Do-it-yourself formwork device from osb. Installation of formwork for the foundation of osb slabs Formwork from osb slabs

OSB foundation formwork. Foundation formwork plays an important role at every construction site. When pouring any elements of a building made of concrete, such as stairs, reinforced belts, ceilings and supporting columns, you also need to pour the formwork.

formwork- This is a type of structure that is required in order to give the concrete mixture a certain shape. As a rule, it is made of wooden boards, metal or plates of various materials. One option is OSB formwork. The advantage of these plates can be called the fact that their installation takes much less time than the installation of boards.

OSB and OSB boards can be easily recognized from thousands by their appearance, as these types of boards have a characteristic wood structure. Oriented strand board is a type of engineered lumber that is somewhat similar to chipboard. Its manufacture is based on the addition of adhesives and the pressing of layers of wood chips, which is oriented in a certain way. OSB has a rough surface, variegated, has individual chips and chips 25 * 150 mm in size, which are unevenly spaced to each other and have a different appearance and thickness.

Application

OSB boards are often used in residential construction. Due to the unique mechanical properties of this building material, it is possible to use it for various purposes. Most often, such slabs are needed for the manufacture of lathing on, walls, roof decking and foundation formwork, as well as other reinforced concrete and concrete building elements. For exterior walls, such panels are produced with lamination on one of the sides, which greatly helps to simplify installation and increase the energy efficiency of the fence design. OSB is also often used in the manufacture of furniture.

Production

Before you buy OSB for foundation formwork, the material is manufactured in production. The boards are made in the form of wide mats, as well as layers of chips that are differently oriented, glued and compressed with synthetic resin and wax adhesives (5% resin/wax and 95% wood). Typically, the resins that are used include phenol formaldehyde, isocyanite, and melamine-molded urea formaldehyde. Each of these binders is resistant to moisture. As a rule, a combination of astringents is used - isocyanite is used in the middle, while urea formaldehyde is present in the front layers. This helps to reduce the number of pressing cycles, and at the same time gives a beautiful appearance to the surface of the board.

The layers are made as follows - the wood is crushed into strips, which are then sifted and further oriented with the help of various devices when fed to the molding line. For the outer layer, the chips are aligned along the strength axis of the plate, and the inner layers are strictly perpendicular. The number of layers placed will to some extent depend on the thickness of the panel to be produced, but is still limited by the equipment used in production. The individual layers can also vary in thickness to give different thicknesses to the slab (usually 17 cm of layer results in panels with a thickness of 1.7 cm). Next, the mat is placed under a thermal press so that the raw material shrinks and holds together due to thermal activation and curing of the resin that coats the wood. After that, individual panels should be cut from mats to the desired size.

Note, that OSB panels for timber structures can be cut and installed just as easily as natural wood.

Technical properties and varieties

Adjustments in the manufacturing process may result in variations in board thickness, size, strength and stiffness. OSB boards for do-it-yourself formwork are good because they do not have internal voids and are water resistant, although they require additional shells to obtain water resistance and are not very suitable for outdoor work. The finished product has properties that are somewhat similar to plywood, but cheaper and more uniform. When testing OSB for fracture, it was revealed that the material has a high load capacity and this indicator is higher than that of milled wood panels.

There are 4 varieties of OSB boards, which are defined in terms of mechanical characteristics and relative resistance to moisture:

OSB/1 - general purpose boards for interior decoration (furniture included), required for use in dry conditions.
OSB / 2 - bearing boards, which are needed for use only in a dry room.
OSB / 3 - bearing type plates that can be used in conditions of high humidity.
OSB / 4 - bearing type plates (for heavy loads), which can be used in conditions of high humidity.

Although OSB does not have a continuous fiber like natural wood, it has an axis along which the resistance force is greatest.

Interesting, that it is the characteristics of the strength of the plates that make their use as a material for the manufacture of foundation formwork expedient, and the ease of processing makes it possible to perform work on one's own, without the involvement of specialists.

