All photos from the article

In order to figure out how to properly assemble a plywood floor, you must first determine whether it will be a face covering or a base for another material. In addition, the material can also be the bottom layer of the floor, intended for subsequent installation of insulation.

Also great importance has a base - it can be concrete or wood (joists or boardwalk), which will change the way the panels are attached. And, of course, the type and brand of plywood is of great importance - we will talk about all this in detail below, and also watch the video in this article.

Plywood floors

Note. Plywood is a fairly durable material, although it is made from thin pine or birch veneer. Two factors give it strength - gluing layers with a perpendicular orientation of the direction of the fibers to each other, as well as impregnation of the veneer (the price of the product depends on the type and brand of sheet).

Material selection

Much about technical properties such construction material says its marking, which is written as an abbreviation. The table below shows the characteristics of the most popular brands, any of which you can use in this case. In this case, the purpose of the room (level of constant or periodic air humidity) should be taken into account.

Marking	Impregnation	Features and where to use
FBA	Albumin casein glue	Due to low moisture resistance, it is used only in dry rooms
FSF	Phenol-formaldehyde glue	It has relatively high wear resistance and high moisture resistance. The most popular brand. It is also used for roofing work
FSF-TV	Phenol-formaldehyde glue and flame retardants	To all the advantages of FSF is added the low flammability of the material
FC	Urea glue	Low water resistance. Typically used in the production of furniture, packaging and interior work
FB	Bakelite varnish	Very high moisture resistance and resistance aggressive environment. Can even be used underwater
BS	Alcohol-soluble bakelite glue	Aviation plywood of the highest strength, elasticity and water resistance. Previously used only in the installation of aircraft and ships
BV	Water Soluble Bakelite Glue	In terms of strength, the same qualities as BS with the exception of water resistance
FOF	Phenol-formaldehyde glue	It has all the qualities inherent in FSF, that is, this is FSF, only with laminated coating. Thanks to the ability to create different colour, it is used as laminated plywood for furniture. It is also very good for installing construction formwork

Table technical characteristics the most popular brands

Assortment:

• as you see on top photo, all products of this kind are classified into varieties, of which there are a total of 5 categories;
• this is the 1st, 2nd, 3rd and 4th grade, as well as the highest category E (elite), where the instructions according to GOST 3916.1-96 do not allow a single natural defect in the wood and a single manufacturing defect;
• for the front covering you, of course, need to use sheets of at least 2nd grade, but rough foundation The 3rd and 4th grades are quite suitable.

Surface treatment:

• in addition to markings on the adhesive or varnish composition, there is also marking on the surface treatment of the panels, which is written in the accompanying documents as Ш1, Ш2 and НШ;
• this means a surface that is sanded on one side, on both sides, and not sanded at all, respectively.

Thickness:

• The thickness of the sheet will depend on the number of layers of veneer that were used for gluing and there are three categories of panels, these are:
• three-layer;
• five-layer;
• multilayer.

Here you can also pay attention to such a parameter as the thickness of the plywood on the floor; it can be from 3 mm to 30 mm. But if you use a thin, 3 mm or 5 mm sheet, then the screed should be perfectly flat, without any drops or dents. Fix thin panels to concrete floor This can only be done with glue - dowels and screws will not work here.

Note. If you laid a warm floor on plywood, then its thickness should be minimal, since wood is a poor conductor of heat. The sheets are naturally fixed with glue.

Laying on plank floors

The above shows how to lay plywood on a floor made of boards - and in this case the installation process is the easiest, and the sheets are fastened using self-tapping screws. If the floorboards are good and dense, then a 3 mm thick panel will be enough for you.

However, if they are rotten, then, of course, they will need to be replaced with new ones. If there are mechanical defects on the surface, then the thickness of the plywood should be at least 10-12 mm or more.

Laying on joists

If plywood is laid directly on the joists, then the distance between them will depend on the thickness of the sheet and vice versa. And the section of the beam is selected according to the span length - see the table below.

Do not forget that the base for the logs must also be rigid - it can be a concrete screed or ceiling, as well as supports made according to the principle columnar foundation. Sometimes, in order to level the beams, the joists are covered with thick boards on top, as shown in the top photo. This method was used in almost all houses built during the reign of Stalin, Khrushchev and Brezhnev (“Stalinka”, “Khrushchevka” and “Brezhnevka”).

Panel thickness (mm)	Lag pitch for plywood (mm)	Span length (mm)	Log section (mm)
10	150	2000	110×60
12	200	3000	150×80
15	200	4000	180×100
18	250	5000	200×150
21	300	6000	220×180
24	400	—	—
27	450	—	—
30	500	—	—

Distance between lags and their cross-section

In addition, the bottom floor is often laid from plywood, on which the insulation is mounted. Look at the top image - there is a board drawn as such a base, but it can also be any sheet material, including OSB and plywood.

