future foundation is supported from all sides.

When choosing internal waterproofing two factors are taken into account: the budget and the size of the filler fractions in the concrete. It is not recommended to use roofing material for these purposes; it is inferior in flexibility to polyethylene (especially in winter). Most often, the choice is made between thick film and moisture-resistant plywood; the second option is optimal when working with heavy coarse concrete.

Rules for uneven terrain

The instructions given imply laying a standard strip foundation; when working on a slope, the process becomes more complicated. In this case, the base is made stepped, at the lowest point the formwork is made higher, at the top the tape should rise above the ground. The bottom is required to be level under any conditions; by analogy, layers of sand and coarser filler are gradually filled in and compacted; it is recommended to fill in a layer of lean concrete.

This type of foundation on a slope will be appropriate when building a house made of heavy bricks (but with differences of more than 1 m, costs unreasonably increase; the height of the strip at the lowest point is not allowed to exceed four times its width); for light buildings, the pile-grillage type is considered a good alternative. The formwork for pouring a hanging grillage is distinguished by the presence of a bottom and additional supports (the weight of the concrete is directed towards it and not towards the ground).

Error Propagation

Technological violations when installing formwork for strip foundations include:

• Using uncut or different-sized boards. From evenness inner surface and the absence of cracks depends on the correctness of the cement hydration process. Serious deviations or gaps lead to leakage of the solution and hardening of the tape with uneven walls (more susceptible to the effects of groundwater later).
• Installation of formwork for the foundation from overdried wood (for similar reasons). In this case, preference is given to raw boards.
• Errors when choosing thickness and width. It is wrong to use plywood without support from the deck, or to knock down too thin boards.
• Removal of formwork ahead of time, rough dismantling (tearing off with force).
• Installing formwork on an uneven base.
• Lack of internal struts at the beginning of concreting. There is an important rule: all wooden elements are removed as the formwork is filled with concrete. Only reinforcing ties made of tin can be left inside the tape.

Ignoring the rules is fraught with bending of structures and excessive consumption of concrete, leakage, the formation of uneven walls and difficulties in further finishing the strip foundation. The involvement of specialists is required if concreting is necessary in winter, work is carried out on difficult soils, limited time installations.

Incorrectly assembled formwork from boards can be strengthened - just cover it from the inside with moisture-resistant plywood. If it is desired to reuse supporting and panel structures, the removed panels are washed, leveled and dried.