Which is cheaper OSB or board formwork. Making OSB formwork with your own hands. Purpose of formwork for the foundation

Formwork is an integral part of construction site. It is used not only for the construction strip foundation, but also stairs, reinforced belts, floor slabs, columns, wall structures. Allows you to create products from concrete mortar 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 panel is a type of engineered lumber that resembles chipboard in its wood structure. It is formed using special adhesives and pressing several layers of wood chips oriented in the required manner. It has a somewhat rough surface, where small chips of wood measuring approximately 2.5x10 or 2.5x15 cm are visible. They are located chaotically, while their thickness and appearance differ from each other.

To create OSB, three thin layers of shavings are used, with the two outermost ones opposite each other being laid lengthwise, and the middle one perpendicularly. It is this oriented arrangement that ensures proper strength. Water-resistant synthetic resins and high-temperature pressure molding are also used to improve performance. Due to their homogeneous structure, they work well in bending and tearing.

OSB formwork has:

• Low hygroscopicity. The material is particularly resistant to swelling or delamination.
• Easy to process. Easy to saw and drill.
• Reusable. OSB-3 does not lose its qualities, since one of the sides is laminated.
• Light weight. It simplifies installation work, which is why 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 production 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, which eliminate 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, slabs do not deform due to impact external factors and atmospheric precipitation, therefore they are used several times without loss of performance characteristics. 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 necessary elements. The material is quite elastic, so it is less susceptible to destruction under bending loads. This is also his low weight makes it possible to easily and quickly create formwork, saving construction time.

OSB boards have some disadvantages:

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

Formwork made of plywood and OSB 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, roofing 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 fencing products. The panels are also used in the manufacture of furniture products.

Required materials

Calculation of formwork for a strip foundation is carried out only after the installation of trenches. In this case, the height of the building’s base and the specific density of the concrete solution, which places a certain load on the panels, must be taken into account. For its manufacture the following are used:

1. Wooden blocks as stiffeners.
2. Hardware for connecting the structure (bolts with nuts, washers, studs).
3. Metal corners for reliable fastening of plates.
4. Plastic pipe for fastening oppositely located panels.
5. Reinforcing bars.
6. Plywood or slats to cover gaps.
7. Self-tapping screws for connecting OSB and glassine.

On preparatory stage slabs of the required sizes, plastic pipes and fittings are cut, and the dimensions of the panels are calculated.

Installation technology step by step

The assembly of the fence begins after excavation work and laying a sand cushion under the strip foundation. The most practical option is a device of removable formwork. Prefabricated panel systems allow you to quickly and easily assemble panels of the required 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 boards are cut to fit the dimensions of the foundation edges, with the height being made slightly larger than the clean level by 15 cm.

2. Frames for the walls are made. Budget option is wooden, but for repeated use you will need shields made of bent-welded metal profiles.

3. The OSB blank is attached to the frame with self-tapping screws, the heads of which must be in inside and slightly recessed.

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

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

6. Plastic pipes are threaded, which will allow maintaining the accuracy of the width on any section of the strip foundation. After pouring the solution and hardening, they remain in the body of the concrete, and work well as ventilation.

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

8. When pouring concrete mixture corner areas perceive the greatest forces, so they are reinforced with wooden blocks driven vertically 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 panels into which embedded reinforcement products are inserted in the shape of the letter “T”. The long side is welded to the reinforcement frame of the foundation and the solution is poured. After hardening, excess parts are cut off with a grinder.

Inclined beams on the outside of the structure in increments of 1 m make it possible to keep it in a vertical position until the very end of construction. Spacers should be attached to the boards at an angle of 30-45°, then the possibility of them collapsing is eliminated. Upon completion of the formwork installation, a control check of the parallelism of the side faces is carried out. To do this you will need a piece of timber and a water level.

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

Formwork reduces construction time by combining the laying of the foundation and its insulation. To do this, at the stage of constructing enclosing structures, polystyrene slabs are laid between the reinforcement frame and the panels.

