What is the best plywood for the floor. What thickness of plywood for the floor is suitable

A wooden floor, like any other base, eventually loses some of its operational properties. Wood is a living material, and gradually it begins to change - it deforms somewhat, the floorboards are no longer so even. But plywood will help to correct the situation (and this may be necessary when laying a laminate or other material demanding evenness of the base). How to lay plywood on a wooden floor?

Plywood is widely used in the construction industry. It can be used to create partitions, wall and ceiling cladding in a wooden house, formwork is built from it, and floors are often leveled with it before laying coatings that require evenness of the base.

This material is a layered "pie" created from wood veneer. To create it, an odd number of veneer sheets (from 3 pieces) are glued together, which are connected in such a way that the wood fibers in different layers are perpendicular to each other. This increases the strength of the material.

For laying in warm and dry rooms, such as residential buildings, plywood is the ideal material. Working with it is easy and fast, which attracts many builders and novice craftsmen to its use. If necessary, sheets that have lost their strength and reliability can be easily replaced with new ones.

On a note! From plywood, an excellent version of a dry screed is obtained, which (unlike ordinary cement) does not have to wait 30 days to dry - you can start laying the finish coat almost immediately after installing the plywood. Using this material will save not only time, but also money during the repair of the premises.

Benefits of plywood flooring

Plywood as a leveling material for wooden floors is so often used for good reason. It has a lot of advantages:

has a low price, and therefore with its help you can perform a budget, but high-quality repair of the floor;
makes it easy to level floors copes with the curvature of the base, and with small surface defects;
is an additional insulating material, thereby reducing heat loss in the room;
can also be used as a finishing option for flooring;
put in by hand without the involvement of masters;
easy to handle;
is an environmentally friendly material, pleasantly smells like a tree.

Plywood itself is a fairly stable material, practically does not deform under the right operating conditions, which means it allows you to create a reliable and durable subfloor that will last for decades. And to work with it, a small set of tools that are in almost every home is enough.

On a note! Sometimes very beautiful options for finishing the floor are created from plywood.

The disadvantage of plywood is its fear of water. Ordinary material does not like a high level of humidity, which means it cannot fit in a bathroom or bathroom. For these purposes, it is better to purchase moisture-resistant plywood.

What are the types of plywood

Plywood is divided into several types depending on its characteristics. For example, according to the presence and number of defects, the material can be divided into 4 groups.

Table. Types of plywood.

Variety	a brief description of
	The best grade of material. Sheets of such plywood do not have defects, they are even, smooth, there are no knots and cracks on them. Although a certain number of small cracks are allowed, they will practically not play a big role in the quality and appearance of the material, since they are not noticeable to the eye.
	Such plywood may have up to 5% defective area of the entire sheet. Defects can be small dents, glue residues (no more than 2-3%).
	Such sheets have knots and wormholes, but in moderation.
	The worst kind of plywood. It can only be used to create formwork, as it has too many external flaws. However, the sizing of sheets, as a rule, is still of high quality.

Also, plywood varies depending on the purpose. There are the following types:

industrial;
for packing;
furniture;
structural;
construction.

Sheets of material can be made from various woods. So, allocate:

birch plywood;
coniferous (made from cedar, larch, pine, fir, etc.).

Coniferous is cheaper than birch. In its manufacture, varieties of deciduous trees can sometimes be used, however, only in the inner layers.

On a note! The size range of plywood sheets is quite large. The parameters vary from 1525x1525 to 3050x1525 mm.

Table. Types of plywood depending on its properties.

