Installation of a log on a concrete floor under plywood. Technology of laying plywood on logs. Floor preparation and priming

Repair in the apartment or in country house is essential to most people's lives. And one of the most common problems problems that have to be addressed in this regard are cold or insufficiently level floors. There are several ways to get out of this situation, one of them is to make plywood floors along the logs. With their own hands, this will be implemented or with the help of specialists, each property owner decides at his own discretion.

What are lags?

Logs are special wooden or polymer bars or pieces of a metal profile laid on concrete base, on top of which the base for the floor is laid. Metal is much easier to work with and more durable than wood. But there is one significant drawback - metal, unlike wood, is critical to changes in ambient temperature, which can cause the floor to warp. Plus, they'll be cheaper.

It should be noted that conifers, especially larch, are the most suitable for the manufacture of logs. Details must be of the correct geometric shape, even and without bends along the entire length.

The choice of material for the base

In order to level the floor with plywood along the logs with your own hands, you need to choose the right material, since not every type of it is suitable for this. There are such types of leveling sheets for the floor:

Plywood is a multilayer material, the number of layers starts from three.
is an excellent material for leveling a wooden floor for subsequent tiling. It is made from shavings and Portland cement with the addition of chemical ingredients.
Oriented strand board (OSB) is a multilayer material in which the chips are glued together with resins with the addition of synthetic wax. Environmentally friendly, but flexes more easily than plywood and is slightly more expensive.
(chipboard) has the lowest rates of strength and environmental friendliness.
Fibreboard (MDF) - a material made by hot pressing wood fiber, very flexible, fragile.

Based on the listed properties of materials, we can conclude that do-it-yourself plywood flooring in a private house is best done from OSB, DSP or plywood.

About material

Plywood is the most acceptable option. It consists of sheets of veneer glued in a special way: in each new layer, the fibers are perpendicular to the fibers of the previous one, which significantly increases rigidity. Plywood differs in terms of moisture resistance, durability and environmental friendliness, which depend on which binder material was used in production:

The FK brand is made using carbamide glue, it is poorly resistant to moisture, and swells quickly. But it is safe for humans, can be used in rooms with low humidity.
The FSF brand contains phenol-formaldehyde glue, it is moisture resistant, but not environmentally friendly due to phenolic emissions.
Brand FB - bakelized plywood, resistant to moisture and aggressive environments.
FOF is a laminated (layer-pressed) material called a laminate. Used as decorative finishes gender.

To make a plywood floor along the logs with your own hands in the country or in the apartment, the best way plywood of the FK and FSF brands from birch with a thickness of ten to fifteen millimeters is suitable.

Benefits of plywood flooring

The device of such a floor has a number of undeniable advantages:

strengthening of soundproofing characteristics;
increase in thermal insulation qualities;
high-quality quick insulation of the floor by laying heat-insulating material between the lags;
ensuring uniform distribution of pressure on the base;
the presence of an empty space between the lags makes it possible to locate various communications in it;
quick leveling of the floor surface;
good strength characteristics of the coating;
the possibility of easy replacement of damaged parts;
even a beginner without special skills will cope with the work;
plywood floor installation on logs does not require specialized heavy equipment or tools.

Preparing for styling

Mandatory measures before laying the floors should be:

ground inspection;
thorough cleaning of large irregularities;
filling gaps and cracks;
floor waterproofing.

Whatever the coefficient of moisture resistance plywood or any identical material has, it has a certain hygroscopicity, which leads to the absorption of some moisture. Therefore, the main stage of preparation is waterproofing. It is usually performed with a thick plastic film (in the simplest case) or with a special coating. The concrete floor is completely covered with material, with a slight overlap on the walls. And so that after the film spoke for her. Parts of the waterproofing at the joints are fixed with construction tape.

To install floors on plywood logs, galvanized hardware is used for fastening with a length that is three times the thickness of the sheets to be fixed.

Which is better: two thin coats or one thick coat?

Plywood is composite material. The layers in it are arranged with fibers crosswise to achieve sufficient rigidity and strength. Based on this, it becomes clear that in order to improve such characteristics, it does not matter at all how many layers will be laid - two ten-millimeter instead of one twenty-millimeter or large quantity. And there won't be a particularly big gain in price.

But when leveling very curved floors, the number of layers plays a significant role here. When laying one layer, the irregularities will, of course, be smoothed out, but differences will remain at the joints of the plywood sheets. This is where a properly laid second layer will help - the joints of the plates of each of them will coincide with the center of the plates of the other layer.

Conclusion: to insulate a flat base, you can mount plywood floors along the logs with your own hands in one layer with sheets twenty millimeters thick. When leveling a curved base, two ten-millimeter layers with staggered plywood boards are best suited.

