Installing plywood on a wooden floor. Do-it-yourself plywood floor on logs - step-by-step instructions from preparation to installation

Content:

Plywood is a versatile building material used for floors, roofs and walls both inside and out. It is a durable material that provides an excellent base for top coats.

It is made of wood veneer sheets glued at right angles. This design makes it resistant to deformation, cracking and twisting.

Plywood is much cheaper than similar solid wood boards. At the same time, it is much stronger than chipboard.

General Purpose Plywood

This is the name of the material from which the plywood floor is laid in rooms for various purposes. The grade and requirements for general purpose plywood are approved by the interstate standard GOST 3916.1-96.

The material in question has an outer veneer of hardwood only. It is designated by this breed: birch, alder, aspen, etc. The inner layers can be from conifers. The appearance of the outer layers determines the grade of the material. There are 5 of them in total. E - elite, then I-IV.

According to the resistance of the adhesive joint to moisture, plywood is divided into grades.

• FC - waterproof.
• FSF - increased water resistance.

Surface treatment is as follows.

• NSh - unpolished.
• Ш 1 - one-sided grinding.
• Ш 2 - double-sided grinding.

The same Standard establishes the following warranty period.

• FC - 3 years.
• FSF - 5 years.

The beginning of the period of storage of such material is considered the day of its receipt by the consumer.

Disadvantages of plywood, their elimination

A significant disadvantage of plywood is hygroscopicity. In a humid environment, when plywood is laid on the floor at a high humidity of the base, the veneer sheets and the adhesive layer swell and the material delaminates. Note that GOST does not allow storage of plywood at a humidity of more than 80%.

When operating in such places, a coating is applied to the plywood, which excludes direct contact of the wood with moisture. This also applies to moisture resistant varieties of plywood.

Water-repellent impregnations for wood are quite widely represented on the market. When choosing such a product, it should be borne in mind that some of them have a specific smell. Plywood does not require antiseptic treatment, since these additives are part of the adhesive layer.

It should be noted that the environmental friendliness of plywood is characterized by an emission class, i.e. unsafe formaldehyde. Internal work, including laying and leveling the floor with plywood, is carried out exclusively from class E1 material, with a minimum content of phenolic resins.

Calculation of the amount of material

Calculation of the amount of plywood for floor repair

The optimal estimate of any repair is as important as its quality. Its basis is the correct calculation of the necessary materials (plywood) for leveling the floor.

1. Determining the area of ​​the room.
2. The choice of optimal plywood sizes.
3. Geometric calculation of the required number of plywood sheets.

Since the vast majority of rooms are rectangular in shape, the orientation of sheets when laying plywood can be in two versions: along or across. We need to find the best option.

D * W= Area, m2 ,

where D is the length of the room in meters, W is its width.

Using the same formula, the area of ​​\u200b\u200ba plywood sheet is calculated. The covered area is divided by the sheet area. The result is the required number of sheets. It is always rounded up (to the whole sheet). When buying, the number of purchased sheets increases by 5%. This is a common reserve. The most common size of FK plywood sheet is 1525 x 1525 mm.

The optimal thickness for the described work is 10-12 mm, the plywood floor is most often arranged from grade II material.

The main ways of laying plywood on the floor

There are three basic ways.

1. On the concrete floor on the screed
2. On the concrete floor along the lags
3. On the old wooden floor along the logs.

The choice of method depends on the material of the old floor, its moisture content. Almost always laying plywood on the floor begins with determining the moisture content of the substrate. In the absence of special paper strips - indicators, a sheet of film about 0.5 x 0.5 m in size is hermetically glued to the old coating with adhesive tape. The appearance of condensate the next day indicates that the base requires additional drying or elimination of the cause of high humidity.

How to lay plywood on a screed?

Method of laying plywood floor on screed

1. The concrete, even, dry floor is thoroughly cleaned, a primer is used for priming: diluted 1 to 4 bituminous varnish or various mastics. If carpet, cork, marmoleum or linoleum is used as a finishing coating, then the floor becomes “floating”. It is attached to the screed only with glue, the floor is leveled with plywood in a butt joint, without mounting gaps between the sheets. The distance between the walls and plywood is left standard - 2-3 cm. The ends must also be covered with glue.

