In this article we will look at how to level an old floor with plywood under a laminate, using two basic bases as an example: wood and concrete.

Using plywood as a leveling layer under the finishing floor covering is considered to be an economical and proven method.

The technology for arranging a dry screed using plywood does not require significant labor costs and large financial investments.

Since the floor can be leveled in a short period of time, and there is no need to wait for the screed to mature, as a result, repairs to the floor surface are carried out without delays.

Leveling a wooden base can be done using two methods: with or without lathing. Which technology is most suitable for leveling your floor under laminate is up to you to decide.

Leveling a wooden floor with plywood over the joists under the laminate involves dismantling the old covering, including the floors and boards lying on the joists.

After the boards are removed, it is necessary to inspect the joists; some of them may have to be replaced with your own hands or simply strengthened with anchor bolts.

If you need to raise the floor height in the house to a certain level, then you can completely get rid of worn-out joists and install new ones, having previously decided on the required step size.

It is best to use beams made of coniferous trees for installing logs. First of all, they make the piping around the perimeter of the room, leaving a temperature gap of 50-100 mm at the walls.

Then the working area is equipped with longitudinal beams with a distance of no more than 60 cm. The correct horizontalness of the logs is controlled using a building level.

The plywood is fixed to the beams in such a way that the butt joint of the sheets rests on the support.

The seams of the leveling layer should not be allowed to hang in the air. If the sheathing beams were laid with a large step, then it is necessary to supplement the supporting base with transverse beams.

At the same time, the smaller the cell of the supporting floor, the better it will be possible to level the base under the laminate with your own hands.

First, an insulating layer is laid; polystyrene foam boards or mineral wool can be used as it. A vapor barrier is installed on top of it with an overlap on the walls.

Installation of plywood sheets on beams:

Taking into account the unevenness of the walls, they control the corners and adjust the outer sheets of plywood to the required parameters;
Installation of plywood is carried out in a running start, so as to avoid the formation of a cross-shaped seam of four sheets. In this case, there should be a temperature gap of about 2 mm between the products;
The distance of the plywood covering from the wall must be at least 20 mm. The free space will subsequently be masked with a plinth;
The plywood is fixed to the beams using self-tapping screws. The length of the fastening element rods is calculated by multiplying the width of the sheet by the number 3;
The holes for the self-tapping screws are pre-countersinked, which will allow their heads to be completely recessed into the plane of the plywood;
Laying plywood on the sheathing is done in strips. The sheets are fastened with a step between fasteners of 20 cm;
If necessary, the extreme elements of the floor are cut with a jigsaw to accommodate the laying of communications, or adjusted in accordance with the protruding parts of the wall;
After the installation of plywood over the sheathing is completed, the uneven areas are puttied.

In addition to the above material, we suggest watching a video on how to level a wooden floor with plywood.

Leveling a wooden base under laminate without lags

It is quite possible to level a wooden floor surface without using joists. This technology can be considered, of all existing ones, the simplest way to level a floor under a laminate.

In this case, there is no need to waste time dismantling the old surface and installing the logs.

In addition to plywood, wood floors can be leveled using cement-bonded or gypsum fiber floor boards.

It will sag under the weight and become deformed over time.

To level a plank floor, it is necessary to select the correct thickness of plywood.

If the floorboards are about 20 cm wide, then the thickness of the product can be 10 mm; if the floorboards are more than 20 cm wide, the plywood thickness should be about 20 mm.

Installation of plywood sheets without joists:

It is necessary to retreat 20 mm from the wall; in order to correctly form the indentation, it is necessary to place mounting bosses along the perimeter of the floor;
When installing sheets between them, it is necessary to leave a temperature gap of 3-8 mm, with the help of which depreciation of the rolling stock will be achieved when the humidity level changes;
When installing plywood under laminate, it is recommended to imitate brickwork. That is, each sheet must be laid offset relative to the sheets of the previous row. The minimum offset value is ¼ sheet of plywood, the maximum value is half the width of the product. Cross-shaped joints of the seams of four products should be avoided;
When fixing the sheets to the board covering with your own hands, you need to correctly distribute the attachment points. In this case, it is necessary to focus on the step between the height differences identified in the process of preliminary measurements. More details in the video below;
Holes for fasteners are made in advance in several stages. First, the hole is drilled using a drill whose diameter corresponds to the size of the self-tapping screw. Then the finished hole is countersunk so that the head of the fastener, after screwing in, is level with the plane of the plywood sheet.
All holes that should be located along the perimeter of the sheet are made by hand with a distance from the edge of at least 20 mm.

Leveling concrete screed with plywood

You can level concrete flooring under laminate using different leveling technologies, but the technique using plywood is the simplest and cleanest. Indeed, in other cases it is impossible to do without concrete work.

Depending on the evenness of the concrete base, the option of final leveling the surface with plywood under the laminate is chosen.

The technology may involve a lag method or floor leveling without the use of a lag structure.

Leveling the concrete base without joists is the best option for a relatively flat screed; the difference in its horizontality can be no more than 1-1.5 cm.

Plywood sheets are glued to the concrete floor with a special adhesive, then additionally secured with dowel nails.

Using the same principle, you can level a concrete floor with your own hands using chipboard slabs.

The main thing is that the base on which the leveling layer will be mounted is strong and level.

Aligning the screed with the sheathing is required when it is necessary to raise the concrete floor or when the difference in height of the horizontal surface exceeds 1.5 cm.