And what kind of insulation can be put under the plywood depends on your desire and technical capabilities.

It could be:

• expanded clay;
• mineral wool of any type;
• Styrofoam;
• extruded polystyrene foam or isolon (foamed polyethylene);
• as well as any type of substrate.

Sealing seams

Now let's figure out how to seal the seams between the plywood on the floor. The material for this purpose can be fugenfüller or, in extreme cases, tile adhesive.

If you use wood putty, then it will be enough to clean the treated area from dust and dirt, after which you can immediately apply the putty mixture. But if it is fugenfüller or tile adhesive, then it would be best to go through these cracks twice, as the composition may crack.

Attention! At the joints, the edges of the plywood may turn out to be unequal in height. Therefore, before sealing cracks or laying a finishing coating, you need to level them yourself using a belt or disk sander.

Conclusion

Laying a floor from plywood sheets is quite simple, if, of course, a good (flat and rigid) base is prepared for it. If you still have any questions, ask them in the comments, we will be happy to help!

Plywood, like many other materials, can be puttied. However, it is important to choose the right putty mixture. Putty for plywood must have special qualities, the most important of which is water repellent properties. This article will discuss the features of plywood processing and choosing the appropriate composition for these purposes.

Properties of plywood

Classification of plywood involves division by grade, mechanical characteristics, elasticity and moisture resistance. A letter marking for the material has been developed, which must indicate the type of glue used to impregnate and secure the veneer during the production of the product.

Plywood characteristics:

1. IN Russian Federation standards provide for the production of plywood of the following sizes (in millimeters): 1525x1525, 1220x2440, 2440x1220, 1250x2500, 2500x1250, 1500x3000, 3000x1500, 1525x3050 and 3050x1525. Thickness plywood sheets can fluctuate between 3 and 30 millimeters.
2. For the production of plywood, birch wood or coniferous species trees (pine, spruce, larch). The veneers are glued together perpendicular to the location of the wood fibers.
3. Each type of product is assigned a specific label: FSF, FBA, FSF-TV, FB, FC, BS and BV.
4. The following grades are suitable for puttying purposes: FSF, FSF-TV, FK, FB and BS. The fact is that these products are characterized by increased moisture resistance, which is an indispensable condition when selecting a material suitable for puttying.
5. Plywood is also classified according to the degree of processing. Laminated and non-laminated varieties are available. Products polished on one side are marked as Ш1. Double-sided grinding is reflected in the marking Ш2. If the slab has not been sanded at all, it is marked as NSh. Of all the listed varieties, unlaminated and unsanded plywood is most suitable for puttying.

Purposes of puttying

Plywood structures are often used for leveling different types surfaces when carrying out repair work. Installation of plywood sheets is carried out on the floor, walls and ceiling. However, without additional procedures, the seams between end-to-end sheets do not look very attractive, and the surface of the material itself is not even enough to lay linoleum on top or glue wallpaper. It is puttying that allows you to create ideal flat surface and hide interpanel defects.

It would seem that puttying is an obvious solution. However, many craftsmen wonder: is it possible to putty plywood, because we're talking about about wood? The fact is that such doubts are justified, since humidity provokes rotting of wood, the development of mold and mildew on it, which gradually leads to the destruction of the material.

There is a way out if for processing you use not the first putty you come across, but a special one - made taking into account the characteristics of the wood. With the help of such compositions, you can eliminate all the problems inherent in plywood sheets without damaging the material. The putty contains moisture-protective agents, which allows the production of mixtures even on a water basis. In addition, thanks to the addition of an antiseptic, the putty is also able to resist the development of fungus and mold.

Types of mixtures

For the right choice putty composition matters whole line factors. The requirements for surfaces before wallpapering differ from the requirements before painting, since in the latter case the composition should have a more delicate effect on the surface. In addition, it is necessary to take into account the humidity in the room and temperature changes (for example, cement putty does not tolerate sudden changes in temperature).

Putty compounds are sold in one of two states:

• powdery;
• V finished form(viscous solution).

Most often, dry putties are used to process plywood. Such compositions are more convenient to transport, and their consistency can be adjusted during kneading to the desired degree of viscosity. Dry mixtures are packaged in bags of different capacities.