Articles

The operational period of the foundation and the indicator of its strength in most cases are determined not only by the initial materials for pouring, but also by the organization of the work. Therefore, it is necessary to approach with full responsibility the installation of a formwork system for pouring the base of an object, so that void areas and other defects that have an impact on the foundation are not left in the foundation body. negative impact on performance indicators. And today, even private developers know that OSB formwork is exactly the option that helps create a reliable foundation for a facility under construction.

Applications

OSB is widely used in the construction of residential buildings. Lathings are assembled from this material 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 commercial buildings erected using 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 has found its application in the installation of sheathing of walls and floors, under roofing decks. 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 must be strong in order to hold the concrete mass until it finally hardens. The use of OSB boards creates quite good advantages over the well-known method of constructing formwork panels from boards.

The advantages of the material include:

• low level of hygroscopicity. The slabs do not swell when exposed to a humid environment, as happens with conventional lumber. This formwork can be used many times, since it does not lose its properties;

• The material is easy to process and saw. The specific gravity of OSB is significantly less than that of wood, making it more convenient to work with;
• the time intervals required for installing formwork are reduced;
• One-piece panels are made from OSB panels that do not have joint areas, which minimizes the likelihood of leakage of the concrete mixture.

It should be noted that with all the advantages of OSB, they have certain disadvantages:

• there is weak resistance to load influences;
• the glue used in the production of the material contains 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 you need for the work.

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

To work you will need:

• OSB boards;
• bars for the manufacture of stiffening elements on OSB boards;
• fasteners for assembling the structure. This will require nuts with washers, studs and bolts;
• tubes from plastic material, with the help of which the connection of opposite formwork panels is carried out;
• 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 the slotted areas in the formwork;
• self-tapping screws They are used to fix boards, plywood and glassine.

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

Design features

OSB - oriented strand boards are considered engineered lumber, with their wood structure reminiscent of chipboard panels. For the manufacture of OSB boards, a special glue is used that connects several layers of compressed wood chips, properly oriented.

The surface of the slabs is slightly rough; small chips can be seen 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 at an angle of ninety degrees. This method of arrangement creates the necessary level of strength.

The production process involves synthetic resin compounds, pressing is carried out under strong pressure and high temperature conditions, which helps to increase performance characteristics slabs

The homogeneity of the structure contributes to the good performance of OSB boards in tearing and bending.

Installation of OSB formwork

We prepare the construction site, dig a trench for the foundation, and arrange a sand cushion at its bottom.

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

The work algorithm looks like this:

• OSB boards are cut according to required sizes. At the same time, we take into account that the height should be ten to fifteen centimeters greater than the upcoming filling;
• frames for shields are manufactured. If we plan to use the formwork repeatedly, then the wooden blocks should be replaced with profile pipes;
• We screw the OSB to the frame using self-tapping screws, leaving the caps on the inner surface;
• The sides of the formwork panels are reinforced with bars, which are packed in increments of forty centimeters. Thus, the foundation geometry will be better formed and the required parameters will be provided when pouring concrete mortar;
• The shields are installed on both sides of the trench and connected with spacer metal pins. For this purpose, holes with a diameter of 1.6 cm are made at the fastening 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 the pressure created by the concrete does not push the pin through the slabs, tearing out the nuts;
• When inserting the pins, we pass them through plastic tubes of the same size. This will help set the formwork to the same width around the entire perimeter. When the structure is dismantled, 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;

• When dismantling such formwork, it is necessary to unscrew the nuts and cut off the ends of the studs. Having removed the shields, pruning is performed again;
• In the corner sections of the formwork, bars are driven into the ground, reinforced with steel corners for reliability. Formwork assembly requires strength corner connections, as the weakest points of each structure. When pouring the concrete mixture, the strongest pressure is generated in such places;
• In order for the formwork made of OSB boards to be durable, in some places of the frame base, using a drill, holes are made into which reinforcing sections shaped like the letter “T” are inserted, welding them directly to the frame. During dismantling of the formwork, all fastening elements protruding outwards are cut off;
• outside the formwork structure, the bars are placed 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 spacer is thirty to forty-five degrees;
• Having completely completed the preparation of the structure, we check the panel edges for parallelism. To do this, you will need a building level and a flat wooden block.

