Characteristics and rules for laying plywood on the floor. Plywood for the floor - which plywood is better for installing floors in the house? Tongue and groove boards or plywood for the floor

Leveling the floors before roughing and finishing directly depends on the height and area of ​​the room. But this process is also influenced by several other factors. What kind of floor covering will there be, what temperature and humidity range will the floor be in, how much is planned to be spent on finishing work, what are the residents’ attitudes towards aggressive adhesives and solutions, etc. All of the above issues make choosing a material for leveling the floor not so simple. Today, home-grown builders and recognized repair masters have tried a lot! Here we will talk about plywood, which is an excellent material for covering floors in residential and non-residential premises. Sheets of plywood of different thicknesses and formats are used both for rough finishing before laying laminate, linoleum or parquet, and for finishing floors in cottages, country houses and at home.

How to use plywood

Initially, it may seem that plywood sheets are fragile and cheap. But practice shows that this material is many times superior to MDF, chipboard, OSB, fiberboard and other recyclable materials. And there is no need to ask a difficult question. The main advantage of plywood lies in the specifics of its production. There is no gluing of the residual mass of wood and a liquid binding substance. Each plywood sheet consists of several layers of working wood. And due to the fact that these layers have multidirectional fibers, the floor is strong and reliable. You can read about what this is in the article.

You can find out how much 1 sheet of moisture-resistant plywood costs from this

Laying a plywood floor aims to achieve three main goals.

1. “Smoothing” uneven surfaces and preparing for final coating.
2. Ensuring the required level of thermal insulation.
3. Protection of parquet boards from moisture.

Of course, there is also plywood for finishing the floor. But we will not consider this option due to its specificity and low prevalence. The plywood is placed either directly on the floor, or raised above it with the help of logs - special beacon bars.

What are the technical characteristics of moisture-resistant plywood can be found in this

The video shows the thickness of the plywood on the floor:

Methods for laying sheets on the floor

Put on the joists

If the differences in height on the floor are quite significant (from 5-10), then plywood can be laid and attached to special joists. They not only allow you to achieve a perfectly flat floor, but also provide an air cushion for thermal insulation and waterproofing and then make it easier to select other finishing materials.

Logs are used almost everywhere. The only obstacle on this path is the low height of the room, since laying plywood on joists “eats” up to 10 cm of the room’s height.

Manufacturers and prices

When choosing a finishing coating, it is useful to know.

The prices for their products are approximately the same. Therefore, experts recommend, first of all, deciding on the type plywood sheets that will be used for flooring.

Leveling the floor with a plywood “underlay” is a common method of dealing with unevenness, cold and operational features of the room. Depending on the task, different types of plywood and their thickness are used. If you are just taking a closer look at the material, it is useful to know.

You can see photos of OSB plywood in this

In each specific case, an assessment of the needs for a particular type should be made by a professional.

Leveling a wooden floor with plywood sheets in order to prepare the base for subsequent finishing with decorative flooring: carpet, linoleum, parquet, laminate.

Wooden floors are a classic in home construction. They are environmentally friendly, wear-resistant, durable. But nothing lasts forever, and one day there will be a need to renew the floor. A wooden floor that is outdated due to wear and tear or outdated appearance (the owners wanted to decorate the interior with a new decorative flooring - laminate, linoleum, etc.) requires adjustment. After all, modern coatings require a perfectly flat surface. Plywood - simple and inexpensive solution to carry out this task.

So what do you need to know and how to attach plywood to a wood floor to transform squeaky floorboards and unsightly surfaces into home decor?

Preparing Worn Wood Floors

Laying plywood on a wooden floor is carried out after inspecting and repairing the old covering:

• Remove the baseboards.
• Rotten floor fragments are replaced with new ones.
• Creaking and sagging floorboards are strengthened by screwing them to the beams with self-tapping screws.
• Places with damaged paint coating treated with an antifungal compound (primer).
• Check the plane with a level to identify differences and irregularities.

If the differences are significant, then leveling is indispensable. Most often, plywood is used for this purpose on a wooden floor - this material is the most popular due to its availability, cost and ease of working with it.

Minor unevenness and protrusions (2 - 4 mm) can be eliminated with a plane and/or a sander - in this case, the decorative coating can be laid directly on the wooden floor.

What kind of plywood is used for the floor

Plywood is available in various thicknesses, sanding and finishing qualities. Therefore, an inexperienced builder is always faced with the question: what kind of plywood to lay on a wooden floor so that it is a reliable foundation for decorative covering.

• The brand of plywood is a difficult choice for the home craftsman. Usually the choice is made between the FS and FSF brands. FC is plywood in which the veneer sheets are glued with a less toxic glue than the FSF brand (read: “Which plywood is better for the floor - choose the brand and type of material”). However, the quality characteristics of FC are weaker: it is not very moisture resistant. Therefore, if environmental friendliness and safety are a priority (floors in a children's room, bedroom), then it is better to buy FC. For rooms with high humidity and traffic (the hallway of an apartment, a country house), FSF is chosen.

Note: there are brands of plywood that combine strength, moisture resistance and safety (for example, FB), but due to the high cost (2 - 3 times compared to FC), the average user rarely considers this option.

• The quality of the material also matters: the higher the grade of plywood, the better, smoother the surface, which means the decorative coating will fit better and last longer. To level the floors, grade 1 and 2 plywood is used.
• Plywood can be sanded on both sides (Sh2), on one side (Sh1), and not sanded (NS). For leveling take Ш1.
• Material thickness. Experts believe that for floor works this material should be at least 8 mm thick, and preferably more (for more details: “What thickness of plywood is suitable for the floor”). What thickness of plywood to lay on a wooden floor is regulated by a simple rule: the thicker, the better. At a minimum, the plywood should not be thinner than the final floor covering.

Sometimes plywood is used as a subfloor, laying sheets directly on the joists. In this case, the thickness is needed from 2 cm.

Do you need any preparation for plywood?

Covering the floor with plywood on a wooden floor begins after preparing the plywood sheets. They need to be brought into the room where installation is planned and left for 2 - 3 days. Wood tends to change dimensions depending on humidity and temperature, so it is necessary that these parameters of the material and the environment coincide.

Experts advise moistening the edges of plywood sheets with water at room temperature if the room in which work is being done is not heated regularly.

It is also advisable to treat the sheets with an antifungal and fire-retardant primer.

Attention: you should not work with plywood in a room with high humidity: if condensation accumulates on a piece of film left in the room during the day, it is recommended to dry the room with available funds (heating devices, turning on the heating).

Measure seven times: cutting and fitting sheets

Cut sheets of the same shape. Experts recommend 0.6 by 0.6 m, but you can do 1 by 1 m or 1 by 0.5 m - it all depends on the thickness of the plywood and ease of use. After cutting, the sheets are tried on: laid on the floor, following the “staggered” method - the transverse joints should not match, the appearance of the laid sheets resembles brickwork (read: “How to lay plywood on the floor - laying rules”). You should ensure that the damping distance is maintained during installation: a gap of 2 - 3 cm from the wall, 0.5 - 1 cm between sheets. If the fitting was successful, the sheets are numbered so that the final attachment of the plywood to the wooden floor goes smoothly, without a frantic search for the right sheet. In addition, it is useful to draw a plan for laying sheets with the corresponding numbering. Finally, you should mark the floor with a pencil or chalk so that you know where to place the joists.

Note: cut plywood is inspected for defects formed during cutting; delaminated or deformed ends of the sheets will affect the quality of the coating; it is better to replace them.

Tools for making a plywood base

Before starting work, you should check that you have the necessary set of tools:

• Electric jigsaw;
• Drill with a set of drills;
• Screwdriver;
• Level;
• Roulette;
• Self-tapping screws;
• Dowels.

After installing the plywood base, you will need to prepare it for decorative flooring: thin coverings (linoleum, carpet) will require careful sanding of the surface. To do this, it is better to purchase a grinder or use a special attachment for a drill. You can use fine-grit sandpaper if the floor area is small.

Plywood leveling technology

Before laying plywood on a wooden floor, a technology of execution is chosen; the choice depends on the magnitude of the differences and unevenness of the wooden floor. Three alignment methods are used:

1. Leveling by laying sheets directly on a wooden floor. It is used if the unevenness is no more than 1 cm and is formed by the ribs of the floorboards. The flatness of the sheet, based on the protruding edges, evens out the difference. This installation method often uses a plywood underlay on the wood floor to act as a shock absorber and improve thermal insulation.
2. Leveling using point supports (bosses). Used as budget option for floors with slight differences. For the bosses, squares cut from plywood, laminate, or boards are used.
3. The sheathing device for leveling floors is used when horizontal differences are 1–8 cm. The strip support is made from beams or cut strips of plywood; this method is the most expensive, but also the most reliable.

For any type of base, the rule is: the thinner the plywood, the closer the support points should be.

The procedure for leveling using joists

Before starting leveling, determine the level highest point floor. From this point they begin laying lags - beams located in parallel. Lay the logs, adhering to the marks made during the initial layout of the plywood fragments. They need to be located at the junction of the sheets.

• The logs are laid one by one and secured to the wooden floor using special glue and self-tapping screws. Each beam is checked with a level in all directions, if necessary, placing bosses under it and filling irregularities with plywood trim. Pieces of trim should be additionally lubricated with glue to increase the reliability of the base. There is a special glue for plywood on wooden floors that does not require additional fastening. But more often, craftsmen use proven methods: they lubricate the required places with available glue (“Bustilat”, “Liquid Nails”, “Moment”), and then secure them with self-tapping screws.
• Then the sheathing is mounted - transverse bars located at a distance equal to the width of the prepared sheets and in accordance with the original marks. It is necessary to carefully observe the markings so that the sheets, during the subsequent installation of plywood, do not, as they say, “hang in the air,” but are attached to the sheathing and form a reliable plywood floor in a wooden house or apartment.
• To improve heat and sound insulation, the sheathing space can be filled with appropriate material, after first getting rid of construction waste.
• Plywood sheets are fastened according to the diagram, checking the number marks. To ensure that the heads of the screws do not protrude above the plane, they are recessed. To do this, drill a recess at the attachment point equal to the diameter of the screw head.

After installation is completed, all that remains is to prepare the plywood floor in accordance with the type of finishing coating. For thin coatings, all irregularities, cracks at joints, and recesses from recessed screws are puttied. For more rigid coatings, a special noise-absorbing underlay may be needed. In any case, it is advisable to varnish the plywood several times to extend its service life.

