Draft floor in a wooden house with their own. Draft floor in a wooden house: we make a strong lag base for a final finish

The durability of the finished floor covering also depends on the quality of the preparation of the base. It is for this reason that laying the subfloor plays such a significant role. The material used for installation must ensure the evenness of the finished structure and be strong in compression. Modern technologies offer several options for arranging subfloors using different materials.

Types of subfloors

The draft floor in the section resembles a layer cake:

• Base. It is on him that all the burden falls.
• Layers of hydro, heat and sound insulation.
• Screed.
• Draft coating.

Far from every owner will build this, however, the subfloor can be done in different ways with your own hands. Fortunately, there are several options for its arrangement.

Wet floors

The most popular methodology Its implementation does not require special skills and high costs. The screed is carried out using a gypsum or cement-sand mortar. Most relevant in houses with slab ceilings. The screed is poured onto the layers of thermal insulation. The top of such a floor must be leveled and dried, and only then covered with the last final layer.

There are three main types of wet screed floors:

• Single layer. They are used to eliminate plate defects, as a rule, with differences up to 1.5 cm.
• Double layer and multi layer. They are used when it is necessary to equalize a significant dissonance of heights (up to 12 cm). They simply cannot be eliminated in one layer.

Subflooring is a great way to create the perfect surface for carpet, laminate or linoleum.

The positive qualities of a wet screed include: moisture resistance, fire resistance, strength and relatively small thickness. The cost of the material is democratic $ 1-3 per kilogram of the mixture.

dry floor

To minimize the laying time of the subfloor, use a dry screed. Solutions practically do not participate in the process of its formation. For this reason, the screed does not need to dry for a long time. Insulating material, lathing and wood flooring are involved in the creation of the "pie". During installation, ventilation gaps are created.

Important! The screed for ceramic tiles must be treated with a primer. Omission of this moment may threaten the delamination of the coating.

prefabricated floor

This is a dry screed. It is mounted on top of slabs or flooring from boards. The prefabricated floor is a structure made of rolled, sheet materials and dry backfill. "Pie" usually consists of screed, heat-insulating materials, logs and dry mixes. A rough floor is mounted on top.

Prefabricated floors have a high level of sound insulation and form the basis for most finished floors. They are almost 2 times lighter than wet screeds, but have a decent thickness, so they are not suitable for thin roll coatings.

Floors on logs

This type of subfloor is most often found in old houses. Logs level and greatly facilitate the installation of a wooden floor, and also do not allow weakening of the load-bearing beams.

Arranging the floors on the logs seems quite simple, but it cannot be done without proper preparation. It is impossible to work with them without knowing all the subtleties.

It is not permissible to align the logs with wooden wedges and spacers made of wood chips. Such a design is not viable and after a while the floor begins to creak and sag. To level, sand is poured under the logs or the material is trimmed.

Antiseptic treatment and ventilation increase the life of the frame. From above it is covered with plates or sheet material, and to lower the reduced noise index, polyethylene foam or fiberboard can be laid under the logs.

Adjustable floors

These floors rest on the floor slab through threaded posts. Contribute to raising the finish coating to a height of up to 7 cm (if we are talking about plywood) or up to 22 (with the help of a log). To create a subfloor, beams, cranial beams and a board made of coniferous wood are used, as a rule, with a reduced grade.

Subfloor materials

To correctly answer the question: how to make a subfloor, you need to decide what materials are needed for its arrangement.

The base is assembled from the following components:

• Bricks. They serve to create pillars that are placed on the cement mortar.
• Metal corners and bolts. Lags are attached to brick pillars.
• Waterproofing. Choose a material that can prevent rotting.
• Insulation. Lay on the bottom layer of the rough base.
• Boards or slabs. Used for flooring.

Of course, this is not all the necessary elements. Their variations are due to the variety of types of rough coating and the wishes of the owner. The quantity is calculated on the basis of the size of the premises for development.

The duration of floor operation directly depends on the proper preparation and positive qualities of the materials included in its composition, including coatings.

