What is plywood: all possible types, classification, grades

How appropriate is it to use plywood

To answer this question, we will consider certain types of plywood sheets, because there are several of them, as well as the expediency of their use in residential premises.

How the product is made

In search of an answer, we need to turn to the process of making a plywood board, because initially most people see in plywood only an element of wood and an external finish for veneer, if any.

The production involves:

• Veneer layers. Wood, in fact, cannot be dangerous to humans, after all, we are talking about a natural, natural material.
• Adhesive component. It is precisely in it that the danger to a person may lie.

Among the glue that is used, we will distinguish three types:

• Formaldehyde.
• Phenol.
• Resorcinol.

In addition to these components, in the process of gluing the veneer, simple PVA glue was used, although it was quickly abandoned - the price of a plywood sheet glued in this way turned out to be too high. Plywood sheets

Hazardous components

So we have come to the heart of the question and the answer is unambiguous - a plywood sheet can pose a danger to human health!

Let's immediately determine that both phenol and formaldehyde contain toxic compounds in their formulas that can naturally harm health. Formaldehyde is dangerous

And no matter how small these doses are, because if we have a large area of ​​application of plywood sheet, then the harm it can have on the state of the body increases in proportion to the number of plywood boards. As to what harm we can experience from plywood with the use of formaldehyde and phenol, here are the simple symptoms of poisoning:

As to what harm we can experience from plywood with the use of formaldehyde and phenol, here are the simple symptoms of poisoning:

• Headaches that begin to appear from being in a room covered with such a plywood sheet.
• Cough appears from frequent contact with sheets.
• Nausea, vomiting. This is already the stage of severe poisoning and it can come if you are in a room decorated with plywood boards with phenol and formaldehyde for a long enough time.

By the way, it is precisely on the basis of impregnation that all plywood boards can be divided into:

• Slabs for interior use, for decoration and furniture collection.
• Slabs for external work, for use in non-residential premises.

Now let's look at everything practically under a microscope.

So, we refer to safe types of plywood:

• FBA. The marking indicates that albuminocasein glue was used in the production, which is a natural product. Of course, this type of product is limited in use due to its low moisture resistance, but we can safely use it in the decoration of living quarters.
• FC. Safe cabamide glue is used here, the instructions for using this type of plywood allow us to work inside residential premises.
• FB, this type is produced using bakelite varnish. Despite the fact that plywood impregnated with this composition is maximally ready to resist aggressive environments, it is safe for our health and can be used in living quarters, kitchens, saunas.

Original interior from plywood sheet

There are several other types of plywood sheet that are impregnated with bakelite glue, and to give credit to this glue, each plywood sheet has incredible technical characteristics.

Yes, this affects the price, and they are not always rational for use simply in ordinary internal work, but their safety and strength can be useful in any construction and repair.

As for the harmful type of plywood sheet, this is the one we have already spoken about. More precisely, this is FSF, it is here that phenol-formaldehyde glue is used and the harm of plywood to health has been proven, but studies are still underway that hint that this is not the latest data.

At the same time, FSF remains one of the most commonly used categories, and it has a number of excellent properties that make it so popular. Plywood slabs in the barn

Unfortunately, not all builders are aware of the fact that FSF can pose a certain health hazard, so the use of this type continues in large volumes and in interior decoration.

How dangerous everything is, we have already described above, so any talk about an insignificant content of phenol and formaldehyde in a product has no basis for interior decoration with such a stove.

Everything related to external work, or non-residential premises, garages, sheds, this is precisely the scope of the FSF.

Standard dimensions of plywood sheet

Sheets can be divided by size into standard and large format. GOST regulates them as follows:

General purpose plywood sheets

Dimensions of laminated moisture resistant plywood

The dimensions of the waterproof sheets are based on the dimensions of the plywood for general use. For example, the size range of the well-known domestic manufacturer SVEZA is as follows:

1) 1220 / 1250х2440 / 2500 mm;

2) 2440 / 2500x1220 / 1250 mm;

3) 1200/1500 / 1525х2500 / 2745/3000/3050 mm

The sizes of the popular Finnish plywood WISA: 1220 * 2440 mm and 1250 * 2500 mm.