Solutions are also produced that are completely ready for use. These mixtures are based on various dispersions, as well as polymers in the form of latex or silicone. Polymer materials have a number of significant advantages, which will be discussed in more detail below. The main advantage ready-made compositions is precisely their complete readiness, since there is no need to spend time and labor on preparing the mixture. Flaw ready-made solutions- significantly higher cost compared to powders.

Answering the question about how to putty plywood, it should be said that the main differences between different putties are the base material.

For plywood puttying, mixtures based on the following components can be used:

• gypsum;
• polymers;
• cement;
• glue.

Below we will tell you a little more about different types putty:

1. Gypsum mixtures are characterized by the simplicity of their composition and the absence of shrinkage. However, putties of this type are not flexible enough, as a result of which there is a risk of cracks at the seams due to insufficiently reliable fastening of the plywood sheets. To the disadvantages gypsum putties This can also be attributed to the rather high cost and frequent defects.
2. Cement mixtures are characterized by fairly high moisture resistance. A significant disadvantage of cement is its tendency to shrink and lack of elasticity. The negative qualities listed above appear especially clearly in hot weather and sudden temperature changes.
3. Putty mixtures for polymer based are most suitable for working with wood. Polymer compositions are characterized by high moisture resistance, and therefore plywood treated with such putties can be used even in damp rooms. Polymers do not shrink, have the highest elasticity, resistance to vibration and mechanical stress. All polymer putties are sold only in finished form (packaged in containers weighing from 3 to 20 kilograms). There are two types polymer compositions: based on acrylic (silicone) and latex. Putties in this group are also divided according to their scope of application: for interior finishing and for facade treatment. The only significant drawback of using polymer compounds is the high cost of purchasing them.
4. Adhesive putty is the result of DIY production at home. This composition is prepared by mixing PVA glue with crushed wood dust in a certain proportion. Adhesive compositions They are characterized by high moisture resistance and elasticity. Advantage self-made It is also possible to bring the solution to the desired consistency. In addition, the cost of such a composition is significantly lower compared to factory-produced putty.

Impregnation with drying oil or PVA

Before laying linoleum on plywood, it is recommended to improve the properties of the base in advance. Puttying plywood under linoleum is carried out by impregnating the material with drying oil or PVA. The impregnation process requires a certain time (usually several days), since the technology provides for the complete drying of all layers, impregnated sequentially one after another. In addition, drying is not forced in any way and occurs naturally.

Note! PVA is applied to plywood without forced acceleration.

When the plywood is impregnated with PVA and dried, it is the turn of the antiseptic, treatment with which helps prevent the development of fungus and mold. Next, the material is coated with acrylic varnish.

Another option for strengthening plywood before puttying and further laying linoleum is to soak the veneer with heated drying oil. Using a water bath, the drying oil is heated to 50-60 degrees Celsius (the temperature should never be exceeded). Heated drying oil is applied to the surface of the material with a roller or brush. Next, the plywood dries at 200 degrees above zero or under the influence of a construction hair dryer. The procedure is repeated again and again - until the plywood retains the ability to absorb drying oil. Impregnation can be stopped as soon as large drops of drying oil begin to linger on the plywood.

Note! Special attention when impregnating, it should be given to the end sections of the sheets, since these are the places that are most vulnerable to external influences.

Padding

When the plywood is laid out on the floor, it needs to be primed. Unlike the impregnations discussed above, which are aimed at protecting against rotting, primer is considered as a way to improve the quality of putty. The fact is that priming allows you to increase the adhesive qualities of the surface (adhesion is the ability to adhere to dissimilar materials). In addition, the primer forms a protective barrier against too much deep penetration paints and varnishes into wood structure.

Note! Puttying is allowed only after completely dry primers.

As in the case of putties, specialized primers designed specifically for wood processing are used for priming. A feature of such compositions is the presence of special components in them, including antiseptics.

So, before you putty the plywood, it needs to be primed. The material is first cleaned of dust, dirt, oil stains and any other contaminants. Primer can only be applied to clean natural veneer.

Next, a primer is applied to the plywood, for which you can use a brush or roller. After this, you need to let the surface dry. Drying time depends on the humidity and air temperature in the room. On average, drying will take from 3 to 6 hours.

Puttying

Applying putty to plywood is carried out according to the same principle as to concrete or brick. The tools you will need are a spatula, a rule and a small spoon. Particular attention should be paid to joints (Fugenfüller is used for this). The normal thickness of the putty layer is 2-3 millimeters.

If small grains remain on the coating after finishing the putty, they should be removed with sandpaper as soon as the surface is dry. However, this development of events can be prevented if you sift the solution through a fine sieve or nylon in advance. Once the surface has completely dried, you can begin further finishing work.