Rules you need to know

Before laying plywood on a wooden floor, it is worth checking and repairing all communications running under the floor, so that later you do not have to open up a new finished floor. It's worth knowing that:

• The length of the screws used in the work should be three times the thickness of the plywood.
• The distance between the screws is no more than 20 cm.
• The sheets are screwed, retreating 2 cm from the edge.
• If there is thin plywood, it is used in 2 layers, placing the sheets so that the seams of the top and bottom layers do not coincide.
• When installing a plywood base using the point method, the bosses are placed at a distance of 20–25 cm.

Photos of beautiful modern coatings do not leave anyone indifferent, and an insufficiently level floor will no longer be an obstacle. Using these recommendations, any man who knows how to hold a tool will know how to lay plywood on a wooden floor and will be able to do it with his own hands.

polspec.com

People planning major renovation in an apartment or private house, you always wonder about leveling the floor. This procedure is really necessary, because in order to make the base strong and perfectly level, you cannot do without it. In addition, many floor finishing options are also very demanding in terms of installation conditions. Floors are often leveled using materials such as OSB boards and plywood. There is ongoing debate regarding both types of material. So, plywood or OSB - which is better for the floor? In this article we will try to answer this question.

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Let's find out the difference

Which material is better - plywood or OSB, because each of them has certain properties and has strict requirements for the installation process. Yes, they are very similar in many ways, the purposes of their use are also the same, but, nevertheless, each has its own pros and cons that limit the use of a specific type of material in a certain situation.

Both OSB boards and plywood are used to create a perfectly flat subfloor, which is covered with finishing material on top. Much here depends on the conditions, because the flooring can be installed either on joists or on top of a concrete screed or old wooden floors.

Important! Installation of any of these materials using logs should be done using fairly thick elements, in turn, the log bars should have a thickness of at least 4 cm. They are attached with self-tapping screws, and not with glue.

So, in order to decide which material to use, you need to figure out which one is better and which one is worse. To do this, you should take a closer look at these varieties, which are used for rough finishing.

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What is plywood?

To decide for yourself what is better to lay on the floor - plywood or OSB, let's carefully study each option, and perhaps start with plywood. She is well known to everyone. These are sheets made of wood veneer, glued together with a special glue and pressed. The result is a solid and fairly strong slab.

Features of plywood manufacturing:

• Veneer is glued, as a rule, in three layers, so the thickness, reliability, strength of the material and the possibility of its use depend on their quantity.
• All layers are laid in such a way that in each of them the wood fibers are located perpendicular to the previous layers. It is due to this that plywood is so strong and elastic.

Important! Plywood is often used for finishing floors or creating various partitions. Even if it is made on the basis synthetic fibers, it does not pose any danger to human health.

The elements are glued together using synthetic glue or natural resins, which increase the environmental friendliness and safety of the material. The finished sheet has an absolutely smooth surface without knots or bumps; on one side it is perfectly sanded. Low-class products may still have roughness and knots, so they are used for rough work.

Important! Plywood is often used to create formwork at all stages of construction; furniture is made from it, floors are leveled with its help, and screens and partitions are constructed.

Kinds

The classification of plywood is as follows:

1. First grade. This is the highest quality and most expensive type of plywood. It has an excellent appearance and durability. This material does not have any defects. This is the best option for creating floors, but the high price prevents many from using it. Simply put, this is an elite option.
2. Second grade. High-quality plywood with a minimum number of defects. The only thing that can scare it away is minor cracks, but they can be easily eliminated even on your own. This material lends itself well to grinding and does not require additional special processing.
3. Third grade. Such plywood definitely needs to be further processed. It has defects, but not that many. More often these are small knots or roughness that can be easily identified by touch. This is the best option for creating a subfloor, since its strength characteristics are quite high, and it costs less than other types of plywood.
4. Fourth grade. This is the cheapest type of material; the sheets have many defects, even small holes are often found. It arises due to the fact that low-quality raw materials are used in production. As a rule, it is not even polished or processed in any way at the factory. Therefore, it is better not to use it for arranging floors.

Of course, it is better to take first grade (class) plywood for finishing, since other options are usually used in cases where a finishing coating is provided. If possible, do not purchase the fourth grade - such a floor will not last long.

Important! Plywood can withstand a humidity of 78% for only 12 hours, but 68% for quite a long time. Untreated material can withstand humidity of no more than 60%.

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What is an OSB board?

We continue to find out what is more suitable for the floor - OSB or plywood. Now let's take a closer look at what an OSB board is. This version of the boards appeared later than plywood; in fact, it was developed in order to replace it in those days when it was not easy to get plywood. Its name is translated as oriented strand board.

Features of material production:

• Wood chips are used for the production of OSB boards, which due to resins and high pressure are combined into one structure.
• In this case, the chips are located outside, they are oriented along the slab, and those that are inside lie across the product.
• The chips used to create slabs must have specific dimensions: length - no more than 1.8 cm, width - from 5 mm to 4 cm.
• Finished products can withstand loads of up to 100 kg/m3.

Important! If the technology for creating the slabs was strictly followed, then they will turn out to be completely safe for humans. From an environmental point of view, OSB boards are better than plywood, fiberboard and MDF.

Considering the above, you can immediately answer one more question: chipboard or OSB - which is better for the floor? Naturally, the second option is more preferable.

Types of OSB boards:

• First type. Such slabs are more afraid of water than others, due to the fact that they are not able to fully resist the effects of moisture due to their low density. In addition, they are among the least durable.

Important! They are mainly used for packaging or making furniture. It is not recommended to use them on floors.

• Second type. This is a durable material that is characterized by low resistance to moisture. Therefore, floors from such slabs are made only in rooms with the lowest level of humidity.
• Third type. This option is characterized by high strength and moisture resistance, which means it is the best option for laying floors in rooms with high or moderate humidity levels.
• Fourth type. Such slabs are not afraid of anything; they do not lose their performance even when used in the most extreme conditions.

OSB boards are also divided into three types, depending on specific characteristics. They can be:

• Lacquered.
• Laminated.
• tongue and groove.

Important! Yes, externally OSB does not look as beautiful as plywood, due to the shavings that are visible on the surface, which is why it is not used for finishing. But this material is ideal as a substrate.

As a material for leveling, plywood has the following advantages:

• Looks prettier.
• Does not deform.
• Dries after getting wet and quickly returns to its original shape.
• Thanks to the special structure, through cracks do not appear on the product.
• Has a smooth surface.
• The material is easy to process.
• Does not lose its characteristics for a long time.

OSB boards are valued in construction for the following advantages:

• The material is relatively inexpensive.
• May have different dimensions.
• Lasting.
• Resistant to moisture.
• Doesn't delaminate.

Disadvantages of plywood and OSB boards

We must not forget that these materials, like others, have some disadvantages. Eg:

• It is not advisable to fill plywood with water, because even though it quickly takes its original shape, it can begin to rot inside.
• OSB boards, when cutting, emit too much dust and minimal amounts of formaldehyde.

Now let’s summarize all of the above in order to clearly answer the question of what is better for flooring - OSB or plywood. We can say for sure that OSB reacts more strongly to water and deteriorates faster than plywood, especially when it comes to wet rooms. In such rooms it is better to use plywood sheets. In terms of thermal conductivity, they are almost the same, but taking into account the strength indicator, it is worth noting that here plywood is better. The choice is yours.

serviceyard.net

Plywood or OSB - which is better for the floor? - Encyclopedia about construction and floor repair

Insulation of floors during renovation is the key to ensuring that the house will be cozy and warm, and you can even walk on the surface of the flooring barefoot without experiencing discomfort. And floor insulation is especially important in Russia, since the climatic conditions here leave much to be desired in most regions. You can insulate the base under your feet with materials that vary in their characteristics - this includes isolon and mineral wool, which is often used in construction. But is it possible to use polystyrene foam for floor insulation? It turns out that it is possible, and this is one of the best insulation options.

What is polystyrene foam, its features

Foam plastic is actually familiar to every person. And areas of application of this material quite extensive. But few people know what polystyrene foam is made of and what it actually is from a physical and chemical point of view.

So, polystyrene foam is light blocks various sizes, consisting of foamed but pressed together granules of a substance such as polystyrene. During the production of the material, granules of this substance are treated with steam, the resulting particles undergo a drying stage, after which they are glued and pressed into a single block. And at the same time, 97% of foam is ordinary air. During the drying process, the foam acquires the same sound and heat insulating qualities that are familiar to us. The production of polystyrene foam is regulated by GOST 15588-66.

GOST 15588-86. Polystyrene foam boards. Technical conditions. Downloadable file (click the link to open the PDF in a new window).

GOST 15588-86

Comparison table of characteristics of polystyrene foam and EPS

Comparative Thermal Conductivity Chart of Polystyrene Foam

Polystyrene foam has low thermal conductivity, which allows it to retain heat for a long time, thereby reducing heat loss in the house. Such indicators can be achieved precisely due to the porous structure of the material.

Polystyrene foam is not afraid of moisture thanks to a special production technology, when raw material granules are treated with moisture-saturated steam; it is resistant to the appearance of colonies of harmful microorganisms and mold growth. Fungus does not develop on it, which from a health safety point of view makes it one of the the best insulation materials for walls and floors. The material also has a long service life and low weight, which is why they like to use it in construction. The material is easy to use, since, if necessary, it can be easily cut into elements of the required size, and you can drag the blocks yourself, without involving the help of third parties.

On a note! To ensure the proper level of thermal insulation of the floor, it is enough to buy very thin blocks of foam plastic - 10 cm of material thickness is enough to cope with this task.

Polystyrene foam is an inexpensive material, somewhat rigid and durable, and does not require any arrangement. plywood structures for laying, does not require special skills or knowledge from the master. This is an ideal option for coverings such as slats or parquet due to its soundproofing characteristics.

The main disadvantage of the material from a construction point of view is its requirement for the evenness of the base on which it will be laid. If this condition is not met, the foam will break and crumble, as a result of which it will lose its properties, albeit partially.

On a note! Polystyrene foam is often confused with expanded polystyrene, which is used for packaging various fragile products. In fact it is several different materials, although they have a lot of similarities. Packaging polystyrene foam is fragile, and its thermal insulation characteristics are much lower than those of polystyrene foam.

Table. Technical specifications.

Disadvantages of polystyrene foam

Polystyrene foam is far from an ideal material; it also has its own disadvantages, which you need to know about in order to draw your own conclusion whether or not to buy such material for floor insulation. The main ones are the following.

