All types of plywood - classification by grades, brands, sizes
Plywood is used in a wide variety of fields - from the production of doors and furniture to the aviation industry and shipbuilding. There are different varieties and types of plywood, each of which has a specific purpose. After reading this article, you will have a complete picture of all plywood boards offered by the modern construction market.
Content:
Plywood grades - classification by type of adhesive
The operational properties of plywood largely depend on the substance used for bonding the sheets. The quality of the impregnation affects the moisture resistance and environmental friendliness of plywood, as well as its ability to withstand temperature fluctuations, humidity and other external influences. On the basis of the adhesive components used in the production, many brands of plywood are distinguished.
Plywood FBA
FBA is the least moisture resistant material. However, the use of albuminocasein glue makes it absolutely safe from an environmental point of view. This plywood is suitable exclusively for rooms with low humidity. In particular, it has found its application in the production of furniture, and is also used to create all kinds of decorative elements of the interior.
Plywood FC
FC - a material with sufficiently low moisture resistance. The function of the binder in this case is performed by a urea adhesive that does not emit harmful substances, which allows the use of this type of plywood for finishing work inside residential premises. In this case, a moderate level of humidity is allowed.
Plywood FKM
FCM - veneer sheets interconnected with melamine glue. The degree of moisture resistance of the material is average.
Plywood FSF
FSF - especially strong wood boards, the layers of which are impregnated with phenol-formaldehyde resin. The material is able to withstand significant loads and withstand moisture. However, the amount of toxins contained in the adhesive allows the use of such plywood exclusively outside the premises. In particular, it is ideally suited for cladding external walls in frame housing construction, erection of walling, and the manufacture of outdoor furniture.
Plywood FB
FB - material in the production process of which bakelite glue is used. Sheets impregnated with such a composition are characterized by increased moisture resistance and are able to withstand almost any temperature conditions. Impregnation reliably protects wood from negative environmental influences, which allows the use of this type of plywood in almost any field.
In this case, plates of the FB type may have characteristic differences, depending on the composition of the adhesive and the sizing technology that affects their characteristics.
Materials treated with alcohol-soluble impregnations are moisture resistant and are divided into three types:
- FBS - plywood of the highest quality, each sheet of which is impregnated as carefully as possible;
- FBS1 - plywood boards, during the manufacturing of which the method of spreading veneer sheets is applied, due to which the quality indicators of the material are reduced;
- FBS1A - belonging to the lower class of bakelite plywood, in the production of which the amount of alcohol-soluble substance applied is limited, which involves the processing of exclusively longitudinally arranged sheets.
Another variety is plywood FBV, in the manufacture of which water-soluble adhesive compositions are used.
There are two types of such plywood:
- Plywood, with the inner layers processed by the smearing method, but impregnated with the outer sheets.
- Plywood boards marked FBV1, for all layers of which only the smear method is assumed.
Grades of plywood
To date, GOST standards have identified five varieties of plywood, differing in the presence of certain natural defects of wood or formed during its mechanical processing.
Grade E
Grade E is a high-quality elite material intended primarily for fine finishing. It is not allowed to have any extraneous inclusions, as well as all kinds of deformations, with the exception of minor deviations in the structure of wood, which are random in nature. Valid pin knots on coniferous plywood, but not more than 3 pieces per 1 m2. The aesthetic excellence of E plywood makes it the most expensive of all materials produced.
1 grade
1 - grade for which some defects in the form of knots, light porosha, repair inserts for closing knots are permissible. Such wood boards are used for both internal and external finishing work.
2 grade
2 - a grade of plywood, in which cracks up to 20 cm can be present, and also small repair inserts for closing knots, knots and wormholes, light and dark poros are allowed. It is permissible to leak glue in separate areas within 2% of the total area of the plywood sheet.
3 grade
3 - grade of plywood, in many respects similar to the second grade, but here the restriction on the number of closed cracks and the number of knots of coniferous plywood is removed. The maximum possible diameter of the knots is increased to 70 mm. Under fine finishing conditions, such defects can be hidden with the help of special paints and varnishes.
4th grade
4 - grade, which includes the lowest quality and most affordable materials. In production, wood with numerous defects can be used, including wormholes, as well as ungrown drop knots. Rough edges of glued sheets with deviations within 0.5 mm are allowed. The main purpose of such plywood is the production of packaging materials. However, it is often used for rough finishing indoors.
Front plywood
One of the parameters by which this material is classified is the technology used in the production of processing the outer surfaces of plywood. Based on this criterion, several types of plywood are distinguished.
1. Unpolished (NS) - the outer surface of the veneer is not subjected to additional processing, as a result of which it has a rather rough structure. The risk of cracking increases. Mostly, such materials are used for rough work, where the surface condition of the plates is not of fundamental importance.