Installation rules

Before you begin work on creating formwork for the OSB foundation, you should prepare all the necessary tools and fixtures, as well as materials for what to connect, strengthen and install.

The required set of tools is standard for carpentry:

OSB boards are easy to cut

On parts of the required dimensions when using a table or electric hand saw. But do not worry if you do not have such a tool - a hacksaw will also cope with this task. Also, cutting of plates can be carried out at a specialized stand in building markets, according to pre-taken standards.

In order to avoid deformations of various parts of the formwork during pouring, they should be reinforced with stiffeners made of wooden blocks. It is also important to screw them around the perimeter of all parts and across. This precaution is of particular relevance if you are going to use sheets that are large in area, for example, in the manufacture of formwork for ceilings or for foundation walls with a large height.

When making formwork from OSB with your own hands

When it is on both sides of a concrete building element, two parts that are opposite each other must be folded together, and then holes for a mounting bolt or stud should be drilled in them, at the bottom and at the top. When a piece of plastic pipe of the required length is installed between the OSB sheets, you can pass a hairpin through it and clamp it with nuts, which will help form the box. In order to prevent the plate from being torn from concrete and its weight, it is advisable to place washers with a large diameter under the nuts.

When making a corner box for the foundation, one of the two walls must be longer in order to form a corner. Now that the boxes are ready, it is enough just to form the foundation of the required design. Finished elements can be lowered into a trench or pit, arranged according to the building design and fixed with bars. The formwork itself should be fixed with reinforcing pegs, which must be hammered into the ground. For a high foundation, in addition to reinforcement, it is recommended to use struts, each should be 0.7 meters in order to prevent the destruction of the structure, which is possible when pouring concrete. Slots between individual boxes can be sealed with polyethylene or glassine.

Important! When fixing the plates, do not butt them together. Slots are needed, the width of which is 0.2-0.3 cm, in order to compensate for minor material movements that are caused by external influences (humidity level, temperature).

If OSB boards are used to make a low foundation

...or a reinforced belt, you can get away with a simplified formwork method. To do this, the details of the reinforced belt should be attached to the bottom of the wall with long self-tapping screws, and on top with wooden bars. After that, take the knitting wire and additionally pull the parts together. The foundation of a small height can be strengthened with self-tapping screws on pegs of blocks that are driven into the ground, according to the plan of the house. After that, the formwork should be strengthened from the outside with struts.

When creating a formwork for overlapping, OSB slabs should be laid on a frequent lattice (0.5 * 0.5 meters) from a supporting beam, which will be installed on racks of the required height. It is desirable that the racks be every 1.5 meters.

Metal pipes will be required for manufacturing, but if they are not available, you can rent or use industrial racks designed for monolithic work. It is also desirable that the concrete be poured along the entire perimeter, while not creating excessive stress at a certain point. If it is not possible for various reasons (organizational, technological) to perform pouring without interruption, then working seams should be made according to the rules for concrete work. For example, the working joint must necessarily be perpendicular to the axis of the concrete element and without slopes.

Base insulation

Also, when building a house and making formwork, you can think in advance about how to insulate your future home. To do this, buy foam sheets of the right size and attach to the OSB front plate from the inside. In order for the sheets of insulation material to be firmly fixed on the concrete base, before installing them on a collapsible structure, pass the wire loops through the foam. Thanks to this construction trick, you will be able to securely attach the foam to the foundation.

OSB boards can be used for formwork many times (at least 10), and even after dismantling, they can be used as hard sheathing on the attic floor or on the roof. It turns out that with the correct organization of the order of work and the careful use of the material, the use of plates will be waste-free, and you will save money.

On any construction site, a foundation formwork is a necessary element. During the pouring of concrete elements of the building, for example, armored belts, stairs, supporting columns and ceilings, formwork is also indispensable. Formwork is a type of structure, the task of which is to give a certain shape to the concrete mixture. It is usually made of wooden boards, plates of various materials or metal. One option is OSB formwork. The advantage of these boards is that they install much faster than boards.