Leveling a concrete screed using beams involves the following series of actions:

First of all, it is necessary to prepare the base, as a result of which the screed should become completely dry and clean;
Along the perimeter of the room, using the building level, determine the boundaries of the future flooring;
The beams are adjusted to the required dimensions, and coniferous wood products are used as the future supporting structure. Logs can be purchased at a hardware store, but, as a rule, they are not always well dried. To construct a rough base, completely dried wood is suitable, otherwise the structure may twist. Suitable material parameters are 40x100 mm;
For the work process, wooden spacers of the following sizes are also prepared: width - 100-150 mm; length – 200 mm; thickness – 250 mm;
The installation of the beams should be carried out transversely to the door opening, in increments of 40-50 cm. The distance from the wall should be 20-30 mm, it is made in order to prevent deformation of the floor due to temperature fluctuations;
To control the evenness of the mounted structure and its compliance with the intended height of the future floor, wooden wedges are placed in uneven places;
In this case, between each element (wooden wedges, gaskets, joists) it is necessary to lay a soft sound-proofing layer, a piece of linoleum or polyethylene foam;
The logs are installed around the perimeter of the room, then the cross beams are attached to them. The voids of the finished sheathing are filled with a thermal insulation layer, which is used as mineral wool or basalt. As a result, the floors will not only be insulated, but also silent;
Then they proceed to laying plywood sheets, they must be well dried, and for ease of installation they are spread out into squares of 75x75 cm. The products are mounted on bars with self-tapping screws with a temperature gap of 2-3 mm.

A thematic video story will complete and complement the above information with details.

A wooden floor that has even slight unevenness causes significant problems when installing any floor covering. Old wooden floors, which characterize houses, cottages, and city apartments that have a long service life, most often require careful leveling. Leveling a wooden floor with plywood will help eliminate all unevenness and prepare the base for further installation of laminate, carpet, linoleum and other types of floor coverings. This method is quite simple and popular, allowing you to create a perfectly flat surface.

Using plywood to level a wooden floor is the best option for situations involving further installation of laminate flooring. In this case, use plywood with a thickness of at least 12 mm, but if the surface is fairly flat, then you can stop at a thickness of 8-10 mm.

Performance characteristics of plywood

Plywood has a number of advantages that position it favorably for leveling the floor in a wooden house:

Plywood has unique characteristics that make it a popular material for renovation work:

Simple processing and installation technology;
High quality grinding;
No unpleasant or foreign odors;
Excellent surface hardness;
Light weight sheet of material;
High strength under load;
Excellent performance properties of moisture-resistant and water-resistant plywood.

The structure of plywood is characterized by a layered appearance. It consists of veneer, carefully pressed and glued together. The thickness of plywood is determined by the number of such layers, which give it resistance to stress and strength. Achieving such important characteristics of the material is possible thanks to the special placement of veneer layers, each subsequent row is located perpendicular to the fibers of the previous one.

It should be noted that the number of layers in any type of plywood is always odd. For example, twelve millimeter sheets have 9 layers of veneer. However, purchasing plywood for leveling a wooden floor requires taking into account not only the thickness of the material, but also a number of other characteristics, such as brand, grade, degree of surface treatment and emission class.

Plywood grades

Plywood is divided into grades depending on the degree of moisture resistance. There are four types of stamps:

Plywood intended for industrial construction work - grades FB, FOF;
Plywood intended for individual construction and repair work - grades FK, FSF.

Let's take a closer look at the grades of material intended for individual construction.

The FC brand is characterized by average moisture resistance. Veneer gluing is carried out using fairly safe adhesives based on urea resins. Plywood of this brand is used for interior decoration and furniture production.

The FSF brand is characterized by increased moisture resistance, but its use at home is undesirable. During its production, veneer sheets are glued together using phenol-formaldehyde-based glue. Although, according to existing standards, plywood of this brand is allowed for indoor work.

Plywood varieties

In accordance with GOST, there are four grades of plywood:

Of course, when choosing the best option for leveling a wooden floor, you should rely on your capabilities. The only thing that can be definitely noted is that grade 4 plywood is not suitable for flooring. The first option is ideal, but in terms of the optimal price-quality ratio, the option of choosing second grade plywood becomes more suitable.

Degree of plywood surface treatment

The surface of the plywood sheet can be sanded or unsanded. This point is reflected in its marking:

NSh – marking for unsanded plywood;
Ш1 – plywood, sanded on one side only;
Ш2 – marking for plywood, sanded on both sides.

Plywood emission class

Sanded plywood must be marked with the free formaldehyde emission class:

E1 – marking indicates that the presence of formaldehyde is less than 10 mg per 100 g of dry plywood mass;
E2 - marking indicates the presence of formaldehyde in an amount of 10-30 mg per 100 g of dry plywood mass.

From the data obtained, we can draw a final conclusion that the best option for leveling would be second-grade plywood with the markings Ш1, ФК, Е1 and a sheet thickness of 10-12 mm.

Tools for leveling wooden floors with plywood

High-quality leveling of plywood floors is impossible without the use of special tools. In addition, you need to have some skills in working with the material and experience with some tools.

To complete the work you will need:

Level;
Self-tapping screws;
Screwdriver;
Roulette;
Jigsaw.

Preparatory work

Before starting work on plywood, it is necessary to check the condition of pipes, electrical wiring and other communications running under the floor. Once all work is completed, there will no longer be free access to this space.