When using parquet, reinforcement of the "rough" floor is required. Plywood sheets are laid out with a mounting gap of 2-3 mm, in the corners and in the center they are additionally fastened with self-tapping screws on dowels.

Laying plywood on concrete floor

Laying plywood floor on logs

2. A concrete flat floor is prepared in the same way as in the first case. Logs are prepared from dried bars, the thickness of which is selected in accordance with the construction solution. If the humidity and temperature in the room can vary within a fairly wide range, then the logs rise to a height of up to 100 mm, and the space under them is filled with insulation intended for residential premises.

It is also desirable to lay laminate and piece parquet on a plywood floor along the logs. Logs are laid with a lattice. Plywood is sawn into fragments so that each of them rests on the logs on all sides. The gap between the sheets is necessary, plywood is fastened with nails. The joists are not attached to the concrete base. Before laying, they are treated with an antiseptic.

Video instruction

How to lay plywood on a wooden floor along the logs?

How to install plywood flooring on an old wooden floor

3. Old wooden floors in residential and public buildings become unusable over time. In this case, laying plywood on a wooden floor is the least expensive way to get a quality underlay for any finish. Such work is carried out only on logs - they will help level the floor. The height of the lag should be minimal. Every centimeter makes the room lower.

Plywood itself is the optimal material for the log. Strips up to 40 mm wide are laid out strictly horizontally over the entire width of the room and attached to the old floor with glue and self-tapping screws. The plywood sheets are then cut into strips according to the width between the joists. After the glue has dried, the absence of squeaks and subsidence is once again controlled. Then the prepared plywood sheets are laid on the logs.

You arestill don't know what it is dry floor screed?

Rather look how simple and easy it is and most importantly fast!

Recommendations for laying plywood flooring

All work requires compliance with certain rules.

• High-quality leveling of the floor with plywood requires strict control of its horizontal level with a water or spirit level. The maximum deviation in any direction should not exceed 4.7 mm per 3 meters of its length.
• Fastening of plywood sheets is carried out with preliminary countersinking of the upper layer for the countersunk head of the self-tapping screw.
• Materials that have passed daily - at least - acclimatization in the room are used.
• To save material, a layout of sawn plywood sheets is drawn. Then plywood is laid on the floor according to the scheme, numbered, and after that preparatory work and installation are carried out.

Recently, moisture-resistant plywood is increasingly being used as the basis for the floor in rooms that are not subjected to harsh stress. We are talking about children's rooms, bedrooms, rooms adjacent to bathrooms. The plywood is coated with a special pour-on enamel. The service life of such floors is at least 20 years.

Plywood flooring is a very convenient subfloor in any living space. It is quite durable, does not deform, such a floor will serve you for a long time and reliably. Of course, it can also be used as a final floor covering, because a quality laid, carefully sanded and varnished plywood looks very noble. But still, plywood is more often used as the basis for parquet boards, laminate, linoleum. In cottages and private houses, laying plywood on a wooden floor is especially popular. This is due to the fact that thanks to the plywood base, 20% more heat is retained in the room. In addition, if you decide to replace the old flooring after some time, it can be removed without much effort. You will not need to do anything with the existing plywood base. You can simply lay a new coating on it.

Plywood laying methods

Plywood sheets are laid on a cement base, logs or on a wooden floor.

When laying plywood on a cement base, it is important to either keep it horizontal and even, or use adjusting stands. This is the most common way to lay plywood on a floor. As a rule, such floors can withstand pressure up to 3 tons per square meter. meter.

The most time-consuming and most expensive option for laying plywood is to mount it on logs. It is important to set the logs so that their upper faces are in the same horizontal plane. Next, a plywood floor is laid on them so that the joints of the sheets fall on the logs. Between the lags, you can hide some engineering communications, as well as put a layer of sound insulation or insulation. It is important to know that with a single-layer plywood flooring on the floor, its thickness should be at least 15 mm, and with a two-layer one - at least 9 mm in one layer.

The only disadvantage of laying on logs is that this method is not very suitable for rooms with a low ceiling, since it takes up to 9 cm in height.