Oriented Strand Board

OSB/OSB board is easily recognizable by its characteristic wood structure. Oriented strand board (OSB) is a type of engineered lumber similar to chipboard that is formed by adding adhesives and then pressing layers of wood chips oriented in a particular way. The surface of OSB is rough and motley, with individual chips (chips) about 2.5 cm * 15 cm, located unevenly to each other and having a different appearance and thickness.

Usage

OSB boards are widely used in housing construction. The mechanical properties of this building material allow it to be used for a variety of purposes. Most often used as a crate on walls, floors, roof decking and formwork for foundations and other concrete (reinforced concrete) building elements. For exterior walls, the panels are pre-laminated on one side; this simplifies installation and increases the energy efficiency of the building envelope. OSB is also used in furniture manufacturing.

Production

The slab is made in the form of wide mats, from layers of differently oriented chips, compressed and glued together with wax and synthetic resin adhesives (95% wood, 5% wax and resin). Commonly used types of resins include phenol formaldehyde, melamine molded urea formaldehyde or isocyanate. All of these binders are resistant to moisture. A combination of binders is often used, typically isocyanate in the core and urea formaldehyde in the top coats. This has the advantage of shortening pressing cycles while imparting a bright appearance to the panel surface.

Layers are created by cutting wood into strips, which are sifted and then oriented with various devices when fed to the molding line. For the outer layers, the chips are aligned along the strength axis of the panel, while the inner layers are aligned perpendicularly. The number of layers to be placed depends partly on the thickness of the panel to be obtained, but is limited by the equipment installed at the plant. The individual layers can also vary in thickness to give different thicknesses to the finished panel (usually a 15 cm layer results in a 15 mm thick panel). The mat is placed in a thermal press to compress the raw material and bond it through heat activation and curing of the resin that coats the wood. The individual panels are then cut from the mats to the desired dimensions.

Wooden OSB panels can be cut and installed with the same ease and the same tools as real wood.

Properties and types

Adjustments in the manufacturing process can introduce differences in thickness, panel size, strength and stiffness. OSB boards are void-free and water-resistant, although they require additional skins to achieve water-tightness and are not recommended for outdoor use. The finished product has properties similar to plywood, but is more uniform and cheaper. When tested for fracture, OSB has a greater load capacity than milled wood panels.

Four types of OSB are defined in terms of their mechanical characteristics and relative resistance to moisture:

OSB/1 - general purpose boards for interior decoration (including furniture) for use in dry conditions;
OSB/2 - load-bearing boards for use in dry conditions;
OSB/3 - load-bearing boards for use in wet conditions;
OSB/4 - load-bearing boards (for significant loads) for use in wet conditions.

Although OSB does not have a continuous fiber like natural wood, it does have an axis along which the drag force is greatest.

It is the strength of OSB boards that makes their use as a formwork material expedient, and the ease of processing makes it possible to do the work yourself.

Installation rules

Before starting work on the manufacture of formwork, it is necessary to prepare tools and additional materials for its connection, strengthening and installation. Tool kit - standard for carpentry:

axes (large and small);
hacksaw (electric saw or jigsaw);
hammer;
screwdriver (screwdriver);
measuring instruments (tape measure, level, plumb line);
wooden beam, pieces of reinforcement and plastic pipes of small diameter;
fastening hardware (long bolts or studs, nuts, self-tapping screws).

OSB boards are easy to cut into pieces of the desired size using a table saw or a hand-held electric saw. A hacksaw will also successfully cope with this. The slabs can also be cut at a special stand in a building materials store, according to previously taken dimensions.

In order to avoid deformation of individual parts of the formwork, when pouring, they should be reinforced with stiffening ribs from wooden bars. They should be screwed around the perimeter of each part and across it. This precaution is especially important if large area sheets are used, for example when making formwork for floors or high foundation walls.