Sheets of plywood must be kept for several days in the room in which the work will be performed. This will allow you to achieve the same humidity in the material used and in the room, which will avoid deformation of the sheets after installation. If the room is regularly heated, then the plywood sheets are placed on edge and kept for at least two days. When working in a room that is heated periodically, the sides of the material should be slightly moistened with warm water. Keep them at room temperature for 24 hours.

The choice of plywood sheet thickness depends on what kind of coating will be used for installation in the future. When choosing a soft covering such as linoleum or carpet, you can use thinner sheets. In this case, you will not achieve complete leveling of the floor, but you will still get rid of large differences. If you plan to lay laminate flooring, then you should definitely choose 10-12 mm plywood. In this situation, you can make the floor perfectly flat by correcting all surface irregularities.

Step-by-step instructions for leveling a floor using plywood

Laying plywood on a wooden floor must be carried out in strict accordance with the basic rules:

It is necessary to ensure a distance of about 10 mm between the plywood sheets and the wall;
Damper (expansion) joints between adjacent sheets of plywood should reach 2-3 mm.

First step

We install beacons, the role of which is played by self-tapping screws. They must be located over the entire surface area and screwed in to the required height. To put it simply, we can say that screws need to be screwed into the corners of squares with sides of 20-30 cm ideally, but you can limit yourself to 30-35 cm.

Important! The thicker the sheets of plywood used for installation, the sparser the beacons should be placed.

Second step

Next, you need to lay plywood logs, which are strips of material 3-4 cm wide. We attach them to the floor using self-tapping screws or special glue intended for wood. Care must be taken to ensure that the laid joists do not sag. In those places where there is space between the joists and the floor, you should place pieces of plywood of the required thickness, pre-lubricated with glue.

Third step

Before carrying out further work, you must wait until the glue has completely dried. Sheets of plywood should be cut into squares with sides of approximately 60 cm. At this stage, a thorough analysis of the resulting blanks is carried out. When examining the ends, initial signs of delamination of the material are revealed, which are very often not noticeable on whole sheets of plywood. Low-quality material must be replaced, since its use will negatively affect the quality characteristics of the entire coating.

Fourth step

We lay squares of plywood on the resulting grid of joists. It should be remembered that the joining of adjacent sheets of plywood must necessarily take place on the joists. We do the installation using a technology similar to brickwork, that is, in such a way that there is no intersection of four planes at one point. We accurately cut the plywood to the required size. In this case, special attention should be paid to places with a complex configuration, where there are arches, various protrusions and other surface features.

Helpful advice! To save material when cutting, you can lay sheets of plywood on the floor before installing the joists. Then use chalk to mark the joints of the squares of material and lay the logs in the required place.

Fifth step

At the final stage, we fix the plywood sheets to the joists using self-tapping screws with a countersunk head. The fastening points are pre-drilled and countersinked. This will prevent the heads from squeezing out the material.

The use of this technology for leveling a wooden floor increases its height by only 2-3 cm.

Further surface treatment depends on the type of future floor covering. If you plan to lay laminate flooring, you must first lay the underlay on a plywood base. When choosing linoleum as a floor covering, you should walk a little over the surface with a sanding machine, carefully treating the joints of the sheets and the fastenings of the plywood to the joists. If the choice is carpet, then the plywood should be coated with several layers of varnish.

Leveling the floor using plywood sheets allows you to get a smooth, durable surface instead of the old uneven floor, fully prepared for laying any floor coverings. When the work is carried out carefully and consistently, a high-quality surface is obtained, which will become the basis for the implementation of the most daring design solutions.

Leveling a wooden floor with plywood: choosing a method and sequence of work

It wears out over time. When it becomes impossible to restore the appearance of the once attractive coating, the time comes to decide on floor restoration. And the first step towards this goal is leveling the wooden base.

If you want to save money and at the same time want the floor to serve faithfully in your home for a long time, the site recommends using plywood. A dry screed made using this sheet material will not require incredible labor costs or significant financial investments. In the work process, you will not encounter any noticeable technological interruptions that could delay. But there are a number of nuances that everyone should know, especially those who are undertaking such a procedure for the first time. First of all, figure out how to level a wooden floor using plywood sheets so you don't have to redo something five times later.

General information

Wood can be classified as a material that requires careful care, because... it is susceptible to drying out, warping, and cracking. Leveling the floor will help remove various irregularities that may later have a negative impact on the new one (on linoleum, carpet, parquet, etc.). Leveling will make the log house overall more reliable and of higher quality.

This work can be done in one of the following ways:

Determining the condition of the wooden floor

Check to see if the boards are rotting or if insects are wearing them down. For these purposes, dismantle one board to inspect the joist from the outside and back. If there are no signs of insects, and the surface looks dry and durable, there is no need to replace the floor. If you find chips or rot, replace the floor or only low-quality boards. It all depends on the extent of the lesion.
Determine how much the floor surface deviates from the horizontal. The easiest way to do this is to use a laser level. Place the device at the highest point of the floor and make marks on the walls around the entire perimeter. If you don’t have a laser level, you’ll have to do a little work: find the highest point on the floor, draw a straight line through this point using the mounting level, and apply markings along the entire perimeter of the room.

Plywood and its characteristics

This material has a number of invaluable advantages that present it in a favorable light, if you need to level the floor:

In all directions, plywood has the same strength;
bends well without forming any cracks;
The sheets are produced in large sizes. This allows you to cover the entire treated area in a short time;
The material is very convenient for transportation. Besides, he is unpretentious.

Plywood is a material with rare characteristics, which is what makes it so popular during construction work:

High quality grinding;
Simple technology, both processing and installation;
No foreign or unpleasant odors;
Low weight of sheet material;
Good hardness;
High performance characteristics;
Increased strength and load resistance.