Do-it-yourself plywood floors on logs: logs and crates

The sequence of steps in this stage is as follows:

To perform the installation, dried flat bars with a section of 10 x 5 cm and a length of at least two meters are used. In addition, they must be aged indoors for two weeks.
Waterproofing is laid on the prepared base, and the bars are treated with an antiseptic.
When installing the log, an indent is made from each of the walls by 25 mm.
To neutralize irregularities, MDF or fiberboard substrates with a square side of 20 cm are used, and linoleum pieces are used to suppress noise. In places where there are substrates, the logs are attached to the cement base with anchor bolts. When laying between the lags, a distance of 40 cm is left.
When all the logs are mounted, they proceed to the device of the crate. Its slats are also installed on substrates with fastening to the floor and logs with self-tapping screws at a distance of no more than half a meter. It is important that the size of the crate matches the parameters of the plywood sheets.
The resulting cavities in the crate are filled with insulation and sound insulator.

Dimensioning, fastening

In order to properly arrange plywood floors along the logs with your own hands (the photo of the actions is presented in the article), it is necessary to cut the plywood into sheets of the desired size, optimally 1250 x 2500 mm. For convenience, they can be numbered.

In order to exclude the possibility of creaking during further operation, strips of glassine are attached to the logs before laying the plywood with a stapler.

Sheets are laid across the log, fastening with screws at a distance of 15 cm. At the joints, the screws are placed in a checkerboard pattern at a distance of 10 mm from the edge of the sheet.

During installation, a gap of about a third of a millimeter is left between the sheets, which is then filled with sealant or elastic mastic and glued with moisture-resistant glue.

Laying starts from the window, the hats of the hardware are completely recessed into the plywood into the drilled holes. If communications are planned, cutouts are made for them.

Do-it-yourself plywood floors on logs: installation of layers

This stage is carried out in the following sequence:

Laying the first layer starts from the window with an indent from the wall of about half a centimeter. You can use plywood of the third or fourth grade, since the presence of knots and appearance do not play a significant role due to further finishing, and at a cost such material is much cheaper.
Intermediate logs can become an addition to plywood. This is necessary to reduce the size of the cells in order to have a good screed between the sheets and the frame. To do this, the logs are connected with crossbars from scraps, screwing them with steel corners. The size of the cells should be a multiple of the plywood sheets so that their edges always lie on the log.
The second layer of sheets is mounted with an offset relative to the first. Between themselves, the layers are fastened with self-tapping screws and glued with PVA or special glue for plywood.
Seal the seams between the sheets.
After laying the last slab, the surface is sanded with sandpaper by hand or with a grinder.

By the same principle, a do-it-yourself plywood floor is laid along the logs on the 2nd floor of a private house.

For the successful completion of the work, it is necessary to pay attention to the following:

It is not recommended to lay tiles on plywood: it can fall off due to the expansion of the wood layer.
Irregularities on the screed can be sprinkled with sand, and cracks and holes in the corners can be foamed.
To check the humidity in the room, you need to cover the base with plastic wrap for a day. If perspiration appears under it, waterproofing is necessary.
It is important to follow all the laying rules when installing a plywood floor along the logs with your own hands. IN wooden house on the first floor above the ground, this is especially true - if the technology is not followed, the entire coating will have to be removed to correct errors.
To ensure good sound insulation, the logs are not fixed rigidly, but are installed on felt or rubber pads to dampen noise.
Before starting the installation of the lag, find zero level and then the rest of the bars are equal to it.
The insulation must be cut strictly according to the size of the cells so that its edges do not bend when laying.
After laying the insulation, a vapor barrier membrane can be attached to the lags with a stapler.
For mounting, it is better to use not ordinary hardened black self-tapping screws, but yellow wood screws with a powerful mounting hole.
Sheets must be laid so that not cross-shaped, but T-shaped joints are formed.

Conclusion

With proper installation of a plywood floor, it can last more than twenty years. Just remember that this material is suitable for laying in dry and warm rooms.

It is also worth noting that plywood is suitable not only for arranging wall cladding and subfloors. Craftsmen make unique decorative compositions in the interior from it. Using the old craftsmanship - artistic sawing, pictures are laid out from plywood parts and parquet is formed.

At repair work ah related to gender, there are always a lot of questions. This is not surprising if you have such nuances, because the floor is a part of the house that is used almost around the clock. There are many options to make this part of the home comfortable, but you need to dwell on how to build a plywood floor along the logs.

The process of laying a plywood floor at the stage of fastening to the logs.

This type of coating is perfect if you need to make insulation, but it is impossible to fill in a cement-sand screed, and even out if there are large irregularities.

The bars, which, when installed, form a crate are called lags. With their help, the surface in the room is leveled, and they also serve as the basis for attaching sheets. They can be made of metal or concrete, but the use of plywood requires the use of wooden blocks.

The device of the floor will not be practical enough without the crate, as it gives the necessary rigidity to the sheets. Of course, there is a way to lay plywood without a crate, but this type of fastening can only be used if there is a flat base in the room. Without this, leveling the floor with plywood without lags will not be done well.

Log laying on the street. First, a frame is built, the sections are interconnected.

For logs, a bar with a section of 50 × 100 mm is usually used. rectangular shape necessary in order for the sheets to be joined on the wide side. In other words, if you do not have a support pad, it will be difficult to secure the sheet.

Also, before the logs are installed, they must be treated with antifungal and fire-fighting agents.

Pros and cons of choosing plywood

To the question: why is this material chosen in order to make an even coating in the room? The answer can only be given if you know its characteristics. First positive quality is durability.