In the manufacture of formwork on both sides of a concrete building element, two opposing parts are stacked together, then holes are drilled in them, at the top and bottom, for a mounting stud / bolt. Having installed a piece of plastic pipe of the required length between the OSB sheets, a pin is passed through it and clamped with nuts, forming a box.

To prevent the plate from tearing from the weight of concrete, it is advisable to place washers of large diameter under the nuts.

When making corner boxes for the foundation, one of the walls of the two boxes is made longer so that a corner can be formed.

From the prepared boxes, it is quite simple to form the foundation of the desired configuration. The finished boxes are lowered into the pit / trench, arranged in accordance with the building plan and fastened together with bars. The formwork of the foundation itself is fixed with reinforcing pegs hammered into the ground. For a high foundation, in addition to reinforcement, it is desirable to use struts, approximately every 70 cm, this will prevent the destruction of the structure, which is possible when pouring concrete. The gaps between the individual boxes can be closed with glassine or polyethylene.

When fixing the plates, you should not connect them end-to-end. Slots with a width of 2 - 3 mm are required to compensate for minor material movements caused by external influences (temperature, humidity).

If OSB boards are used to make an armored belt or a low foundation, you can get by with a simpler method of mounting the formwork. The details of the armored belt are attached to the wall with the bottom part using long self-tapping screws, and on top with wooden bars. Then, with the help of a knitting wire, the parts are additionally pulled together. A low foundation is reinforced with self-tapping screws on stakes made of wooden bars, which are driven into the ground, in accordance with the plan of the house. Then the formwork is reinforced with struts from the outside.

In the manufacture of formwork for overlapping, OSB boards are laid on a frequent (50 * 50 cm) lattice of supporting beams, which is installed on racks of a given height. It is advisable to install racks every one and a half meters. For their manufacture, you can use metal pipes or, if it is possible to rent them, use industrial racks for monolithic work.

It is advisable to pour concrete around the entire perimeter, without creating excessive stress in one place. If it is impossible, due to various reasons (technological, organizational), to carry out pouring without interruptions, then work joints should be created in accordance with the rules for concrete work. So, for example, the working joint should be perpendicular to the axis of the concrete element, without any bevels.

In this video you can see how to make an armored belt formwork from OSB:

OSB boards can be used repeatedly (up to 10 times), and after dismantling the formwork, they can be used to make rigid sheathing on the roof or floor in the attic. That is, if you properly organize the order of work and carefully use the material, then when using these plates, you can do without waste and, accordingly, save money.

It is almost impossible to build a monolithic foundation of a building without formwork. Indeed, in the foundation there should not be a single defect that has a negative impact on its operational properties. More recently, they were built from boards.

The main disadvantage of wooden fencing is the long-term assembly and installation of the structure. Therefore, today even private developers use oriented chipboard for this purpose.

A little about her

OSB board is a building and finishing material created on the basis of thin wood shavings arranged in three layers.

Their position in the outer layers is oriented along the length of the plate, and in the inner layer - perpendicular to its length.

Such multidirectionality of the chips, as well as their processing with synthetic waterproof resins and pressing under pressure at high temperatures, determine the special strength of the material. The homogeneity of the structure of oriented particle boards ensures their integrity under bending loads.

OSB board is characterized by low hygroscopicity, which makes it particularly resistant to delamination and swelling. This material is quite light and easy to process, and even surpasses plywood in technical properties. For multiple use in the arrangement of formwork, OSB - 3 boards are best suited, as the surface of one of their sides is laminated.

Large sheets of material allow a small number of joints to be made when lining up the formwork walls. The light weight of oriented particle boards, which simplifies the installation work, makes them in demand among private developers.

Video

Practical video about the manufacture of formwork.