Plywood is layered in structure. It consists of veneer, which is well pressed and firmly glued together. The more such layers and the better quality they are, the stronger and more resistant to stress the material becomes. Achieving such important characteristics is possible if the veneer layers are placed in a special way, i.e. Place each subsequent row perpendicular to the fibers of the previous one. We remind you that the number of plywood layers is always odd. For example, nine layers of veneer have sheets twelve millimeters thick. the site emphasizes that its quality depends not only on the thickness of the plywood.

A number of other characteristics are also important: grade, emission class, brand, degree of surface treatment.

Popular brands of plywood

Depending on the degree of moisture resistance, plywood is divided into grades.

There are four of them:

Two for industrial work: FOF and FB;
Two for individual repair and construction work: FSF, FC.

Let's stop and look at the second type in more detail. The FSF brand is famous for its increased level of moisture resistance. However, it is not recommended to use it at home. This is because veneer sheets, when used, are attached to glue based on phenol-formaldehyde.

The level of moisture resistance of the FC brand is average. The veneer is glued together with a safe adhesive based on urea resins.

This material is popular in the production of furniture and interior decoration.

Plywood varieties

There are four varieties that comply with Russian standards (GOST):

It is the best in quality. There are practically no external defects. However, the presence of warped veneer and cracks is allowed;
This grade includes wood inserts, the glue may bleed through slightly, and there may be scratches on the sheet;
Material with fallen knots and wormholes.
The variety is of the lowest quality with the largest number of defects. But despite the low quality of the variety, the quality of veneer sizing remains at a high level.

Degree of plywood surface treatment

Its surface can be unpolished or polished.

This factor is indicated in its labeling:

Ш1 – plywood sanded only on one side;
Ш2 – sanded plywood on both sides;
NSh – unsanded plywood.

Tools for leveling plywood floors

You will not be able to carry out quality work if you do not stock up on the necessary equipment. In addition, it is advisable to have experience in handling tools and some skills in working with the material.

You will need for work:

Screwdriver;
Jigsaw;
Roulette;
Level;
Self-tapping screws.

Techniques and methods for leveling plywood

The condition of the floors and the degree of deviation from the horizon directly affects the choice of leveling technology.

Plywood can be used:

If properly laid, the floorboards are deformed evenly. There is only a difference in levels (five millimeters); the floor can be leveled by attaching plywood sheets to it;
If the height difference in one square meter is equal to two millimeters, leveling is not necessary. As a preventative measure, you can putty with a homemade mixture of PVA glue and moistened sawdust or treat the floor surface with acrylic sealant.
Laying is correct when the builders alternated the boards according to technological requirements, i.e. bulges and depressions should fall through one board.
If in some places the differences exceed one centimeter, the first thing you will have to do is create strip or point supports, and then level them. Only if there are no complaints from the technical characteristics, plywood can be used.

If it is not possible due to large differences in height, then it is better to dismantle it and lay a new one.

Determining differences in height

The most important tool for you at this stage will be the laser level. After all, it is with its help that it is most convenient to examine the floor surface. In the corners of the room being repaired, you need to mark points, find and mark the centers of the lines connecting the walls and floor. Inspect each area, first dividing the room into separate segments. Having assessed the results obtained, you will formulate an overall picture of the upcoming repairs.

Although inspection and repair of the foundation must be carried out, despite the range of upcoming work. Update the fasteners, eliminate creaks, if any, check whether underground communications are damaged, replace damaged elements.

Preparatory work

Leave the plywood sheets in the room where the work will be carried out for several days. Thanks to this measure, the room will be equally damp, and the material used will be equally damp.

How to level the floor (video)

Leveling the floor using plywood

Method one. We do not install lags

When the plywood “gets used” to the room in which the work will take place, you can begin leveling. The easiest way is without installing a log. There is no need to install timber, since its function is adequately performed by the tubercles of curved floorboards, distributed evenly over the surface.

For these purposes, in addition to plywood, other materials are suitable: gypsum plasterboards, gypsum boards.

It makes no sense to use fiberboard for leveling if the floor is wavy, since during operation the material will sag, repeating all the bumps and grooves of the rough base.

If the floor is plank, and the width of its floorboards reaches twenty centimeters, and each of them is curved like the other, then plywood of ten millimeters is suitable for leveling. If boards more than twenty centimeters wide were installed on the floor, then the thickness of the plywood, accordingly, should be greater - up to two centimeters.

To form a two-centimeter indentation from the walls, place bosses around the perimeter of the entire floor;
The gap between the sheets when laying them should be three to eight millimeters. Due to this, movement absorption during moisture fluctuations will be achieved. Imitate brickwork by laying several rows - place the slabs of the next row relative to the previous slabs with some offset. There should not be a cross-shaped intersection of four butt welds at one point. The site reminds us that the minimum offset size is a quarter of a plywood sheet, the maximum is half.
At the points indicated during the inspection, we attach the sheets to the “ridges” of the boardwalk. Try to distribute the attachment points evenly, focusing on the distance between the bulges identified as a result of measurements.

The site recommends pre-drilling holes for fasteners. It is advisable to do this in two steps. To begin, use a drill whose size matches the diameter of the screw. Then work on a hole that matches the diameter of the cap, which can be completely recessed into the plywood sheet. Along the perimeter of this sheet, the dowels should be at least two centimeters away from the edge.