Gypsum boards

GVL and GVLV create a perfectly even base for a finishing coat. Usually they are laid in two layers, fixing with glue. It is customary to use these plates for leveling on expanded clay backfill or for creating a coating of heat and sound insulation. They are also suitable for flooring on the old subfloor. The only thing that should not be done is to combine GVL (GVLV) with lags. In such a combination, the material does not withstand local loads: even furniture legs can break through the floor.

The base is suitable for almost any finishing surface: laminate, carpet, tile, linoleum, cork or parquet. To protect the subfloor from the influence of possible leaks, it is necessary to treat the plates with a hydrophobic composition.

Moisture resistant chipboard

The material withstands heavy loads (we are talking about the idea of ​​high-density chipboard) and allows you to form a fairly even base. Due to its increased strength, it can be laid both on backfill and on logs.

Chipboard has good indicators of heat and sound insulation. Usually plates, like drywall, are fixed with glue. They are laid in two layers, not forgetting about the treatment with a hydrophobic composition.

Important! Chipboard is best used in dry rooms and covered with carpet, parquet or linoleum. For additional sound insulation, the plates are pasted over with technical cork.

Cement particle board

The material has great features:

• High strength;
• environmental friendliness;
• Water resistant.

DSP does not burn and is not afraid of even serious leaks. On the market there are plates with a thickness of 1-3.2 cm. They are laid on the backfill or on frame logs, laid in two layers (the top one is treated with a waterproofing or water-repellent composition).

DSP is excellent for laying parquet and laminate. The only drawback of the plates are minor deviations in thickness at the joints (up to 2 mm). In this case, it is unacceptable to cover the surface with cork or linoleum without preliminary preparation of the base. Deficiencies are eliminated by grinding and puttying.

Moisture resistant plywood

Multilayer plywood has many variations in thickness (from 0.3 to 3 cm) and cost ($ 2.7-39). Due to its high strength, it is often laid on frame logs, but it is also often laid directly on a concrete base under parquet or laminate.

Important! Rough plywood flooring makes the floor warmer, but does not solve the soundproofing problem.

Everyone understands that it is impossible to live indoors without arranging the floor. Whether it's a house or an apartment, you can't do without it. But whether a draft floor is needed in a wooden house, not everyone knows. Why do we need additional expenses for its arrangement? Isn't it possible to get a clean finish? And what is meant by this name? This article is for those who want to figure it out and make a subfloor on their own.

What is a subfloor?

The draft floor is a kind of base for a finishing coating, creating a horizontal flat plane for it. It serves to distribute the load on the floor covering.

The classics of the draft coating is considered to be the device of the subfloor on the logs. This is exactly what is usually done in wooden buildings. For him, logs with a certain distance from each other are laid on the base base. On large areas, a double frame system, the so-called crate, is provided.

In it, between the lags, jumpers from a bar (crossbar) are installed. At the same time, the horizontal alignment of the surface of the logs is constantly monitored. A cranial bar is attached to the lower part of the lag. On it, the laying of a subfloor made of plywood or wood board is carried out. Subsequently, insulation material and waterproofing are laid between the lags.

Insulation and vapor barrier are laid on top of the subfloors. For the manufacture of a rough coating, chipboard or fiberboard or plywood is used.

Stages of subfloor device

And now more about how to make a rough floor with your own hands. There are two options for installing a lag: on the floor or on the base. In any case, before installing the subfloor, it is necessary to take care of the ventilation of the subfloor. For her, it is enough to drill a few round holes in the corners of the house. Subsequently, they are closed with bars. Also, before starting work, the entire underground space is treated with an antiseptic. These measures serve as a guarantee of the strength and durability of a wooden house.

Preparing the lag for construction

In fact, logs are bars from which a frame is made for the future floor. For them, boards made of wood of the second or third grade are used. Since such logs usually have an uneven surface, they must be prepared before use.

To do this, the side on which the finishing floor will be attached must be leveled with an ax. It will not work to make the surface perfectly flat, but it is necessary to level it a little. The horizontality of the finishing coating depends on this. From above, the logs are covered with antiseptics.