Necessary materials

OSB sheets - 3 not less than 15 mm thick.
Wooden bars 100 x 150 mm.
Pipe profile metal.
Steel studs with nuts and washers.
Self-tapping screws.
Pieces of rebar.
Pipe plastic 20, cut into segments equal to the width of the formwork.

Process of creation

The assembly of the formwork structure is started after the trenches for the foundation have been dug and the sandstone has been laid.

The most common option is to install removable panel formwork from OSB boards. Prefabricated - panel formwork structures are easier to install according to the dimensions of the foundation and to correct the corners.

When erecting formwork, it is necessary to provide places for laying pipes along the perimeter of the foundation. Subsequently, this will simplify the connection of communications.

The sequence of work is as follows:

OSB boards, cut to the size of the base of the building. We make the height a little more than the intended fill (by 10 - 15 cm).
We make frames for shields. They can be made from wooden blocks. If it is assumed that the formwork will be used repeatedly, then it is more practical to weld a metal frame from a profile pipe.
We fasten the OSB blank to the frame with self-tapping screws. Their hats should be on the inside.
The sides of the formwork structure are reinforced with wooden bars, which we nail every 40 cm. This is necessary to form the geometry of the foundation and ensure the specified dimensions during concreting.
Opposite shields in the foundation trench are fastened with steel studs. To do this, we drill holes with a diameter of 16 mm in the attachment points. The studs should be about 2-4 cm longer than the width of the formwork. We use nuts with washers to fasten them. Fasteners must be chosen wide enough, otherwise it may happen that, under the pressure of concrete, the stud will push the plate through with the nut.
Between the shields, we pass the studs through pieces of plastic pipes of a given length, to ensure the same width of the foundation around the entire perimeter. After the formwork is removed, the pipe sections remain in the concrete. Subsequently, they can be used for ventilation.
In the absence of pipes, fastening is done with nuts and washers on both sides. In this case, 4 nuts with washers are required per stud.
When dismantling such formwork, the nuts are unscrewed, and the protruding ends of the studs are cut off. After removing the OSB boards, it is necessary to cut off all the remnants of the studs again.
For the corner connection of the shields outside the corners, we drive vertical bars into the ground. They can be additionally fastened with metal corners. When assembling the formwork, it is important to reinforce the corners well - the weakest point in any formwork. During the pouring of concrete, maximum pressure is created in these places.
In order for the OSB formwork to hold on stronger, sometimes through holes are made with a drill in several places of the shield frame. Small pieces of reinforcement in the shape of the letter "T" are inserted into these holes and welded to the reinforcing cage of the foundation. When disassembling, the protruding part of the reinforcement is cut off.
The installation of inclined beams outside the formwork structure with a step of 1 m allows it to withstand the weight of poured concrete. The spacer element should adjoin the shield at an angle of 30 - 45 degrees.
After the formwork structure is completely ready (before concrete), it is worth checking the parallelism of the edges of the panels. This is easy to do with a bar and level.

If you take breaks during pouring, in other words, fill it with a small layer around the perimeter of the foundation, then the concrete will have time to set a little, due to this, the pressure on the formwork will decrease.

Conclusion

The use of OSB formwork allows you to lay foundations and at the same time insulate them. To do this, it is necessary to lay polystyrene slabs between the formwork panels and concrete.

The construction of formwork structures, from oriented particle boards with your own hands, not only reduces the time for building the foundation, but also significantly reduces the cost of laying it.

In contact with

The operational period of the foundation and its strength index in most cases are determined not only by the starting materials for pouring, but also by the organization of the work. Therefore, it is necessary to approach with full responsibility the installation of the formwork system for pouring the base of the object, so that there are no void areas and other defects in the foundation body that have a negative impact on operational performance. And today, even private developers know that OSB formwork is exactly the option that helps create a reliable foundation for an object under construction.

Areas of use

OSB is widely used in the construction of residential buildings. From this material, crates are mounted and formwork structures are installed.