Dimensions of bakelite plywood

Dimensions 5700 mm x 1250 mm or 2800 mm x 1250 mm. The sheet thickness ranges from 5 mm to 40 mm.

Like any other sheet material, plywood does not have perfect geometry. In the process of cutting, flaws arise. They are not so large as to be visible to the naked eye, but you need to know that they exist and this is normal

This is especially important for furniture makers who cut parts from sheets to exact dimensions.

GOST 3916.1-96 regulates the maximum permissible geometric deviations in relation to the length and width of the plane. These data are shown in the table below.

Geometric tolerances

There is also an allowable take-off run in terms of thickness. It depends not only on the standard value, but also on the degree of surface processing. The pivot table looks like this:

The presence of deviations in the geometry of the sheet does not mean that it needs to be rejected. First, it is worth making sure that this take-off exceeds the tolerance allowed by the standards. And after that, plywood needs to look for another application that does not require the preservation of strict geometric shapes.

Save the page to your browser bookmarks. Information about the dimensions is indispensable when calculating the cost price, to estimate losses in the form of scraps. In addition, there are logistic aspects. Before transportation, it is necessary to calculate how much space (how much) the plywood will take. Storage also involves calculating the capacity of the room.

It's interesting: How to choose a laminate for quality - we study from all sides

Main characteristics and application

The photo shows the creative use of plywood.

The scope of application of the moisture-resistant type is diverse:

• finishing material;
• furniture manufacture,
• production of equipment for playgrounds;
• temporary structures;
• automotive industry.

The following qualities have been recognized in various fields of activity:

• insignificant weight;
• pleasant texture;
• strength;
• wear resistance;
• moisture resistance.

The cost depends on the methods of production, it is divided into the following categories:

• joinery board;
• lined with veneer;
• combined.

The joiner's board is characterized by a high level of strength and has a thick core. Layers are rather narrow strips of wood that, for quality assurance purposes, are laid in strict accordance with generally accepted technology with or without glue.

Veneered plywood sheets are characterized by a high level of strength. Their distinctive feature is resistance to deformation, quality characteristics are provided by a special gluing method.

Combined is made from various types of wood.

The best option for the production of furniture and all kinds of finishing work is considered to be moisture-resistant plywood sheets, which have a number of advantages:

• impeccable quality of processing and grinding;
• decent external characteristics;
• ease of installation;
• environmental friendliness.

FC plywood parameters

In the photo - plywood brand FK.

The most common material used for the production of waterproof type or FC plywood is birch veneer, which is glued with urea resins.

According to GOST 3916.96, the main characteristics of FC plywood imply its division into grades:

• I grade;
• II grade;
• III grade;
• IV grade;
• V grade.

It should be noted that each manufacturer uses certain technologies, which, of course, are reflected in the final result. As a comparison, you can take two leaves of the same grade from different manufacturers, the difference will be obvious.

According to the quality of processing of the outer layers, plywood is divided into:

• sanded on one side - Ш1;
• unpolished - NSh (not processed in production conditions);
• sanded plywood on both sides - Ш2.

The advantages of FC plywood

Plywood production.

The main requirement for all materials, without exception, is environmental friendliness.

There is no doubt about the environmental friendliness of plywood, it is enough to familiarize yourself with the components used in the production process:

• veneer;
• urea resin.

Plywood, made in accordance with the established production rules, is completely harmless, it can be safely used for all kinds of interior work, furniture manufacturing. FK plywood is the best option for interior work. For external ones, it is recommended to give preference to FSF.

One of the most attractive qualities of plywood for users is its ease of processing, which does not require professional skills and significant physical effort:

• drilled;
• sawed;
• polished;
• sticks together;
• colored;
• mechanical strength. The slabs can be easily used for flooring of premises in which significant loads are expected.