Compared to chipboard and USB boards, plywood will last much longer. The reason for this is the technology of its manufacture. Unlike other types of wood-based panels, plywood is glued from veneer, which gives it strength. Three types of adhesives are used for gluing veneer, two of them are moisture resistant, so plywood long time can withstand moisture without breaking and rotting.

When using this design, additional communications can be carried out under it without resorting to cutting niches in the walls.

Plywood is stronger than other floor coverings and will last much longer

The negative nuance is that this material is the most expensive of the entire group of wood-based panels. But, the opinions of experts always agree on one thing, it is better to do it once and for a long time than to redo it due to the use of low-quality materials.

What plywood to use for the floor on the logs

In order to make a plywood floor along the logs with your own hands, you need to know what type of plywood to choose. Considering that water leakage is possible at the installation sites of heating radiators, a moisture-resistant type should be purchased. Perfectly fit sheets of the second and third grade. It is also necessary to take into account the size of the sheets. Size 1525×1525mm or 2500×1250mm will be ideal solution. Such dimensions are chosen in order to cut the sheet into four parts and carry out installation with them. If the work is carried out in an apartment that is located in a multi-storey building, it will be problematic to lift sheets of large sizes.

Types of plywood

Today, the industry produces 5 types of plywood, which are characterized by classes.

The first class is sheets that are polished on both sides and do not have flaws. They are used in the furniture industry;
The second and third classes are sheets polished on one side, while the other remains untouched. Such plywood is multi-purpose;
The fourth and fifth grades are not sanded plywood. It is used for draft work.

The belonging of the sheet to the class can be recognized by the seal, which is installed by the manufacturer.

Dimensions of unsanded birch plywood for flooring

Also, plywood is divided into three types according to water resistance. This factor depends on the type of adhesive used.

Sheet thickness

The thickness of the plywood for the floor along the joists is also taken into account in the calculations. Thin sheets will bend, which will lead to destruction, and thick sheets are not very comfortable to work with. But there is a way out of this situation, and moreover, it will play into our hands. The minimum thickness of floor sheets should be 20 mm. For a more durable coating and ease of installation, sheets with a thickness of 10 - 12 mm are used, which are stacked in two stands. Thus, a complete coating is formed.

With this technology, the plywood floor will be durable and reliable.

Walkthrough

On initial stage work, it is necessary to dismantle the old coating, if any. If the laying of the plywood floor on the logs will be carried out on a screed, then all cracks and potholes must be repaired on it. Then the entire perimeter of the surface to be sewn must be primed. After preparing the base, it is required to lay a film for waterproofing. To do this, it must be spread over the entire surface in a small overlap on the walls.

The next step is to install lags. Initially, the lag should be fixed around the perimeter of the room. To do this, the lag level is marked on the wall. If a laser level is available, then there is no need for markup. With this device, alignment can be carried out at the installation site. All our logs will be installed on substrates made of pieces of plywood or wooden blocks, or boards. The substrates are installed along the line of placement of each log at a distance of 50 - 60 cm from each other. After installation at the level of one log, the substrate is fixed to the floor with dowels. You also need to remember that when installing substrates for each of them, you need to adjust a piece of old linoleum or roofing felt.

Preparing the lag for further plywood laying

It is important to note that the logs that are installed around the perimeter should not come into contact with the wall, that is, they are installed at a distance of 20 - 30 mm from each other. Such placement is necessary for ventilation. After installing the log along the perimeter, the remaining parts of the crate are mounted. The distance between the floor joists for plywood in our case is 70 cm. This distance was obtained by dividing the sheet in half. If sheets of other sizes are used, then the distance between the lags will be different. For different cases, it is 40 - 70 cm.

After installing the crate between the lags, insulation is laid. It can be polystyrene, mineral wool or expanded clay. As practice shows, the best option mineral wool will serve for the floor. It is not recommended to use polystyrene indoors due to harmful fumes, and expanded clay is less effective. Insulation mats should be cut 1 cm larger than the crate cells. When laying such a mat will be tightly inserted between the bars of the crate.

After installing the insulation, the next step is to install the vapor barrier. It needs to be fixed on the logs with a stapler.

Work tools

To do all the work efficiently, you will need a tool, such as:

Level;
Roulette;
Electric jigsaw;
Miter saw;
Perforator;
Screwdriver.

As can be seen from the list, for all work, a hand-held power tool is mainly required.

Custom size

In most cases, when it comes to installing flooring, the problem is uneven walls. This nuance does not allow to install parts of the coating exactly along the lags. To do this, you will need to cut each part along a line parallel to the wall.

We fasten the plywood sheet so that there is a small gap against the wall

Marking and sawing is not difficult. The sheet is attached to the wall so that the second edge fits strictly perpendicular to the lag. You will also need a rail that is set parallel to the wall. A cutting line is drawn along it. In this way, trimming is done around the entire perimeter. When adjusting the dimensions, it should be borne in mind that there should be a gap between the wall and the coating.