Often, OSB formwork is installed to fill the foundation. In addition, it is used in the construction of fences and buildings for economic purposes, erected by monolithic casting.

The material is easy to process, which allows you to create structures of various shapes from it.

It should be noted that OSB have found their application in the installation of wall and floor battens, under roofing. The manufacturer produces OSB material with a laminated surface, which greatly facilitates installation work and increases the energy efficiency of the entire structure. Finally, OSB boards are used in furniture production.

Advantages and disadvantages

The formwork for pouring the foundation base must be strong in order to hold the concrete mass until it finally hardens. The use of OSB boards creates good advantages over the well-known method of arranging shuttering boards from boards.

The advantages of the material include:

low level of hygroscopicity. Boards do not swell under the influence of a humid environment, as happens with ordinary lumber. Such formwork can be used repeatedly, since it does not lose its properties;

The material is easy to process and cut. The specific gravity of OSB is much less than that of wood, it is more convenient to work with them;
the time intervals required for the installation of formwork are reduced;
solid boards are made from OSB panels that do not have docking areas, which minimizes the likelihood of leakage of the concrete mix.

It should be noted that with all the advantages of OSB, there are certain disadvantages:

there is a weak resistance to loading influences;
in the adhesive involved in the production of the material, there is phenol, which poses a threat to the body.

Materials used

To prepare OSB formwork for the foundation with your own hands, you need to prepare everything that is needed for work.

The necessary calculations are performed when the foundation ditch is prepared. The height of the plinth and the specific gravity of the concrete solution should be taken into account.

For work you will need:

OSB boards;
bars, for the manufacture of stiffeners on boards from OSB;
fasteners for the assembly of the structure. This will require nuts with washers, studs and bolts;
pipes made of plastic material, with the help of which the opposite formwork panels are connected;
metal corners. They are installed on the corner sections of the formwork to increase the reliability of the OSB structure;
reinforcing bars for pegs;
plywood material or glassine. They lay slotted areas in the formwork;
self-tapping screws. With their help, plates, plywood and glassine are fixed.

At the preparatory stage, the slab material is cut into the necessary elements, the dimensions of which correspond to the calculations performed.

Design features

OSB - oriented strand board is considered engineering lumber, with its wood structure resembling chipboard panels. For the manufacture of OSB boards, a special glue is used that connects several layers of pressed wood chips, properly oriented.

The surface of the plates is slightly rough, small chips are visible on it, the dimensions of which are 2.5 by 10 or 2.5 by 15 cm. They are arranged randomly, differing in thickness and appearance.

When forming an OSB board, three layers of chips are used, the outermost of which are laid lengthwise in relation to each other, and the middle one is laid at an angle of ninety degrees. This arrangement creates the necessary level of strength.

Synthetic resin compounds are involved in the production process, pressing is carried out under strong pressure and high temperature conditions, which helps to improve the performance of the boards.

The uniformity of the structure contributes to the good work of OSB boards in tearing and bending.

Installation of OSB formwork

We are preparing a construction site, digging a trench under the foundation, arranging a sand cushion at its bottom.

When pouring the foundation, do not forget to determine the places for laying pipes along its perimeter, into which we will then pass communications.

The work algorithm is as follows:

OSB boards are cut to the required dimensions. At the same time, we take into account that the height should be ten to fifteen centimeters more than the upcoming pour;
frames are made for shields. If we plan to use the formwork repeatedly, then the wooden bars should be replaced with profile pipes;
OSB with the help of self-tapping screws is fastened to the frame, leaving caps on the inner surface;
The sides of the formwork panels are reinforced with bars, which are stuffed in increments of forty centimeters. Thus, the foundation geometry will be better formed, the required parameters will be provided when pouring the concrete solution;
shields are installed on both sides of the trench, connected by spacer metal studs. For this purpose, holes with a diameter of 1.6 cm are made at the attachment points. The length of the studs should exceed the width of the formwork structure by several centimeters. Fastening is carried out with nuts and washers. These elements must be wide so that from the pressure created by the concrete, the stud does not push through the plates through, pulling out the nuts;
inserting the studs, we pass them through plastic tubes of the same size. This will help to set the formwork to the same size in width around the entire perimeter. When dismantling the structure, the tubes remain in the concrete monolith. In the future, they can be used for ventilation devices;
if there are no tubes, the studs are attached to four nuts on both sides;