Before laying the log, grooves are made in the upper crown of the walls. Planed logs should lie exactly in these grooves, but with a distance from the end to the walls of 2-3 mm. Later, a gasket is installed between them for sound insulation. In addition to the grooves in the beams, for long logs, additional support is installed in the form of brick pillars. The distance between the lags depends on the thickness of the boards used for flooring. The thinner the boards, the more often the lags are located.

Under boards with a thickness of 35 mm, the distance between the lags is at least 50 cm, 35-40 mm - 80 cm, more than 40 - 100 cm

Note! After installing the lag, their ends must be fastened together. This is necessary so that they do not disperse in the process of laying the roughing boards.

The surface of the base before performing work is leveled, covered with crushed stone and compacted. Next, measurements and markings for supports are made. Either a grillage covered with roofing felt, or bars of the lower strapping can act as supports. In the first version, the mark is placed on the roofing material, in the second, on the bars.

The horizontality of the lag is checked not only relative to the ground, but also relative to each other. They must lie on the same level. The maximum allowable deviation per 1 m² is not more than 1 mm

Support pillars are installed on a foundation, the minimum dimensions of which for one element are 40 × 40 cm. Its height must be at least 20 cm, and 5 of them are above the ground. Waterproofing material is placed on the supports under the logs. It will protect the wood from mold. Logs are attached to the posts with the help of corners and self-tapping screws with dowels. The same device has a draft floor in a brick house.

timber fastening

For support under the draft floor on the logs, a bar with a section of 50 × 40 mm or 50 × 50 mm is used. Attach it to the bottom of the lag on both sides. In this case, it is necessary to take into account the size of the future insulation, which will be laid on the rough coating. It is more economical not to purchase ready-made bars, but to buy a 150 × 40 board and dissolve it into three parts. As a result, three bars of 50 × 40 mm will be obtained from one board.

Subfloor laying

Perform a draft floor of plywood or sheets of OSB, chipboard. It is advisable to use boards with tongue-and-groove ends with a thickness of about 20 mm. It is allowed to use sheet materials with a thickness of 12 mm in two layers. To secure them securely around the entire perimeter, a crate is made of additional transverse bars to the lags. Subfloor boards are fixed with self-tapping screws in increments of 90-140 mm. If the floor is made of sheet materials, the joints should fall on the central axis of the additional beams.

Note! Some craftsmen advise using not high-quality material for the subfloor, but a junk board, slab or picket fence. This is due to the fact that the rough coating reacts to changes in humidity and temperature. And such material is capable of deformation.

After completing the installation work, proceed to the laying of thermal insulation material and waterproofing. You should be very careful. Sub-floor boards can break under heavy weights. Therefore, it is advisable to walk along the logs or thick boards thrown over them.

Results and video with an example of work

That's all, the rest is in your hands. Unnecessary, it would seem, waste on such a device of floors will pay off over time. A layer of insulation laid on a rough coating will help save on heating. And you will agree that this is a significant argument in favor of the device of the subfloor. In addition, a high-quality rough floor is a guarantee of the durability of the finish coating.

A subfloor is required for laying "small" or "soft" floor coverings. The article tells about the features of the arrangement of wooden floors, which are often used in houses, and the choice of materials, which is determined by the type of foundation and the type of finish flooring. The schemes and stages of work on the arrangement of the subfloor are described. After reading the article, you will learn how to make a reliable, durable draft floor with a flat surface.

The subfloor is the top of the floor pie

Kinds

The most common option for a subfloor in a frame or wooden house (go "black") is to create a solid flooring based on beams. But for the first floor it is also possible when the logs are installed on the floor of the reinforced concrete slab along the strip foundation, on the shallow foundation slab or on the concrete floor on the ground. The last three options do not fundamentally differ from each other, although in all cases the methods of fastening and leveling the log along the horizontal level are different.

Since the concrete base itself is strong and reliable, it can be considered as the “underlying” part of the floor of the lower floor (according to the normative terminology of SNiP 2.03.13-88). In this case, it remains to equip only the "leveling" part (wet, dry or prefabricated screed) and the "intermediate" part (heat, steam and waterproofing). And already on the leveling part lay the finish coat.

