Which is better - plywood or OSB?

Oriented strand board (OSB) and plywood - 2 building materials with similar technical parameters and performance. However, there are small differences that turn out to be extremely important in the construction industry. To choose the right building material, you need to find out their features, pros and cons.

Plywood and OSB are often used to level wall and floor bases before facing work. They are installed on top of obsolete wooden floors, on logs or concrete screed.

Plywood board is made from wood veneer. During the manufacturing process, the strips are covered with glue, connected and pressed on hydraulic equipment. This creates a solid and durable slab. Its technical parameters depend on the number of layers, type of glue, wood species. The more planks used in production, the thicker and stronger the product will be.

Plywood sheets come in several varieties:

• 1 - expensive and of high quality without visible external defects;
• 2 - with a minimum of scrap (small cracks, amenable to grinding);
• 3 - with visible "flaws": knots, roughness, wormholes;
• 4 - cheap with a lot of external damage.

Plywood boards are classified depending on the type of impregnation used in production. There are 4 types of plywood on sale:

• FC - characterized by low moisture resistance, urea glue acts as a binding base;
• FSF - (product with phenol-formaldehyde glue) is recommended for outdoor work;
• FB - with bakelite varnish, designed for use in aggressive environmental conditions;
• FOF is an abbreviation indicating a laminated surface.

Oriented strand board is made from wood chips and glue. During production, the components are mixed, pressed under high pressure, forming a one-piece structure. There are 4 types of such a board:

• 1 - a fragile base, more than others exposed to moisture;
• 2 - solid bar, unstable to high humidity;
• 3 - product with increased reliability and moisture resistance;
• 4 - a board that is not afraid of moisture, it is able to retain its properties even when used in extreme conditions.

The two compared materials have different sheet sizes - they come in small, medium and large sizes.

Plywood and OSB are very different in appearance. Veneer planks are more aesthetic, which is why their 1 and 2 grades are allowed to be used for external decoration. On the surface of the OSB board, wood shavings are visible, due to which it loses its decorative effect. These structures are not suitable for cladding work, but as a rough covering, they compete with plywood boards. Materials differ not only in appearance, but also in characteristics.

OSB standard sizes 1220x2440, while its thickness varies from 6 to 25 mm. Plywood has 5 standard sizes - from 1.22x1.22 m to 1.525x1.525 m. Less commonly, sheets are produced with a large format from 1.830 by 1.525 m to 3.05x1.525 m. At the same time, the smallest thickness of the plywood plank does not exceed 4 mm, the maximum is 30.

To find out which is stronger, materials bend. In this case, the maximum possible stress during deformation is taken as the ultimate strength, which does not lead to external damage to the board. According to GOST R 56309-2014, the strength of OSB-3 sheets ranges from 15 to 22 MPa. The final indicator is influenced by the value of the plank thickness. A plywood board manufactured in accordance with GOST 3916.1-96 has a strength of 25 to 60 MPa. The exact value depends on the type of wood and the grade of the material.

The weight of the boards is influenced by their dimensions and specific density. When identifying the weight of materials, their density indicators are compared. OSB boards have a density of not more than 650 kg / m³. Moreover, the thinner the layer, the denser it is. The density of plywood planks ranges from 670–680 kg / m³. If birch veneer was used in the production, the values ​​can reach over 730 kg / m³. A cubic meter of plywood board is heavier than OSB. However, in construction, this difference is insignificant.

The areas of use for plywood and OSB boards are about the same. Moreover, both materials have a similar processability. Structures are cut by hand or using electrical equipment. The ends are also processed using a similar technology. However, chip designs produce more flakes, which will require more detailing to obtain a perfect edge.

Compared materials hold fasteners approximately equally... But when installing plywood, builders recommend that you first make holes in it and only then screw in the fasteners. Self-tapping screws sink into OSB easier.

Plywood and OSB have one flammability class - G4. It means that:

• they ignite easily when exposed to open flames;
• maintain combustion even if external sources of flame are eliminated.

When ignited, a large volume of high temperature gases is formed.

In the manufacture of plywood FSF and OSB, synthetic binders based on phenol are used. This component is harmful to human health, so it makes no sense to say which is more harmful and which is safer. OSB-cloth is produced using numerous chemical impregnations that negatively affect the environment. However, only natural resins are used in the manufacture of FC plywood. Such material will be more environmentally friendly.

OSB boards are less resistant to moisture than plywood. If you trim the walls or ceiling in a room with high humidity with planks based on shavings, they will swell. After deformation, OSB practically does not return its former appearance. As a result, the finish cladding will suffer, which will require repairs to be done again. FK and FSF boards are more stable in this regard. With a slight swelling, they are able to completely recover.

In the manufacture of these two materials, special impregnations and anti-mold agents are used. When the boards are used in high humidity conditions, the risks of fungus are minimal.

1-2 grades of plywood look more attractive than OSB canvases. However, low-grade products have no external decorative effect. It often contains traces of knots, pits, wormholes of various sizes and other defects. Such strips are inappropriate to use when finishing work. For finishing, plywood strips of 1 and 2 grade are used. It is recommended to use particle boards of any mark only as a bedding material.

When choosing a material, it is worth considering the conditions in the room in which it will be operated.

1. For decorating a children's room, it is advisable to give preference to FC plywood. It is made from environmentally friendly raw materials and does not emit toxic components into the environment.
2. When choosing a building material for the floor under linoleum or laminate in the kitchen and bathroom, it is best to buy waterproof plywood. When wet, it can deform, but when it dries, it is completely restored.
3. For finishing the ceiling or floor in the bedroom, it is advisable to use OSB strips, since they are distinguished by better sound insulation.

It is recommended to use OSB for the subsequent coating of the floor with varnish, for finishing rooms with high traffic, in summer cottages that are not heated in winter. If the budget is limited and you need to trim a large area, it is also better to use chip strips to save money.

When decorating walls, OSB is also preferable for a number of reasons:

• due to the light weight, minimal loads are created on the bearing supports;
• due to the lighter weight, installation will be easier;
• good holding qualities, due to which it is possible to drive nails into the surface;
• low price, which is especially appreciated for large working volumes.

And you also need to figure out what will come out cheaper. For the price, plywood will cost more than OSB. The cost of grade 3 chipboard will be close to the plywood board with grade 4, the worst mark. According to average estimates, OSB canvases are about 2 times cheaper.

Compared building materials are popular in the construction industry. When choosing boards for cladding, you need to carefully study their specifics. With proper use of plywood and OSB sheets, both materials will give positive results.

The next video tells you which is better to choose - plywood or OSB?