Installation of the first layer

If it was initially decided that the structure would be laid in two layers, after all work with insulation and lathing is completed, you can start laying the first layer - this is a draft plywood floor along the logs. In order to properly make the installation, you must first decompose the cut parts along the entire row.

Their fastening to the lags is carried out using self-tapping screws. Between the sheets there should be a gap of 3 - 4 mm. This gap must be sealed with sealant. This technological gap is required for expansion. In this sequence, the installation of the first row is carried out.

It is worth noting that for the first layer, moisture-resistant plywood for the floor must be used without fail. To drill holes, you need to use a tool such as a comfirm. This nozzle is worn on a drill and makes a pot for the hats of self-tapping screws. The head of the self-tapping screw, when screwed in, will sink into the plate.

Second layer

When installing the second layer of the floor, all work is repeated, as with the installation of the draft. An important point there is that the sheets must be screwed with a mixture of joints. For greater strength, the layers must be glued together. This is done with building glue. Installation of sheets must be carried out with a clean side. Due to this, at the end of all work, a wooden coating is formed.

The scope of this sheet material is quite extensive. When doing work on your own (construction or repair), plywood is often used in arranging the floor - both for leveling it for the finish coat, and for mounting it on logs of light flooring for further painting or applying varnish. Regardless of the goal pursued by the home master, the technology is identical in both cases.

And given the exact geometry of the plywood sheets, the simplicity of their cutting and low weight, all activities for installing the floor from plywood along the logs at each stage can be done by hand, without resorting to the services of various advisers and assistants.

By itself, the process of arranging a plywood floor will not cause any difficulties even for a non-specialist. The main thing in this work is competent preparation for it. The quality and durability of the coating directly depends on the choice of appropriate materials. For those who are really interested in the final result, the author strongly recommends that you carefully study the information below, and only then master the nuances of installing plywood along the logs.

Sheet stacking scheme

You should start with this. In order to draw a plan of a particular room on a sheet, taking into account all the features of its configuration, you do not need to be a specialist. The main thing is to maintain the scale. After that, measurements of all the linear parameters of the room are made and put on the diagram. It turns out a drawing that will be needed to calculate the required volume of purchase of the required materials.

What is the feature? Plywood sheets have the correct geometry, and go on sale. Mostly for domestic use, samples of 244 x 122 or 152.5 x 152.5 (cm) are purchased - this is the standard format. There are more overall products, and when finishing large areas, it is much more convenient. But the question arises - how to transport it? For example, with a sheet length of 3.6 m (these are also sold).

After drawing up the plan of the room, it remains only to apply a “grid” on it, the cells of which are projections of each sheet. The task is simple - to draw up a diagram of their laying in such a way as to engage in cutting as little as possible. For those who first come across the issue of arranging floors on plywood logs, it is worth explaining what such careful planning gives.

The amount of waste is reduced, therefore, construction (repair) is partially cheaper. A zealous owner will appreciate this.
When it comes to doing this or that technological operation with your own hands, it is understood that House master uses household tool. Does every home have a jigsaw? So, you have to cut plywood with what is at hand. For example, a hacksaw. And this is both time and low quality of the cut.

What to consider?

When drawing up a plywood laying scheme, it is necessary to arrange all the sheets so as to cover the maximum possible area with them, and it is with whole samples. Naturally, there will be separate sections for which you will have to cut (in size) fragments. But in this case, you can also purchase the so-called substandard. It is in every building / materials store and is sold at bargain prices. As an option - buy sheets of plywood of smaller sizes (there are also such).

Such careful preparation will significantly reduce costs. By the way, this applies not only to plywood (the number of sheets and their sizes), but also to logs. They are also characterized by different lengths, so you have to decide on them.

Choice of plywood

By variety

One of the tasks of do-it-yourself work is to achieve maximum savings. From the same point of view, you need to approach the acquisition of consumables. In terms of quality / cost per sheet for arranging floors, the best are. Both of them are moisture resistant, are sold in a large assortment, have identical linear dimensions and sample thickness. What is the difference?

FSF costs 1.5 times cheaper than FC.
In the manufacturing process of both plywood, adhesives are used to hold the veneer layers together. But if the preparation for FC does not contain toxic components, then they are present in the glue for PSF (formaldehyde). That is why the last modification is recommended mainly for external work, since when the temperature rises environment harmful substances begin to be released from such plywood.

How to proceed? If the floor is arranged along the lags in a residential area, it is unambiguous to focus on the FC sheets. For installation in unheated utility rooms (sheds, outbuildings), cheaper plywood with the FSF marking is also quite suitable.

Thickness

The purchase of plywood for this parameter is complicated by the fact that the following points must be taken into account. Firstly, the interval between the lags, which is selected depending on the characteristics of the arrangement of the floor. For example, how and with what it is supposed to be additionally insulated. Secondly, it is possible to increase the strength of the flooring not only by increasing the thickness of the sheets or by reducing the distance between the lags, but also by laying plywood not in 1, but in 2 layers.