If you allow breaks during concreting, pouring in layers, the concrete solution will set gradually, reducing the pressure on the formwork system.

Conclusion

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

The choice of material depends largely on the type of structure, since it is necessary to calculate the strength of the boards, panels, metal and other elements that participate in this “interactive event”. Let's assume that it is being built one-story house or garage. For the formwork we will need OSB sheets 12 mm thick, 10 mm is possible, but we will need to pour the concrete gradually so that the “belly” does not squeeze out anywhere. Instead of OSB sheets, you can use old ones wooden doors, metal gates, iron sheets and anything that is not weaker in strength and has a smooth surface.

It doesn't have to be even on both sides. Even on the inside, unevenness of 2-3 centimeters is allowed - this is quite normal and will not affect the process in any way. The main thing is that you can then easily pick this material out of the concrete, that is, without any elements that fall into the space intended for pouring concrete. Next we will need a wooden beam 50x50 mm, which we will cut. It is desirable that he be from durum varieties wood, ideal option– larch. Its cost, of course, is considerable, so if you don’t have enough money, you can buy 10 meters of pine timber.

We install the formwork and internal screed

In order for the formwork for the foundation to be level, it is necessary to level the sole, make sure that its angle of inclination is insignificant, and that there is a small gap between the OSB sheets and the ground, which can easily be filled with mortar. Next you need to follow the instructions.

Step 1.

We cut the wooden beam into 25 centimeters (depending on the width of the foundation, if it is 30 cm, then we cut it into 30 centimeters), and make sure that the cut is as even as possible. We will need about 4 such pieces per 1 linear meter of the foundation, if its height is 150 centimeters (average for a house).

Step 2.

We place 2 sheets of OSB or boards opposite each other, insert a 25-centimeter long block between them and screw 1 screw from different sides through the OSB board. This procedure is also necessary when installing ordinary boards as formwork, as it significantly increases the strength of the entire structure.

Step 3.

We fasten the next block of OSB or any other material so that there is a minimum gap between them, and screw it with strips. So we expose everything to the very end so that there are no gaps anywhere. The thickness of the foundation will be the same everywhere, since you can control it using wooden block. This arrangement of strip foundation formwork can significantly increase its accuracy.

Now we have a finished structure, which needs to be leveled left and right. It still moves easily and can be adjusted, but it is better to initially set everything one by one to avoid possible “waves”. It is much more difficult to work with boards, although it will be 20% cheaper. The thickness of the board for foundation formwork does not have to be large - 1.5 cm will be enough, because the main thing is internal reinforcement and external supports.

External spacers

Now let's move on to the most important part of our business - the external supports for the formwork. Without them, it will simply fall apart, so you need to take a little time and allocate materials for the construction of such elements. Let's consider step by step instructions how to do it.

Step 1.

We cut the wooden beam into sizes of 60, 90 and 120 centimeters. We leave 1 edge cut at an even angle, and make the other 45 degrees.

Step 2.

Every meter we install 3 supports at a height of 60, 90 and 120 centimeters, respectively. We press it into the ground at a right angle and hammer the beam in a little, after which we tilt the pointed end towards the OSB sheet, to which it fits perfectly. Screw in the screw.

Step 3.

We hammer in the vertical supports. Basically, the entire structure will rest on them. You need to take a stepladder and metal pipes, corners, squares - everything that has good load-bearing capacity and drive them 50-60 centimeters into the ground, and right next to the formwork. This will prevent the bottom from moving away.