The material classified as the highest grades has attractive external characteristics, the texture is relevant for interior decoration.

Scope of FC plywood:

• rough floor;
• base for parquet, laminate;
• decorative elements.

Durable and cheap material is a smart investment. The surface and structure make it easy to work with expensive floor coverings, providing ideal conditions for their installation. A smooth surface is the guarantor of the durability of decorative materials.

Designers have seen in practice the advisability of using plywood to create original interiors. It is possible to create structures of any complexity from an environmentally friendly material: arches, partitions, etc.

Difference by brand

FK plywood is used for the manufacture of containers and packaging, as well as in construction and furniture production.

Now more about the brands of plywood sheets. They classify products according to the degree of their resistance to moisture.

1. Bakelized (bakelite) plywood (grade FB) has high performance. It is often called Finnish. It is impregnated with bakelite varnish and can be used in any climatic conditions, aggressive environments and sea water. It is preferred by the builders of small vessels. The unique properties of FB are evidenced by its use in the construction of formwork for pouring with concrete. The floors made of this plywood have an almost unlimited life, but its price is significantly higher than the cost of products of other brands.
2. BS - plywood, which is called aviation. The veneer is impregnated with alcohol-soluble bakelite glue. The qualities of this plywood are superior to those of BK, so it was widely used in ship and aircraft construction. It is distinguished by increased flexibility, strength, water resistance and resistance to fungi.
3. BV plywood is also glued with bakelite compounds, but they are soluble in water. Sheets of this brand have high strength characteristics, but they are not able to withstand dampness.
4. FC - sheets glued with carbamide adhesives. This plywood is familiar to almost everyone. Its moisture resistance characteristics leave much to be desired, but the building material is one of the most environmentally friendly. It is possible to improve the resistance of FC to moisture by treating plywood with various impregnations.
5. FBA - veneer is glued with albumocasein adhesives. This brand is also afraid of moisture, but plywood is an environmentally friendly product that can be used to make products for food storage.
6. FSF - waterproof plywood is made using phenol-formaldehyde resins. FSF is needed for the floor only on some external site, since this brand has a high level of formaldehyde emission into the atmosphere.

Factors influencing the choice of plywood

Before making a plywood floor in a wooden house, you need to decide on the type of material. What to take into account when picking up sheets:

1. Base type. For example, a concrete base has a high thermal conductivity; losses can be reduced with sheets of greater thickness (from 15 mm). But it is better to sheathe a subfloor made of plywood on logs with a material with a layer thickness of at least 12 mm.
2. Room type (area of ​​application). For residential areas, professionals recommend choosing the FC grade, it is produced without volatile chemicals.
3. Thickness. Arrangement of plywood flooring on logs requires selection of parameters, since the service life of the subfloor depends on the thickness - the thicker the board, the less it will bend when walking. However, it is not necessary to bend in the direction of increasing the size - this increases the mass of the flooring, which also negatively affects the design of the log.

Important! Professionals advise to be guided by the distance between the lags (step). If the cell size is 0.5-0.6 m, the sheet thickness must be at least 15 mm

Considering all the factors, choosing plywood for a wooden floor is not difficult.

Thickness of sheets

The size range of plywood is varied: the length can reach 6 m, the width is 3 m, and the thickness starts from 3 mm. For roughing and finishing work on horizontal bases, the following are used:

• 1525 * 1525 mm with a thickness of 15 mm - this is the most popular product for mounting sheets on logs;
• 1210 * 2440 mm - used for leveling foundations in multi-storey typical buildings;
• 500 * 3000 mm - sheets for studio-type rooms.