Method two. Setting up a strip support

You will need to construct a sheathing using crossbars and longitudinal joists, which are placed in the same horizontal plane. Along the perimeter, the logs should be placed at a distance of three centimeters from the walls. The size of the plywood sheet determines the step of laying the longitudinal components.

Typically this value varies from forty to fifty centimeters.

Algorithm of actions when leveling the floor with plywood:

Start with fitting. Without attaching, lay the plywood on the base, being mindful of gaps and ensuring a standard brickwork pattern. Outline the slabs. The lines you make will become your guide for the future location of the joists. Don't forget to number the sample sheets.
Install logs along the walls, following the markings made on the floor. If you want to optimally arrange the strip sheathing under the plywood, then use a square beam with a side of forty to sixty centimeters. If you don't want to raise the floor too much, use second-grade boards or cut plywood into strips to make joists.
Install the crossbars at a step calculated according to the dimensions of the sheet. Attach them to the joists with self-tapping screws. It is better not to use metal corners.
We place transverse elements and logs in a single vertical plane. Follow the level readings. Adhere to the requirements formulated in SNiP number 3.04.01-87. It is prohibited to drive wedges from leftover lumber under joists. To level it, just use sand. If the deviations are insignificant, you can use roofing felt or roofing felt for the same purposes. To achieve an even plane of the lag, various wooden spacers are most often used.
Once the joist system is level, attach it to the base using galvanized metal angles. Dowels can also be used for these purposes. Their length should be three times the thickness of the logs.
The final stage is laying and fastening the plywood.

Method three. Installing mini logs

This method is most suitable if the floor has a slope or a height difference of up to eight centimeters. You will need to install wood shims and battens to create a unified support system for the plywood. It will be quite difficult for you to cope with such a very difficult task if you do not first carry out the necessary engineering calculations. First, try it on.

Then calculate the size of each support element based on the lines marked on the floor.

Method three. We make a lathing from point supports

Therefore, install the slab pads with the smallest increments. As a result, you should have comfortable cells.

Laying plywood (video)

Plywood is a relatively inexpensive, fairly durable and easy-to-process material, perfect for leveling a wooden floor. Plywood is mainly used to level out small differences in the height of the base before the upcoming laying of the finishing coating. If desired, you can even lay tiles on top of the plywood.

It is not surprising that this sheet material has gained such wide popularity both among professional builders and among private developers. After reading the information below, you will get a complete understanding of choosing the right plywood and the process of leveling a wooden floor using different methods.

Among the key strengths of plywood, the following points should be noted:

relatively large sheet sizes, which allows you to level the floor as quickly as possible with a minimum amount of waste;
ease of installation;
high levels of strength, reliability and durability;
possibility of use even in rooms with high levels of humidity (this means either special moisture-resistant plywood or pre-treated material, more on this later);
absence of strong unpleasant odors;
ease of processing.

Also among the important advantages of plywood is the fact that when used, there is an additional increase in the thermal insulation performance of the floor structure.

Most often, leveling a wooden floor with plywood is used in the following cases:

if necessary, eliminate minor unevenness of the base;
when preparing the surface for subsequent laying of the finishing coating;
when installing a thermal insulation layer.

Choosing plywood for leveling a wooden floor

Plywood can be used both for arranging a subfloor and for installing a finishing structure - it all depends on the quality of the material and the characteristics of a particular situation.

Plywood is classified into 5 grades. The best is grade E - this material has absolutely no defects. It is not advisable to use expensive grade E plywood to level the floor. It is used mainly in the food industry, furniture making, arts and crafts, etc.

Information on other existing varieties of the sheet material in question is given in the table.

Table. Plywood varieties

Variety	Description
	As a rule, first grade plywood has no external defects, although GOST allows for the presence of microcracks and minor chips.
	In accordance with approved regulatory requirements, the number of traces of glue should be no more than 2% of the area of such plywood, small dents and scratches - up to 5%. Second grade plywood is optimal for leveling a wooden floor in terms of price and quality ratio.
	Third grade material will contain a relatively small number of wormholes and knots.
	Worst option. The quality of veneer sizing is usually quite high, as is the number of external defects. Such plywood belongs to the category of technical materials and is used extremely rarely for leveling floors, except in various temporary buildings and non-residential country houses.

To level a wooden floor, it is most advisable to use plywood of 2-3 grades, made without the addition of phenols (labeled as FC). Such sheet material will have a certain number of external defects, but in terms of quality and cost it is the best.

It is advisable that one side of the plywood be sanded. This can be understood either by visual inspection of the material or by the marking Ш1. If finishing finishing material will be laid on top of plywood, to ensure better adhesion to it, the sheet leveling layer is laid with the unsanded side up.

The optimal thickness of plywood intended for leveling the floor is 12-16 mm. If the floor of the room will be subject to high loads, it is advisable to increase the thickness of the sheet covering.

It is best to buy certified material from a trusted manufacturer/seller. In this case, the chances that the plywood has passed all the necessary technological stages of production increase significantly.

Additionally, veneered plywood can be included in a separate group. This plywood is characterized by increased moisture resistance and is well suited for use in rooms with increased humidity levels.

Prices for plywood sheets

plywood sheet

Video - Types of plywood

About the preliminary preparation of plywood

Plywood of the FK, FSF brands and special tongue and groove material are suitable for use in residential premises. The first is characterized by less strength and moisture resistance, but is cheaper, the last two are more durable and resistant to moisture, but expensive.

If you plan to level a wooden floor in a room with a high level of humidity and you do not want to overpay, buy FK plywood and prepare it accordingly for the upcoming operating conditions.