Making formwork for a strip foundation in this way will maximize the safety of the structure from breakage, even when the foundation is quickly poured. But don’t rush, it’s better to do everything in several stages - the effect will be much better.

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

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

The strip foundation has matured - the formwork can be removed

Purpose of formwork for the foundation

The formwork for the foundation is a box-shaped structure consisting of panel fences and fastenings in the form of longitudinal and transverse struts and corner stops. Its main purpose is to give the concrete base the required construction project forms.

Formwork is necessary to build any type of foundation, but the most large sizes it reaches when arranging strip foundations. The structure must have sufficient elasticity and strength to withstand the pressure of the concrete solution poured into it. For this reason, building materials for its assembly are selected taking into account the indicated characteristics.

Choosing the type of formwork: removable or permanent?

The currently existing huge variety of formwork types can be divided into two large groups: removable and non-removable type. Removable formwork can be used repeatedly, non-removable formwork can be used once. The choice is made depending on the operational requirements.

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

Building structures, built using permanent foam formwork, have excellent sound absorption and heat conservation characteristics. They are conditioned polystyrene foam blocks remaining on the outer surface after curing of the concrete mixture poured into the cavities of the blocks. This technology can be used both in the construction of private houses and in the construction of buildings up to nine floors high.

The fixed option is not used for buildings with a basement floor, since in this case it is impossible to fully waterproof the foundation.

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

Materials for removable formwork

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

Beam, edged board, plywood or OSB are popular materials for creating formwork

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

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

What else can you assemble a concrete fence from? Instead of OSB, it is, of course, possible to use ordinary chipboard, but it swells from moisture and will only serve once.You can also construct formwork for your home using available materials at hand, such as old doors, slate sheets and other materials that can actually be joined together without gaps in their side surfaces. The only advantage of this solution is its low cost. Several options for arranging removable formwork

Negatives much more. These include:

• increased difficulty installation work;
• the possibility of leakage of concrete mixture;
• low performance bearing capacity designs;
• the need for additional fasteners.

This type of structure can only be used in the construction of small buildings. At capital construction formwork made from similar materials is not used.

We install the formwork for a strip foundation with our own hands

Installing removable formwork for a strip foundation with your own hands involves performing a large amount of work. The concrete base strip is located along the perimeter of the constructed building, following its contours load-bearing walls on both sides.

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

Assembly and connection of shields

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

Shields from edged boards ready for formwork installation

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

Panel construction based on plywood or OSB

Panels made of plywood sheets and OSB boards mounted on a pre-fabricated frame made of wooden beams. The illustration shows the design of a shield made of plywood. In this case, it is convenient to use sheets measuring 1525x1525 mm, which are sawed in half. The finished panels are connected to each other using bolts and nuts through holes in the side bars.

Installation of formwork in a pit

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

• vertically located pegs mark the perimeter of the formwork installation;
• Shield fences are aligned along them, the distance between them should correspond to the width of the foundation strip;
• Every meter of length, the shield fences are supported from the outside by inclined stops;
• the joints of the shields, if necessary, are additionally reinforced with wooden blocks;
• pipes are installed in the upper part of the fence to create technological holes in the foundation;
• all parts of the structure are carefully strengthened; they should not wobble even with significant force.

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

The easiest way is to install panel fences with slats placed vertically on them, pointed at the bottom. They are immersed in the ground, and the panels are leveled using a building level.

Fixing shields

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

Options for strengthening formwork depending on the height of the foundation

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

• a section is placed between the opposing formwork panels plastic pipe;
• a pin is threaded into it through the drilled holes;
• metal washers are installed on the inside to protect the formwork from damage;
• Nuts are screwed onto the threads from the outside.

Spacer bushings and sleeves for communication holes

When dismantling the formwork, the first step is to unscrew the nuts, then pull out the studs and remove the stops and braces. Boards from panel fencing can be reused. It is difficult to disassemble the formwork if self-tapping screws were used to secure its elements. Their heads become clogged with dirt and are very difficult to unscrew.