For a single-layer installation scheme, it is worth purchasing sheets with a thickness (mm) in the range of 15 - 18 (depending on the expected load on the floor). Reducing this value will not ensure the reliability of the coating, increasing it will complicate the work with sheets (first of all, cutting them) and increase the weight of the entire structure to be mounted (and this is an additional load on the floor).
If it is planned to lay plywood in two levels, then samples with a thickness of about 8 - 10 mm can be purchased.

By grade of plywood

As a rule, when arranging the floors along the logs, a cheaper one is purchased sheet material. After all, all its flaws are reliably hidden by the finishing. The main thing is that the samples do not have significant defects in the form of chips or emerging cracks.

In some cases, the owner leaves the flooring as it is, covering the plywood only with varnish. With a similar organization of the floor, the purchase of sheets with a grade below 2/4 is impractical. What is the feature of this product? GOST allows the presence of defects on its surface, but only on one side. When arranging the floor along the logs, such plywood (2/4) is the best choice.

According to processing

It is appropriate to note such a characteristic of the sheet material. In order to optimize costs, you should pay attention to plywood, the abbreviation of which contains the designation NSh (unsanded) or NSh1 (with one-sided grinding). Accordingly, what is better to buy depends on how it is planned to finish the subfloor further. If you only paint (apply varnish) - then NSh1. In other cases, cheaper sheets with the designation NSh are sufficient.

Log selection

By material

There are only two possible options - metal or wood. If we consider from the point of view of ease of installation, weight, correct geometry and a number of other parameters, then the conclusion is unequivocal - it is better to purchase metal logs for arranging the floor. But such a judgment does not take into account all the nuances of operation.

In any room, the microclimate changes, sometimes quite dramatically. First of all, this refers to temperature. Its differences cause deformation of materials. To make the design as stable as possible, when combining several different types of elements, they are selected according to expansion coefficients; they should be as equal as possible.

What is a plywood joist floor? Sheets are glued and pressed layers of wood veneer. Therefore, it is better to choose a wooden base on which they are supposed to be fixed. That is, a beam or a thick board mounted on an edge. No matter how convenient metal is to work with, it is unlikely that warping of the floor will be avoided with such lags. If not immediately, then in a couple of years it will definitely manifest itself.

By type of tree

The specifics of the room (dry or wet) does not yet give a complete understanding of the conditions in which the wood will be. Logs are mounted on the ceiling. What is under it - a heated room on the ground floor, a basement or something else? Options may vary. But the probability of rotting, deformation of the material in any case cannot be ruled out.

What is recommended? Larch is the best solution. This coniferous wood is not only resistant to moisture, but unlike other similar species, it does not tar so intensely when the temperature rises, and when wet (in the future) it only gains strength. No wonder it is her experienced craftsmen who use it when laying the lower crown of the log house. In addition, the price of lumber is quite acceptable.

Geometry

It's short here. All joists must be absolutely straight. Even the slightest distortion is unacceptable. Otherwise, not only their alignment when laying on the base will be complicated. Even slight mismatches in the upper cuts in height will lead to the fact that the plywood floor will turn out to be uneven. It is extremely difficult to fix such defects of it, and even in several places, with your own hands.

The optimal cross-section of the beam for the log (mm) is 100 x 50.

According to wood moisture

You need to purchase for the log only lumber dried in production (with an indicator not higher than 12%). It costs more than natural moisture products, but it is here that the savings are not justified. It is unlikely that it will be possible to achieve proper drying of wood on your own - this is a complex process that requires time, a suitable place, and competent organization.

Choice of fasteners

The plywood floor is good because it is easy to repair by replacing the sheets. Therefore, as fasteners - only self-tapping screws (for wood).
Since any floor is necessarily subjected to wet cleaning, the hardware must be made of stainless metal. There are enough galvanized self-tapping screws on sale.
Leg length. It is selected depending on the thickness of the plywood sheets and should exceed it by about 2.5 times - this general rule for work related to fixing materials on the basis.

Plywood floor on logs - work procedure

Foundation preparation

The main goal is to eliminate defects in the floor and ensure its high-quality waterproofing. If the floor is arranged along the logs in a new house, then the task is greatly simplified. It is enough just to lay a p / e film (thickened) on the base with the expectation that its edges wrap onto the walls, and fix the sections with construction tape. The excess above the floor - the height of the lag + the thickness of the plywood sheets + another 2 - 3 cm. The protruding film will subsequently be covered with a plinth.

If the leveling of the subfloor is carried out in an already inhabited room, then there are two possible options.

Complete dismantling of the entire structure and work from scratch.
Removing the flooring (with the lag remaining) and waterproofing the floor with penetrating compounds.

The feasibility of a particular solution is determined by the state of the lag and the base on which the installation is carried out.

Installation of the supporting frame

Many questions arise regarding the interval between lags. Partially about what needs to be taken into account (plywood thickness, room area, installation scheme) has already been said. But the main criterion is the dimensions of the sheets. They are laid on logs so that the cuts coincide with the longitudinal axis of the guide.

Therefore, you should focus on the distance between the lags within half a meter. If it is required in some areas, then additional logs are mounted. Actually, the drawing is also drawn up in order to determine their optimal placement in the room. As a result, the supporting structure should look something like this.