Laying plywood on a wooden floor: the main rules

Laying plywood on a wooden floor becomes especially relevant when the plank floors have dried out, loosened and become unusable. Plywood will allow you to make repairs in the most optimal way - quickly, inexpensively and reliably.

• First of all, you should check whether the wooden floors sag along the logs (of course, if there are any). If they sag, you will have to completely disassemble the flooring and repair the base of the wooden floor. If it's not about the lags, then the best way out is to lay plywood on a wooden floor.
• Remember that plywood is not recommended for use where there are too large temperature fluctuations and high humidity. Plywood is not suitable for bathrooms and unheated rooms. To check if your floor has high humidity, place a sheet of polyethylene 1x1 meter tightly on it and leave it for three days. If condensation does not appear on the inside of the polyethylene, it is ready for further use.
• The plywood sheets are stacked "dry" with an offset in such a way that a maximum of three seams converge at one point. So individual sheets are adjusted to the size of the room, bypass the ledges and fill the niches. When carrying out this procedure, remember that a space of about 8-10 mm wide should be left between the scattered sheets - these are the so-called damper seams. It is important to know: there must be a gap of 15-20 mm between the extreme squares of plywood and the walls. Do not worry that this will spoil the overall look, because later these indents will be covered with skirting boards.
• In order not to confuse the fitted sheets during the final assembly, it is worth numbering them and, focusing on the numbers, draw up a small plan of their location.
• When choosing plywood, keep in mind that the thickness of the plywood sheet should be at least 12 mm, and even better - 15 mm. On perfectly flat surfaces, the use of sheets with a thickness of 8-10 mm is allowed. If you are planning, then plywood with a thickness of less than 15 mm will not suit you.
• It is recommended to cut plywood sheets into squares with a side of 60 cm. This way you will get the optimal number of damper joints. In addition, it is easier to detect delaminations that are not visible in whole sheets.
• Before finally laying the plywood, the base should be very carefully cleaned of dust and debris. In addition, it is recommended to carry out priming - this is the treatment of the floor with a special primer.
• It is better to lay plywood on glue, but it is quite possible to do without it. According to numerology, each sheet is placed in its place and fastened with self-tapping screws along the edges and diagonals in increments of 15-20 cm. Indent from the edges - 2 cm.
• It is important to know that fasteners must exceed the thickness of the sheet in length by at least 3 times. For example, for a sheet of 12 mm, 40 mm self-tapping screws are suitable.
• After installation, carefully

Innovative technologies for decorating rooms today have also affected floor coverings. The most commonly used material for this is laminate, cork, parquet board. Such coatings require a perfectly flat surface, so the technology that considers the question of how to properly lay plywood on a wooden floor is more relevant than ever.

Plywood as a material for leveling wooden floors has many beneficial advantages.

Material advantages:

1. Low cost of purchasing material.
2. Due to the peculiarities of the manufacturing technology, during which the layers of plywood are laid perpendicular to each other during gluing, the material receives a high level of strength.
3. Plywood sheets can have a large format, due to this you can greatly facilitate and speed up the process of covering large areas.
4. Due to the excellent flexibility, the material can be bent without getting damaged.
5. Does not create problems with storage and transportation.
6. Unpretentiousness in operation.

Material laying features

The laying procedure becomes especially relevant when the plank floor dries out, loosens and becomes unsuitable for further use. Using plywood you will save not only cash costs, but also your efforts.

Features of working with plywood:

1. Before laying plywood on a wooden floor, check to see if it sags at the joist placement. If this happens, you must perform a complete disassembly of the coating and repair the underlying wooden floor. If there are no problems with the lags, then you can start laying plywood directly on a wooden base.
2. Plywood should not be laid in rooms where there is a sharp change in temperature or a high level of humidity. Unheated rooms and bathrooms are not suitable for laying this material.

Note! In order to find out how high the level of humidity of your floor is, it is necessary to tightly lay a polyethylene sheet with parameters of 100x100 cm on its surface and leave it to lie in this position for at least three days. After this period, look at the inside of the polyethylene, if you do not find condensation there - the floor is suitable for laying plywood.