Once the structure is ready, concrete can be poured into it. Read about this in a special article.

Features of arranging round formwork

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

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

After the concrete hardens and the corrugated sheet is dismantled, a surface of the appropriate shape will be obtained. It can be treated with coating waterproofing, but it cannot be used in roll form.

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

Support bars are installed on the inner and outer parts of the round formwork, taking into account the thickness of the plywood. The smaller the bending radius and the lower the strength, the smaller the distance between them along the perimeter sheet material, but not less than 50cm. On the inside of the formwork, locally curved plywood sheets are fastened to the supports with self-tapping screws.

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

The formwork is strengthened using stops and braces, as described above. Device examples round design shows a photo. In order to equip the foundation for round walls, it is possible to use a large number of fencing elements small sizes. In this case, the internal panels are made shorter than the external ones. It is convenient to determine their size by drawing a sketch of the formwork to scale. The construction of shields is stronger than that of bent plywood, and is preferable for arranging large foundations.

Let's calculate the amount of materials needed

The required amount of material for arranging formwork with your own hands is determined as follows. The length and height of the concrete base known from the design documentation must be divided, respectively, by the length and width of the boards intended for use. By multiplying the resulting numbers, the number required for the construction of a specific formwork is determined. In addition to the boards, you need to purchase wooden beams and spacers. Their cost can reach up to half the cost of purchasing boards. It is necessary to take into account additional costs for studs and fasteners.

Useful properties of polyethylene film

It is not possible to make a shield fence without any gaps at all, and the concrete mixture seeps out, staining the formwork elements. Polyethylene film or roofing felt attached to the inside of the formwork perfectly protects the surface of the boards from contamination with the concrete mixture not only from the inside, but also from the outside of the structure.

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

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

We rearrange the panels and fill the foundation in parts

Pouring the foundation in parts provides for the vertical or horizontal arrangement of the joining seams. When they are located vertically, the concrete base is separated by partitions. After the concrete mixture has cured in the first section, the partition is removed and moved to the length of the next section. This way the entire perimeter of the base is filled.

Pouring the foundation in parts with vertical division

When the joining seams are located horizontally, partitions are not installed. Most often, this method is used when constructing strip foundations. The concrete strip is divided in height into several parts and successively filled with layers of concrete mixture until the ground level is reached. Joint seams cannot be placed on reinforcement belts; they must be located above or below their level.

OSB foundation formwork. At every construction site, foundation formwork plays an important role. When pouring any building elements made of concrete, for example, stairs, reinforced belts, floors and support columns, you also cannot do without pouring formwork.

Formwork- This is a type of construction that is required in order to give the concrete mixture a certain shape. As a rule, it is made from wooden planks, metal or plates of all kinds of materials. One option is formwork made of OSB boards. The advantage of these boards is 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, since 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 production is based on the addition of adhesives and pressing layers of wood chips, which are oriented in a certain way. OSB has a rough, variegated surface, with individual shavings and chips measuring 25*150 mm, which are unevenly spaced to each other and have different appearances and thicknesses.

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 elements of the building. For external walls, such panels are produced with lamination on one side, which greatly helps to simplify installations and increase the energy efficiency of the fence structure. 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 slabs are made in the form of wide mats, as well as from layers of chips, which are differently oriented, glued and compressed with adhesives made of synthetic resins and wax (5% resin/wax and 95% wood). Typically, the resins that are used contain 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 used 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 slab.