As for what thickness of plywood to use for the floor along the logs, the type of prefabricated screed is taken into account, the load level:

1. The degree of load. The greater the load on the floor, the thicker the sheets. Living quarters allow a parameter of 10 mm with a lag step of 0.4 m, but in commercial and other premises it is better to take plates of 22 mm thick.
2. Finishing type. The materials of the final cladding also have their own weight, static load, which will press on the logs. If it is a laminate, then there is no big threat of an increase in mass, which cannot be said about an array of boards or tiles.

Types of plywood

Depending on the scope of application, the material differs:

• building;
• furniture;
• constructional;
• industrial;
• packing.

According to the classification, material is distinguished:

1. Scope of application. For the arrangement of the prefabricated screed, structural and building types are shown.
2. Brand. Determined by the type of adhesive used. It differs as follows:

• FSF - sheets with increased moisture resistance, can be used in rooms with normal and high humidity levels. Adhesive resin composition with the addition of phenol-formaldehyde components;
• FC - products of medium moisture resistance, it is better to use in dry rooms. The adhesive composition is urea-formaldehyde;
• FBA - sheets practically do not tolerate moisture. Glue with albumin-casein components.

1. Grade. It differs in the permissible number of wood defects, processing defects:

• E - extra class, in the manufacture of which oak, walnut, birch are used. Perfectly flat sheets without knots, chips and other defects;
• I - there are knots of a light or dark shade no more than 3-5 units / m2. There is no more marriage;
• II - knots (captive) with a diameter of no more than 6 mm in the amount of 6-8 units / m2 are visible, there may be cracks 0.2 cm long and up to 0.2 cm wide (fused or sealed);
• III - sheets with wormholes, knots up to 6 mm in the amount of 8-10 units / m2, cracks 0.3-0.6 cm long, 0.5 cm wide (sealed), dents, scallops;
• IV - grade with defects, chipping along the edge without restrictions.

Important! If you look at what plywood to use for the floor on logs of inexpensive cost, then grade 1-4 is suitable. But double marking of sheets is possible: 1/3, 2/2 - this means that one side corresponds to a high grade, and the other to a low grade

1. The nature of the processing differs in grinding: Ш1 - processing of one side, Ш2 - both sides are ground, NSh - no grinding. You can use any slabs for the floor on the logs, but it is better to take one-sided grinding in order to get a perfectly smooth base for the finishing.

Having figured out what thickness of plywood for the floor on the logs is better, you should determine other suitable dimensions:

• FC brand;
• emission class E1;
• grade: for rough floor 3-4, for finishing 1-2;
• humidity 12-15%;
• number of layers (thickness) 8-12 mm.

Advice! Please note that with a two-layer flooring, the thickness of the overall structure is divided by 2. However, the choice of price here matters: 15 mm thick plywood sheets are not much more expensive than a 30 mm sheet, but laying and transporting lighter material is more convenient

Peculiarities

There are many options for such a material, they all differ in their width, coating and manufacturing features.

In order to choose the optimal product, you need to pay close attention to the study of the characteristics. Plywood is an ordinary sheet that is created using wood

In turn, it goes through several stages of processing, which gives the product its unique properties.

The process of gluing the layers is due to the use of special compounds, which are usually obtained on the basis of resins. The result is a lightweight material that can also boast of its resistance to temperature extremes.

Among the main advantages of such a product are the following.

• Resistant to moisture, so the material can even be used to decorate a bathroom. This can be achieved due to the fact that upon contact with water, the plywood sheets do not delaminate and do not lose their shape.
• Ease of processing and installation. This material is famous for its strength, so you can use any tools for processing without fear.Plywood can be easily cut, sawn or drilled, which favorably distinguishes it from the background of other materials.
• The ability to combine with other materials. It should be noted that film faced plywood is very often used as an additional material, therefore it is perfect for finishing the ceiling, floor or roof. Most experts use this plywood in combination with natural wood.
• Huge scope of application. Film faced plywood can boast of its unique performance characteristics, which makes it possible to use it in the process of finishing works, in the production of furniture and decorations.