2. SH1 - polished plywood, the processing of which is performed on one side. Practically not prone to cracking.
3. Ш2 - material subjected to grinding from two sides. The ability to absorb moisture is minimized. As in cases with Sh1 plywood, it can be used for finishing work, as well as in the manufacture of decorative products and individual structural elements of furniture.
4. Laminated plywood sheetsfor the processing of which special resins containing phenol and melamine are used. It is also relevant to apply a PVC film to the surface of plywood. Thus, the moisture resistance of the material is improved. Lamination allows you to extend the life of wood boards. In addition, the surface looks quite aesthetically pleasing. Such plywood is often used in the arrangement of interiors.
Environmental Plywood
Since a material such as formaldehyde is used in the manufacture of wood-based panels, a generally accepted scale has been developed that determines the level of permissible formaldehyde emissions. According to the level of emission of harmful substances, plywood can be assigned to class E1 or class E2.
E1 class plywood
Class E1 includes materials that emit no more than 10 mg of a harmful substance per 100 g of dry wood. Such indicators are considered acceptable for the use of plywood in a residential environment.
E2 class plywood
Class E2 boards are recommended for outdoor use only, since the emission level can reach 30 mg.
However, some unscrupulous manufacturers often indicate in the annotations to their products a class that is not true. Using such materials under certain conditions is quite risky, so it is advisable to give preference to trusted manufacturers.
Varieties of plywood for the composition of raw materials
According to the composition of raw materials, all plywood offered today can be divided into three categories.
Hardwood Plywood
The deciduous species of wood from which plywood sheets are made are primarily birch. The veneer made on its basis is distinguished by increased density and uniformity of structure. Moreover, in comparison with other types of materials, strength indicators are higher by an average of 20%. The only conditional disadvantage of birch plywood is its cost, which is higher than that of coniferous plywood.
Plates made from hardwood are in demand not only in private construction. Similar types of plywood are used as packaging elements for the transportation of goods, in the field of shipbuilding and carriage building, as well as in various areas of the automotive industry.
Softwood plywood
Coniferous wood, as a rule, is cheaper. Domestic manufacturers of such plywood mainly use pine, which has high strength indicators. Finished products are light enough, and the natural woody pattern adds aesthetic appeal to them. Due to the presence of resins of natural origin, the material has a longer operational period. Coniferous plywood has found its application in housebuilding, and is also actively used in arranging the interiors of residential premises.
Composite plywood
Combined plywood sheets include both deciduous and coniferous wood veneers. This combination allows to reduce the cost of products, almost without compromising on their quality, since the technical specifications are as close as possible to sheets made of birch. Basically, such plywood is in demand in the field of furniture production.
Varieties of plywood for its intended purpose
Plywood boards are used not only in the construction of buildings and interior decoration. The scope of their application is much wider.
Furniture plywood
It is durable and environmentally friendly. In most cases, this is combined FC plywood, acceptable for use in moderate humidity.
Building plywood
Slabs made on the basis of birch are ideal for almost all types of roughing.
Shuttering plywood
Due to the increased strength and moisture resistance, plywood brand FB is able to be in an aggressive environment.
Decorative plywood
As a rule, high-quality veneers are used in the production of plywood intended for fine finishing. In this case, ideally smooth external surfaces of the outer sheets are assumed, on which textured patterns are also visible.
Automotive plywood
With the help of plywood, the FSF sheathes the body elements of freight vehicles. Plates, as a rule, have a laminated, and sometimes mesh-ribbed outer surface.
Ship plywood
In shipbuilding, moisture resistant sheets of FB are quite in demand, in the production of which bakelite adhesives are used.
Sizes of plywood sheets
The standard width of plywood sheets can be either 1220 or 1525 mm. The minimum length is 1525 mm, and the maximum reaches 2500 mm. Modern manufacturers mainly offer slabs of rectangular shape with a size of 2440x1220mm, as well as square, the dimensions of a plywood sheet for which are 1525x1525mm.An exception is large-format products for which the permissible length can reach 3050 mm.
Standard sizes of plywood, mm.
1220x1220;
1525x1220;
1525x1525.
Large-format plywood sizes, mm.
1830x1525;
2440x1220;
2500x1250;
3000x1500;
3050x1525.
The thickness of plywood depends primarily on the number of layers. According to the requirements of GOST, there are regulated minimum and maximum - from 3 to 30 mm. At the same time, there are approved norms that allow some specialized enterprises to produce plates with a thickness of 1 mm or more.
Plywood marking
Each type of this product has a marking that complies with GOST regulations, which contains the following information:
- Country of manufacture of building material.
- Manufacturer trademark or brand name.
- The exact number of items in the package.
In addition, the symbol of plywood boards is provided, including:
- brand of plywood;
- wood material species;
- variety of products;
- emission class;
- surface treatment method used in production.
Knowing about all the listed features of plywood boards, you can easily choose a material that is fully consistent with specific needs.