1. Low strength indicators. The material is easy to damage or break. But at the same time it is easy to cut.
2. The material is afraid of the effects of varnish or paint - it is destroyed because of them.
3. This is not a breathable coating, although it is full of air in itself.
4. If there are mice or rats in the house, they can greatly damage this type of insulation. Therefore, it is best to cover foam blocks with plaster.
5. This is not an environmentally friendly material, and if it is set on fire, it releases a huge amount of toxic fumes into the air. But the foam itself is absolutely safe for humans.
6. You still need to create a frame for foam plastic, but in the case of this material it can not be made as powerful as when using the same mineral wool.

Insulation of wooden floors

Wooden floors are quite common both in apartments and in private sector houses. They are environmentally friendly, easy to install and have good strength characteristics. However, on the lower floors, the relatively low thermal conductivity of wood is simply not enough to provide the proper level of heat, which means that the floors still need to be insulated. And here foam plastic would be an excellent option.

As far as we know, a wooden floor is an entire structure that requires the presence of an air gap between the plank covering and the ceiling. And it is precisely in this space that foam blocks need to be laid. Even a novice builder or a person who is far from construction, but decided to repair or simply insulate the foundation himself, can do this work.

In any case, the use of polystyrene foam requires careful preparation of the base. That is, it must be cleaned, leveled, and all cracks must be sealed. After this, a waterproofing coating is laid, on which the foam is then laid. But first, logs made of wooden beams are installed.

On a note! As waterproofing, you can use any material suitable for these purposes, even ordinary polyethylene film.

Foam blocks must be laid tightly, without gaps, and the joints between them can be foamed to reduce the number of cold bridges. Next, it is recommended to cover the foam with another layer of waterproofing.

Advice! To install insulation in a private home, it is better to buy foam plastic with a thickness of at least 10 cm. Moreover, the higher the humidity in the room, the thicker the insulating coating is used.

Insulation of concrete base

Concrete floors are distinguished by high reliability indicators; they are usually very smooth and durable; they are not afraid of serious loads. However, it cools down quickly, does not retain heat, and the cold lets in easily. That is why concrete floors must be insulated. And here, too, polystyrene foam comes to the rescue. However, depending on whether there is a basement under the concrete floor or not, the insulation technology will also differ.

If there is a basement

This section is relevant for owners of private houses or those who have apartments on the ground floors. Concrete floors in these cases are quite cold, and even a good floor covering will not save you from discomfort. Here it is recommended to mount the insulation from the basement side, then the concrete slab, that is, the ceiling will be in a layer of air and will better retain heat, and the cold will not penetrate the house.

It is best to use foam plastic with a thickness of 5-10 cm, as is the case with wooden floors. If the concrete slab is uneven, then in any case it is important to prepare it for the installation of foam sheets. All cracks on it, if any, are sealed with polyurethane foam.

You can fix the foam on the concrete using dowels 12-14 cm long. You need to work slowly, drilling holes in the concrete with a hammer drill, marking places for fastenings. Before fixing the material, apply a special adhesive suitable for foam plastic to the surface of the concrete. The joints between fixed sheets can be covered with polyurethane foam.

Important! Polystyrene foam burns well and is easily damaged. Therefore, after installation, it is in any case important to protect it with plaster or ceramic glue using a thin reinforcing mesh.

No basement

If there is no basement in the house, and the apartment is located above the first floor, then another technology for floor insulation with foam plastic is used. In this case, the sheets are installed above a concrete surface. The old floor covering is completely removed, all cracks in the base are sealed, and the floor is leveled. It is best to seal cracks with thick cement mortar. Only after this is the floor waterproofed with special compounds or materials. The easiest way is to use bitumen mastic, but in some cases roll material will also be convenient.

Afterwards, a reinforcing mesh or ordinary masonry is laid on the surface of the waterproofing. And only then sheets of foam plastic are placed on it. But here you can use thin sheets about 2-3 cm thick. The main thing is to install it with a minimum of joints so that cold bridges do not form. It is best to fix the foam with special glue.

Next, after laying the foam, the beacons are installed using a laser level. They can be fixed with the same mounting adhesive. Beacons are placed at a distance of no more than 1.4 m from each other, but at the same level. After this, a screed solution is poured over the foam - a regular concrete screed is performed, and the foam will be sealed on both sides with concrete surfaces.

Advice! You can level the surface of a concrete screed using a self-leveling mixture.

Foam plastic in floor construction on the ground

In private houses, in some cases, the first floor is not built above the basement, but directly on the ground. Here it is important to pay maximum attention to heat and waterproofing. It is best to lay not one, but two layers of thermal insulation material. The floor can be either above or below ground level. In any case, it is important to use the thickest foam possible when installing floors.

The base under such a floor must be carefully leveled and compacted. After which it is important to make a so-called cushion of gravel or crushed stone and compact it, and then cover the surface waterproofing coating. The best option is roofing felt. Next, the foam boards are laid very tightly to each other. Moreover, the joints of all seams should not converge in one place - it is better to lay the sheets in a checkerboard pattern. All joints between individual sheets are foamed.

Advice! The latest sheets should be taken slightly larger than the required dimensions in order to install them with some effort.

Then further waterproofing work is carried out again. You can cover the foam with a polyethylene film, but it is thick enough and durable. Next, the screed is poured according to conventional technology. The thickness of the screed layer should not be less than 4 cm.

An example of floor insulation with foam plastic

Let's take a step-by-step look at insulating the floor in a house with polystyrene foam. This is a fairly simple option, and any person can perform such insulation.

Step 1. First of all, the rough base needs to be cleared of debris and all irregularities removed. If necessary, cracks are sealed and protrusions are ground. It is important to remember that polystyrene foam does not tolerate a crooked base. Next is laid waterproofing layer. In this case, roll material is used, which is laid in separate strips overlapping each other. In this case, the individual strips are fixed to each other using heat. blowtorch. Waterproofing should be applied to the walls by approximately 10-15 cm.

Step 2. Next you need to install the floor joists. In this case, they are wooden beams on which the floor under your feet will subsequently rest. Logs should only be used from dry wood. The lags can be fixed to the base using dowels. The step between the lags can be equal to the width of the foam sheet.

Step 3. After installing the joist, all communications that will be located inside the floor pie should be laid. This could be wiring, pipes, and so on. Laying should be done in accordance with the project of the house or renovation. As for the water supply, especially in a private house on the ground floor, it is best to place it on thermal insulation material.

Step 4. Next, you need to lay foam plastic on the surface of the waterproofing layer between the joists. It is laid consistently and tightly so that no gaps are formed. But if they appear, it is best to cover them with polyurethane foam. The logs should be of such a height that they are approximately 5-10 mm above the level of the laid foam.

Step 5. Then you need to “sew up” the floor cake with plywood sheets, OSB sheets or a regular board. That's it, the floor is ready, you can install the finishing floor covering.

Video - Floor insulation with foam plastic

Polystyrene foam is a truly convenient and practical, and most importantly, inexpensive material that is excellent for insulating floors in the house, as well as in any building. It is easy to work with, and the material performs its functions properly. So the main thing is to work without violating the technology, and then after installing such insulation in the house it will be comfortable and cozy.

pol-exp.com

Laying plywood on a wooden floor with your own hands

Often during repairs, dismantling the old wooden covering is not practical, but it is necessary to level the surface for further work. In this case, experts advise simply laying down sheets of plywood, thereby creating the necessary “platform”.

Laying plywood on a wooden floor

Plywood: advantages and disadvantages of the material

Pressed sheets are an excellent material for rough and primary work. They are inexpensive, easy to transport, easy to install and are good at eliminating small differences in floor level. Often they prefer to lay linoleum, parquet boards or laminate on plywood, since it has the following advantages:

• laying sheets significantly reduces the time of preparatory work before installing the final finishing floor covering;
• prevents rotting bottom side floor coverings, due to good ventilation between the material and the concrete screed;
• a floor lined with plywood prevents premature wear or deformation of linoleum or carpet, extending the life of the decorative coating;
• provides a smooth subfloor;
• plywood sheets are light, hard, durable, resistant to stress and abrasion;
• plywood is flexible enough and does not break during installation;
• has no pungent odor;
• has good sound and heat insulation properties;
• due to the large size of the sheets, the number of joints is minimal;
• high-quality factory grinding prevents slipping of the sheet and materials placed on it.

Popular types of plywood used for renovation

Sheets produced by industry are classified according to various criteria:

• wood used;
• presence and method of impregnation;
• variety;
• number of layers;
• surface treatment;
• moisture resistance.

For repair work, when the part of the structure made of plywood will be hidden from view, it is recommended to use moisture-resistant plywood of grade II or III. The sheet must be at least 10 mm thick, but the recommended value is 14-22 mm. A thinner one will not cope with the load, and a too thick one will be inconvenient to work with.

The number of layers is not of fundamental importance. If possible, you should purchase sheets sanded on both sides.

48 hours before the start of work, the material must be brought into the room where it will be installed and laid horizontally. There are two ways to lay plywood.

Method 1. Installation on old wood flooring

When laying plywood on a wooden floor, there are many options for fixing the sheets:

• on self-tapping screws;
• on glue;
• for liquid nails.

Adhesive compositions include water-based adhesive, two-component adhesive, assembly adhesive and bustylate. However, self-tapping screws are preferable.

Materials and tools

To successfully install plywood sheets, you will need the following tools and materials:

• plywood sheets;
• jigsaw;
• level;
• roulette;
• marker;
• self-tapping screws;
• screwdriver;
• substrate;
• construction vacuum cleaner or broom.

You may also need a sanding machine, a roller and primer, glue and sealant.

Preliminary preparation and priming of the floor

Installation of plywood on wooden floors is carried out only if the height difference when checking the level is no more than 1 cm. In this case, you will also need a substrate to compensate for unevenness and tape, which will need to be used to glue the joints of the strips of material.

Inspect the condition of the floors. Strengthen creaking and loose floorboards, replace rotten and damp floorboards. Do not try to restore boards that have traces of mold, damage, or have been attacked by rodents. They definitely need to be removed and the room ventilated.

Use a broom to sweep away dust and dirt from the floors. If desired, go over the wood surface primer twice to ensure better adhesion of the materials. And dry the base for at least 16 hours.

Marking and cutting

Plywood sheets are sawn so that the number of joints is minimal, taking into account damping joints of 3-4 mm between sheets and 8-10 mm between plywood and the wall. This will help avoid swelling of the sheets, since during operation, under the influence of the microclimate and temperature fluctuations, the workpieces will increase in area by several millimeters.

The cutting is done with a jigsaw, while the ends of the workpieces are carefully inspected for delaminations and sanded. On large areas, for ease of installation, plywood can be cut into squares of 50x50 or 60x60 cm. This technique will help to more accurately level the surface and eliminate possible installation defects.