A distinctive feature of moisture-resistant film faced plywood is that it takes much longer to process during the manufacturing process, and is also covered with thicker paper. This paper is impregnated with a special composition, which makes the finished product durable and allows it not to lose its properties for a long time. In addition, it provides water resistance.

Film faced plywood differs from other materials in that it is almost not susceptible to temperature changes, therefore it can be used even in a bath. The special layer also protects against the effects of cleaning agents, including aggressive abrasives. Another feature of such plywood is that it contains a minimum amount of phenol. As a result, a more elastic and durable material is obtained, which also has a varnished protective polymer layer.

The most common building material

Types and grades of plywood

This product is made from several types of hard and soft woods.

Is different:

• by appointment;
• service life;
• appearance;
• cost.

The Russian industry produces plywood of four grades, the “elite” grade is practically not produced in Russia.

1. ... In accordance with GOST 3916.1−96, the maximum permissible defect is 3 non-consolidated knots per square meter and 5 healthy knots. The size of the knot is no more than 6 mm. Cracks, pricks, rot, ribbing and other serious defects are not allowed. Premium plywood is used to make furniture.

1. ... Plywood of this grade is used in construction, for facing with finishing materials.
2. ... There can be an unlimited number of intergrown healthy knots, and 10 per sq.m.
3. ... There are no restrictions on the number of knots, the only requirement is a strong gluing of the layers.

These products can be different in thickness.

This building material differs not only in terms of grades. There are many types of plywood on the modern construction market.

Plywood varieties:

Quality veneer aircraft plywood

• Bakelized - veneer impregnated with synthetic resins is used;
• General purpose - made from different types of trees (ash, alder, beech, birch, aspen, oak, linden, pine, spruce, fir);
• Construction - more often they use coniferous or combined, with a layer of more than 2 mm;
• Furniture - high requirements are imposed on it;
• Decorative - represents a material covered with a film coating;
• Laminated - the surface is resistant to environmental influences.

Laminated decorative products

Depending on the resistance to the action of water, plywood is:

• waterproof F - glued with cresol and frenol-formaldehyde adhesives;
• medium-water resistant FC - urea and albumin adhesives are used in the production;
• limited water resistance - the sheets are glued together with adhesives based on animal and plant proteins, for example, casein.

By design, plywood is distinguished between equal-layer (the thickness of all veneer layers is the same) and non-layer (veneer layers of different thicknesses), diagonal (the fibers of the "shirt" are located at an angle of 45 degrees to the middle layer), star-shaped (the fibers of adjacent sheets are located at angles of 30 and 60 degrees) ...

The most common sheet sizes in meters: 1.525x1.525; 1.525x1.22; 2.44x1.525; 2.44x1.22; 1.83x1.22; 1.525x0.75; 1.22x1.22; 1.22x0.725.

Properties and characteristics of plywood

Plywood furniture: photo

Unique properties make this building material one of the most popular and widely used. It is used in shipbuilding, aviation, furniture production, construction - for interior decoration. The layered structure makes it extremely durable and lightweight at the same time.

Large sheet sizes allow cutting solid parts from it. Plywood bends, does not crack - it is a practical and reliable material. It is environmentally friendly and has an attractive appearance.

The low price is also a very strong argument in favor of plywood. According to the degree of surface treatment, polished and unpolished products are distinguished.

Wide range of plywood

Lamination and processing of the ends with special impregnations prevent the appearance of mold and blue stain, protect against adverse weather conditions, which is important when used outdoors. What negative qualities can spoil the impression of this wonderful building material?

What negative qualities can spoil the impression of this wonderful building material?

Plywood is resistant to weak acids, but chlorine, organic solvents (gasoline, acetone) should not be allowed to get on it, they cause swelling and a decrease in the strength of the material.

Easy flammability, flame resistance at a thickness of 18 mm is 13-15 minutes; low sound insulation, the coefficient at a thickness of 18 mm is 22-25 dB.

How to work with plywood

Photo - DIY tools for working with plywood.