What to consider:

A wooden “shoe” is placed under each rail (from pieces of MDF, OSV, fiberboard, trimming a thin board). It is easy to fix it on the ceiling. What is the advantage of such a solution? Firstly, there will be good air circulation under the plywood floor, which will partially prevent the formation of mold. Secondly, with this method of installation, it is easier to align the upper sections of the log.
Work begins at opposite walls. Along each, with an indent of 3 ± 0.5 cm, one log is laid. They are aligned in a horizontal plane, and later serve as a guide for mounting the rest.
To achieve maximum alignment of the lag with your own hands, it is advisable to make a special device. The device is simple - a long rail, in the middle part of which a level (building) is fixed. Even better is to buy (or rent) a level. Then there won't be any error.

Floor insulation

From the point of view of "easier, faster, cheaper" - pour expanded clay between the lags or lay mats mineral wool. The work is so simple that it is not worth considering this issue in more detail.

At the same stage, engineering communications are laid (if necessary) - TV lines, Internet, and so on.

Fixing plywood sheets

Work feature:

First, a “fitting” layout of the sheets is done. After they are aligned and adjusted, the installation points of the fasteners are marked.
Each sheet is additionally processed (edges are cut at an angle) and holes for self-tapping screws are drilled.
Countersink. It is mandatory, since the fastener caps must be recessed into plywood after screwing it in.
Placement of sheets. They are mounted one at a time, starting from any of the corners of the room. After alignment with the lags, it is advisable to make “channels” in the beam with a thinner drill. Then the leg of the self-tapping screw will enter the wood quite easily. If the installation is carried out with a screwdriver, then this can be neglected. The main thing is that the fasteners "went" strictly vertically, without distortions.

The figure shows an approximate scheme of their laying.

What to consider:

The placement of self-tapping screws depends on the dimensions of the plywood. Mandatory fastening - around the perimeter of the sample. But the additional fixation is determined by its size. For large-format sheets - according to the scheme crosswise, for small fragments it is enough only in the center.

To reduce the so-called “shat” of sheets, it is worth putting strips of roofing material under them (on the logs).
Plywood is laid so that when it is joined, the bevels form a groove. It is easily filled with sealant, completely closing the resulting gap. This increases the hydro, heat and sound insulation of the floor.
To mask the hats of fasteners, special compounds are also used. They are on sale in various colors. If the plywood is varnished, then it is not difficult to match it to the tone.

If plywood is laid in two layers, then its fastening is done as follows.

The final stage is the cleaning of all joints. As a rule, it is enough to go over the seams with sandpaper to remove excess dried sealant. And then - according to the plan: coating with varnish or paint, finishing with other materials. The main thing is that the plywood floor is completely ready.

Often during the repair, the dismantling of the old wooden coating is impractical, but it is required to level the surface for further work. In this case, experts advise simply laying sheets of plywood, thereby creating the necessary "platform".

Laying plywood on a wooden floor

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, it is on plywood that they prefer to put linoleum, parquet board or laminate, since it has the following advantages:

stacking sheets significantly reduces the time preparatory work before installation of the final finishing floor covering;
prevents rotting of the underside of floor coverings, due to good ventilation between the material and the concrete screed;
a floor leveled with plywood prevents premature wear or deformation of linoleum or carpet, extending the life of the decorative coating;
provides a flat draft floor;
plywood sheets are light, hard, durable, resistant to loads and abrasion;
plywood is flexible enough and does not break during installation;
does not have a strong 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 the materials placed on it.

Popular types of plywood used for renovation

Sheets produced by the industry are classified according to various criteria:

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

For repair work, when the part of the structure made of plywood is 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 too thick one is inconvenient to use.

The number of layers does not matter. If possible, you should purchase sheets sanded on both sides.

1. If possible, before starting work, the plywood should be dried for 2-3 weeks. The sheets are dried vertically at a temperature slightly above room temperature.
2. It will be useful after the end of the drying process to treat the plywood with an antiseptic and ventilate it well.

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. Mounting on an old wooden floor

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

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

Among the adhesive compositions, water-based glue, a two-component composition, mounting glue and bustilat are distinguished. However, self-tapping screws are preferable.

Materials and tools

For the successful installation of plywood sheets, the following tools and materials will be required:

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

You may also need Sander, roller and primer, glue and sealant.

Floor preparation and priming

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, a substrate compensating for unevenness and adhesive tape will also be required, which will need to glue the joints of the strips of material.

Check the condition of the floors. Strengthen creaking and loose floorboards, replace rotten and damp ones. Do not try to restore boards with traces of mold, damage, attacked by rodents. They must be removed and the room ventilated.

Sweep dust and dirt from the floors with a broom. If desired, go over the primer twice to wooden surfaces for better material adhesion. 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 damper joints 3-4 mm between sheets and 8-10 mm between plywood and the wall. This will help to avoid swelling of the sheets, because during operation, under the influence of the microclimate and vibrations temperature conditions workpieces will increase in area by a few millimeters.

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

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

plywood laying

Mounting blanks has several features.