Abbreviation (designation)	Characteristic
	The impregnation in these plywood sheets is represented by albumin-casein glue. Such plywood is afraid of water, but it is absolutely safe for human health, as it is environmentally friendly.
	Plywood is impregnated with carbide glue. It does not have increased moisture resistance and therefore can only be used for the manufacture of furniture and for indoor work. It will not tolerate exposure to precipitation outside or high levels of humidity.
	Also called aviation. Manufactured using bakelite alcohol-soluble adhesive. Previously used in shipbuilding, the creation of aircraft and other aircraft. Possesses the increased durability, resistance to influences of external factors, is not afraid of water and microorganisms.
	Bakelite-based glue is used to create this plywood. It is water-soluble, and therefore the sheets are not used to create any structures in the open.
	Layers of material are impregnated with bakelite-based varnish. This plywood can be used in a fairly aggressive environment. If necessary, the material can withstand moisture for a long time.
	Plywood with high fire resistance. Otherwise, this material is unremarkable.
	The layers of this plywood are impregnated with formaldehyde glue. It turns out a durable material that is not afraid of moisture. It also practically does not burn, which is important for the construction industry.

floor plywood prices

floor plywood

Which plywood to choose

How among such a variety of plywood types to choose one that is suitable for the subfloor and will cost moderate money? To do this, it is important to assess the operating conditions of the material. For example, in an ordinary room, plywood without any special properties can be used to level a rough wooden floor. This may be a material belonging to grade III or IV, because a finishing coating will be laid on top of it and defects will still not be visible.

Next, you should think about choosing the type of plywood. In a residential building, ordinary FC plywood will serve its time perfectly. Moreover, it will even cope with the level of humidity that can be observed in the bathroom or kitchen. And in the nursery, you can lay sheets marked with the abbreviation FBA. This is the most environmentally friendly type of material.

Advice! You should not buy plywood made using phenolic glue for an apartment or house. It may be too toxic. Although, it is worth recognizing, the level of moisture resistance is at its best.

The dimensions of the sheets are also important, in particular their thickness. To make wooden floors even, it is enough to use sheets 10-15 mm thick. Although some experts argue that only sheets more than 18 mm thick can withstand the load. And to achieve optimal strength, plywood can be laid in two layers. Here it is easier to evaluate the actual costs and see which option will be more profitable in terms of budget. For ease of transportation, you need to pay attention to the length and width.

The nuances of laying plywood sheets

Plywood is a simple material, but, nevertheless, it requires compliance with certain rules when laying. If they are neglected, then it will not be possible to achieve the desired effect, or such a foundation will quickly become unusable.

How to lay plywood on the floor: laying methods

The process of laying plywood will directly depend on the condition of the subfloor, as well as on additional work. For example, sheets can be laid directly on a wooden base if it has not yet become unusable and is still strong, although it has ugly gaps between individual boards or has lost its appearance. Sheets are placed in compliance with small gaps - up to 3-5 mm between them. A distance of 15-20 mm must be maintained to the wall. Sheets are attached with self-tapping screws or glue. The consumption of glue is about 1.2-1.5 kg/m 2 . The installation of the sheet should be carried out by screwing the screws around the perimeter, and then diagonally.

Plywood can be closed and a somewhat curved floor. In this case, the material is partially laid on the base itself, as well as on small bars, which will act as a kind of lag. The bars can have a different section depending on the curvature of the floor. Sometimes even cutting boards are used.

Less often, when the subfloor has completely become unusable, a new base is created from plywood installed on logs or supports. In this case, the old base is completely dismantled, and then the logs are installed, on which fresh sheets are attached. They are laid in such a way that the edges of the sheets do not sag - on the contrary, they must have a support under them.

Necessary tools and materials

The following tools may be required to install plywood sheets on a wooden base:

screwdriver;
drill;
a hammer;
screwdriver;
level;
electric jigsaw.

The materials used are self-tapping screws, usually 30-50 mm long, nails or glue. The first ones are preferable, since they are the easiest to work with.

Preparation for work

Before laying plywood sheets, a number of preparatory work should be carried out. It includes:

assessment of the condition of the wooden base and its repair, if necessary- replacement of cracked floorboards or floor screed. Floors should not “walk”, bend, creak;
checking and measuring the humidity level in room;

On a note! You can find out the humidity like this: a piece of polyethylene about 1x1 m in size is laid on the floor, fixed on the base. After 3 days have passed, the film rises, its condition is assessed. If condensation has accumulated on it, then the humidity in the room is increased and plywood can only be laid moisture resistant.

removal of all debris from the rough base. If it remains, then the plywood will not lie flat. Floors can be swept and vacuumed, if necessary - washed;
plywood itself must also be cleaned of sawdust and dust;
recommended treat the old wooden surface with a primer mixture.