The material is easy to process, and therefore its popularity is growing rapidly. However, in order to achieve flawless results, the instruction recommends adhering to the recommendations.

Plywood drilling

The structure is easy to drill, but it is necessary to act with extreme caution: the sheets are vulnerable to mechanical stress, chips and other damage are easily formed. It is quite problematic to eliminate defects

It is practiced to use chipboard or a backing sheet, which must be pressed tightly against the surface to be treated.

Particular attention should be paid to the choice of the drill, it must have a good sharpening and a front cutter

Fastening with nails and screws

The material is easily fastened with nails (threaded), but it is preferable to use plywood screws. The use of wire nails is practiced. In order to prevent the plywood from splitting, you must first blunt the nail.

Bonding plywood sheets

You will need wood glue, the specific characteristics of which must be appropriate for the application. For example, for interior work - PVA.

Grinding

It is recommended to grind the surface with emery paper, movements should be carried out across the fiber or in a circular motion.

In the absence of practical work experience, it is recommended to use qualified advice, they will help you choose and carry out the correct calculation, eliminating unnecessary expenses.

Classification by the composition of the adhesive impregnation

Technical characteristics, sanitary safety, directions of use are largely determined by the composition of the means with which veneer sheets are glued.

Plywood is a well-known material for the production of which both historically established gluing technologies and innovative methods and composites are used. In addition to traditional types, decorative plywood is produced using expensive types of wood or paper with a texture pattern. According to the method and material of seams gluing, five main groups and several subgroups can be distinguished.

FBA

FBA-products have the safest adhesive impregnation, consisting of two protein fractions:

• albumin;
• casein.

Environmental friendliness of plywood is associated with insufficient water resistance, because protein substances tend to swell in the presence of water. Sheet products are not recommended for use in rooms containing wet vapors, can be used for the production of furniture, the manufacture of decorative elements for finishing dry rooms.

FC

Products with the abbreviation FC in the marking are made by bonding veneer with urea adhesives that do not emit harmful vapors into the surrounding space. The material is relatively resistant to moisture and can be used to decorate rooms with a moderate concentration of water vapor.

FKM

The products of this group demonstrate good resistance to moisture, and have confirmed their absolute safety for the ambient air. Melamine glue, by means of which the veneer is connected, does not fonite, does not become a source of harmful fumes, which makes it possible to use FKM products for interior decoration of any premises, for the manufacture of furniture.

FSF

Plywood with the designation FSF has an increased resistance to moisture, which is due to the use of phenol-formaldehyde resinous polymers for gluing sheets. The adhesive may contain a residual amount of monomeric aldehyde, which evaporates during use of the material. The regulations allow the use of FSF sheets of different sizes for exterior finishes, the production of outdoor furniture.

FB

FB-products are obtained using bakelite compounds that are resistant to moisture and high thermal influences. The ability to withstand heavy loads from the environment makes it possible to operate the material in aggressive spaces, for example, in sea water. Bakelite products can have different modifications, soluble in alcohol or water. Depending on the characteristics of the bakelite agent used in the production of plywood, it is divided into two subgroups: FBS and FBV.

The material with the abbreviation FBS (or BS) has maximum resistance to all types of impacts, which allows it to be used for finishing aircraft and sea vessels. Plywood glued with an alcohol-soluble bakelite agent has flexible properties and is easy to work with. Ceiba veneers from the tropics are especially flexible.

Flexible plywood is divided into subgroups depending on the features of applying to the adhesive sheets:

• FBS - of the highest quality (thorough impregnation);
• FBS 1 - of moderate quality (coated with glue);
• FBS 1A - quality satisfactory for some types of work (overcoating only longitudinal sheets).

FBV (or BV) is an abbreviation for products glued together with water-soluble bakelite. The material is also subdivided into subgroups. FBV plywood is completely thoroughly impregnated; FBV 1 sheets are obtained by smearing each sheet. The products are of excellent quality, only you need to take into account the susceptibility of PVF-material to moisture.