The sawn sheets are numbered, and similar to their numbers, a schematic arrangement of the workpieces is drawn on a wooden base.

Laying plywood

Installation of blanks has several features.

Upon completion of installation, you should check the quality of the coating, remembering that the ideal gap between the level and the plywood is 2 mm, the maximum is 4 mm.

Method 2. Installation of plywood on joists

A more complex and labor-intensive method of laying plywood material along beams is justified if the height difference is more than 1 cm. Joists can be installed on an old wooden floor only if you are sure that everything is in order under it

Preparatory stage

Old flooring must be removed from dust and debris, paying sufficient attention to the gaps between the floorboards. The largest cracks can be filled silicone sealant or mounting adhesive.

At this time, you should prepare the plywood - you need to saw the material, make markings on a piece of paper and number the squares, taking into account that they will be laid out in bricks.

Installation of logs and plywood sheets

Logs are guides that help level the floor surface. They are slats 1.5-2 m long and 40x15 mm in cross-section, which are attached to wooden boards with dowels or self-tapping screws. The logs are positioned in such a way that their upper boundaries form a single plane, and the slats themselves form a sheathing.

The spaces between the guides must be filled with soundproofing insulation.

If necessary, cords and communication wires can be hidden in layers of insulation.

According to the drawing, the plywood squares should be installed. Fastening can be done with liquid nails or self-tapping screws; in the latter case, the heads of the screws must be thoroughly recessed. The holes can be pre-marked and countersunk.

Final processing

After laying the materials, the joints of the plywood sheets should be treated with fine-grained sandpaper, this will smooth out all the unevenness and differences of the adjacent sheets. After sanding, the entire surface must be coated with several layers of varnish.

1. If a laminate or parquet board, then the thickness of the plywood should not be less than the finishing coating.
2. Try not to allow 4 plywood sheets to touch at one point at once.
3. The width of the log step should be 0.5 m from the side of the square.
4. Plywood cannot be used in rooms with high humidity, even if it is a moisture-resistant grade of material.
5. If non-moisture-resistant plywood is used in the work, then laying a layer of waterproofing will be a prerequisite at the next stage of work.
6. The length of the screw should be at least 2.5-3 times the thickness of the plywood.
7. When laying plywood on joists, after sealing the gaps between the boards, the base can be primed and a layer of heat and waterproofing can be applied, and only then the guides can be installed.

It is important to remember that defective plywood sheets cannot be used in the work, even if they are intended to be further covered with decorative materials.

Video - Laying plywood on a wooden floor

pol-spec.ru

which is better, advantages and disadvantages, photos and videos

Construction of a subfloor is a necessary step when laying various floor coverings, such as linoleum or parquet. As a base for the floor, materials made from veneer or shavings glued together with special compounds are used.

Any construction begins with the choice of material, so you have to decide: what is better - chipboard or plywood for the floor. We will help you make a decision by talking about the advantages and disadvantages various materials, as well as their installation.

Composition and structure

Main material used for chipboard production and plywood is wood, but plywood is a more natural material, because... Less glue is used to glue it together.

The main differences between plywood and chipboard:

• Plywood is a multilayer material that consists of veneer sheets glued together. Inexpensive tree species are used as veneer: spruce, birch and pine. The number of veneer layers determines the thickness of the plywood sheet.
• Chipboard (chipboard) is made from wood waste: shavings, sawdust, etc. All this waste is mixed with a large amount of glue and pressed into sheets.

Features and Benefits

Plywood or chipboard for the floor - which is better? To answer this question, you need to carefully understand what you want to get from the material, because plywood has a set of some properties, and chipboard has others.

Comparative characteristics of materials:

• For the installation of a subfloor, the aesthetics of the material used is of little importance, however, it is worth noting that plywood can even be used for finishing flooring, treated with varnish.
• Chipboard and plywood are materials with poor moisture resistance. FK grade plywood is able to withstand the effects of a small amount of water, while chipboard does not at all resist the action of water, drying out and finally deforming.
• Chipboard has a more fragile structure: during operation, the material will begin to wear out quickly, crumbling under loads when fastening, for example, self-tapping screws hold less well in glued shavings.
• Despite all the disadvantages, chipboard is often used as a material for subfloors, because these boards have better noise and heat insulation than plywood, and also have greater bending strength.
• Another advantage of chipboard is its price. When comparing plywood and chipboard of the same quality, you will notice that the price of particle board is significantly lower than the price of plywood.

Both materials should be used only in dry, heated rooms, because when exposed to moisture, the sheets will rot, as well as spread mold and mildew, which will render them unusable, and also ruin the finished flooring. It is recommended to treat the material with special antiseptics even in dry rooms (for more details: “How to treat plywood on the floor - is it necessary to impregnate”).

If the humidity of the floor in the house is high enough, then you can use special boards - OSB, also laying plastic film for additional waterproofing.

Do not forget that for the manufacture of boards with a high degree of moisture resistance, more toxic adhesives are used, which can negatively affect your well-being during operation.

Both materials are easy to install. You can install the subfloor yourself using tools that can be found in any home. Chipboard is a heavier material than plywood, but it is easier to saw (read also: “Which plywood is better for the floor - choosing the brand and type of material”).

Also, do not forget that when sawing chipboard, a lot of toxic dust is formed in the air, so you should use a respirator to avoid allergic reactions.

Having considered all the properties of both materials, it is difficult to choose one, because each has its own pros and cons, so when asked: “Plywood or chipboard for the floor - which is better?” everyone must answer for themselves.

Construction of a subfloor made of sheet materials

The subfloor can be laid on an old covering, for example, a plank floor, as well as on a concrete screed or joists.

Chipboard or plywood on the floor from old boards is easily attached using self-tapping screws and glue, but it’s worth talking about fastening to screeds and joists in more detail (read: “Independent installation of chipboard on the floor - options for arranging the floor”).

Flooring on concrete screed

Concrete screed is the most reliable foundation, but its construction takes a large number of energy and time. Installation of such a screed begins with markings: draw along construction level horizontal lines along the walls of your room. These lines are the upper edge of the future concrete screed.

Next stage– this is the selection and laying of bars. The internal frame is organized with bars, so they must be thinner than the screed itself, so that cement mortar covered them. The bars are laid in a grid, the cells of which are equal to 1 square meter.

Pouring concrete is the final stage of constructing a concrete screed. For pouring, cement-sand mortar is used in proportions of 1:3. Fill the cells with concrete and smooth it into an even layer, then let the concrete dry.

If the quality of the resulting screed is important to you, then take care that it does not crack. To do this, maintain a high level of moisture, for example, by covering the concrete with polyethylene for 8-10 days.

You should start laying the subfloor only after the concrete floor has completely dried, otherwise the material used will become unusable.

There are two ways to check floor moisture:

1. Use an expensive moisture meter that you can rent.
2. Lay polyethylene over the concrete area and press it around the perimeter, then leave it overnight. If the concrete is not dry enough, then in the morning you will find condensation on the surface of the film, and if there is none, then you can safely begin installing the subfloor.

Laying sheets of plywood or chipboard begins with their adjustment. Cut the sheets so that there is a distance of 2 cm between the wall and the outer slabs, and also maintain a gap of 2-3 mm between the slabs. Read also: "How to attach plywood to a concrete floor - installation options."

The slabs should be laid according to the brickwork rule to prevent premature wear of the material. After that, number them so you don't get confused later.

Apply glue to the concrete and lay the slabs, then additionally secure them with dowels. You can see the finished result in the photo.

Installation of subfloor on joists

Installing sheet material on joists is a simpler method, but it is in no way inferior to the previous one. The main advantage of this method is the space between the lag cells, in which noise and heat insulating material can be laid, as well as utility lines located in them.

Laying a subfloor on joists requires a more durable material, so the thickness of plywood and chipboard should be at least 20 mm, provided that the distance between the joists does not exceed 40 cm (read: “How to make chipboard floors on joists with your own hands”).

Installation process:

1. Draw up a scheme for laying the lags so that the joint of the sheets occurs in their middle. As a result, you should get a grid with cells of 30-50 cm.
2. Level the longitudinal joists using spacers or a plane. Leave a distance of 2-3 cm from the walls.
3. Attach the transverse joists to the longitudinal ones using nails driven in at an angle. The result of the work done is a grid of bars, as in the photo.
4. Start laying the sheets from the corner, retreating 10-15 mm from the walls. Mark the middle of the intermediate joists on the edges of the sheet and connect them so that you can later screw screws along this line into the center of the joist. Secure the sheet of plywood with long self-tapping screws that go deep into the joist. Maintain a step of 10-15 cm.
5. Attach the remaining sheets in the same way, maintaining a distance between them of 2-3 mm.

Important amendments:

• Do not forget to lay the sheets according to the brickwork rule.
• Using tongue and groove sheets, there is no need to leave a gap between the plates. Coat the joints of the plates with glue and compact the sheets together using a mallet.

Plywood sheets should be additionally treated with antiseptics and drying oil.

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Which is the best plywood for flooring?

Plywood is a material that is great for creating and repairing various floor coverings. Its use opens up significant prospects for builders in arranging not only the finishing floor, but also the fastening of the subfloor. In this article we will try to figure out what kind of plywood you need to buy for the floor and what you need to focus on when purchasing this material?

The use of plywood sheets to create flooring can be explained by several circumstances. Plywood for flooring is inexpensive, looks great in the interior, and makes it possible to level the floor with the least amount of time and resources, which significantly simplifies the repair procedure. Plywood is perfect for both finishing works indoors, and for installing a base for finishing materials, as well as for repair work or eliminating small defects.

Most often, differences in floor levels in old apartments varies up to 10 cm, so the simplest option for laying the floor covering head-on cannot be implemented. And if you are going to lay laminate flooring or parquet tiles in your home, the site must be perfectly level. But those with a crooked floor should not be upset, because plywood is an excellent raw material for leveling the surface. This procedure can be carried out independently.

The main advantages of plywood include:

• naturalness of the material, because plywood, unlike OSB and fiberboard, is created from natural raw materials, and not from production waste
• Humidity levels range from 12 to 15%
• plywood takes the brunt of variable loads. As a result, the screed remains intact, but microcracks form in the wood. However, they have absolutely nothing to do with the quality of the floor
• Due to the fact that it is made from wood, it creates good contact with finishing materials. Consequently, the period of operation of the latter increases
• Using this material, you can obtain a floor covering that meets the specified parameters with less time and money.
• No special preparation is needed to lay plywood on the floor; this work can be carried out in several stages
• it acts as a certain kind of insulating material because it reduces heat loss through the base
• plywood sheets can be used to create both rough and finished floors, it all depends on the type and nature of processing.