Concrete floors, equipped on the ground - this is another common option.

Wooden subfloor: structure

The draft floor is only part of the wooden floor. It is made from edged boards, sheet moisture-resistant wood materials. The thickness of the flooring (board or sheet) and the layout of the log have a "direct" relationship: less thickness - less interval between runs.

Important! If we are talking about a board, then with diagonal laying (for example, in rooms with complex geometry), the lag step should be even less. Moreover, the angle between the board and the run must be greater than 45 °.

Wood decking is the top layer of the pie. Layer by layer, the whole structure looks like this:

Binder. It does not affect the load-bearing properties of the floor, but acts as a support for the insulating materials.

The thickness of the lining must be sufficient to support the weight of the insulation

Waterproofing. Membrane type materials are used. They do not let water through, but allow water vapor to escape from the insulation, which then exits through the vents in the basement (intake) of the foundation.

thermal insulation. Usually these are mineral wool mats, which, unlike polystyrene, are non-combustible materials.

vapor barrier. There are three types in total. Films with limited vapor permeability, which maintain a "balance" between moisture transfer from the room to the insulation and from the insulation to the outside. Vapor-proof films are a vapor barrier that almost completely excludes the penetration of warm air with water vapor into the insulation. Foil materials (reflex films) are a vapor barrier that returns part of the heat back into the room. All three types, as it should be for vapor barriers, have waterproof properties that protect the insulation from above, from the side of the room, from water ingress.

Flooring.

Multilayer plywood subfloor sheet will withstand heavy loads

On our website you can find contacts of construction companies that offer turnkey services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Device options

There are two main stitching options:

under the beams. The disadvantage of this method is that there is often not enough “space” in the subfield of the house to perform the fastening procedure. Advantage - almost the entire volume between the beams can be used for insulation. Only in the case when reflective vapor barrier materials are laid, it is necessary to leave a small gap between the film and the flooring.

Fastening to each beam, on both sides of the "opening", cranial bars - a filing is mounted to them. The most common and easy to implement method. The disadvantage is that the insulation layer will be less than the thickness of the cranial bar plus filing.

This is how the overlap scheme looks like with filing to the cranial bar

over the beams. The disadvantage is that the height of the lag is chosen more than the thickness of the insulation. As an option, it is possible to lay an additional counter-lattice on top of the log for another layer of thermal insulation.

In principle, such a complex overlapping device is only necessary for a heated residential building. In a seasonal garden or country house, you can limit yourself to only wooden flooring without hemming and insulation, although waterproofing must also be laid in this case to protect the wood from moisture.

Important! All wooden elements, from filing to flooring, must be impregnated with antiseptics and fire retardants. And after sawing and drilling, the ends must be processed again with these compounds with a brush.

Fire bioprotection is an obligatory stage of wood processing working in extreme conditions

Material requirements

For flooring, usually choose the following materials:

edged board;

waterproof plywood;

Fiberboard or chipboard with waterproof treatment;

• cement-bonded particle board (DSP) or GVL.

Plywood is stronger due to its multi-layer structure, and it is much thinner for a subfloor.

Video description

How to choose sheet material for the subfloor in the video:

Classic scheme

A feature of the classical scheme is a significant distance between the beams.

Usually the layout step is 0.8-1 m, and this is “reflected” in the choice of board thickness.

It looks like a "powerful" overlap of a log house

A typical subfloor structure looks like this:

timber with a section of 15x15 or 15x20 cm;

cranial bar with a section of 4x4 cm;

filing with a board 2.0 cm thick (can be unedged, but cleared of wane) or plywood 1.5 cm thick;

waterproofing (glassine, polymer membrane);

insulation (stone wool) with a thickness of not more than 10 cm - this is all that allows the remaining volume between the beams after installing the cranial bar with filing;

vapor barrier;

board 4.5-5.0 cm thick.

And now this design is used, but it no longer meets modern requirements for thermal protection. Therefore, a counter-lattice is mounted on top of the beams, between which another layer of thermal insulation is laid.

