OSB (OSB) board: size, prices, application

Sheet building materials are used in frame housing construction, with dry leveling of planes. One of these materials is OSB board (OSB, OSB). She pushed plywood, chipboard, plasterboard. And all because with good technical characteristics, it has a low price. 

What is OSB board and OSB

One of the sheet building materials is OSB (also called OSB). The name is an abbreviation of the full name of the material – “oriented strand board”. That is, it is correct to call this material OSB. The second name – OSB – comes from the transliteration of the English version of the name – OSB (oriented strand board). English letters were simply replaced with similar ones in Cyrillic. 

OSB is a multilayer material (3 or more layers). Each layer consists of wood, ground into chips, mixed with resins. Wood chips are used long and thin (several millimeters thick, up to 7 cm long). The chips in the layers are located in different directions: the outer layers have a longitudinal orientation, the inner ones have a transverse orientation. This results in high elasticity and dimensional stability. Various resins are used as a binder. They give the material water resistance, but contain formaldehyde. It is the content of this substance that stops many from using OSB. But, if the material is produced in accordance with GOST, the formaldehyde emission does not exceed the performance of wood. But this can only be verified in laboratory conditions. So the ordinary buyer can only rely on the inspection authorities. Or choose another material.

Types of OSB

Depending on consumer properties, oriented strand boards are produced in several types:

• OSB 1 – for structures without loads, operation is possible only in dry rooms;
• OSB 2 – for load-bearing structures in conditions of normal humidity (for sheathing frames in the room);
• OSB 3 – for load-bearing structures in conditions of high humidity (outside sheathing in frame housing construction, including as a continuous crate for some types of roofing materials).
• OSB 4 – for load-bearing structures with significant loads, operated in conditions of high humidity.
  

• Grooved. The edges of the plates are cut in the form of a tongue/groove lock. With such an edge, there can be any type of OSB (from 1 to 4). Are applied if it is necessary to create a continuous flooring on the plane (for a floor, a roof or walls).
• Laminated OSB. On one or both sides it is covered with a layer of laminate. It is used to create reusable formwork for the construction of foundations, monolithic walls made of concrete, wood concrete, etc.
• Lacquered OSB. Lacquer coating on one side increases moisture resistance.

If you need moisture-resistant OSB, carefully consider the choice of manufacturer. Be prepared for the fact that OSB 3 is more expensive than non-moisture resistant brands. Even more money will have to be paid for OSB 4. We do not recommend looking for cheap material. Too many complain that the purchased OSB 3 swelled by 3-8 mm from moisture, in some cases it even bloomed or overgrown with fungi. All this is due to attempts to reduce costs. To do this, use fewer disinfectants, a cheaper binder. Chinese manufacturers instead of pine chips put hardwood, which is easily affected by fungi and diseases.

Properties and specifications

OSB boards compete with other sheet materials both in the field of construction (for sheathing frames, creating formwork) and in the field of finishing (leveling walls, floors, ceilings). This is facilitated by the properties of OSB:

• The strength is about the same as that of plywood and 2,5 times higher than that of chipboard.
• High degree of moisture resistance. According to the standards, water absorption when in the water during the day is not more than 10%.
  

• OSB boards can be sawn, drilled with standard carpentry tools.
• You can fasten with screws, self-tapping screws. Fasteners are held better than in softwood plywood and chipboard.
• Not damaged by rodents, beetles.
• With normal quality, voids, delaminations and other defects are rare.

Once again, we draw your attention to the fact that moisture resistance and resistance to deformation are characteristic of OSB, which were made in compliance with the technology. Unfortunately, the Russian-made material is not of high quality. Less powerful presses are used, they try to save on the binder, do not apply markings. As a result, there are many examples of negative experience: plates swell from moisture, warp them, glue is washed out … The way out is to look for plates of imported (Europe or USA) production. Due to the growth of the dollar, they now have considerable prices, there are very few of them on the market, but, if desired, you can find or order with delivery.

The situation is aggravated by the fact that in appearance it is impossible to distinguish moisture-resistant OSB3 from non-moisture-resistant OSB2 or 1. The latter cost much less. Unscrupulous sellers sell cheaper ones under the guise of moisture resistant ones. This is where trouble comes in. As a way out, you can do this: buy one sheet of OSB 3, check its behavior at high humidity. If there are no visible changes, buy a batch.

Application area

The properties of OSB make it possible to use this material as a building or finishing material. Here are the jobs it can be used for:

• Sheathing of frames and walls from the inside and outside.
• Floor and ceiling leveling.
• Flooring of a rough or finishing floor along the logs.
• Removable formwork when working with concrete.
• Solid crate for bituminous tiles, metal tiles, slate, soft roofing materials.
• Production of SIP panels and thermal panels.

There is a constant debate among developers about how safe OSB is. In its production, resins are used that emit formaldehyde. Manufacturers claim that the release of this substance does not exceed 1%. Materials with such formaldehyde emission are considered absolutely safe. About the same amount of this substance emits wood. Therefore, such materials are allowed for the construction of children’s furniture. In addition, OSB boards with an emission of 0,5% appeared. You can distinguish them by two criteria: the name contains the prefix Bio or Green and they are more expensive.

Please note that the level of formaldehyde emission must be controlled. Each batch of material must be checked, the actual parameters must be indicated in the accompanying documents. Despite all the arguments, not everyone considers this material to be safe, preferring to use natural material – boards. They are, without a doubt, an environmentally friendly material, but it takes longer to work with boards, they are more expensive. In general, everyone decides for himself whether to use OSB boards or not.

Dimensions of oriented strand boards

Since the purpose of the OSB board is different, different sizes can be convenient. The situation with the size of OSB boards is not easy. On sale there are constantly 1220 * 2440 mm and 1250 * 2500 mm. There are also formats 1250*2800 mm, 1250*3000 mm, 1200*6000 mm, but they are extremely rare on our market, although in many cases they are much more convenient to use. Having picked up the right size, you get rid of the need to “grow” the missing centimeters or saw off the extra ones. But there are not so many of them on the market, since these are imported plates, and now it is difficult to import …

The OSB board can also be of different thickness – 9 mm, 12 mm, 15 mm, 18 mm, 22 mm, 25 mm. Each type of use has its own thickness:

• Sheathing of walls, ceiling – from 9 mm.
• Solid crate for roofing materials – from 12 mm.
• An OSB board from 15 mm thick will go to the floor.

OSB board is a convenient building material. It can be sawn with a conventional wood saw, use a grinder with a cutting disc, a jigsaw. The material is well drilled, screw nails can be used without pre-drilling. But then their hats stick out, which is not always convenient.

Before finishing, the OSB board is coated with a primer. It is selected depending on the finishing materials – to equalize the absorbency and improve adhesion to other materials.