1. Plywood is laid in such a way that the sheets move slightly. As a result, at least three seams should converge at one point. Be prepared for the fact that you will have to adjust some sheets to the parameters of your room. Such nuances can be caused by the presence of a niche or ledges in the room. Between plywood sheets, as well as in the area near the wall, it is imperative to leave gaps. Subsequently, these distances will be covered with skirting boards or sealed.
2. In order to facilitate your work and not confuse with the placement of sheets after cutting them, plywood should be numbered and a plan for its laying should be drawn up.
3. The most convenient size is a square with sides of 0.6 m. Using plywood of this format, you can provide yourself with the required number of damper joints and at the same time reveal delaminations that are invisible on solid plywood sheets.

1. Before you start laying plywood, you need to prepare the floor surface, remove traces of dirt and dust, apply a primer layer.
2. Plywood sheets are laid on the adhesive composition. Otherwise, you will have to fix the material with self-tapping screws, not only along the edges, but also along the diagonals in increments of 20 cm. You need to step back a couple of centimeters from the edges. Self-tapping screws must be well recessed.
3. The length of the fasteners must be at least three times greater than the thickness of the plywood sheets. For example, with a sheet thickness of 1.2 cm, you will need to take self-tapping screws 4 cm long.
4. After the laying is completed, the surface must be sanded using a parquet sander and sandpaper with large grains.

If you want to learn more about how to lay plywood on a wooden floor, the video review below describes all the nuances of this procedure.

Cutting plywood and installing a log

Cutting plywood is carried out to fit the sheets to the parameters of the room. As for the damper joints, the gap between the sheets should be at least 4 mm and one centimeter at the walls. If you ignore this nuance, subsequently, when temperature changes occur in the room, the floor surface will begin to deform and swell.

After cutting the material, check the end pieces. In places where incisions are made, delamination and other defects usually occur.

Note! If the plywood sheet is damaged, it is better not to use it.

All sheets cut according to the size of the room must be placed on the floor in the order of their further fixing. It is not necessary to achieve a joint at four corners, it is better to take the technology of placing bricks as a basis. In places where a joint of plywood sheets is formed, a lag should pass.

The logs themselves should have a thickness of 3-4 cm, they are fixed with an adhesive composition intended for wood. You can also use self-tapping screws. During the installation of the lag, gaps may form between them and the floor, which must be closed with pieces of plywood of the appropriate thickness. To do this, the sheet is lubricated on both sides with an adhesive composition and placed in the required place.

The procedure also looks like if you get inaccuracies in height. Be sure to control the horizontal placement of the lag using the building level, because it will depend on how even your floor will be. In the space that forms between the lags, sealing material should be placed.

Before fixing the plywood on the logs, it does not hurt to treat all the sheets with an antiseptic.

The floor from the boards is durable, environmentally friendly, resistant to abrasion. However, after several decades, the boards begin to creak, dry out or rot from the high humidity in the room. If you lay linoleum or carpet on an unprepared plank floor, lay a laminate or parquet, then the surface will not be perfectly flat. All defects in the rough base will be visible through the final fine coating, and in the case of locking systems, installation will not be possible if uneven.

To make the floor high-quality and durable, you need to lay a substrate under the floor covering. For this, sheets of plywood are suitable, which will hide all the bumps and imperfections of the wooden floor.

Peculiarities

To choose plywood for leveling the floor, you need to understand the features and classification of the material on the market. Plywood differs in grade, thickness, moisture resistance and material of manufacture.

The main characteristics will help you choose the right sheets.

There are 4 grades of plywood that can be distinguished visually:

• The fourth grade has defects on the surface, rough, there are holes from knots, since the lowest quality raw materials are used for manufacturing.
• The third grade is better than the previous one and there is less marriage on the surface.
• The second grade has minor cracks, smooth.
• The highest quality and most expensive first grade is well polished, all sides are free of defects.

When choosing a variety, they are guided by price and quality. For the construction of the subfloor, plywood of the second and third grades is suitable. According to the processing method, there are:

• Unsanded plywood.
• Sanded (one or both sides).

For installation on the floor, one-sided sanded material is taken, laying the smooth side at the top.