The advantage of the method is also that the layout of the lag can be reduced to 30-40 cm, and the subfloor boards can be selected with a thickness of 20-24 mm.

Scheme of complex insulation of a frame house with a double thermal insulation contour of the floor and a mesh as a filing

The modern scheme of laying the subfloor for a wooden house is more perfect and allows you to insulate the floor without additional "add-ons" in the form of a counter-lattice:

Boards placed on edge. Attached to the strapping beam, and, if necessary, relying on intermediate supports, they serve as a lag. The thickness of the board is 5 cm, and the width is at least 20 cm. The layout step can be made 60 cm (under the width of stone wool rolls), and in terms of wood consumption for runs, this option is more economical than the classic scheme.

Polymer (wire mesh) for supporting waterproofing and insulation.

Wind and waterproofing film membrane type. Allows excess moisture to ventilate, protects the insulation from water ingress and fiber weathering.

stone wool in the form of semi-rigid mats 20 cm thick.

vapor barrier.

Flooring from boards 36 mm thick.

The only drawback of the modern scheme is poor lag stability. This is due to the large difference between the width (supporting part) and height. To ensure the stability of the structure, additional transverse braces are used, which “connect” the logs to each other and to the strapping (grillage).

A typical overlap of the first floor of a frame house from a board on the "edge"

The advantages of the scheme are obvious - saving on lumber (in "volumetric" equivalent) and a simple one-layer insulation scheme.

Draft floor of the second floor (attic) or cold attic

There are no living rooms under the wooden floor of the first floor, so “simple” materials can be used for filing without finishing or decorative surface treatment. Interfloor overlapping from below is hemmed with a planed board or clapboard.

And although the insulation of the floor between the heated floors is not required, mineral wool is laid between the logs. In this floor pie, it acts as sound insulation. Ideally, acoustic wool should be used. It differs from the usual "chaotic" fibrous structure. But heat-insulating modifications can also be laid - with the same thickness and density, their sound absorption coefficient is lower than that of acoustic modifications by only 10-15%.

The ceiling of a cold attic must be insulated.

Installation of the cold attic ceiling begins with the installation of a vapor barrier

And since even an “uninhabited” attic is exploited in a low-rise building, the insulation must be covered with a subfloor (but without further fine finishing).

The cold attic floor plan looks like this (from bottom to top):

hemmed ceiling of the underlying heated floor;

vapor barrier laid in a continuous and continuous layer with sizing sealing tape around the entire perimeter of the ceiling;

insulation between the beams (lag);

membrane-type waterproofing laid on the surface of stone wool;

remote bar stuffed on beams, providing a ventilation gap;

rough attic floor.

Important! The layered structure does not reflect the installation sequence. At the first stage, a vapor barrier film is attached to the bottom of the floor beams. And on top of it, a bar is mounted on the beams, to which a crate for a false ceiling is attached. If you first hem the boards, then the film will have to be laid on top of the beams. In this case, water vapor will penetrate into the wood, but there will be nowhere for them to vent, which will lead to wetting of the floor beams and create conditions for their decay.

Subfloor under tiles

The technology of how to make the correct draft floor of a wooden house for laying tiles has its own characteristics if a board is chosen for the flooring.

Tiles in a wooden house in some rooms are simply necessary due to the nature of their operation.

Unlike wood, ceramic tiles do not change their linear dimensions with changes in humidity levels. Moreover, the tree reacts differently to such differences in the directions along and across the fibers. And in order to compensate for these changes, a "damper" layer must be laid on top of the boards.

Plywood or moisture-resistant drywall is chosen as the top layer of the leveling part of the subfloor. Plywood, although made of wood, does not change its linear dimensions due to the multilayer structure with a multidirectional arrangement of fibers in each layer. But it must be borne in mind that both materials are subject to deformation during prolonged contact with water or when used indoors with a “wet” mode. And in such areas, before laying the tiles, it is necessary to make another waterproofing layer.

Plate

If a wooden house stands on a slab (foundation or ceiling on a brick plinth), then the floor of the first floor is equipped with a screed. In this case, the same technologies are used as in stone houses.