However, this material is not suitable for rooms with significant temperature differences (for example, for summer houses or buildings for seasonal residence), as well as with high levels of humidity.

What kind of plywood to lay on the floor

When purchasing plywood at a hardware store, you need to pay attention to the following parameters:

• brand. For interior work, it is preferable to use FK grade material. Its level of moisture resistance fully satisfies the conditions of use in residential buildings
• emission class. Only class E-1 is suitable for creating a floor
• grade of material. In the process of creating a subfloor, it is permissible to use raw materials of grades 3 and 4, and for finishing - grades 1 or 2
• humidity level. Material with a moisture content of 12-15% is of high quality.
• number of layers. Veneer for plywood is used with a thickness of 1.7 to 1.9 mm. It is the number of layers that determines the thickness of the sheet. As the number of layers increases, strength increases. When creating a subfloor, a material with a thickness of 12-18 mm is used, and a finishing floor - 10-12 mm
• sheet dimensions. Floor plywood comes in format and large format. Dimensions are established by GOST. Size matters a lot for shipping and storage
• manufacturer company. Foreign and Russian companies sell raw materials decent quality. But material is often received from China negative reviews and often does not correspond to the stated parameters.

Based on the type of adhesive used, plywood sheets are of the following types:

• FC – has average resistance to humidity
• FSF – characterized by increased moisture resistance
• FBA is a non-waterproof material, but at the same time highly environmentally friendly
• FB is a material used in water.

Laying a subfloor is quite simple. This work takes little time and does not require special equipment. This can be done in several ways:

• the material spreads directly onto the concrete base using a special adhesive composition. In this case, it is imperative to leave a 3mm tolerance between the sheets so that destruction does not occur during operation. Because when room temperatures fluctuate, natural raw materials will expand or contract. This flooring option is preferable in rooms without differences in height
• If you are going to create an adjustable floor, then installing joists is not necessary. Height differences are eliminated using fasteners located under the plywood sheets
• The most tedious procedure is the creation of heated floors; in this work, plywood is laid on joists.

In addition to the subfloor, specialists even create palace parquet from plywood. However, in this case, it is necessary to use only 1st grade material, the front surface of which is carefully polished. To obtain a unique pattern, stain must be applied to the plywood, and the parquet must be thoroughly sanded and varnished several times.

In case if finishing coat There will be linoleum; experts do not recommend laying plywood on a plank base.

Experts recommend the two most suitable methods:

• If the old wooden floor is in satisfactory condition without serious flaws or creaks, it can be leveled with a sanding machine. Plywood fits perfectly on a wooden floor. Before this procedure, you need to recess the nail heads so as not to damage the device. Linoleum can be immediately laid on the base obtained in this way. FK material grades 3/3, 3/4, 4/4 are suitable for this work.
• if the old floor is very poor condition with rotten areas or dents. In this case, you need to dismantle the old base and lay 18 mm plywood on the joists. On such a base you can install anything, even artistic parquet. But do not forget to leave a compensation gap of 3-5 mm between the sheets. And the gaps between the logs must be filled with expanded clay for moisture and sound insulation.

Many people wonder: what kind of plywood to use for flooring? Craftsmen prefer to use FSF sheets due to their high moisture resistance. However, it is better not to buy this material, because the layers are glued with an adhesive composition containing phenol-formaldehyde resins, which can release phenol. This volatile compound will definitely penetrate the room and will not bring any health benefits.

Floor plywood FC is often produced square shape, so the material very often needs to be sawed. A jigsaw connected to an industrial vacuum cleaner is most suitable for this purpose. This way you can get excellent results. When using a fine-toothed hacksaw, the result may not be very beautiful.

Floor plywood is subject to heavy loads. If plywood is installed on a solid plank covering, the sheets will not sag. However, when mounted on joists, the support area is minimal, and the thickness of the plywood must be increased. Experts recommend the FC brand with a thickness of 15, 18 or 20 mm. Birch plywood is best suited because it is more durable than coniferous plywood. The gaps between the joists should not exceed 400 mm. And the thickness of the logs themselves should be more than 50 mm. The bars must be chosen intact and strong: material with defects must be immediately put aside and not used.

We hope that the material presented in this article will help you decide which plywood is best to lay on the floor.

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which one to use, lay it, what variety to choose, how to put it in photos and videos

Plywood is quite durable, and at the same time, a natural material. Unique mechanical properties are imparted to plywood due to a special manufacturing technology, which involves gluing an odd number of thin layers of wood veneer with perpendicular alternation of fibers.

Due to its low cost and high fracture strength, plywood has become widely used in construction. This interest is caused by the fact that for a long time in the past, plywood was, so to speak, the only finishing material that could be easily obtained. For this reason, many varieties and types of plywood have appeared on the market.

Types of plywood

Plywood is divided into types based on its scope of application: construction, furniture, structural, industrial, packaging.

The type of plywood is determined based on the glue used during production:

• FC is a water-repellent type of plywood. Its sheets are glued together using urea glue;
• FSF is plywood with enhanced water-repellent properties. In this case, the layers are glued with phenol-formaldehyde glue;
• FBA is ordinary plywood, the sheets of which are glued with albumin casein glue. Such plywood is afraid of moisture, but it is chosen because of its harmlessness to humans;
• FB is plywood created for use in special wet conditions, even in water. Such qualities are acquired by the material due to its impregnation with bakelite varnish.

Listed above are only the most famous types of plywood. There are additional classifications depending on the thickness, wood used, and surface quality.

Pros and cons of laying plywood on the floor

Advantages and which plywood is better for the floor:

• Plywood is a very environmentally friendly material made from natural raw materials, which cannot be said about fiberboard and OSB, which are industrial waste.
• Plywood moisture content does not exceed 12-15%.
• Due to its strength, plywood perfectly absorbs impacts. In the event of a strong impact, the screed will remain undamaged, and the plywood will only receive microcracks. This will not make the floor any worse.
• Plywood has excellent contact with various floor coverings because it is made of wood.
• A floor made of plywood will meet the required quality characteristics, while it does not require a lot of time and resources to manufacture, and you do not need to have special skills. It can be done step by step.
• In addition, plywood serves as a kind of insulation, protecting the room from the cold given off by the concrete base.
• Plywood – perfect solution when leveling a floor with large differences, since the screed in this case will be more expensive, and the base will significantly increase in mass.
• Many varieties of this material allow it to be used as a rough and finished floor.

The negative qualities of plywood include the impossibility of its use in rooms with strong temperature changes (cottages or houses with temporary residence) and excessive humidity (baths, saunas, baths and swimming pools).

Choosing plywood for flooring

In order to understand which plywood is best for the floor, you need to remember two things: important factors:

• What type of floor will be used will significantly clarify the situation, since it is impossible to choose plywood for the floor without taking this nuance into account, otherwise you may end up with a low-quality floor.
• In addition, the type of room itself will influence which plywood to use for the floor. For example, if the room is residential and there will be children in it, then it is recommended to use only FK grade plywood. It does not contain formaldehyde, therefore it is harmless. The main thing is that the humidity level in the room is maintained. If the plywood will be laid in a production facility with normal ventilation installed, then the best answer to what kind of plywood to put on the floor will be the FSF grade of 1st emission class. This class indicates the inclusion of formaldehyde no more than 100 mg per 1 kg of plywood board.

Plywood classifications

When deciding which plywood is best to lay on the floor, you need to navigate the following parameters:

• Plywood brand. As described earlier, FK plywood is ideal for living rooms with moderate humidity.
• Plywood class. That is, its emission, for the floor, only class E-1 can be used.
• Type of plywood. There are 4 grades, however, different sides of plywood sheets may differ in grade. For example, you can see the markings: 1/1, 1/2, 2/2 and others. For a rough base, grades 3 and 4 are suitable. For a finishing base, grades 1 and 2 are suitable.
• Humidity. For high-quality plywood varieties, the moisture level should be 12-15%.
• Number of layers. The veneer used can have a thickness of 1.7-1.9 mm. Plywood with more layers is stronger. This parameter determines where it will be used. For a rough coating you will need plywood with a thickness of 12-18 mm, and for a finishing coating - 10-12 mm. For installation of plywood in production, it is recommended to use plywood more than 25 mm thick (read: “What thickness of plywood is suitable for a floor”).
• Dimensions of plywood boards. There are small-format, large-format and format sheets. The dimensions of plywood boards are more important for transportation than for installation. Large sheets are more difficult to work with, but they can always be adjusted to the desired smaller size. The main thing is not to forget to number the cut sheets before installation, so as not to confuse them during installation. Experts recommend laying sheets with a shift.
• Manufacturer of plywood. Plywood samples are approximately the same in quality self-made, as well as from European manufacturers, which cannot be said about Chinese plywood, which is often negatively reviewed by buyers due to inconsistencies with the specified characteristics.

Installation of plywood on the floor

Laying as a subfloor

Using plywood as one of the types of subflooring is the simplest and most affordable solution.

• Laying plywood on a concrete floor is carried out in sheets 10-12 mm thick, which are glued directly to the base. It must be prepared and have an even coating. During the installation process, be sure to leave 3-4 mm gaps between the sheets, as well as a space between the sheets and the wall. This will allow the plywood to easily expand due to changes in climate conditions.

In addition, large differences in height can be leveled with plywood; the main thing is to arm yourself with special fasteners.

• If you plan to install adjustable floors, then logs will not be required; you only need special fasteners installed under the plywood.
• It is possible to lay plywood sheets on joists or floor beams. You will need slabs of at least 12 mm and a finished frame base. This kind of floor will require the most time to implement; it is necessary when you need to insulate the floor or raise it to the required height. Usage adjustable joists eliminates differences in floor heights.

Plywood as a leveling layer

Very often there are situations when the old floor has already lost its former appearance, but can still be used without problems. You can safely lay flooring on such a floor.

But if you don't want it to spoil ahead of schedule, it is worth installing an additional intermediate leveling layer of plywood.

Installation of plywood on a wooden floor is done using self-tapping screws. This process is quite easy and fast.

We have now figured out which plywood to choose for the floor in this case.

However, in order for it to last for a long time, you need to adhere to a number of rules during installation:

• the sheets must be fastened securely, do not forget about the gaps;
• the heads of the screws should fit under the countersunk;
• all irregularities should be removed with a grinding machine;
• all cracks and depressions must be puttied;
• Additionally, you need to lay the backing.