Plywood is made from hardwood and coniferous wood (most often from pine and birch). Wood veneer is bonded together with natural and synthetic resins. The top layer can be treated with a lacquered water-repellent compound.

According to resistance to moisture in residential premises, brands are distinguished:

In bedrooms and other living rooms with low humidity, FC and FBA brands are laid, made on the basis of carbamide and albumin-casein glue. They differ in environmental friendliness and average resistance to moisture.

The FSF brand is placed in the corridor and in the kitchen, where greater moisture resistance is needed.

The thickness of the canvas determines the number of layers of veneer. Their odd number is laid perpendicular to the previous one, creating a durable building material. For subfloor flooring, plywood with a thickness of 10 mm or more is taken.

Plywood lends itself well to fastening with self-tapping screws, does not crumble or crack.

The analogue of plywood in the construction market is OSB - oriented strand board. Such materials have similar properties, but differ only in production. For plywood, wood veneer is the raw material, and for OSB, wood chips are processed with natural resins.

OSB is divided into different categories:

• The first is suitable for minimal stress and dryness.
• The second - is made for impenetrable residential premises.
• The third one is characterized by high moisture resistance and durability.
• Fourth - used in the construction of walls.
• Lacquered or laminated - covered with a protective layer of varnish or laminate.
• Grooved - at the joints has a connecting groove.

The best solution for the subfloor will be OSB 3, grooved and easy to install. Such sheets are produced with a thickness of 0.5 cm to 4 cm.

Advantages and disadvantages

When it is difficult to decide which substrate is better: plywood or chipboard, you need to consider the advantages and disadvantages of each material. plywood cover has the following advantages:

• Withstands heavy loads.
• Light weight.
• It is flexible, has high bending strength and deformation.
• There is no foreign chemical smell.
• High leveling ability.
• Easy to handle, saw.
• Easy to operate.
• Smooth beautiful outer surface.
• Keeps the heat in the room.

Advantages of using oriented strand boards:

• Affordable.
• They don't flake off.
• Surface without defects.
• Various sizes.
• The panels are lightweight.
• Resistant to harmful insects.

But all wood materials have a common drawback - moisture has a great influence on them. Humidity will quickly destroy wood raw materials, so it is better to lay moisture-resistant brands of coatings. The reverse negative side of moisture-resistant panels is environmental friendliness. They emit formaldehyde, which is harmful to health, but it is he who helps fight moisture.

Both leveling materials have a high degree of ignition from open flames, therefore, before laying the material, care must be taken to increase the fire retardant properties.

If you lay the flooring on the logs, then up to 10 cm in the height of the room disappears. This is not always acceptable in certain situations. To lay the sheets, it is necessary to make a clear calculation so that there is no waste and unnecessary work on alteration. It is recommended to fasten these materials with self-tapping screws with an average pitch of 20 cm.

Such sheets tolerate fasteners well and are tightly attracted.

The differences in price between plywood and OSB of the same brand are not the most significant, but OSB is cheaper. In suitable and unpretentious conditions, OSB boards can be laid, but plywood is suitable for a durable wear-resistant coating.

Materials and tools

Plywood and OSB are similar in laying technology. To cover the floor with wood sheets, use the same installation tools. Mounting materials are the same. In order to quickly and efficiently lay plywood sheets on a rough plank floor, you need to stock up on basic construction tools. The work will require:

• Level for measuring the evenness of the floor.
• Screwdriver or screwdriver for screwing screws.
• Drill for drilling holes for dowels.
• Roulette for measuring the required length.
• Jigsaw or hacksaw for sawing plywood sheets to the desired dimensions.
• Sanding attachment for a drill or grinder for grinding joints between sheets.
• Roller or paint brush for applying primer.
• Broom or vacuum cleaner for garbage collection.
• Spatula for applying glue.
• Hammer for nailing.

To improve the moisture-resistant and fire-retardant properties of the material, it is advisable to use special flame retardant compounds and primers.

It is better to lay plywood or OSB on water-dispersion glue bustilat, PVA. These grades are suitable for gluing wood surfaces. They are safe for health, have no smell and dry within a day. The adhesive is easily applied with a spatula or brush (depending on the consistency).