Logs can be installed on a solid base even on point adjustable supports

Even for a wooden subfloor, there is a choice among a wider list of methods:

installation of logs on stands on a concrete base without fixing to the basement and load-bearing walls (floating floor);

installation of logs on adjustable supports;

installation of adjustable plywood.

Video description

Subfloor installation steps in this video:

It might be interesting! In the article at the following link, read about.

Conclusion

Knowledge of the features of technologies and materials helps to correctly navigate when choosing the type of subfloor, since most of the finished projects are compiled with the ability to link to different types of foundation. In some cases, you can even avoid unjustified costs for materials and payment for "extra" work. But this is only possible when non-professionals or unscrupulous contractors are engaged in the design and execution of work on arranging the foundation and linking to the conditions of the site. Therefore, it is better when all the work from "scratch" is done by the company the author of the project, or it also carries out architectural supervision.

Many novice builders who have just started building their home are already considering what kind of linoleum or laminate they will lay in the future room.

And soon, before them the question arises - How and on what to lay this linoleum. Of course, we all understand that first you need to make the so-called subfloor - the basis on which, in the future, you can lay any floor covering you like. But, how to make the floor “from scratch” correctly, so that it is reliable, even and, most importantly, warm. You will find the answer in this article.

To make a rough floor with your own hands, you do not need any professional skills or special tools. The main thing you need is good physical strength and a head on your shoulders, as well as some, the most common tool. But more on that later, first you need to decide what building material you will need to purchase for the construction of the subfloor. The choice of materials for the floor on the construction market is now huge, but we will consider the most common option - no less reliable and at the same time not expensive.

We use the following lumber:

- a wooden beam with dimensions of 100 by 150 mm (or 150 by 200 mm) and a length of 6000 mm;
- a wooden block with dimensions of 50 by 50 mm (or 60 by 60 mm) and a length of 3000 mm;
- planed boards 50 mm thick and 6000 mm long;
- OSB sheets with dimensions of 1250 by 2500 mm and a minimum thickness of 12 mm.

As a heater, it is desirable to use basalt insulation (in a simple way, glass wool). To protect lumber from mold and decay, you need to purchase a special solution (antiseptic). You may also need cement mortar during the construction of the floor. Now let's look at all the lumber used separately, as well as what role they play in the subfloor.
Lumber used.

Wooden beams, with dimensions of 100 by 150 mm, are used as load-bearing logs, on which, subsequently, the entire floor in the room will rest.

Bars with dimensions of 50 by 50 mm are designed to accommodate insulation in the floor.

The cost of timber, on average, is about 6,500 rubles per cubic meter. To calculate the total cubic capacity of all bars, you will need to calculate the volume of one bar and multiply by the required number of bars. The volume of any bar is considered as the volume of a parallelepiped.

Choosing the right board
The board plays an important role, therefore it is better to use planed larch as the base of the subfloor. The cost of one cube of such a board is about the same as that of the bars. Cubature is considered similar.

All of the listed lumber should be made mainly from coniferous trees, such as larch, it is less afraid of moisture and dampness, which means it will last longer. By the way, the whole of St. Petersburg, which is already over 300 years old, was built from it!

When buying beams and boards, you will need to take into account that the drier the lumber, the better and more expensive it is. After all, the dried boards will no longer warp and will not go (by helicopter), for example, during the heating of the house. Therefore, lumber is selected based on the following criteria:
- the lower the humidity level, the better, you can take it straight from the dryer;
- timber or board should be smooth, surfaces without significant defects, cracks and delaminations.
Sheets (plates) OSB

These so-called OSB boards complete the construction of the subfloor. Subsequently, OSB panels will serve as the final basis for the flooring. Translated into Russian, OSB is translated as OSB - oriented strand board. The material itself is a board pressed from sawdust.

Over the past 5 years, OSB boards have become increasingly used in the decoration of walls and floors and are considered a fairly good basis for almost all types of finishing materials.

The main advantages of OSB boards:
- high moisture resistance;
– high mechanical strength;
- the material is easy to install.