If necessary, a substrate is placed on the old wooden coating, the strips are glued together with adhesive tape.
Holes for self-tapping screws are drilled in advance, and then countersunk with a slightly larger diameter drill.
Self-tapping screws are sunk into plywood sheets.
Laying plywood begins with niches, podiums, ledges. Further, the sheets are arranged from the middle to the edges with a brick shift of the squares relative to each other.
Slots and gaps in the old flooring can be filled with glue, allowed to dry and sanded.

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

Method 2. Mounting plywood on logs

A more complex and time-consuming method of laying plywood material along the beacons is justified if the height difference is more than 1 cm. Logs can be installed on the old wooden floor, only if you're sure everything underneath is ok

Preparatory stage

old flooring you need to calculate 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, plywood should be prepared - the material needs to be sawn, markup on a piece of paper and number the squares, given that they will be laid out with a “brick”.

Installation of logs and plywood sheets

According to the drawing, plywood squares should be installed. Fastening can be done with liquid nails or self-tapping screws, in the latter case, the screw heads must be properly drowned. Holes can be pre-marked and countersunk.

Final processing

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

If a laminate will be mounted on top of the plywood or parquet board, then the thickness of the plywood should not be less than the finish coating.
Try to avoid cases where 4 plywood sheets come into contact at once at one point.
The step width of the log should be 0.5 m from the side of the square.
Plywood cannot be used in rooms with high humidity, even if it is a moisture-resistant grade of material.
If non-moisture resistant plywood is used in the work, then the laying of a waterproofing layer will be a prerequisite at the next stage of work.
The length of the self-tapping screw should be at least 2.5-3 times the thickness of the plywood.
When laying plywood on logs, the base, after sealing the cracks between the boards, can be primed and a layer of heat and waterproofing can be laid, and only then the guides can be mounted.

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

Video - Laying plywood on a wooden floor

Video - How to put plywood on a wooden floor

Plywood sheets are often used for dry floor screed. The material has many advantages and, with the right selection, installation, suitable for any floor covering, in particular for ceramics, laminate, linoleum and other claddings. We will understand the types, types, quality indicators of products, and at the same time we will consider what thickness of plywood is required for the floor along the logs.

Pros and cons of using plywood

Representing sheet material from many layers of wood glued together, OSB is durable, practical and easy to use. For production, peeled veneer of birch, coniferous woods, sometimes beech, oak or linden is taken.
The advantages of the material include:

ultimate load strength;
relatively low weight of sheets with increased strength indicators;
reduced thermal conductivity;
reduced humidity level - plywood is suitable for cladding in rooms with changes in humidity and temperature;
can be combined with any type of underfloor heating system;
a wide range of product types;
affordable price of the material;
ease of transportation, self-installation.

The disadvantages include the presence of an adhesive composition, which is not environmentally friendly. But this minus is leveled when buying plywood of emission class not lower than E1.

Factors Influencing the Choice of Plywood

Before making a plywood floor in a wooden house, you need to decide on the type of material. What to take into account when choosing sheets:

Foundation type. For example, a concrete base has a high thermal conductivity; losses can be reduced by thicker sheets (from 15 mm). But it is better to sheathe a draft plywood floor on logs with a material with a layer thickness of at least 12 mm.
Type of premises (field of application). For residential areas, professionals recommend choosing a grade of FC, it is produced without volatile chemicals.
Thickness. The arrangement of flooring from plywood on logs requires the selection of parameters, since the service life of the subfloor depends on the thickness - the thicker the board, the less it will sag when walking. However, bending in the direction of increasing the size should not be - this increases the mass of the flooring, which also negatively affects the design of the log.

Important! Professionals advise to be guided by the distance between the lags (step). If the cell size is 0.5-0.6 m, the thickness of the sheet must be at least 15 mm.

Given all the factors, choosing plywood for a wooden floor is not difficult.

Sheet thickness

The size range of plywood is diverse: the length can reach 6 m, the width is 3 m, and the thickness starts from 3 mm. For rough and finish type work on horizontal bases, the following are used:

1525 * 1525 mm with a thickness of 15 mm - this is the most popular product for mounting sheets on logs;
1210 * 2440 mm - used for leveling the bases in buildings of multi-storey standard buildings;
500 * 3000 mm - sheets for studio-type rooms.

As for what thickness of plywood to use for the floor along the logs, the type of prefabricated screed is taken into account, the load level:

Load degree. The greater the load on the floor, the thicker the sheets. Residential premises allow a parameter of 10 mm with a lag step of 0.4 m, but in commercial and other premises it is better to take plates of 22 mm thickness.
Type of finish. The materials of the final cladding also have their own weight, a static load that will put pressure on the logs. If it is a laminate, then there is no big threat of an increase in mass, which cannot be said about an array of boards or tiles.

So, how thick should the plywood for the floor be on the logs: at least 8-12 mm when installing in two layers, at least 10-22 mm for a single-layer layout.

Types of plywood

Depending on the scope of application, the material differs:

building;
furniture;
structural;
industrial;
packaging.