Laying plywood on an old wooden floor

Step 1. If necessary, the rough foundation is repaired. The evenness of the floor is checked using the building level, after which the protruding parts can be filed. The floor should be as level as possible.

Step 2 Holes are drilled in the floorboards in places where the lag lies and screws are screwed in. This procedure will make the floors stronger. Self-tapping screws are screwed into each board at a distance of approximately 50 cm from each other.

Step 3 The draft base is covered with a thin substrate. Its individual strips are fastened together with adhesive tape. The strips are overlapped by about 10-15 cm.

Step 4 The first sheets of plywood are laid so that there is a small gap of 2-3 mm between them, and the gap to the walls is about 10-15 mm.

Step 5 Sheets of plywood are screwed to the boards with self-tapping screws in increments of about 20 cm.

Step 6 Plywood in the next row is laid with joints shifted by 1/3 of the sheet. If necessary, the sheets are sawn in accordance with the measurements taken.

Step 7 The joints of individual plywood sheets after installation can be glued with adhesive tape. The base is ready for laying the top coat and installing skirting boards that will hide all the gaps near the walls.

Video - An unusual way to lay plywood on a wooden floor

Video - Mounting plywood on a wooden base

Checking the quality of plywood floor installation

Immediately after the installation of plywood sheets has been completed, it is recommended to check the quality of work. This is important to do before laying the final coating. With the help of a long even rail, the evenness of the laying of the material is checked - the gaps between it and the floor level should not be more than 2 mm in accordance with SNiP 3.04.01-87. Next, you need to use the building level and evaluate the horizontal position. The allowable slope cannot be more than 0.2% according to the same document.

SNiP 3.04.01-87. Insulating and finishing coatings. Download file (click on the link to open the PDF file in a new window).

The base, covered with plywood, is tapped with a hammer at the end of the work. The procedure is necessary to identify the places of possible delamination of materials. Where the sound on impact will be deaf, there is a problematic place. The sound when tapping the entire plywood floor should be the same if the sheets were laid correctly and not damaged during installation.

Plywood is not in vain called a universal material. It also works well for leveling floors. And if the installation of the sheets was carried out correctly, then the master provided himself with high-quality and reliable flat floors for many years.

For laying parquet or other types, a level base is required. Therefore, leveling the floor surface is a prerequisite for finishing work. You can use plywood for this.

Which plywood thickness to choose

Plywood is several layers of veneer glued together. contains an odd number of layers. The strength and thickness of the sheet depends on their number.

For example, a sheet that contains nine layers will correspond to a thickness of 12 mm, and if there are 11 layers in a sheet, then its thickness will be 16 mm.

The raw materials for the manufacture of plywood are:

Sheet thickness and method of fastening plywood

concrete;
on the lags.

If plywood sheets are laid on a screed, its moisture content must be checked.

Sheets must be done only on a dry base. You can determine if your concrete screed has dried out in a very simple way. To do this, you need to lay out a plastic film on the floor around the entire perimeter, firmly pressing its edges to the concrete surface. If no condensation appears on it after 48 hours, then the screed is dry enough for laying plywood.

When laying plywood sheets on concrete, wooden floor, great importance is not given to its strength. Another thing is if the plywood is attached to the logs. In this case, sufficiently strong plywood sheets are required, the thickness of which will be at least 12-16 mm. We recommend reading the article on .

When choosing plywood sheets, you should pay attention not only to the thickness of the sheet, but also to a number of other equally important characteristics:

Grinding quality. Manufacturers produce sanded plywood: on one side (Sh1), on both sides (Sh2) and unsanded. If plywood is used as an underlay for parquet or other flooring, W1 or unsanded sheets can be used.
Water resistance of plywood. For the floor, an average moisture resistance material corresponding to the FK brand is used.
Glue composition. In the manufacture of FC, adhesive compositions with carbamide resins are used, which can be used in dwellings. FSF plywood with increased moisture resistance cannot be used even in rooms with high humidity (kitchen, bathroom), since the layers of the sheet are glued together with toxic adhesives based on phenol-formaldehydes. Plywood sheets of this brand are used only for external work.