dismantling such a formwork, it is necessary to unscrew the nuts and cut off the ends of the studs. After removing the shields, trimming is performed again;
on the corner sections of the formwork, bars are driven into the ground, reinforced with steel corners for reliability. Formwork assembly requires the strength of corner joints, as the weakest points of each structure. When pouring a concrete mixture in such places, the strongest pressure is formed;
so that the formwork from OSB boards is durable, in some places of the frame base, holes are made with a drill into which reinforcing sections shaped like the letter “T” are inserted, welding them directly to the frame. During the dismantling of the formwork, all fasteners protruding outwards are cut off;
outside the formwork structure, the bars are set at an angle. The installation step is one meter so that the system can withstand the pressure created by the concrete mixture. The angle of inclination of the strut is thirty - forty-five degrees;
having fully completed the preparation of the structure, we check the shield edges for parallelism. This will require a building level and a flat wooden block.

If breaks are allowed during concreting, pouring in layers, the concrete mortar will set gradually, reducing the pressure on the formwork system.

Conclusion

The use of formwork systems made of OSB boards makes it possible not only to pour a reliable foundation, but also to carry out its insulation. For this purpose, polystyrene sheets are laid between the shields and the concrete layer. The construction of formwork from oriented strand boards will reduce the time of work and reduce financial costs.

Formwork is an integral part of the construction site. It is used not only for the construction of a strip foundation, but also for stairs, armored belts, floor slabs, columns, wall structures. Allows you to create products from a concrete solution of a certain shape. Often the main elements for its manufacture are wooden boards or metal plates. One of the most practical options is OSB.

Oriented strand board is a type of engineered lumber that resembles chipboard in its wood structure. It is formed with the help of special adhesives and by pressing several layers of wood chips, oriented in the necessary way. It has a somewhat rough surface, where small chips of wood with dimensions of approximately 2.5x10 or 2.5x15 cm are visible. They are randomly located, while their thickness and appearance differ from each other.

To create OSB, three thin layers of chips are used, while the two extreme opposite to each other are laid along, and the middle one is perpendicular. It is this oriented arrangement that provides proper strength. Water-resistant synthetic resins and high temperature pressure molding are also applied to improve performance. Due to the homogeneous structure, they work well for bending and tearing.

OSB formwork has:

Low hygroscopicity. The material is particularly resistant to swelling or delamination.
Ease of processing. Easy to saw and drill.
Reusable. OSB-3 do not lose their qualities, since one of the sides is laminated.
Light weight. It simplifies installation work, therefore it is in demand among private developers.
The possibility of using large-sized slabs, which allows you to create large-panel formwork with a small number of joints.

Advantages and disadvantages of such formwork

The manufacture of OSB is carried out by pressing large chips (50-80 cm) under high temperature. At the same time, waterproof resins and chemical additives are added that exclude damage by fungal microorganisms or mold. Under the influence of moisture, the products are not able to warp and collapse for a long time, due to which they are effectively used in the construction of formwork for the foundation.

Compared to wooden boards, the boards are not deformed due to the influence of external factors and atmospheric precipitation, therefore they are used several times without loss of performance. They have perfectly smooth edges, which is not always possible to achieve from ordinary wood.

Since OSB is easy to saw, you can create panels of any size, which makes it easy to select the right elements. The material is sufficiently elastic, therefore it is less prone to destruction under bending loads. Also, this and its low weight makes it possible to easily and quickly create formwork, saving time on construction.