One sheet of OSB with dimensions of 1250 by 2500 mm and a thickness of 12 mm will cost you about 700 rubles. Many Russian manufacturers sell OSB boards for less than 500 rubles a piece. You should not lean towards a cheaper option, it is cheap OSB panels that have received bad reviews due to their low level of environmental friendliness.
We figured out the materials, now we will find out what tool you will need to install the subfloor. Prepare or buy the following tool with which you can simplify your work as much as possible:

- a hammer;
- electric jigsaw;
- hacksaw or electric saw;
- roulette;
- level 1.5 meters long;
- stationery knife;
- nails 50-100 mm long.

Stages of subfloor construction

Let's first figure out how to properly position the lags. Before we figure out the correct location of the lag, let's go back a little to the past. It is advisable to take care of the floor arrangement even before the construction of the main walls of the house, that is, immediately after preparing the foundation. After all, then it will be impossible to fix something in the location of the lag.

First, all the bars (for the first floor) are treated with a special solution (antiseptic) against mold and decay. The fact is that the logs are located near the ground, under the house and will always be exposed to a humid environment.

After laying the beams, check that they do not touch the ground (the distance from the bottom of the beam to the ground must be at least 20 cm). That is why all the space inside the foundation is always cleared in advance.

So, we place the bars perpendicular to the direction of the longest side of the future room with a step of 80-100 cm. The more often you keep the step, the less the floor will wobble and play, but this will require more building materials, respectively, and costs.
We have all the bars with a “rib” to increase the rigidity of the floor and make it as high as possible from the ground level. Agree a room on the first floor with too low windows is not the best option. We have all the logs, strictly in a horizontal position, checking their level from the edges, in the middle and between adjacent bars. If necessary, the edge of the beam can be raised with cement mortar.

The bars should rest with their edges on almost the entire width of the foundation, and their ends should be smeared with cement mortar or closed from the street. It is not necessary to specially fix the logs to the foundation - we just lay them, but so that they stably adhere to the surface of the foundation and do not stagger.

All boards, even before the walls are erected, it is advisable to lay them out on logs and cover them with the same anti-mold solution. You can also adjust them to size and cut a little too long boards, so that later, indoors, it would be more convenient to work with them.

Finally, we make the base of the floor after the erection of the walls. We measure all the boards so that there is a gap of 3-5 mm from the end between the wall and the board. This gap is needed so that the board does not rest against the walls during the shrinkage of the house. We lay the boards perpendicular to the direction of the lag.

We nail each board with nails “weaving”, through one or two logs. You should not hammer three nails into each beam - this will not win you anything. Boards, just do not press hard against each other. The first board lies with an indent of 3-5 mm from the wall, the last one is adjusted in size. You may need to adjust the last board and cut it lengthwise.


For floor insulation we use bars and basalt insulation. To insulate the floor, it is necessary to build a kind of frame in the form of a lattice of bars 50 by 50 mm. In the cells of this frame you will lay a heater with a thickness of 50-60 mm. The insulation in our case comes with plates, but if you don’t like it so much, you can insulate it with soft wool, just keep in mind that for the same soundproofing effect as from plates, you will need twice as much soft wool. For example, if you open a wooden floor in a Soviet apartment, you will see a similar grating, and in rare cases, even with a heater.

The bars must be distributed in increments equal to: the width of the OSB board divided by two, that is, approximately 620-630 mm. Bars are also laid across, here you determine the step at your discretion.

Try to put all the bars in a horizontal level. This can be achieved with small wooden wedges. Wedges are not difficult to make yourself.
Important! We nail the bars to the boards with nails, as in the previous case.
We lay the insulation in small rectangles, cutting out the desired size with a clerical knife.
Important! When working with insulation, be sure to wear goggles and a mask.

A small digression.
There is another pretty good way to insulate the floor. Although it is used mainly for warming the floor of the second floor, it is also suitable for the first floor. Here, the insulation is placed in the space between the lags. In order for the insulation to hold, boards 80-100 cm long are nailed to the lags from below, you see, it’s not very convenient. Moreover, the boards should be tried to be nailed tightly to each other so that the insulation does not crumble over time and does not fall to the ground inside the foundation. However, in this case, you can lay the insulation in a thicker layer, and the floor will be better insulated as a result. With this method of insulation, the device of bars 50 by 50 mm will not be mandatory.