For interior decoration, FC from hardwood veneer is suitable.

There are four groups of plywood FC:

Plywood sheets of the first group have practically no flaws.
The second group of these building materials may have knots.
The third group has a lot of different defects.
The fourth is the lowest grade.

The second group of plywood is suitable for floors.

There are two classes of plywood according to the content of formaldehyde - E1 and E2. When working indoors, class E1 is used, containing the minimum amount of formaldehyde.

Summing up, we can say that plywood for leveling the floor is the most acceptable option. For interior work, plywood FK-2U1Sh1 is suitable, with a thickness of 12 to 16 mm. This is a relatively inexpensive material that can be used for laying parquet, linoleum. We recommend reading the article .

Plywood is a building material that is very often used in flooring. But in order for this to be done qualitatively, you need to know what thickness and type should plywood be. You can complete the classification of plywood, its types and other parameters.

Plywood floor on logs, video

Thickness and brand of plywood for the floor by logs

For logs, you need to use unplaned boards of the second and third grades, from healthy coniferous or soft hardwood. Before carrying out the robot, all wooden elements must be impregnated with an antiseptic, including plywood.

FBA is a brand made on the basis of natural glue, its disadvantage can be considered low moisture resistance. And the advantage is the absence of harmful substances, so all plywood components are made on the basis of natural substances.
FC - plywood of medium moisture resistance, suitable for almost any floor.
FSF - plywood with high moisture resistance, designed for outdoor robots but can also be used indoors. And if your basement is damp, then for a longer service life you can use this brand of plywood. But unfortunately it is slightly toxic, so its use in residential areas is not recommended.

When you have decided on the brand of plywood for the floor, you can and will determine what thickness of the plywood for the floor according to the logs is the best. According to the standards, it is best to use plywood of the following thickness:

10 mm is the minimum thickness of plywood for the floor, but it is better to choose thicker plywood;
12 -16 mm is the ideal thickness of plywood for the floor, if the standards for lags are met.

The choice of plywood thickness for the floor can be affected by the finish. If these are boards, then the plywood can be thin, because the entire load will fall on the floorboards. But for other materials - linoleum, laminate and other similar plywood coatings, it is better to use thicker ones.

Thickness of plywood for leveling a wooden floor

Plywood is the perfect material to level an old wood floor. When choosing plywood, you need to focus on the differences in the old floor, if they are small, then you can choose less thick plywood - 12 mm plywood is also suitable. If there are dips, ledges or large drops, it is of course better to minimize them, but still with such an uneven wooden field plywood must be at least 14 mm but not more than 16 mm.

Well, if the wooden floor is perfectly flat and you want to use plywood to improve the appearance of the surface, then you can not overpay and choose plywood with a thickness of 8 to 10 mm.

Plywood is an excellent material, it can be used to level any surface for any topcoat. And often plywood is used to level the floor under linoleum, because it is this material that needs a very flat surface, which guarantees a long service life of the floor.

The thickness of the plywood for the floor under the linoleum should be between 12 and 16 mm are the ideal dimensions.

If you properly make the floor from such plywood, then the floor will be reliable and last for many years.

Thickness of plywood for laminate flooring

Laminate flooring can be easily laid on a flat plywood floor. Since this material can apply part of the load on itself, the plywood for it can be chosen a little thinner. But in any case, the thickness of the plywood under the laminate should not be less than 8 mm and more than 16 mm.

Thickness of plywood for parquet flooring

If you are going to use a top coat for parquet, and use plywood as a base, then the thickness of the plywood for the floor for parquet should be 12 mm. This will be enough to make the floor reliable.