You can fasten plywood sheets on self-tapping screws and nails. If the laying of materials is carried out in an apartment, it is preferable to use self-tapping screws with dowels, since working with a drill and a screwdriver is easier and quieter than a hammer with nails.

Preparatory work

Before starting the installation of plywood on a wooden floor, basic preparatory work is carried out. First, an assessment is made of the original rough wooden base. Visually assess the condition of the floorboards, the presence of ill-fitting and creaky floorboards.

Check the construction level for differences and uneven surfaces.

Then the skirting boards are removed. All loose boards must be additionally fixed with nails or self-tapping screws to the lower beam. Floorboards affected by the fungus are replaced or cleaned, impregnated with an antifungal compound. Warped and damaged boards must be replaced. The protrusions on the surface are cut off with a planer and polished. Slots and cracks are filled with sealant or glue.

After the repair, garbage, sawdust and dust are cleaned with a broom or a vacuum cleaner. The untreated plank floor is treated with an antiseptic. Roll material can be laid under the plywood floor as noise insulation and insulation.

Penoplex or isolon of small thickness is suitable for the substrate. Connect the strips of the substrate to each other with construction tape.

The plywood is fastened after drying to avoid deformation. To do this, the material is brought into the room and left for 2-4 days. The best solution for protecting against moisture and fire is to treat both sides of the panel with a primer or acrylic varnish. The technology of laying wood sheets requires an indent from the wall in the amount of 1-1.5 cm between sheets up to 0.5 cm.

This must be taken into account when cutting and laying plywood blanks on the floor.

To relieve stress from the material during operation and ease of installation, the sheet is cut into 4 parts using a jigsaw. All parts are preliminarily placed and adjusted, the layout is drawn and the workpieces are numbered. Lay the sheets with an offset to reduce the number of joints and avoid crossing.

If you follow all the rules when laying plywood, it will serve as a high-quality, durable base for any floor covering. The finishing decorative material can be re-layed, and the plywood base will remain the same.

Alignment methods

The leveling method depends on the evenness of the subfloor. Differences in height of more than 1.5 cm suggest plywood flooring along the logs. Minor irregularities are covered with plywood directly on the wooden floor.

Boards with a difference of less than 1 cm are aligned with supports in the right places. As a support, thin squares, bars of wood or plywood are used.

Laying plywood on the floor can be done with or without underlayment. The lining roll is rolled out over the entire surface and fastened with adhesive tape. Plywood material is spread on top in accordance with the scheme, the evenness is checked and fixed with self-tapping screws. In this case, sheets with a thickness of 1 cm are needed.

Without the use of gasket material, an adhesive fastening method is used. A small area of ​​​​the room is covered with glue for 2-3 mm, starting from the corner. A sheet of plywood blank is superimposed on top and pressed tightly. Additionally, you can screw a few screws for better fixation. This method is used to install the rest of the room.

Laying birch plywood does not require special skills and can be done by hand.

When a plywood sheet does not lie flat, bends, there are slight differences in height with other blanks, supports are used. Anchor points are placed in ill-fitting places and fixed through with self-tapping screws.

If fiberboard lies on a wooden base, then dismantling is carried out if the material is old, warped from moisture, crumbles and exfoliates at the edges. Fiberboard is not recommended to be laid on the floor, since the sheets deteriorate from moisture and have poor leveling properties due to their small thickness.

To level significant differences in height, logs are used. As a log, boards of the required length with a section of 3-5 cm by 7-10 cm or coniferous plywood slats of the same size are used. The location of the lag depends on the thickness of the plywood and the load during operation. Small thickness requires a smaller distance between the lags, starting from 40 cm. You should not use sheets less than 1.5 cm in height. The installation of the log is designed in accordance with the layout of the plywood in the room, so that the joints are laid in the middle of the timber.

The horizontal installation of the lag is measured by a water or laser level. The evenness of the entire floor depends on the accuracy of installation. The lags are attached to the glue and screwed with screws. Bars are placed perpendicularly between them, obtaining a reliable crate, on which plywood blanks are laid.

Many beginners in construction sooner or later wonder how to lay plywood on the floor. This material is often used in cases where floors cannot boast of an ideal appearance and require leveling.