OSB boards have some disadvantages:

Poor resistance to high concentrated loads.
They have phenol in adhesive compositions, which is harmful to human health.
Panels 3 and 4 types can only be placed outside the building.

Plywood and OSB formwork is often used in the construction of buildings and structures for various purposes. Due to their mechanical properties, they are widely used for wall cladding, roof floors, foundation frames, floor slabs and other reinforced concrete monolithic structures. There are elements with a laminated surface, which greatly simplifies their installation and increases their effectiveness as enclosing products. The panels are also used in the manufacture of furniture products.

Necessary materials

Calculation of the formwork for the strip foundation is carried out only after the installation of trenches. In this case, the height of the basement of the building and the specific density of the concrete solution, which imposes a certain load on the shields, should be taken into account. For its manufacture are used:

Wooden blocks as stiffeners.
Hardware for connecting the structure (bolts with nuts, washers, studs).
Metal corners for reliable fastening of plates.
Plastic pipe for fastening opposite shields.
Reinforcing rods.
Plywood or slats to cover gaps.
Self-tapping screws for connecting OSB and glassine.

At the preparatory stage, plates of the required dimensions, plastic pipes and fittings are cut, and the dimensions of the shields are calculated.

Step-by-step installation technology

The assembly of the fence begins after excavation and laying a sand cushion under the strip foundation. The most practical option is a removable formwork device. Prefabricated panel systems allow you to quickly and easily assemble panels of the desired size with correction of corner sections.

Provide places for laying engineering and plumbing communications that will be located on the construction site.

Installation is carried out in the following sequence:

1. OSB-plates are cut according to the dimensions of the edges of the foundation, while the height is made slightly larger than the net level by 15 cm.

2. Frames for walls are made. The budget option is wooden, however, for repeated use, you will need shields made of metal bent-welded profiles.

3. The OSB blank is attached to the frame with self-tapping screws, the caps of which should be on the inside and slightly recessed.

4. Each side of the formwork is reinforced with transverse bars in increments of 40 cm. This will allow you to observe the geometry of the structure being created.

5. Opposite elements are connected with metal studs, which are threaded through previously drilled holes with a diameter of 16 mm. Fasteners should extend 3-4 cm beyond the shields on each side to ensure secure fastening with washers and nuts. The lateral plane of the fasteners is chosen wide so that under the pressure of the mixture they do not push through the OSB.

6. Plastic pipes are threaded, which will allow you to maintain the accuracy of the width on any segment of the strip foundation. After pouring the mortar and its hardening, they remain in the concrete body, while working well as ventilation.

7. If there are no pipes, fastening can be done with nuts. Then there are about 4 pieces with washers per side. When dismantled, they are removed and the ends of the studs are cut off flush.

8. When pouring the concrete mixture, the corner sections perceive the greatest efforts, therefore, reinforcement is carried out with wooden blocks vertically driven into the ground. For additional reinforcement, steel corners are used to connect the shields to the pegs.

To give maximum rigidity, holes are made in the shields into which embedded reinforcement products are inserted in the shape of the letter "T". The long side is welded to the reinforcing cage of the foundation and the mortar is poured. After solidification, the excess parts are cut off with a grinder.

Inclined bars on the outer side of the structure with a step of 1 m allow you to keep it in a vertical position until the very end of construction. Spacers should be attached to the shields at an angle of 30-45 °, then the possibility of their collapse is excluded. At the end of the formwork device, a control check of the parallelism of the side faces is carried out. This will require a piece of timber and a water level.

Concrete work can be carried out in layers, taking small breaks between pouring. Then the solution will set, and the spacer pressure will decrease. However, if the foundation area is small, it is recommended to lay the mixture in full, excluding the appearance of cold joints.

Formwork reduces construction time by combining the laying of the foundation and its insulation. To do this, at the stage of the installation of enclosing structures, polystyrene plates are laid between the reinforcing cage and the shields.

Articles