Along with the novelties that have appeared in recent years in stores, there is a certain list of building materials more familiar to the domestic buyer. Such materials include plywood, its pros and cons are well known to the consumer, but because of this it does not lose its popularity. The main parameters when choosing are the thickness and size of the sheet of plywood: its prices also depend on these characteristics.
What is a sheet of plywood: features of production
A sheet of plywood is a slab, glued together from 3-5 layers of wood veneer. It is produced from various wood species – hardwood (birch, alder, oak) and coniferous (pine). The highest quality and, accordingly, the most expensive is birch plywood, the cheapest – from coniferous trees. To reduce the cost of the final product, different types of wood are often combined. For example, veneer of hardwood trees is used for the inner layers of plywood, and softwood – for the outer. This is done not only in order to save. The outer layer of cedar veneer is used to give a beautiful pattern to the plywood sheet.
In the manufacture of plywood from a tree trunk, special machines using the method of spiral sawing remove thin sheets (veneer). These sheets are stacked on each other (most often across the fibers to give the material greater strength), and then under high pressure they are pressed into monolithic blocks. Many types of wood do not need special adhesive impregnation. However, special natural or synthetic compounds are often used to improve performance.
In accordance with GOST, 4 grades of plywood are distinguished. Minor defects are allowed on sheets of first grade plywood. On second-class plywood there may be areas that have been repaired, cracked, seeping glue. The third grade assumes the presence of knots on the surface, wormholes, but the total number of defects should not exceed 9. Plywood of the fourth grade has a very low quality and has a large number of defects (accrete knots, a large number of wormholes, uneven edges). It is used mainly for the manufacture of containers.
Interesting fact! Production of plywood was put on an industrial basis at the end of the 19th century, and the method by which a sheet of plywood was glued together from several layers of veneer was called Russian, because it was Russia who invented the method for producing peeled plywood and the machine for its implementation.
There are several main types of plywood. All of them are different in their features and areas of application. The plywood sheet size and thickness are also different. All these characteristics determine how much a sheet of plywood costs:
- FC plywood (moisture resistant plywood.) The advantage of this type of plywood is environmental friendliness. In its production, glue compositions based on urea, a natural chemical compound, are used, which makes it possible to use this material even when finishing residential premises, in the manufacture of furniture and packaging in the automotive industry. This plywood is durable and easy to process. Its serious disadvantage is the average indicator of water resistance. FC plywood is produced in polished and not ground;
- FSF plywood (plywood of the increased water resistance). This type is characterized by a high level of moisture resistance, which is associated with the method of its production, in which glue based on formaldehyde resins is used. This explains the good wear resistance of plywood, and mechanical strength. It retains its shape well and is widely used in construction, including roofing, suitable for painting, cladding, easy to process, whether cutting or drilling. However, this type of plywood has a significant drawback – it is not environmentally friendly. During operation, formaldehyde resins, which give it such strength and water resistance, begin to release vapors and may cause irreparable harm to health. Despite this, FSF plywood is very popular among domestic consumers;
- FOF plywood (laminated plywood). A special method of processing sheets of plywood can significantly increase its moisture resistance. Laminated plywood is characterized by high mechanical strength, wear resistance, holds the shape and is suitable for painting and cladding. The disadvantage of plywood, as in the case of FSF plywood, is its environmental friendliness due to the presence of formaldehyde resins in the composition;
- Plywood FBS or FBV (bakelite plywood, delta wood) is a very special product on the building materials market. This type of plywood is notable for its increased wear resistance, fire resistance (it does not ignite when burning, but is charred), resistance to moisture and rapid temperature changes. By its strength, it approaches low-alloy steel. It is made from pine or birch veneer impregnated with special alcohol or water-soluble resins (the exact impregnation used is indicated by the abbreviations PBS and FBV, respectively). Its service life is 10-15 years. The disadvantage of this type of plywood can be attributed to its high cost, therefore, as a rule, it is used in professional construction, for example, for formwork panels in the construction of monolithic buildings. The dimensions of the PBS and FBV plywood sheets are standard and do not differ in great diversity: 5700X1250 mm and 2850X1250 mm.
It is interesting! Bakelite plywood can even be used in seawater and in tropical conditions, it can withstand temperature drops from -50 to +50 degrees Celsius.
There are several basic sizes of plywood sheets:
- 1220X2440 mm;
- 2440X1220 mm;
- 1525X1525 mm;
- 1500X3000 mm;
- 3000X1500 mm;
- 1525X3050 mm;
- 3050X1525 mm.
Helpful advice! Depending on how the fibers are arranged (along or across the face layer), longitudinal and transverse plywood are distinguished. You can determine this by marking. If we are talking about the second type, then when specifying the size of a sheet of plywood in the first place put the width (for example, 1525X3050 mm).
According to GOST standard plywood sheet length is 2440 mm, and width – 1220 mm. Nevertheless, one of the most common formats is 1525X1525 mm.
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The thickness of the plywood is determined by the thickness of the veneer and the number of layers. At present, a single standard has not been adopted, and sheet thickness varies significantly among manufacturers. The minimum thickness of plywood presented in stores is 1.6 cm, the maximum is 7.6 cm.
The price of a sheet of plywood depends on many factors: the type of plywood used in the production of wood, the manufacturer, the type of material, size, thickness.
The wholesale price for a sheet of moisture-resistant plywood 10 mm ranges from 309 to 560 rubles (the price for a sheet of plywood 10 mm 1525X1525 mm is indicated). When the size of a sheet of plywood is 12 mm, its cost will be from 371 to 505 rubles. The wholesale price for a sheet of plywood 18 mm 1525X1525 mm averages from 536 to 1182 rubles.
In laminated plywood, sheet size and price are slightly different from previous types. So, with a thickness of 18 mm, the price per sheet is approximately 1,580 rubles; in 21 mm, 1,845 rubles. Often found and the size of a sheet of plywood 10 mm, 12 mm and 15 mm.
The price of different types of plywood may vary by region.