Laying plywood on the floor helps prepare the perfect floor for finishing: laminate or parquet.

If you decide to replace the flooring and opted for laminate or parquet, be sure to measure the floor level with a special device. In most cases, a spread within a few centimeters is immediately detected. The most neglected cases are when the difference is already ten centimeters or more. To correct this situation, flooring with plywood will help.

It is laid on a pre-prepared base.

A concrete screed is perfect.

If you prefer it to other types of bases, remember that it completely hardens after a month and a half.

After that, work can be resumed. In most cases, a layer of waterproofing is laid on top of the concrete screed. And then lay plywood. You should choose plywood with a high level of moisture resistance. Its thickness, as a rule, starts from 1.5 cm.

Rule: before laying plywood on the base, be sure to test it for moisture resistance.

How to measure the moisture content of a concrete base under plywood

To do this, use a polyethylene film 1 m wide. Spread it on concrete. Press the edges. This can be done with the help of improvised means. For example, bars. Leave the center free. Wait a few days.

After that, inspect the polyethylene. If its surface is not wet, then the humidity is within the normal range.

But if condensation appears, you should wait some more time for the concrete base to dry completely. Otherwise, you will have to change plywood.

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Types of plywood used for the floor

Plywood differs in the number of pressed layers and in the types of glue that affect the degree of moisture resistance.

If you decide to lay the floors in your house with this material, you should familiarize yourself with its types.

You may be interested in: How to make a floor screed

Plywood is a sheet covering that consists of several pressed layers.

But the number of these layers depends on several factors, more precisely, the purpose for which one or another type is required. For example, strength or increased load.

Plywood is divided into classes:

Their differences are in the degree of moisture resistance, the top coat and the type of adhesive used to hold the layers together.

If we talk about the first type of plywood FK, it can be described as a high-quality coating. It is used for decoration of residential premises. It has an average degree of moisture resistance. The adhesive is dominated by carbamide resin.

The second type of plywood - FSF - is more suitable for arranging floors in rooms with high humidity. For example, bathrooms, kitchens or saunas. It has a suitable level of moisture resistance. This is achieved thanks to the special composition of the adhesive, which includes phenol formaldehydes.

If the first two types are used in residential facilities, then the third type is most often used in industry.

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How is plywood processed?

Plywood grades are distinguished by the degree of processing and the raw materials used.

You should also pay attention to such a factor as material processing. Plywood can be produced from different types of raw materials. For example, birch or coniferous wood. Softwood plywood is made from veneer. It attracts buyers with resistance to fungal attack and a reduced level of decay. This variety is most often used for construction work related to the roof.

In the production of furniture or interior decoration, birch plywood of the FK type is used. It is made from larch veneer. Birch plywood for outdoor finishing work should be PSF.

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Classification of plywood by formaldehyde content

This factor is taken from the calculation for every 100 g of dry sheet material.

For finishing residential premises, plywood of the first type is used - with a minimum formaldehyde content.

Two types are produced:

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The first option is calculated according to the formula 10 mg of formaldehyde for every 100 g of dry sheet material.

The second type is a spread of 10 to 30 mg of formaldehyde for every 100 g of dry sheeting.

The first type of plywood marked E1 for interior finishing is most often used.

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How to lay out plywood: features

Plywood is produced in sheet form. The standard size of a sheet of plywood is 125x125 cm. But due to its considerable size, it makes work difficult.

First, the sheets need to be cut. It is best to do this in the form of squares. After that, it is laid out on the surface of the base. It is necessary to fit the sheets around the perimeter of the room, taking into account all the depressions and protrusions. When laying out plywood, leave a small distance from the walls.

https://website/youtu.be/r1qtd4NaK04

Important! Make sure that the edges of the plywood sheets do not come into contact with the walls.

Gaps may form between some sheets of plywood. In this case, you need to follow the seams. Their width should not exceed 1 cm.

Tip: to make plywood sheets easier to lay after measuring and cutting, numbering should be done with a pencil on the reverse side.

Saw sheets should be carefully and slowly. Try to avoid delamination of the material. If, nevertheless, defects appear, the only conclusion follows: the material turned out to be of very poor quality. And it is worth considering whether it is worth using it.