The only thing is that laying plywood is impractical if there is a wooden floor on top. Solid boards Such a floor can be laid both on logs and on a concrete floor.

Plywood as a finishing coating

Experienced specialists can make real palace-style parquet out of plywood. Typically, only the highest quality parquet was previously used for these purposes.

Currently, to achieve such a result, you need to take first-grade material with a polished front surface. To get a beautiful pattern, after laying the plywood is sanded and covered with stain and parquet varnish.

Processing, operation and storage of plywood

If during transportation the plywood accidentally gets wet, looks just damp and has not had time to swell, it should be dried as soon as possible. To do this, you need to leave it in a ventilated area, placing the sheets close to each other.

It should be remembered that FC plywood and its other types cannot be dried by direct exposure to heat - this can cause its destruction, it will most likely swell, or even worse, catch fire. The best drying is exposure to natural dry air.

If plywood is stored in an insufficiently dry place before starting work, it is better to check all sheets before starting work. Good plywood, which can be laid, should not have peeling or stains, which may indicate the spread of fungus over the surface.

If you want your floor to last for many years, you need to protect the sheets during the installation process.

When handling plywood you need to remember a few things: important conditions.

Need for acclimatization.

You cannot lay newly purchased material; it must be aged in the operating climate. This period depends on previous storage conditions: position, temperature and humidity.

If the difference between the previous and current temperatures, as well as humidity, is minimal, and the material was stored in a dry room and on a flat surface, then it will be enough to leave the material for a day. If the temperature difference is 5-8 oC, and humidity is 10%, then the plywood should be kept for 3-5 days.

If the difference is more significant than these values, and the sheets have slightly changed their correct, even shape, then the sheets will have to be kept for more than a week. However, to level the plywood, you will need to place something heavy on the stack, and during installation you will need to use more self-tapping screws than usual.

Dampness in the room

Rapid changes in humidity can dramatically damage wood material, in this case plywood. The humidity level in the room should be constant and not exceed 70%, and short-term increases should not exceed 80%. Do not place plywood on a wet floor.

To control the moisture content of wood, you can use a special device. To check a concrete floor, you need to take a plastic sheet and lay it down, slightly lifting the ventral part. If condensation forms, additional drying of the room will be required.

Installation temperature

It is ideal when plywood is laid at 20-30 °C. Such conditions are the most favorable for wood materials.

Material quality

It is very important to achieve the best operating conditions that the material is well processed. It is important to coat the sheets with an antibacterial primer, which will protect the plywood not only from microorganisms, but also from various fungi.

If you additionally impregnate the plywood with putty with the addition of PVA glue, this will improve its moisture-repellent properties. And opening it with acrylic varnish will enhance the strength characteristics of the outer layer.

In this article, you got acquainted with what type of plywood is best for flooring, what types there are, how best to store and install it. Properly selected plywood will not only simplify the installation process, but will also enable the future floor covering to last as long as possible. And the most important thing is that all work can be done without the help of specialists.

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

To make the floor high-quality and durable, you need to lay a backing under the floor covering. For this purpose, sheets of plywood are suitable, which will hide all the unevenness 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 varies in grade, thickness, moisture resistance and material of manufacture.

The main characteristics will help you choose the right sheets.

There are 4 types 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 production.
• The third grade is of better quality than the previous one and there is less defect on the surface.
• The second grade has minor cracks and is smooth.
• The highest quality and most expensive first grade is well polished, all sides are without defects.

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

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

For installation on the floor, take one-sided sanded material, laying smooth side upstairs.

Plywood is made from deciduous and coniferous wood (usually pine and birch). Wood veneer is bonded together using natural and synthetic resins. The top layer can be treated with a varnished water-repellent composition.

Based on resistance to moisture in residential premises, the following brands are distinguished:

In bedrooms and others living rooms with low humidity, FK and FBA brands are laid, made on the basis of urea and albumin casein glue. They are environmentally friendly and have average resistance to moisture.

The FSF brand is installed in the hallway and in the kitchen, where greater moisture resistance is required.

The thickness of the canvas is determined by the number of layers of veneer. An odd number of them are laid perpendicular to the previous one, creating a durable building material. For laying the subfloor, use plywood with a thickness of 10 mm and above.

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

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

OSB is divided into different categories:

• The first one is suitable for minimal load and dryness.
• The second is produced for low-traffic residential premises.
• The third is characterized by high moisture resistance and strength.
• The fourth is used in the construction of walls.
• Varnished or laminated – covered with a protective layer of varnish or laminate.
• Tongue-and-groove - has a connecting groove at the joints.

The best solution for the subfloor would be OSB 3, tongue-and-groove and easy to install. Such sheets are produced with a thickness from 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 covering has the following advantages:

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

Advantages of using oriented strand boards:

• Affordable.
• They don't delaminate.
• 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 types of coatings. The other negative side of moisture-resistant panels is environmental friendliness. They emit formaldehyde, which is harmful to health, but it is what helps fight moisture.

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

If you lay the flooring on joists, you lose up to 10 cm in the height of the room. 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 rework. It is recommended to fasten these materials using self-tapping screws with an average pitch of 20 cm.

Such sheets tolerate fasteners well and are tightly attached.

The price differences 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. The materials for fastening are also the same. In order to quickly and efficiently lay plywood sheets on a sub-plank floor, you need to stock up on basic construction equipment. In this work you will need:

• Level for measuring the evenness of the floor.
• Screwdriver or screwdrivers for screwing screws.
• Drill for drilling holes for dowels.
• Tape measure for measuring the required length.
• A jigsaw or hacksaw for sawing sheets of plywood to the required dimensions.
• Sanding attachment for a drill or sander for sanding joints between sheets.
• Roller or paint brush for applying primer.
• A broom or vacuum cleaner for cleaning up debris.
• Spatula for applying glue.
• Hammer for nailing.

To increase 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-dispersed adhesive bustilate or PVA. These brands are suitable for gluing wood surfaces. They are safe for health, odorless and dry within 24 hours. The glue is easily applied with a spatula or brush (depending on consistency).

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

Preparatory work

Before installing plywood on a wooden floor, basic preparatory work is carried out. First, the initial draft is assessed wooden base. Visually assess the condition of the floorboards, the presence of poorly fitted and creaky floorboards.

Check the building level for differences and surface unevenness.

Then the baseboards are dismantled. All loose boards must be additionally secured with nails or screws to the lower beam. Floorboards affected by fungus are replaced or cleaned, impregnated with an antifungal compound. Deformed and damaged boards need to be replaced. The protrusions on the surface are trimmed with a plane and sanded. Gaps and cracks are filled with sealant or glue.

After repairs, remove debris, sawdust and dust using a broom or vacuum cleaner. The untreated plank floor is treated with an antiseptic. Rolled 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 optimal solution for protection from moisture and fire is to treat both sides of the panel primer composition or acrylic varnish. The technology for laying wood sheets requires a distance of 1-1.5 cm from the wall between sheets of 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 first placed and adjusted, a layout diagram is drawn and the workpieces are numbered. Sheets should be laid offset to reduce the number of joints and avoid crossing.

If you follow all the rules when laying plywood, it will serve as a quality, durable base under any floor covering.

The finishing decorative material can be re-laid, but the plywood base will remain the same.

Alignment methods

The leveling method depends on the levelness of the subfloor. Differences in height of more than 1.5 cm require plywood to be laid over joists. Minor irregularities are covered with plywood directly onto the wooden floor.

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

Without the use of cushioning material it is applied glue method fastenings A small area of ​​the room is covered with 2-3 mm of glue, starting from the corner. A sheet of plywood blank is placed on top and pressed tightly. Additionally, you can screw in several screws for better fixation. This method is used to install the remaining part of the room.

Laying birch plywood does not require special skills and can be done with your own hands.

When a sheet of plywood does not lie flat, bends, or there are slight differences in height with other pieces, supports are used. The support points are placed in poorly fitting places and are fixed through and through with self-tapping screws.

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

To level out significant differences in height, logs are used. As logs, 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 joists depends on the thickness of the plywood and the load during operation. Small thickness requires a smaller distance between the logs, starting from 40 cm. You should not use sheets less than 1.5 cm in height. The installation of the joists is designed in accordance with the layout of the plywood in the room, so that the joints are laid in the middle of the beam.

The horizontal installation of the logs is measured by water or laser level. The evenness of the entire floor depends on the accuracy of installation. The logs are attached with glue and screwed in place. Between them, bars are placed perpendicularly, creating a reliable sheathing on which plywood blanks are laid.

Dry prefabricated floor screed is most often made from plywood sheets. It is believed that this is an ideal base for any type of flooring, including linoleum, laminate, carpet and even ceramic tiles. A high-quality and durable plywood floor on joists requires attention to the nuances and compliance with the basic rules specified in SNiP.

Plywood is a multi-layer wood-sheet material that is made by cross-gluing an odd number of layers of rotary-cut veneer. For production, birch raw materials are most often used or conifers technical varieties, less often - oak, beech, linden and others.

Advantages of plywood:

• high mechanical strength to any load;
• relatively light weight;
• low thermal conductivity coefficient;
• acceptable level of humidity (8–12%), which allows the use of some types of plywood in damp and unheated rooms: kitchens, bathrooms, balconies, loggias, etc.;
• use in combination with water- and infrared-type “warm floor” systems.

The disadvantage of sheet material is that the production uses adhesives that are unsafe for human health. As a rule, products are assigned an emission class of at least E1.

Plywood products are classified according to the following criteria:

Scope of application.

The areas of application of sheet material are limitless - from construction to electrical engineering. But to form a prefabricated screed or finished floor, it is recommended to use structural and construction varieties.

Brand.

This parameter is determined by the type of adhesive used. Let's consider three basic types:

• FSF (plywood glued with phenol-formaldehyde resin glue). The product is considered moisture resistant and is used for finishing rooms with normal and high humidity levels.
• FC (plywood glued using urea-formaldehyde glue). Refers to products with average moisture resistance, recommended for use in dry rooms.
• FBA (plate on albumin - casein glue). Positioned as a material of limited moisture resistance.