On average, the moisture content of plywood is kept at 12-15%. To increase the moisture resistance of the material, polyvinyl acetate putty is used, which in its external qualities resembles PVA glue (polyvinyl acetate is its main component).

Buy the putty mentioned, prepare it for use according to the manufacturer's instructions and do the following:

take a sheet of plywood and start covering it evenly with putty;
apply 2 layers of putty on the back side of the sheet;
leave the plywood for 3-4 days in a room at room temperature and normal humidity levels;
treat the dried sheet material with an antiseptic.

If you are not particularly limited in budget, you can initially purchase moisture-resistant plywood.

To further increase the strength of the plywood, it can be coated with a double layer of acrylic varnish on each side. Wait until the old one is completely dry before applying a new coat of acrylic varnish.

Important! Paint and varnish coatings should not be used in rooms with elevated temperatures.

Most often, plywood for floor leveling is sold in sheet format with dimensions of 1220x2440 and 1250x2500 cm. Experienced craftsmen recommend cutting such sheets (with a jigsaw or other suitable tool) into 4 squares with sides of about 600 mm. There are several advantages of such a solution:

Important! After sawing a sheet of plywood, make sure there are no delaminations at the ends of the elements. Sand any identified defects. If you leave everything as is, the finished design will be of extremely low quality.

Before laying, allow the plywood sheets to sit in the room being furnished for several days. To avoid deformations, stack the elements on top of each other. Such actions will allow the sheets to get used to the room conditions. If you lay out the floor right away, the sheets will become deformed. Along with them, the finishing coating will also deteriorate.

Helpful advice! If possible, check with the seller about the conditions in which the plywood was stored in warehouses. If there is no difference between the temperature in the storage location and the room being equipped, the acclimatization time will be 1-2 days; if the difference is up to 8 degrees, the sheets should be allowed to lie down for 3 days; if the temperature changes are more significant, the acclimatization period will last for a week.

In the future, methods of fastening plywood using self-tapping screws will be mentioned. You cannot use ordinary black fasteners for such work - low-power screwdrivers will not be able to screw them in, and high-power ones will simply break them. To avoid such inconveniences, fix them with special yellow wood screws.

Important! With any fastening option, the plywood is laid in a spaced pattern, forming T-shaped seams between the sheets in adjacent rows.

Prices for putty for plywood

putty for plywood

Plywood fastening methods

There are several methods for attaching plywood to a wooden floor:

with height differences of up to 5-10 mm, plywood is attached directly to the base;
with differences of 10-80 mm - on logs or adjustable studs.

Attaching plywood to the base

The simplest option. The procedure is as follows.

Note! The illustrations contain third-party fasteners. We don't pay attention to them.

First step. The plywood sheets are allowed to acclimatize, after which they are marked into squares of approximately 60x60 cm (you can change the sizes at your discretion to make it convenient), cut with a jigsaw or other suitable tool along the marking lines and the resulting elements are laid out on the floor of the room, thereby determining the most optimal, correct and rational stacking scheme in terms of the amount of waste.

Let the plywood acclimate

Second step. A visual assessment of the coating and seams is carried out. The plywood is laid with bandaging, so that the seams between elements placed in adjacent rows do not intersect. The correct option for laying sheets is shown in the image. Any inaccuracies found are immediately corrected. The gap between sheets of plywood is up to 2-3 mm (most often a 0.5-1 mm gap is maintained), between plywood and adjacent walls - from 5-10 mm.

Third step. The sheets are numbered for greater convenience in their future placement. At the same stage, if necessary, the surface is sanded with a special tool or manually with sandpaper (long and labor-intensive).

Fourth step. The covering is disassembled, the sheets are temporarily removed to the side. The base is cleaned of debris, dust and other contaminants.

The sheets are laid out on the surface in accordance with the previously selected pattern and compliance with the mentioned gaps. The flooring elements are attached to the wooden base using self-tapping screws.

The optimal length of fasteners is 3.2 cm. Recess the screw caps into the plywood by a couple of millimeters.

The optimal arrangement of fasteners is as follows: one for each corner of the sheet, one in the center of each side, one in the center of the sheet.

Helpful advice! If plywood is laid on top of a solid plank flooring, you can use PVA wood glue to attach it in combination with self-tapping screws. In this case, firstly, better bonding of the plywood to the base will be ensured, and secondly, the risk of squeaks when walking on the floor will be further reduced.

It is convenient to use a notched trowel to apply the glue. Either the base or a sheet of plywood is covered with a binder composition - whichever is more convenient in a particular situation. For recommendations regarding the optimal thickness of the adhesive layer, please refer to the instructions for the composition used. The order is as follows: first the sheets are glued, then additionally fixed with self-tapping screws.

Also check the glue drying time in the instructions for the selected binder composition.

Prices for PVA glue for wood

PVA glue for wood

Video - How to level a floor with plywood yourself

Video - How to level the floor with your own hands under laminate, linoleum, floor coverings

For arranging logs, high-quality coniferous or deciduous (except poplar and linden, as they are not strong enough) boards of 2-3 grades, 4 cm thick, 8-10 cm wide, are well suited.

Under the logs there are pads 10-15 cm wide, 2.5 cm thick and about 20-25 cm long. The thickness of the pads can vary depending on the existing differences in the base. The linings are set strictly according to the level so that the logs, and with them the plywood laid above, do not deviate from the horizontal.