According to the classification, the material is distinguished:

Scope of application. For the arrangement of the prefabricated screed, structural and building types are shown.
Brand. Determined by the type of adhesive used. It differs like this:

FSF - sheets with increased moisture resistance, can be used in rooms of normal and advanced level humidity. Adhesive composition resin with the addition of phenol-formaldehyde components;
FC - products of medium moisture resistance, it is better to use in dry rooms. The adhesive composition is urea-formaldehyde;
FBA - sheets practically do not tolerate moisture. Glue with albumin-casein components.

grade. It differs in the allowable number of wood defects, processing defects:

E - extra class, in the manufacture of which oak, walnut, birch are used. Perfectly even sheets without knots, chips and other defects;
I - there are knots of a light or dark shade of no more than 3-5 units / m2. There is no more marriage;
II - knots (captive) with a diameter of not more than 6 mm are visible in the amount of 6-8 units / m2, there may be cracks 0.2 cm long and up to 0.2 cm wide (fused or sealed);
III - sheets with wormholes, knots up to 6 mm in the amount of 8-10 units / m2, cracks 0.3-0.6 cm long, 0.5 cm wide (closed), dents, scallops;
IV - a grade with defects, chips along the edge without restrictions.

Important! If you look at what kind of plywood to use for the floor according to the logs of an inexpensive cost, then grade 1-4 will do. But double marking of sheets is possible: 1/3, 2/2 - this means that one side corresponds to a high grade, and the second to a low grade.

The nature of processing differs in grinding:Ш1 - processing of one side, Ш2 - both sides are polished, НШ - no grinding. You can use any slabs for the floor along the logs, but it is better to take one-sided grinding to get a perfectly smooth base for finishing.

Having figured out what thickness of plywood for the floor according to the logs is better, you should determine other suitable sizes:

FC brand;
emission class E1;
grade: for subfloor 3-4, for finishing 1-2;
humidity 12-15%;
number of layers (thickness) 8-12 mm.

Advice! Please note that with a two-layer flooring, the thickness general design divided by 2. However, the choice of price here matters: sheets of plywood with a thickness of 15 mm are not much more expensive than a sheet of 30 mm, but laying and transporting lighter material is more convenient.

Sizes and prices for plywood

The linear dimensions of the sheets are of great importance, as is the cost of the material. The most used formats (in mm) with prices:

1525 * 1525 - a popular product for the floor on the logs, besides, the squares are easier to cut into fragments for laying on the floor and move. Price $6-10.
1210 * 2440 - softwood rectangles with a thickness of 5 mm or more are estimated at $ 5-7.
1500 * 3000 - convenient for commercial premises, made from hardwood and softwood, cost from $ 6.5-12.

Log and plywood laying technology

When choosing logs for the floor under plywood, preference should be given wooden beam chamber drying with a moisture index of 12-18% without cracks, rot and traces of bark. The support length parameters are 2 m, thickness - from 4 cm, width - 8-10 cm. It is most practical to use logs with parameters of 50 * 40, 50 * 50, 50 * 70 and more mm.
The height is selected according to:

load level;
insulation thickness;
indicators of floor height;
personal requests of the owner.

As for the type of wood, you can take inexpensive varieties: spruce, pine or more practical larch, aspen. Wooden elements should be treated with bioprotective, water-repellent and antiprene impregnation.

Underlayment elements for logs are sheets of hardboard, OSB, MDF with dimensions of 10 * 10 cm or 10 * 15 cm with a minimum interval between them of 30 cm. Fasteners are selected with the condition of strength to temperature changes, humidity indicator. These are nails, universal screws, metal corners, anchors and other hardware. Dimensions depend on the parameters of the support: category M6-M12 is used for underlay elements, the length depends on the thickness of the support (from 5 cm or more).
Materials for the manufacture of lag:

plywood;
lags;
lining material for leveling the bases;
primer;
hardware;
insulating materials (noise, heat, waterproofing);
damper tape;
sealant or putty on wood;
drill / screwdriver;
construction level;
pencil, meter, spatula, brushes, roller;
cutting tool for sawing sheets, bars;
rags for cleaning garbage;
individual protection means.

To make an OSB floor on logs in a wooden house, step-by-step preparation and observance of technological subtleties will be required:

Clean the base from dust and debris.
Inspect the base, replace or repair damaged areas.
Floor waterproofing is carried out if necessary: there is residual moisture, a basement is located under the ceiling, or floors on logs are mounted in the bathroom, kitchen.

Advice! Any material is useful for insulation: film, membrane, roll materials. If sound insulation is required, floorings from mats are mounted under the logs, and mineral wool is placed in the openings between the logs.

The power frame is formed in the form of longitudinally arranged beams or as a single or double crate. If there is increased traffic in the room, the frame must be made across the course of movement in order to eliminate the risk of uneven load distribution.
Mark the zero point at which the supports are aligned, then you can mount the logs in compliance with the gaps:

between the extreme rail and the wall from 20 cm;
interend gap 0-0.5 cm.

Advice! If you need to soundproof the room, then the base is laid desired material, but only before mounting the lag frame.

The masters lay damper layers on the supports, which will eliminate the risk of lag squeaking during operation.

It remains to fix all the lags, but in doorways it is necessary to lay a broadened rail with the calculation of the protrusion beyond the partition by 50-100 mm on each side.