Thickness of plywood for floor tiles

You can even lay tiles on a plywood floor, but you need to take into account that if the plywood sags from the load, the tile will easily fall off. Therefore, when choosing the thickness of plywood for such a floor, it is better to choose a thicker material. European standard plywood floor thickness under the tile must be at least 22 mm.

In most cases, plywood is laid on logs - it is for this floor that specialists recommend 30mm plywood, this allows you to make a reliable floor to which the tiles will be glued for a long time.

plywood sheet- sometimes an indispensable building material. As for the arrangement of floors, using plywood, you can not only carry out minor repairs, but also lay a new full-fledged flooring.

Using at work, you can:

lay first draft floor. For example, if your concrete base is not perfectly even, then by laying this material you will achieve a flat surface on which you can already lay parquet boards, linoleum, etc.
issue finishing flooring. Alternatively, plywood is used to cover the floor in country houses or cottages. To do this, sometimes choose special laminated products with a high level of moisture resistance.

Using FK slabs to level the base, you achieve greater sound insulation, and laying along the logs allows you to additionally insulate the floors or put communications under them. Since plywood is a relatively fragile material, we suggest you figure out how to choose plywood for the floor, taking into account all its varieties.

What you need to know about plywood to choose a quality product

Most craftsmen know what and how plywood boards are made from. Therefore, we will not go into production details. What you should know when choosing this building material is that the adhesive for veneer (formaldehyde resin) is a source of harmful fumes.

In addition to the formaldehyde composition, protein and carbamide mixtures, which are less dangerous, are also used for gluing layers.

Pay attention to rates. If the price of a plywood sheet is suspiciously low, then most likely it is a low-grade product made in China. Plywood from China not only does not meet European quality standards, but is also a very low-quality material with low performance.

Advice! Plywood sheets should not be used for arranging floors in the kitchen and bathroom, as warm and humid environments are aggressive for them. In addition, this leads to an increased emission of formaldehyde. For the floor in the bathroom, tile is more suitable, and for the kitchen - linoleum.

Now let's consider what kind of plywood is needed for the floor, and more specifically, some parameters of this product, focusing on which you can choose the right building material.

grade

The first thing to start from is the types of plywood for the floor.

GOST 3916.1-96 dictates five grades of plywood sheets, which differ in the number or presence of defects obtained during processing:

IV - a product of very low quality, on the sheet of which you can find wormholes up to 45 mm in diameter. Edge defects can be up to 4-5 mm deep. Over the entire surface, intergrown knots may be visible.
III - the total number of defects on a standard size slab should not exceed 9. The permissible number of wormholes per 1 m² area is up to 10 pcs. The defect diameter should not exceed 5-6 mm.
II - cracks up to 200 mm in size, minor wood inserts are allowed on the canvas.
I - the length of cracks or any other defects cannot be more than 20 mm.
E - an elite variety, the presence of defects in which is not permissible.

Advice! For the arrangement of the subfloor, it is permissible to use sheets of IV, III, II grades. To design the finishing flooring, it is better to purchase a product of I and E grades.

Marking

This product is divided into brands according to resistance to moisture, which is achieved through various impregnations.

The maximum moisture resistance is laminated plywood.

FBA- the veneer is glued with an albumin-casein composition. This is an environmentally friendly product, but its use is very limited due to the lack of resistance to moisture.
FSF- the layers are glued together with a resin phenol-formaldehyde composition, as a result of which the final product acquires excellent operational qualities (moisture resistance, wear resistance, mechanical strength).
FC- the veneer is glued with a urea compound. This production technology allows the use of FC for repair and installation work indoors.
FB- material that is impregnated with bakelite varnish. Differs in the increased resistance to moisture. Plates FB can be used even in the tropics.
BS- veneer impregnated with bakelite glue (C - alcohol-soluble). It is also called aviation, since previously this product was used only in the ship and aircraft industry. It has amazing properties: flexibility, resistance to fungi, moisture, strength.
BV- sizing with the same bakelite composition, but water-soluble. Therefore, BV boards are durable, but not moisture resistant.