Variety

According to GOST 3916.1–96, products differ in the number of permissible defects and defects of wood, as well as defects during processing. There are five degrees of quality:

• E – extra or elite. The product is made of oak, alder, birch and other species, has a perfectly flat, smooth surface, without the slightest defects. Slight deviations in the structure of random wood are allowed.
• I – pin and healthy light or dark knots are possible – no more than 3–5 pieces. for every square meter of surface. Cracks (except for closed cracks) and other types of defects are excluded.
• II – healthy, partially fused, unfused and falling out knots with a diameter of up to 6 mm, wood inserts and open cracks up to 200 mm long and no more than 2 mm wide are allowed.
• III – there are: a) wormholes and holes from fallen knots with a diameter of up to 6 mm in an amount of no more than 10 pieces. per 1 m² of area; b) diverging cracks with a length of 300–600 mm and a width of up to 5 mm (subject to sealing with putties or sealants); c) dents and scallops.
• IV – surface with all kinds of defects: from fused and fallen knots without limiting the number to defects along the edges up to 5 mm deep.

For subfloors on joists, as a rule, sheet material of grade 1–4 quality is used. Please note: Plywood is usually double marked, such as 1/2 or 2/2. Matches the grade of each side. That is, a product of class 1/3 is characterized by the fact that one surface is assigned category 1, and the second - 3.

Nature of processing.

Sanded and unsanded plywood.

Plywood boards can be sanded or unsanded. Marked:

• Ш1 – processed only on one side.
• Ш2 – polished on both sides.
• NS – unpolished.

Laying the floor along the joists is done using slabs of any type. But common sense dictates that it is better to use products that are polished on at least one side. This will allow you to create the most even and smooth floor for installation of linoleum, laminate, etc.

Dimensions.

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

• 1525x1525 is the most commonly used size for floor joists. The amount of waste is small and convenient to transport.
• 1210x2440 – for leveling foundations in multi-story buildings standard series having elongated room shapes.
• 500x3000 - convenient for multi-storey or commercial new buildings, where the principle of studios or open plan is implemented.

The optimal thickness of plywood for floor joists depends on the type of prefabricated screed and the level of load. If you plan to install in two layers, then it is better to choose products with a cross-section of 8–12 mm, and for single-layer installation – 8–22 mm.

Joists and fasteners

According to SNiP 3.04.01–87 (SP 71.13330.2017) “Insulating and finishing coatings” are used to form the floor along joists wooden beam chamber drying, humidity 12–18%, without cracks, bark and traces of rot. In this case, the length of the joined supports must be at least 2 m, the thickness must be from 40 mm, and the width must be 80–100 mm.

Although many experts recommend purchasing slats with an aspect ratio of 1:1.5 and 1:2, in practice, logs of 50x40, 50x50, 50x70 and more are most often used. Moreover, the height of the supporting elements depends on various parameters: the load level, the cross-section of the insulation used, the maximum floor height and even the personal preferences of the customer. There are no universal recommendations; components are selected in each case separately.

To equip a load-bearing frame in apartments and private houses, you need the most even, durable timber made from inexpensive species: pine, spruce. If finances allow, you can purchase products made from larch, aspen, and alder that are resistant to changes in humidity.

Do not forget that wooden structural elements are not highly bioresistant. Therefore, they must be treated with fungicidal and hydrophobic agents. This will significantly increase the service life of the entire floor structure.

It would be useful to mention the support elements for the logs. Building codes do not recommend the use of wooden wedges and bosses due to the fact that the material easily changes shape with changes in humidity. When installing on a concrete or plank floor, mineral screed or point supports under the timber, it is better to lay strips of hardboard.

In practice, many craftsmen prefer to lay pieces of OSB, chipboard, MDF or moisture-resistant plywood on the floor. The minimum size of the lining should be 10x10 cm or 10x15 cm, the interval between them should be at least 30 cm.

Laying joists on glued plywood pads.

As an alternative, which is insensitive to moisture, you can use special support and fastening elements with an anti-corrosion coating, designed for the installation of adjustable floors.

Let's consider another important component of the floor structure - hardware. In addition to the joists, you will need fasteners to secure them to the base, as well as to attach sheets of plywood to the frame. These can be anchors, nails, universal or self-tapping screws, metal corners, etc.

The range of fasteners is huge. For fixing pads or directly to the joist concrete base Most often, dowels are used - nails with a thread with a diameter of at least 6 mm or metal anchors of a mechanical type. The former are cheaper, but the latter provide more reliable and durable fixation of the slats to the base.

An example of fixing joists to the floor with corners.

Anchor fasteners for concrete and brick are made of high-quality alloys - brass, stainless steel. It consists of a spacer or working sleeve (changes dimensions when forming a connection) and a non-spacer part - a rod. To mount the frame to the base, a hole is drilled in concrete with a diameter equal to the cross-section of the sleeve or 0.5 mm less than it. When driven or screwed in, the mounting post pushes the sleeve inserted into the channel. And due to this, it is firmly fixed in concrete.

The dimensions of the hardware product depend on the dimensions of the supports. For the installation of underlay elements made of chipboard, plywood, OSB, as well as wooden logs, products of category M 6 are most often used – M 12, that is, with a rod or wedge diameter from 6 to 12 mm. The length is selected based on the thickness of the joists and/or support supports, taking into account the depth of insertion into the concrete of 5 cm or more. The approximate interval between fasteners is 30–60 cm.

To rigidly attach shims or joists to wood subfloor, you can use wood screws with rare threads or universal galvanized ones with a diameter of 4 mm. The distance between hardware is at least 30 cm, screwing depth is from 30 mm.
To attach plywood to joists, it is most convenient to use special self-tapping screws for gypsum fiber boards and chipboards or universal galvanized ones. The first ones differ from the standard ones by mixed screw threads and notches on the cone-shaped head, which provide countersinking. The length of the hardware should be 2–2.5 times the thickness of the coating, the diameter should be 3.5 mm or more.

It is not recommended to use black hardened wood screws for plywood on joists. Practice shows that with seasonal changes in geometric dimensions, this type of hardware breaks under load, and the structure “loses” its rigidity.

You can also use regular nails with a cylindrical shaft and a sharp end. The efficiency and speed of work will increase several times if you use fasteners not in bulk, but in a cassette designed for nailing. The product is often aimed at the base or supporting frame at a distance of 15–25 cm.

Step-by-step instruction

To install a prefabricated screed yourself, you will need:

1. Sheets of plywood of suitable thickness.
2. Wooden logs.
3. Lining material for leveling the base.
4. Antiseptic primer.
5. Hardware.
6. Soundproofing and/or thermal insulation with components.
7. Repair compounds for partial restoration of damaged foundations.
8. Waterproofing.
9. Damper tape.
10. Silicone sealant or elastic wood putty.
11. Tape measure, marking pencil, metal ruler or lath.
12. Drill/screwdriver or hammer/nail gun (nailer) with accessories.
13. Laser or water level.
14. Spatulas, brushes, rollers.
15. Cutting tools with accessories for wood and plywood ( a circular saw, jigsaw, etc.).
16. Grinder machine.

The technology for installing prefabricated screeds is partially presented in SNiP 3.04.01–87 (SP 71.13330.2017) “Insulating and finishing coatings.” In accordance with the recommendations of these standards, installation is carried out in 4 stages.

Preparation

Any repair begins with cleaning the base from debris, dirt and dust. It is advisable to remove oil, bitumen and similar stains, traces of soot and soot from the surface.

No professional will begin work without partially repairing the damaged areas. Rotten, damaged elements of the wooden flooring must be replaced, and cracks and loose areas of the mineral base must be restored. To do this, you need to open up the cracks, remove dust and fill with repair compounds. If possible, it is better to clean off fragile sections, and smooth out the resulting pits using cement-sand, self-leveling and other quick-drying mixtures.

If necessary, the floor is waterproofed. It is needed if:

• it is necessary to protect the structure from residual moisture of the concrete base;
• there is a cold basement under the ceiling;
• the floor on joists is installed in the bathroom and the room located on the floor below should be protected from possible leaks.

To create waterproofing, the entire available range of materials is used: films, membranes, rolled adhesive products, coating compounds, painting agents, and the like.

In some cases, soundproofing of the base is required. According to the rules, the acoustic layer is laid between the base floor and the screed. Therefore, sound-absorbing mats are laid under the logs. If sound-insulating mineral wool (stone or glass) is used, then it must be laid in the openings between the joists, and the support rails themselves must be fixed using point acoustic pads.

Laying logs on acoustic pads.

It is advisable at this stage to treat the timber, bosses and other wooden structural elements with antiseptic impregnations.

Formation of a power frame

The frame of logs can be formed in the form of longitudinally located beams or as a single or double sheathing. Of course, the second option creates more reliable support for the plywood.

SNiP 3.04.01–87 (SP 71.13330.2017) recommends laying slats across the light flow, and in corridors and other rooms with a certain direction of foot traffic - perpendicular to the movement. Of course, in the future the frame will not be visible under the coating, but the essence of the advice is different. The developers of the building code determined that if the frame is formed across the most intensive movement of people, then the loads will be distributed over the majority of the supports of the load-bearing frame, and not among 2–3 elements. Or even worse - between them.

First of all, the zero mark is identified, relative to which the supports are aligned. Next, the beacons are mounted under the joists or the required level is stamped on the wall with thread and dye. But the most convenient way to construct a reference line is a laser level with a plane builder.

If sound insulation is required, before installing the supporting frame, it is necessary to lay acoustic material on the base: slabs, membranes, rolled products.

Now you can begin installing the logs, observing all the necessary gaps:

• Between the outer batten and the wall - at least 20 mm.
• Between adjacent supports - from 30 cm, but not more than 50 cm. We remind you: the higher the load on the floor, the more frequent the logs should be.
• Between the ends of one row – 0–0.5 cm.

For leveling, spacers made of chipboard, OSB, MDF, etc. are installed under the frame elements. After checking with a level, the bosses or backing boards are attached to the base dowel - with nails, screws or anchors.

Plywood linings.

Joists on wooden bosses.

To drill holes for hardware in underlay components, joists and plywood, you should purchase feather or special wood drills with a countersink.

Many craftsmen recommend laying damper layers on firmly fixed supports. Such a preventive measure will prevent the structure from starting to creak in the future.

The penultimate step is to fix the joists over the entire area of ​​the room using suitable hardware. Please note that a wide strip should be laid in doorways, which will protrude beyond the partition by 50–100 mm on each side.

For maximum leveling accuracy, you can use fastening and supporting hardware designed for adjustable floors. Essentially, these are powerful anchors that are installed in the floor slab. The adjusting nuts are screwed onto the main bolts, then the beam is placed and secured with a lock nut. The excess anchor rod is cut off with a grinder or a metal file.

If you plan to insulate the floor, then under the frame, in accordance with the manufacturer’s recommendations, you need to lay a vapor barrier. But after installing the logs, a suitable thermal insulation material is placed in the resulting “windows”: mineral wool, expanded clay, ecowool, linen or synthetic mats.