Puttying work with plywood is not much different from processing other materials. However, it must be remembered that any wood is vulnerable to moisture, and therefore needs protective measures, which we discussed in our article.

Plywood, depending on the type and quality of finishing, can be used both for leveling surfaces, including floors, and as a finishing material. But the point is what remains natural material, and for a long service life it is necessary to leave technological gaps between adjacent sheets. During the process of installing the floor, the question may arise as to what is the best way to seal the seams so that this has a positive effect on the quality and durability of the floor covering.

The choice of material for sealing seams depends on several points:

• From the material that will be used as a finishing decorative finish
• From the thickness of the gap, if the plywood has already been laid and you have to choose based on the available data
• From the characteristics of the room itself in which the renovation is being carried out.

Before you start sealing the seams themselves, you first need to carefully prepare work surface. The most important step at this stage is sanding the seams to be sealed. The softer and thinner it will be finishing, the better all defects will be visible on it.

Even small gaps in the seams can cause a lot of trouble in the future if there is linoleum or even a more durable and thick material on top

The easiest way to bring sheets of plywood and the joints between them to the required condition is by using grinder. This tool will allow you to quickly remove all unnecessary irregularities and joints from the surface. If you don’t have a sanding machine, then these same steps can be done manually, but it will take much more time.

How to seal the seams?

The most significant criterion when choosing putty for joints is its elasticity. Since the sheets of plywood still cannot be secured perfectly firmly, the dry and non-elastic putty will quickly crack over time and begin to fly out of the seams. This will quickly render the floor unusable and the work will have to be done again.

When caulking seams, you should follow several rules:

• • It is best to use acrylic putty showing top scores when working with plywood.

• • If there are wide and deep seams, the composition is applied in several stages, and each time you need to wait until the applied layer has completely dried.

• • Silicone putty can only be used for small seams. These compounds are too soft, and under heavy load they can simply be pressed through the seams without achieving the required effect.

Since you have decided to seal the ceiling with plywood, you should know that the plywood must be impregnated with waterproof agents, since with minor fluctuations in air humidity, the plywood will expand and contract, so any seams will subsequently crack and stopping this process is quite difficult, so any advice maybe bad...

So what should you do if you have already installed sheets of plywood on the ceiling and now you need to cover the seams?

We take acrylic sealant and carefully pour it into the joints between sheets of plywood or plywood and the wall, without allowing the sealant to dry, level it with a spatula. After the sealant has hardened, it is necessary to seal the seams with sickle tape and paint them with a special rubber paint which has the properties of stretching and contracting. In this option, the novelty of the ceiling can be preserved longer....

In my opinion, and application in practice also showed that the use acrylic sealant not a reliable remedy. Firstly, the sealant requires further finishing, and secondly, after six months, when the sealant dries well, it will turn yellow and crack (checked several times). I suggest regular silicone, namely silicone, not silicone sealant, but pure construction silicone which smells strongly of vinegar. It is silicone that will hold the sheets of plywood together well and hermetically, and most importantly, will fill the seams for a long time, after hardening, providing elasticity to the seams and eliminating the creaking and cracking sounds of plywood during deformation under the influence of external factors.

It would be better to sew such a ceiling directly onto plywood without any frames in sheets moisture-resistant plasterboard 8 mm, so that the seams of the plywood sheets are tied with VGKL sheets. And then further finishing of such a ceiling for painting. There will be no cracks 100%. And if you also seal the drywall completely with fiberglass and putty with Shitrok, and sand it under the light bulb, then you can forget about the cracks forever

How can I seal the seams on a plywood floor under linoleum?

And so I'll give you one interesting way when the seams will not show on the linoleum and the plywood itself will not deteriorate for a long time. When the entire floor has been treated with a primer, let it dry thoroughly; to do this, you can put a fan in the room so that the air circulates throughout the day quite sufficiently. Then knead epoxy resin with wood dust in a metal container, then the resin must be heated to 40 degrees so that it becomes liquid and fluid, and only then we begin to fill the cracks and other flaws on the plywood. Then we let it harden for a day and you can start sanding. All linoleum will fit perfectly and in the future there is a full guarantee that the seams will not come apart or crack.

Before you begin laying linoleum on plywood, you must carefully prepare the surface of the plywood. To do this, it is necessary to seal it with putty for wooden products all existing seams at the joints, small cracks, and dents in the plywood, if, of course, there are any, can be filled with silicone sealant.

In addition, the plywood must be treated with a special antiseptic, which is included in the primer.

And only after the plywood has dried after all processing procedures can you begin the direct installation of linoleum.

But before doing this, do not forget to make sure that the entire surface of the plywood is smooth and clean.