For the first time plywood began to be made in the mid-19th century. At the moment, this is a very common material used for interior decoration, erection of structural elements of buildings, in the manufacture of furniture, containers, toys, etc. Modern industry produces a wide variety of plywood. The dimensions of the sheets, their thickness and quality determine the scope of this material and its cost.
What is this material
Plywood consists of several layers of veneer glued so that the fibers in adjacent layers are perpendicular. Therefore, it is devoid of the main disadvantages of wood - the ability to crack, dry out and deform. Of course, since chemicals are used in the manufacture of plywood , in particular phenolic or carbide formaldehyde adhesives, it is significantly inferior to wood in environmental safety.
Standard sizes
When buying this material, you should pay attention primarily to the length and width of the sheets. Most often in stores you can find plywood of standard sizes. Such sheets are quite convenient in installation and during transportation. The standard length of plywood according to GOST is 2.44 m, the width is 1.22 m. Sheets are also available in larger and smaller sheets. A fairly common variety is plywood 1.525 m wide (usually square). The length of the sheets can reach 3.66 meters. Thus, the standard dimensions of plywood are 2.44 x 1.22 m.
What can be the thickness
Of course, length and width are far from the only parameters by which plywood can vary. Another important indicator is its thickness. In the manufacture of containers and furniture, for example, rather thin sheets are used. In the finishing works, as well as in the construction of buildings, much thicker plywood is used. The dimensions in this regard depend both on the number of layers and on the thickness of the veneer.
Plywood is produced by ordinary companies and enterprises, as well as specialized ones. In the first case, material is made from a thickness of 3 to 30 mm. In this case, the step between the values is about 3 mm. Specialized enterprises also produce “aviation” plywood, the thickness of which - while maintaining strength - can be very small.
What you should know about
By marking, you can also determine the direction of the fibers of the facial layers. Usually they are located along, that is, along the length of the sheet. But sometimes there are options in which the fibers are directed in width. In this case, the size of the plywood sheet is indicated with the length in second place. It looks something like this - 1.22 x 2.44 m. In standard sheets with the usual direction of the fibers, the size is indicated as follows - 2.44 x 1.22 m.
The number of layers of plywood
This indicator may also vary. However, usually sheets have an odd number of layers (at least three). Sometimes in the manufacture of veneers from the same wood species are used, sometimes from different ones. Front layers are usually made of the highest quality material. In the middle, veneer plates may be worse. Sometimes plywood with only one high-quality outer layer is also on sale. In this case, the back of the sheet is called the inside.
Grades of material
So, for any purpose you need plywood. Dimensions, thickness and number of layers are not the only parameters that should be considered when buying. You must also look at the alphanumeric designation of the quality of the face layer. Currently, according to GOST 30427-96, there are only four grades of plywood:
- And - the first grade. In this case, up to three small knots per 1 m 2 are allowed on the front surface. This is a very smooth plywood, used mainly in the decoration of structural elements of buildings.
- In - the second grade. There can be up to 10 knots on such plywood. This material is worth a little cheaper than first-class.
- C is the third grade. Such plywood is usually used for the manufacture of containers or hidden structures.
- D is the fourth grade. This variety is also used mainly for the production of containers.
Similar markings are currently used, but are considered obsolete. Therefore, the variety on the label can be indicated simply by the Latin number from I to IV. The letter E in the new marking marks the best elite material.
Plywood size 10 mm
This is the most popular type of material. Such plywood is used mainly in the construction of buildings and for the manufacture of building envelopes, including loaded ones.
The size of plywood 10 mm may be different. However, as with any other thickness, standard sheets of 2.44 x 1.22 m are most often sold and used.
Varieties of moisture resistance
Among other things, there are different brands of this material. In this case, the ability of plywood to maintain its working properties at varying degrees of humidity is taken into account. The quality of the material in this regard mainly depends on what glue was chosen for bonding veneer sheets.
Moisture resistance marking:
- FC - material used for interior work in dry rooms. This is not very moisture resistant plywood, but the environmentally friendly. In this case, the layers are bonded with adhesives based on urea resins.
- FSF is moisture resistant plywood, the dimensions of which can be both standard and not. This option has greater hardness and mechanical strength than FC. Use it mainly for outdoor work, for example, when the base is installed under the roof. The layers in such a material are fixed using adhesives based on formaldehyde resins.
- FOF - laminated plywood. In this case, the outer layers of the sheets are additionally glued with a special film, which serves as an excellent protection not only from moisture, but also from ultraviolet radiation, as well as from exposure to various kinds of aggressive environments.
Varieties by degree of processing
In addition, plywood, the dimensions and degree of moisture resistance of which can be different, also varies in the quality of processing of the facial layers. In this regard, the material is classified as follows:
- 1 - sheets are polished only from one - front - side;
- 2 - grinding is done on both sides;
- NSH - raw plywood.
Tree species
As already mentioned, plywood can be made of different materials. It can be both coniferous and hardwood. In the first case, fir, pine or spruce is usually used. From hardwood (birch, beech, linden), more solid plywood is obtained. Sometimes tropical wood is used to make this material - gobun, meranti, latan. A very interesting variety is decorative plywood. In this case, the front layer can be made of cherry, beech or oak.
Plywood: sizes and prices
Of course, the cost of the material will also depend on the dimensions of the sheets. The greater the thickness, length and width, the more expensive the sheet. Affects the price and grade of plywood. So, the material marked with the letter D 1.52 x 1.52 m, will cost about 210-250 p. A large standard sheet of the first grade 6.5 mm thick - 1000 r. The 12 mm version will cost about 1300-1500 rubles. Quality plywood in 2.1 cm will cost 2000 p.
How to choose material when building a country house
Plywood, the sizes and prices of which are interrelated, can be used in the construction of buildings for a variety of purposes. Common areas of its application in this case:
- Sheathing of frame walls externally for plaster. In this case, material of the FSR brand should be used with a thickness of at least 9 mm.
- Sheathing of frames from the inside. For this purpose, plywood FSR is also suitable.
- The device of a continuous lathing under the roof. It is also made from the FSR. The size of the plywood sheet is often standard. Its thickness should be at least 9 mm with a rafter pitch of 30 cm, 12 mm at 60 cm, 18 mm at 90 cm.
- Sheathing the walls and ceiling of ordinary rooms on top of the insulation from the inside. In this case, plywood of the second grade FC, rather thick, can be used.
- Alignment of old wooden floors. Since plywood FSR can emit harmful formaldehyde fumes, it is also better to use the FC variant to carry out such work. However, under the sheets should be laid waterproofing.
As you can see, plywood, the thickness, quality and dimensions of which can be different, is a material that is almost universal, has excellent performance characteristics and is easy to install.