Plywood was first produced in the middle of the 19th century. At the moment, this is a very common material used for interior decoration, construction 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 in such a way 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, and in particular, phenolic or carbamide-formaldehyde adhesives, it is significantly inferior to wood in terms of environmental safety.
Standard sizes
When buying this material, you should pay attention primarily to the length and width of the sheets. Most often found in storesplywood in standard sizes. Such sheets are quite convenient in installation and transportation. The standard length of plywood according to GOST is 2.44 m, the width is 1.22 m. Sheets are also produced and larger or smaller. 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.
How thick can it be
Of course, length and width are far from the only parameters by which plywood can differ. Another important indicator is its thickness. In the manufacture of containers and furniture, for example, rather thin sheets are used. In finishing works, as well as in the construction of buildings, much thicker plywood is used. The dimensions in this plan depend on both the number of layers and the thickness of the veneer.
Plywood is produced both by ordinary companies and enterprises, and specialized ones. In the first case, material is made with 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
By marking, you can also determine the direction of the fibers of the front 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 set to the secondplace. 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.
Number of layers of plywood
This figure may also vary. However, sheets usually have an odd number of layers (minimum three). Sometimes veneer from the same type of wood is used in the manufacture, sometimes from different ones. The front layers are usually made from the highest quality material. In the middle, worse veneer plates may be located. Sometimes plywood with only one high-quality outer layer is also found on sale. In this case, the reverse side of the sheet is called the wrong side.
Material grades
So, you need plywood for some purpose. Dimensions, thickness and number of layers are not the only parameters to consider when buying. You also need to look at the letter or number designation of the quality of the front layer. At the moment, according to GOST 30427-96, there are only four grades of plywood:
- A - the first grade. In this case, the front surface is allowed to have up to three small knots per 1 m2. It is a very smooth plywood used primarily in building structural elements.
- B - second grade. Knots on such plywood can be up to 10 per 1m2. It costs a little less than the first-class material.
- С - the third grade. Such plywood is usually used for the manufacture of containers or hidden structures.
- D - the fourth grade. This type is also usedmainly for the production of containers.
Similar markings are currently in use, but considered obsolete. Therefore, the variety on the label can also be indicated simply by a Latin numeral from I to IV. The letter E in the new marking marks the best elite material.
10mm plywood size
This is the most popular type of material. Such plywood is used mainly in the construction of buildings and for the manufacture of enclosing structures, including loaded ones.
10mm plywood size may vary. However, as with any other thickness, standard sheets of 2.44 x 1.22 m are most often sold and used.
Varieties in 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 environmental humidity is taken into account. The quality of the material in this regard mainly depends on what kind of glue was chosen for fastening the veneer sheets.
Moisture resistance marking:
- FK - a material used for interior work in dry rooms. This is not very moisture resistant plywood, but the most environmentally friendly. In this case, the layers are held together with adhesives based on urea resins.
- FSF - moisture resistant plywood, the dimensions of which can be either standard or not. This option has greater hardness and mechanical strength than FC. It is mainly used for outdoor work, for example, when arranging a base underroofing. The layers in this 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 the effects of various kinds of aggressive environments.
Varieties according to the degree of processing
Among other things, plywood, the dimensions and degree of moisture resistance of which can be different, also differs in the quality of processing of the front layers. In this regard, the material is classified as follows:
- Ш1 - sheets are polished from only one - front - side;
- SH2 - grinding is done on both sides;
- НШ – raw plywood.
Wood species
As already mentioned, plywood can be made from different materials. It can be both coniferous and deciduous trees. In the first case, fir, pine or spruce is usually used. Hardwoods (birch, beech, linden) produce harder plywood. Sometimes for the manufacture of this material tropical wood is also used - gobun, meranti, latan. A very interesting variety is decorative plywood. In this case, the face 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, a material marked with the letter D 1.52 x 1.52 m will cost about 210-250 rubles. A large standard sheet of the first grade with a thickness of 6.5 mm - 1000 r. The 12 mm option will already cost about 1300-1500 rubles. High-quality plywood 2.1 cm will cost 2000 rubles.
How to choose material when building a country house
Plywood, the sizes and prices of which are interconnected, can be used in the construction of buildings for a variety of purposes. Usual areas of its application in this case:
- Sheathing frame walls outside under plaster. In this case, FSR brand material with a thickness of at least 9 mm should be used.
- Sheathing frames from the inside. FSR plywood is also suitable for this purpose.
- The device of a continuous crate under the roof. It is also made from FSR. The size of the plywood sheet is most 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 of walls and ceilings of ordinary rooms over insulation from the inside. In this case, plywood of the second grade FK, thick enough can be used.
- Smoothing old wooden floors. Since FSR plywood can emit harmful formaldehyde fumes, it is also better to use the FK option for such work. However, waterproofing should be laid under the sheets.
As you can see, plywood, the thickness, quality and dimensions of which can be different, is an almost universal material with excellent performance andeasy to install.