Everyone knows that it is not possible to fully live in an apartment or house without an equipped floor. It is simply necessary. Is it worth doing it in a wooden house - this question worries many. Their logic boils down to the fact that why spend money on an additional subfloor, it might be easier to just lay a finishing one right away. Everything is ambiguous here.

Of course, you can get by with a fair one, but in this case you will not be able to get a reliable and beautiful coating. But the main thing that the floor should stand out with is reliability, strength, a flat surface, as well as some other parameters that are extremely difficult to achieve without a subfloor. Changing the final floor every year, if there is no rough one, is an unaffordable luxury.

Photo: draft floor in a wooden house

Draft floor - what is it?

A subfloor is a special base for a finishing floor, which forms a flat horizontal plane for it. The subfloor provides distribution of the load that acts on the floor covering.

In a wooden house, the draft floor can be done in several ways:

• wooden on logs;
• plywood flooring;
• pouring concrete.

Wooden draft floor on logs

In a wooden house, the installation of a subfloor on logs is practically the same as its installation in monolithic or brick houses. The main difference is in the fastening of the lag.

General scheme of the device

lag mount

Floor logs should not be attached to a wooden wall, and you do not need to crash into it. It is advisable to fix the logs to the plinth or grillage of the foundation, retreating from the wall by a few centimeters. At the same time, the distance of the support, which falls on the foundation, must be observed at least 10 cm on either side of the log.

Legs are attached to the plinth

Before laying the logs on the foundation, you need to lay the lower harness, made of long thin boards, to which the logs will be attached using metal anchors (corners).

The lags should not be fixed rigidly to the harness - they only need to be fixed so that they do not travel while laying other layers of the subfloor. The created structure will have a few cm indent from each wall, where thin insulation can be installed.

Definitely need waterproofing

If the distance to the foundation is less than 10 cm, then it is better to crash into the walls, however, it will be necessary to initially lay the lags on the foundation, and then attach a log or beam to them. Measure the contour of the cut and then cut out the necessary grooves in the wood with the dimensions necessary for the distance of the support (for subsequent expansion, the lag should be added about 2 cm).

Do not forget that the laying of beams and lags is carried out on the plinth or grillage only after laying the waterproofing layer.

Lags are attached to the foundation grillage

The standard step between the lags is 40-60 cm. However, its choice depends on the width of the insulation, as well as the direct load. The cross section of the lag is also selected from the current load. With a light section, choose 15 × 10 cm, with an average - 15 × 15 cm, with a heavy one - 15 × 20 cm.

If the beam has a small cross section, and the effect of the load is significant, then it must be placed at a distance of 30-40 cm - this is a fairly optimal option.

Installation of the subfloor on the logs

With the end of the laying of the log, the standard installation of the floor on the logs is carried out. It looks like this:

Between the insulation and the floorboard you need to leave a ventilation gap

Important! Boards, bars and logs should be treated with an antiseptic to prevent them from being exposed to various fungi and insects.

Subfloor plywood

A plywood floor will serve reliably for a long time. She has high strength. Plywood can even be used for final flooring, as if carefully sanded and varnished, it will look quite noble. However, it is more often used as a base for coating with laminate, parquet and linoleum.

Laying plywood on an old floor

Plywood can be laid:

1. On a cement base, but it is necessary to ensure the evenness and horizontality of the base, or use adjusting racks.
2. Fastening on the logs. Here the difficulty is in setting the lags to ensure that the joints of the sheets hit them. Logs must be set so that their upper surface provides one horizontal plane. Engineering communications are hidden in the logs, insulation and sound insulation are laid.

Laying plywood on logs

Important! When laying plywood in one layer, it is necessary that its thickness be at least 15 mm, if in two layers, then you need to choose at least 9 mm for the layer.

All dust and debris must be removed from the subfloor before final laying of the plywood. It is also desirable to perform priming, that is, to process with a special primer.