Formwork for the OSB foundation. At every construction site, foundation formwork plays an important role. When pouring any elements of a building made of concrete, for example, stairs, reinforced chords, ceilings and support columns, you also cannot do without pouring the formwork.
Formwork is a type of structure that is required in order to give the concrete mixture a certain shape. As a rule, it is made from wooden planks, metal or slabs of all kinds of materials.
One of the options is OSB board formwork. The advantage of these boards 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 a thousand by their appearance, since these types of boards have a characteristic wood structure. Oriented strand board is a type of engineered lumber that is partially similar to chipboard. Its manufacture is based on the addition of adhesives and the pressing of layers of wood chips, which are oriented in a certain way.
OSB has a rough surface, motley, has individual shavings and chips measuring 25 * 150 mm, which are unevenly spaced to each other and have a different appearance and thickness.
OSB plates are often used in housing 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 floors, walls, roof decking and foundation formwork, as well as other reinforced concrete and concrete elements of the structure. 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 structure.
Also OSB is often used in the manufacture of furniture.
Before buying OSB for foundation formwork, the material is produced in production. The boards are made in the form of wide mats, as well as layers of shavings, which are differently oriented, glued and compressed with adhesives of synthetic resins and wax (5% resin / wax and 95% wood). Typically, those resins that are used contain phenol formaldehyde, isocyanite and melamine molded urea formaldehyde. Each of these binders is moisture resistant.
As a rule, a combination of astringents is used - isocyanite is used in the middle, while the face layers have urea formaldehyde. This helps to reduce the number of pressing cycles, and at the same time gives a beautiful appearance to the board surface.
The layers are made as follows - the wood is crushed into strips, which are then sieved and then, using various devices, are oriented when feeding to the forming line. For the outer layer, the chips are aligned along the strength axis of the board, 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 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 (as a rule, from a 17 cm layer, panels with a thickness of 1.7 cm are obtained). 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. After that, the individual panels should be cut from the mats to the desired size.
Note that OSB panels for timber structures can be cut and installed just as easily as natural wood.
Adjustments in the production process may affect the fact that there will be differences in thickness, size of boards, as well as their strength and rigidity. OSB slabs for do-it-yourself formwork are good in that they do not have internal voids and are waterproof, although they require additional shells to obtain waterproofing and are not very suitable for outdoor types of 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 carrying capacity and this indicator is higher than that of milled wooden panels.
There are 4 types of OSB boards, which are defined in terms of mechanical characteristics and relative resistance to moisture:
Although OSB does not have continuous fiber, like natural wood, it has an axis along which the resistance force is greatest.
Interestingly, 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 work with your own hands, without the involvement of specialists.
Before starting work on creating formwork for the foundation from OSB, you should prepare all the necessary tools and fixtures, as well as materials for that what to connect, strengthen and install.
The required set of tools is standard for carpentry work:
Into parts of the required dimensions when using a table or hand-held electric saw. But don't worry if you don't have such a tool - a hacksaw will do the job too.
Also, slabs can be cut at a specialized stand in construction markets, according to pre-taken measurements.
In order to avoid deformations of different 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 floors or for foundation walls with high heights.
When it is on both sides of the concrete element of the building, two parts that stand opposite each other must be folded together, and then in them, at the bottom and top, holes should be drilled for the mounting bolt or stud.
When a piece of plastic pipe of the required length is installed between the sheets of OSB, you can pass a pin through it and clamp it with nuts, which will help form a box. To prevent the slab from tearing from the concrete and its weight, it is advisable to put washers with a large diameter under the nuts.
When making a corner box for a foundation, one of the two walls must be longer to form a corner. Now that the boxes are ready, it is enough just to form the foundation of the required structure. The finished elements can be started to be lowered into a trench or foundation pit, placed according to the building design and fixed between themselves with bars.
The formwork itself should be secured with reinforcing pegs, which must be driven into the ground. For a high foundation, in addition to reinforcement, it is recommended to use struts, each should be 0.7 meters each in order to prevent the destruction of the structure, which is possible when pouring concrete. The gaps between the individual boxes can be sealed with polyethylene or glassine.
Important! When securing the boards, do not butt-joint.
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).
. or a reinforced belt, you can get by with a simplified formwork installation method. For this, the details of the reinforced belt should be attached to the bottom with long screws, and from above with wooden bars. After that, take the knitting wire and pull the pieces together further.The foundation of a low height can be strengthened with self-tapping screws on pegs made of blocks that are driven into the ground, according to the plan of the house.
After that, the formwork should be reinforced from the outside with struts.
When creating slab formwork, OSB slabs should be laid on a frequent lattice (0.5 * 0.5 meters) from a supporting beam, which will be installed on the posts of the required height. It is desirable that the racks are every 1.
Metal pipes are 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 impossible for various reasons (organizational, technological) to fill without interruption, then work seams should be made according to the rules for concrete work. For example, the working seam must be perpendicular to the axis of the concrete element and without slopes.
Also, when building a house and making formwork, you can think in advance about how to insulate your future house. To do this, buy foam sheets of the required size and attach them to the OSB front plate from the inside. In order for the sheets of insulation material to be firmly fixed on the concrete base, pass the wire loops through the foam before installing them on the collapsible structure. Thanks to this construction trick, you can securely attach the foam to the foundation.
OSB slabs can be used for formwork many times (at least 10), and even after dismantling works, they can be used as rigid sheathing on the attic floor or on the roof.
It turns out that with the correct organization of the order of work and careful use of the material, the use of the plates will be waste-free, and you will save money.
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