The layers are made as follows - the wood is crushed into strips, which are then sifted and then oriented using various devices when fed to the molding line. For the outer layer, the chips are aligned along the strength axis of the slab, and the inner layers are strictly perpendicular. The number of layers placed will depend to some extent on the thickness of the panel that needs to be manufactured, but is still limited by the equipment used in production. Individual layers can also differ in thickness to give different thicknesses for the slab (usually, a 17 cm layer produces panels with a thickness of 1.7 cm). Next, the mat is placed under a thermal press so that the raw material is compressed and held together due to thermal activation and hardening of the resin that covers the wood. The individual panels should then be cut from the mats to the required size.

Please note that OSB panels for wood structures can be cut and installed as easily as natural wood.

Technical properties and varieties

Adjustments during the production process may result in differences in the thickness, size of the slabs, as well as their strength and rigidity. OSB boards for do-it-yourself formwork are good because they do not have internal voids and are waterproof, although they require additional shells to obtain waterproofness and are not very suitable for external types of work. The finished product has properties somewhat similar to plywood, but is cheaper and more uniform. When testing OSB for fracture, it was revealed that the material has a high load-carrying capacity and this indicator is higher than that of milled wooden panels.

There are 4 types of OSB boards, which are defined in the plan mechanical characteristics and relative resistance to moisture:

• OSB/1 – general purpose boards for interior finishing of premises (furniture inclusive), required for use in dry conditions.
• OSB/2 - load-bearing boards that are needed for use only in dry rooms.
• OSB/3 – load-bearing type boards that can be used in conditions of high humidity.
• OSB/4 – load-bearing type boards (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 strength characteristics of the slabs that make their use as a material for the manufacture of foundation formwork expedient, and the ease of processing makes it possible to carry out the work with one’s own hands, without the involvement of specialists.

Installation Rules

Before you begin work on creating formwork for an OSB foundation, you should prepare everything necessary tools and fixtures, as well as materials for connecting, strengthening and installing.

The required set of tools is standard for carpentry work:

OSB boards are easy to cut

On parts of the required dimensions when using a table saw or hand-held electric saw. But don’t worry if you don’t have such a tool - a hacksaw will also cope with this task. Also, cutting of slabs can be carried out at a specialized stand in construction markets, according to pre-taken measurements.

To avoid deformation different parts During pouring, formworks should be reinforced with stiffening ribs 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, when making formwork for floors 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, the two parts that face each other should be folded together, and then holes should be drilled in them, at the bottom and at the top, for a fastening bolt or stud. When a piece of plastic pipe of the required length is installed between the OSB sheets, you can pass a pin through it and tighten it with nuts, which will help form a box. To prevent the slab from tearing due to the concrete and its weight, it is advisable to place washers with a large diameter under the nuts.

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

Important! When securing the slabs, do not butt them together. Slots are needed, the width of which is 0.2-0.3 cm, to compensate for minor movements of the material 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 by with a simplified method of installing formwork. To do this, the parts of the reinforced belt should be attached bottom to the wall with long self-tapping screws, and on top with wooden blocks. After this, take the knitting wire and further tighten the parts together. A foundation of low height can be strengthened with self-tapping screws on pegs made of blocks that are driven into the ground, according to the house plan. After this, the formwork should be strengthened from the outside using struts.

When creating formwork for the floor, OSB slabs should be laid on a fine grid (0.5 * 0.5 meters) of a supporting beam, which will be installed on posts of the required height. It is advisable that the racks be every 1.5 meters.

For manufacturing, you will need metal pipes, but if you don’t have them, you can rent or use industrial racks designed for monolithic work. It is also desirable that the concrete be poured around the entire perimeter without creating excess stress at a certain point. If it is not possible for various reasons (organizational, technological) to fill without interruption, then working seams should be made according to the rules for concrete works. For example, the working seam must 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 the right size and attach to the OSB front board from the inside. To ensure that the sheets of insulation material are firmly fixed to the concrete base, pass wire loops through the foam before installing them on a collapsible structure. 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 after dismantling work, they can be used as rigid sheathing on the floor of the attic or on the roof. It turns out that when proper organization the order of work and careful use of the material, the use of slabs will be waste-free, and you will save money.