A more modern method of leveling the base involves installing joists on adjustable studs. Information regarding determining the working level and installing joists on adjustable supports was provided in the publication dedicated to.

Adjustable jog design

The logs under the plywood are installed in 40-50 cm increments. The supports are mounted across the room. A 2-3 cm gap is maintained between the ends of the joists and the walls.

The procedure for installing joists followed by laying plywood flooring is given in the table.

Table. Leveling the floor with plywood along the joists

Work stage	Description
	The leveled base is cleared of all existing dirt and debris.
	Recommendations for determining the working level according to which the surface will be leveled are available at the previously provided link.
	To level out height differences, in this example, bosses are used - pads made from pieces of timber, plywood, etc. In order to increase the accuracy of level control and the stability of the structure, place the bosses not only at the edges, but also in the center of each joist. If the log length exceeds 2 m, install additional pads in 50 cm increments. By changing the height of the bosses, ensure that they are located in a single plane. You can make sure that there are no differences using a level or, even simpler, a rule - a straight strip with a length (specifically for this case) of at least 200 cm. The principle is as follows: lay the rule on the bosses and make sure that the tool lies flat and without gaps on all the pads . Helpful advice! Place a piece of linoleum or roofing felt on top of the bosses. The material will take on the functions of a shock absorber and allow you to more accurately adjust the level of fastening of the logs. Do not fix the bosses at this stage. The wooden floor is leveled, so later, after laying the logs, you can tighten them to the base using self-tapping screws or other suitable fasteners directly through the pads.
	Proceed with laying the joists on the bosses. Maintain the pitch between the lags in accordance with the dimensions of the plywood sheet (in the example under consideration - 600 mm). Make sure the lags are evenly positioned using a building level or a rule according to an already familiar pattern. Eliminate any deviations found by adding or removing material from the corresponding bosses. To attach the logs to a wooden floor, as noted, it is convenient to use self-tapping screws. Screw 2 fasteners into each point.
	Without cross slats, plywood flooring will very quickly deform and fail. The slats are made from the same material as the joists. In the center of each future cross member, place bosses on the base. Attach the rail to the base through the bosses using self-tapping screws - 2 for each lining. To fasten the crossbars to the joists, use metal corners. The step between slats is up to 50 cm.
	Having finished arranging the sheathing, proceed to laying the sheet material. Each sheet must be supported by at least 2 joists. To prevent squeaks from occurring when subsequently walking on the floor, lay the sheets with gaps of up to 0.5 mm. The plywood is attached to the joists and intermediate slats using self-tapping screws. Maintain a 50-70 cm spacing between fasteners. Recess the heads of the screws slightly into the wood.

Video - Leveling the floor with plywood along the joists

Fastening plywood with adjustable studs

This option for leveling the floor with plywood is the simplest and fastest in its implementation: anchors are screwed into the base and plywood is put on them through pre-prepared holes. By screwing in/unscrewing the anchors, the required floor level is set.

The system looks like this:

It was discussed in detail in the corresponding publication on our website, be sure to check it out.

Video - Laying plywood on adjustable studs

As noted, the technology allows the use of plywood to level bases whose height differences do not exceed 80 mm. But what if the irregularities are more significant? Stop using plywood? Not necessary.

Recommendations regarding the mandatory preliminary elimination of differences in height are given for the simple reason that the sheet material, under the influence of the loads placed on it, will follow the contours of the unevenness, become deformed and fail.

To prevent this from happening, do the following.

To begin, take a long level and find places with the most pronounced differences in height. In the identified areas, screw screws into the floor in increments of about 20 cm. By tightening/unscrewing the screws, ensure that their heads are located at the same horizontal level.

The plywood will be laid on screwed screws. To prevent the sheets from sagging, the void between them and the uneven base needs to be filled with something. A mixture prepared from a share of small sawdust and the same amount of PVA glue is perfect. Before laying plywood, coat the recesses with the specified composition. Additionally, cover the side of the sheet with which it is laid on the base with a double layer of PVA glue. The mixture dries within a week.

To ensure the highest quality and even fit of the plywood to the base, secure the sheets with self-tapping screws. Maintain a 50cm step. The correct layout of fasteners is shown in the image.

Video - How to level a wooden floor with plywood

Plywood has been and remains a universal, widely in demand material, with the help of which a wide variety of work is carried out when building a house or furnishing an apartment. For example, leveling the floor with plywood is one of the easiest and fastest ways to get its surface in order. Moreover, in a similar way you can level both concrete and wooden bases. It is necessary to immediately clarify that this method is mainly used if the surface has small differences. However, some craftsmen manage to fix severely deformed floors using plywood sheets.

Plywood has gained wide popularity for leveling and covering surfaces not only among professionals, but also among private developers. All this is due to its unique characteristics, information about which will also be discussed in detail in this publication.

Advantages of using plywood for floor leveling

So, the advantages of plywood sheets include the following characteristic features and application possibilities.

Various linear parameters of the sheets allow you to choose the desired option, depending on the area of the floor to be leveled. Therefore, it is possible to install the material with virtually no waste.
In addition, fairly large sheet sizes significantly speed up the work of leveling the surface.
Easy to install - anyone can master it.
There are various ways to use plywood to level the floor - you can choose the most suitable one for specific conditions.
The material can be laid in either one or two layers.
What is attractive about plywood is its high strength characteristics, reliability and long service life of coatings.
It is possible to use sheets both in dry rooms and in areas with high humidity. The latter uses a moisture-resistant grade of plywood.