Laying plywood boards

The most controversial issue is the thickness and number of layers of plywood. There is no single correct opinion. It is clear that the higher the expected load on the floor (weight of furniture, intensity of foot traffic, etc.), the greater the thickness of the slabs should be and the smaller the distance between the joists. This will avoid sagging of the structure and its damage.

What type of flooring is best - single or multi-layer? There is no clear answer to this question. Each type has its own advantages and disadvantages. But the total thickness of the plywood flooring must remain constant - at least 18 mm.

Installation of slabs begins with their preparation. You should cut them to the required sizes, make cuts for communications or enclosing structures of complex shapes. Then a preliminary arrangement is carried out. The first row is laid out from the far corner along a solid wall.

If necessary, plywood sheets are adjusted, drilling points for hardware are marked with a distance from the edge of 2–3 cm and an interval between fastenings of 15–30 cm. An expansion joint of 0.4–1 cm must be maintained between the plates, as well as between the plates and the walls.

After one row of plywood is drilled and the sawdust is removed with a vacuum cleaner, the sheets are fixed with suitable fasteners. Start screwing in hardware experienced craftsmen It is recommended to start from the center of the slab, gradually moving diagonally to the edges, and then along the perimeter. This approach will straighten the plywood and avoid waves. Do not forget that the hardware must be “recessed” into the plywood by at least 0.2 centimeters.

The second and subsequent rows are laid in compliance with the rule that the seams are offset by at least 1/3 of the length. If plywood is installed in two layers, then the joint areas of the first layer should not coincide with the seams of the second.

Finishing the floor

After installation, professional craftsmen recommend “walking” the surface with a grinding machine with an abrasive attachment from 80 to 120 units to eliminate the slightest differences between the sheets. After this, the flooring is cleaned of dust and sawdust, and the seams are filled with sealant or elastic wood putty.

It is not advisable to use polyurethane foam for seams, as it begins to sag and crumble over time.

A plywood floor can be installed even without extensive work experience, sophisticated equipment or construction education. For clarity, we recommend watching videos from professionals.

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Plywood is a durable, multi-layer material made from natural wood. The physical and mechanical properties and technical characteristics of plywood are determined by the process of its production itself. Namely, an odd number of sheets of thin wood veneer are glued together using glue.

The veneer sheets are arranged in such a way that the direction of the wood fibers is perpendicular to each other. This makes the plywood very resistant to breaking, stretching and chipping (see table below).

Due to these parameters and affordable cost, plywood flooring is often used in construction.

Bending strength of plywood

Specification for plywood - table

Birch, coniferous, laminated and combined
(TU 5512-001-44769167-02 and TU 5512-002-44769167-98).

It should be noted that due to the fact that plywood for a long time remained almost the only material available to our compatriots, it was used everywhere. This, in turn, led to the emergence of different types and types of plywood.

Types of plywood

Types of plywood are determined by the scope of its purpose:

• construction;
• furniture;
• structural;
• industrial;
• packaging

Types of plywood depend on the glue used in production:

• FC- waterproof plywood. Kabamide glue is used in its manufacture;

• FSF- plywood with increased moisture resistance. Here the veneer sheets are glued together using phenol-formaldehyde glue;

• FBA- non-waterproof plywood. In this case, albumin casein glue was used to glue the veneer. FBA plywood has little moisture resistance, but is highly valued by those who prioritize the environmental friendliness of the material;

• FB- plywood, which, thanks to the use of bakelite varnish, can be used in particularly damp conditions and in water.

And these are just the main types of plywood. There are many more stages of classification, depending on the thickness of the sheet, the number of layers, type of wood, grade, degree of finishing and type of additional processing.

1. Using plywood for flooring “+” and “-”

Advantages of plywood:

• plywood, unlike OSB and fiberboard, belongs to natural materials, and not recycled production waste. Therefore, it is more environmentally friendly;

• plywood moisture levels are in the range of 12-15%;

• plywood takes the brunt of variable loads. Thus, the screed retains its integrity, and the wood receives microcracks. However, they do not affect the quality of the floor;

• Due to the fact that plywood is made from wood, it has better contact with floor coverings. As a result, the service life of the latter increases;

• plywood makes it possible to obtain a floor that will meet the specified characteristics (flatness, surface quality) with less time and resources;

• laying plywood on the floor does not require special preparation and can be performed in several stages;

• plywood plays the role of a kind of insulation, allowing to reduce heat loss through the concrete screed and floor slabs;

• If there is a significant difference in height across the floor, the use of a screed is not recommended due to its high weight and cost. But plywood, on the contrary, would be an ideal option;

• Depending on the grade and quality of polishing, plywood can be used for rough and finished flooring.

But:

• plywood is not suitable for rooms with a significant temperature difference (for example, for dachas or houses of non-permanent residence), as well as with a high level of humidity (in a bathroom, bathhouse, sauna, swimming pool).

2. What kind of plywood to lay on the floor

To begin with, it is worth clarifying two important factors.

• First point - what type of floor is plywood intended for?. After all, the floor, in fact, is a two-layer structure, which consists of a rough (underlay) and a finishing (front) layers of coating.

• Second point - in which room should I lay plywood?. So, for example, in a living room, and even more so in a bedroom or children’s room, it is permissible to use only FK plywood. It contains no formaldehyde. Consequently, its use is absolutely safe, with satisfactory moisture resistance. IN production premises with good ventilation, it is permissible to use FSF brand plywood. But only 1st emission class. The class means that the formaldehyde content does not exceed 100 mg. per 1 kg. sheet of plywood.

Depending on the above points, the question of which plywood for the floor is better (which one to use for the floor) will be decided.

3. Which plywood to choose for the floor

When choosing plywood for the floor, you should pay attention to the following parameters:

• plywood grade. As already noted, for residential premises it is better to purchase FK brand plywood. Its moisture resistance indicators fully meet the operating conditions in residential premises;

• plywood class(emission class). Only class E-1 is suitable for flooring;

• grade of plywood for flooring. Plywood is divided into 4 grades. In this case, the sides of the sheet may have different grades. It is marked as 1/1, 1/2, 2/2, etc. Plywood of grades 3 and 4 is suitable for the subfloor. For finishing - 1 or 2 grade;

• moisture content of plywood. A quality sheet is one with a moisture content of 12-15%;

• number of layers of plywood. The thickness of the veneer in a sheet of plywood ranges from 1.7 to 1.9 mm. Consequently, their number determines the thickness of the sheet. The more layers a sheet has, the more durable it is. However, the thickness of plywood is selected taking into account its purpose. So for a subfloor you need plywood with a thickness of 12-18 mm, for a finishing floor 10-12 mm. When using plywood in production - at least 25 mm. Please note that if plywood is laid in two layers, then the thickness of the sheet should be divided into two;

• plywood manufacturer. European or domestic manufacturers offer material good quality. But Chinese-made plywood causes complaints from users and often does not meet the stated characteristics.

4. Laying plywood on the floor

4.1 Plywood for subfloor

Laying a subfloor made of plywood is the fastest, most affordable and easiest way, which also has several varieties.

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Sheet 10-12 mm thick. glued to the base. It is used when there is a smooth concrete screed of normal quality. The main thing is not to forget about expansion joints when laying. The gap is 3-4 mm. between the sheets, as well as between the sheet and the wall, will allow the plywood to play and adapt to its surrounding conditions.

This installation method can be used when there is a difference in height. It is enough to use special fasteners.

Adjustable floors made of plywood do not require the installation of logs, and the height difference is leveled by fasteners located under the plywood.

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Laying plywood on joists or floor beams.

Plywood, thickness over 12 mm. mounted on a prepared base. The method is labor-intensive, usually used when it is necessary to insulate the floor or raise it to a certain height.

allow you to install a sheet of plywood so that it can compensate for the height difference across the floor.

A fairly common situation is when you have partially lost appearance, but nevertheless do not cause any complaints. Then the flooring is laid on top of them.

But to prevent the finishing coating from becoming unusable, an intermediate floor (in this case, plywood) should be laid on the boards, which will level the surface.

Laying plywood on a wooden floor is carried out using hardware and is characterized by simplicity and high speed of work.

In order for plywood laid under laminate, under linoleum or to perform its functions for a long period, you must adhere to the following installation rules:

• securely fasten all sheets taking into account deformation gaps;

• “drown” the heads of the hardware into the sheet;

• remove irregularities using a grinder;

• fill in depressions and cracks;

• lay the substrate.

But laying plywood under a wooden floor is absolutely not required. Due to the massiveness of the floorboard, it can be laid on joists or on a flat concrete screed.

4.3 Finish plywood floor

Craftsmen can create real palace parquet from plywood. In this case, special requirements are put forward for the quality of plywood. Only the first grade can be used; the surface of the front side of the sheet must be polished. To create a beautiful pattern, the plywood is treated with stain, and the laid plywood parquet is sanded and covered with several layers of parquet varnish.

5. Plywood for flooring - protection, operation and storage

In order for a plywood floor to serve you faithfully for a long time, you need to provide protection for the sheets at the installation stage. When working with plywood you need to consider:

• plywood needs acclimatization. Only the purchased material should not be used immediately. It needs to be given time to rest in the conditions in which it will be used.

  The holding period depends on where, how, in what position, at what temperature and humidity level the plywood was stored. The acclimatization period can be:

• day. If the difference in temperature and humidity at the place of sale and installation is minimal, and the sheets were stored in a dry room, on a flat surface in a horizontal position;

• 3-5 days. If the difference exceeds 5-8°C and 10% (temperature and humidity, respectively);

• over a week. If the deviations are significant or the sheets are slightly deformed. The latter can be eliminated by pressing down the stack of sheets with weights and using more hardware per 1 square meter. leaf.

• dampness destroys plywood. Rapid fluctuations in humidity can cause serious damage to the wood from which plywood is made. At the same time, constant humidity in the room cannot be higher than 70%, and short-term - 80%. Laying plywood on a wet base is unacceptable. To check the moisture level of a wooden base, use a special device. And concrete is covered with film for a day. The presence of condensation under the film indicates that it is worth holding off on installing the plywood;

• plywood sheets are laid at a temperature of 20-30°C. In this case, the leaf is in optimal conditions;

• additional processing improves the performance characteristics of plywood. For example, an antibacterial primer will protect the sheet from the effects of fungi and microorganisms. Impregnation with PVA-based putty will increase its moisture resistance. And applying acrylic varnish will increase the strength of the surface layer.

Conclusion

Having become familiar with the types and types of plywood for flooring, as well as the nuances of its selection, storage and installation rules, you can confidently say which plywood is best suited for flooring.