The smoothness of the plywood surface reduces the work on finishing the structure created from it.
Absence of unpleasant odors both during installation and during use of the floors.
Another advantage of plywood leveling is the ability to lay any decorative covering on top of it, from carpet to ceramic tiles.
Plywood has good thermal insulation qualities, so if it is necessary to level a concrete floor, the problem of its insulation is immediately partially solved.

How to choose plywood for leveling the floor?

Both wooden and concrete bases are covered with plywood in the following cases:

When there is a need to eliminate surface unevenness.
When creating an insulating structure.
When arranging the base for laying the finishing decorative floor covering.

Plywood is used both when installing subfloors and when laying finished floors. For these purposes, materials of different quality are used. Thus, plywood sheets are divided into five grades - elite (highest), first, second, third and fourth.

Leaf appearance	Brief description of material characteristics
	The elite grade of plywood (E) has a fairly high cost. The sheets should not have any visible defects on their surface. GOST allows minor deviations in the structure of wood, except for knots of any size. The plywood should not have holes, wormholes or dark veins of any color. Therefore, the material can be used for finished floors even as a decorative coating. If the plywood has a beautiful textured pattern, it is enough to lay it correctly and secure it, and then varnish it. However, its main purpose is the manufacture of furniture, arts and crafts, etc.
	The first grade of plywood should not have serious external defects. However, GOST allows the presence of microscopic cracks, as well as small single point, unfused or fused and captive knots. In addition, the surface may contain wormholes not exceeding 6 mm (three pieces per 1 m²), fused healthy knots up to 15 mm in diameter (five pieces per 1 m²), and minor brown veins. The material can be used as a finished floor under varnish, painting or other decorative coating.
	On the surface of second grade plywood, according to approved standards, the presence of unfused, partially fused, falling out knots, wormholes no larger than 6 mm in size (6 pieces per 1 m²), healthy knots with a diameter of up to 25 mm (10 pieces per 1 m²) is allowed. In addition, there may be defects on the surface that are filled with veneer inserts. This type of material is well suited for leveling floors for decorative flooring or painting.
	The third grade may have unfused or fused knots on the surface, falling out knots, as well as holes from them, healthy fused knots in unlimited quantities, wormholes up to 6 mm in size (10 pieces per 1 m²). Plywood can be used for rough and finished floors for laying hard decorative coverings - laminate, parquet boards, parquet, etc. If it is necessary to use this type of material under a soft covering, linoleum, carpet, cork, then it will have to be properly puttied.
	In the fourth grade of plywood sheets, any natural and manufacturing defects are allowed, and in unlimited quantities. However, the layers of material must be well glued together and free from deformation. This variety is used for arranging subfloors and flooring on a rigid base under laminate or parquet boards.

For flooring in residential premises (and, in general, for any interior work), it is necessary to choose plywood with minimal formaldehyde emissions. According to this indicator, it is divided into classes, designated by the letter E and digital indicator.

So, for indoor use, you should only purchase plywood of a class not lower than E1. This selection criterion should not be neglected, even if the price of lower class plywood seems much more attractive. Phenolic fumes have a very adverse effect on human health, and children in particular.

Based on the degree of water resistance of the adhesive joint of the layers (in fact, according to the type of glue used), plywood is usually divided into moisture-resistant (FK) and increased water-resistant plywood (FSF or EXT). It is selected depending on the type of room where it will be used.

Plywood also differs in the degree of surface polishing. That is, it may not be polished at all (NS) or have undergone a certain processing (Ш1 - one-sided, or Ш2 - on both sides). For a finished floor, sanded plywood Ш1 is best suited. If it is purchased as a decorative coating, then it is mounted with the sanded side up. In the same case, when it is planned to lay a decorative coating on top of the plywood layer, then for better adhesion of the materials, and simply from the point of view of profitability, there is not much point in overpaying for sanded material.

When purchasing plywood sheets, you need to pay attention to their linear dimensions. You can find different types of sheets on sale. The most common are the following:

1525×1525 mm;

2440×1220 mm;

2500×1250 mm;

3000×1500 mm;

3050×1525 mm.

Other sizes, much larger, may also occur. But they are usually used in the field of industrial construction.

The thickness of the sheets varies from 4 to 40 mm. For a finished floor, where one layer of plywood is planned, fixed to joists, the optimal material thickness is 18÷20 mm. If the sheets will be used to level a slightly deformed board covering, sheets with a thickness of 12÷18 mm will be suitable. Naturally, the greater the thickness of the material, the higher its cost.

It is recommended to purchase plywood sheets manufactured by a large company that has been producing them for many years. In addition, it makes sense to request a certificate of conformity from the seller, which must confirm all declared parameters, including the formaldehyde emission class.

Plywood produced under optimal factory conditions is a guarantee of quality. During its manufacture, all technological processes are under strict control.

Plywood is purchased in quantities depending both on the area of the room in which the floor will be leveled and on the size of the sheets. Usually a reserve is made, since when cutting, one way or another, there may be scraps left that will not be used. As a rule, 10% reserve is quite enough.

Prices for birch plywood

Birch plywood

As already mentioned, if there are options to choose from, then it is better to purchase sheets of a format that will provide a minimum amount of unused material. The following calculator can help the reader with this question. He will not only tell you how many sheets should be purchased for the job, but will also show the approximate amount of waste. That is, if, for example, as a result of calculations it was determined that 5 sheets of plywood of a certain size should be purchased, but in reality only, say, 4.15 sheets will be used, then it makes sense to calculate the consumption with other formats. It is quite possible that there will be a more acceptable option.