A high-quality and beautifully made floor is half the success of the repair being performed. There are a great many variations of floor coverings: tiled, linoleum, parquet.

One thing they have in common is that they are all placed on the subfloor.

What it is? By and large, this is any leveled base on which the flooring is laid. Therefore, without any exaggeration, we can say that those who want to lay the floor in the house with their own hands should know the structure of the subfloor as a multiplication table.

Who wants to walk on creaky parquet, stumble over bumps under linoleum, or see furniture shaped like the Leaning Tower of Pisa?

How to make rough floors? It depends on the structural features of the house, and on what type of floor the developer chooses. According to the manufacturing technology, they can be divided into "wet" and "dry" methods of floor installation.

Dry way

Draft floor on logs. Logs are wooden bars on which the floorboard or flooring is attached.

The installation of this floor takes much less time than the manufacture of a cement screed coating, and is much easier. Plus, the installation is carried out without the use of water. This means that the humidity in the room does not rise, which allows you to carry out other finishing work. Logs are placed on beams, or on a concrete base.

Installation of subfloors along the logs is not very difficult, but certain rules must be observed:

• We produce horizontal floor markings. You can pull the cord across the lag at the level found, and proceed with the installation. Or throughout the work, constantly check the horizontal level.
• Make sure that the wood to be worked on is well dried.
• Place the simplest waterproofing under the logs to protect the floors from condensation that can form on a concrete base.
• We determine the distance between the lags according to the expected load on future floors. For residential premises, this is 350-450 mm. The size of the lag varies: in width from 80 to 100 mm, and in thickness from 25 to 60 mm.
• If the reinforced concrete floor is uneven, then the logs are fixed on linings. For this, it is most convenient to use pieces of plywood. So that the linings do not slip out from under the lag, they are glued together with glue (such as PVA) after determining the desired thickness.
• A hole is drilled for the dowels in the base of the floor. A plastic dowel is hammered into the hole, after which the lag is screwed to the base with screws.
• If necessary, use a heater.
• Chipboard is most often used as subfloor flooring. For rolled floor coverings, it is better to take a solid slab. Under the laminate, you can take chipboard of medium hardness.

Draft floor on adjustable joists. This method of installation attracts more and more supporters. It is carried out with the help of plastic screw-racks, which are a development for our military industry.

They are very reliable and strong. Such floors do not creak, are quickly mounted (100 square meters in 2-3 days) and their verticality can be set like furniture legs. The lags do not touch the floor slab, which is undoubtedly a big plus.

It is mounted as follows:

• Each lag is prepared separately. A hole is drilled in it. Where does the screw stand go.
• The lag is placed in the required place. The distance from the wall to the log is 10 mm.
• Fastening the log to the base begins with the extreme screw-racks.
• The screw-stand is hollow. Through it, the base is drilled 45 mm deep, and a dowel is placed there. We hammer in the dowel nail. With a special tool, we adjust the desired position of the log, tightening those screw-racks that are necessary.
• Further, everything is as on a regular floor on logs.

As a variation of the floor on adjustable joists, the floor is made of plywood on special bushings with internal threads. They are inserted into holes drilled with a pen drill. On a standard sheet of plywood - 16 holes.

It turns out that the sheet of plywood stands, as it were, on legs. At the same time, it withstands about 5 tons per square meter.

Draft floors with dry screed. They are convenient in that they equalize the unevenness of the floor well. And you can mount it all year round, regardless of the temperature.

The technology of the device is as follows:

• A vapor barrier layer is laid on the base of the floor. Secure with adhesive tape. Near the walls, the film should rise to the level of the dry screed.
• Then the backfill is laid: perlite, silica or quartz sand, slag, etc. The size of the granules is 2-5 mm, the moisture content is not more than 1%.
• The backfill is leveled with a rail to the marked level.
• Dry screed boards are laid: chipboard boards, waterproof plywood, gypsum fiber sheets. They overlap with each other.

Wet mounting method

Floor screed. This method is quite common, since the materials are relatively inexpensive and are always on sale.

Perform them as follows:

• The base is cleared of debris. Lay hydro and thermal insulation.
• With a step of 2 m, beacons are fixed - special steel slats. With their help, the horizontal screed is maintained.
• The prepared solution is applied in portions, and leveled with a rule and a trowel.
• A top coat is required if the finished floor is made of delicate materials. Most often, self-levelling compounds up to 15 mm thick are used.

self-leveling floor. This is the name of the rough floor, when the rough and finish screed are performed in one process.

A fluid solution is poured onto the prepared base (cleaned and primed) and leveled with a special spiked roller that removes air bubbles.

The thickness of such a cement-polymer floor is from 0.5 to 3 mm, so the drying time is much less than that of a cement screed - from several days to two weeks.

Draft floor in a wooden house

Features of his device:

The underground must be well ventilated and dry. To do this, holes for ventilation are arranged in the foundation. It happens that the soil in the basement is damp, then it is necessary to lay a waterproofing layer of clay or concrete.

Waterproof the foundation with roofing felt, or other material with similar properties.

It is necessary to treat beams, crowns, logs, floorboards with an antiseptic. We must not be too lazy, and do it twice, with a break of 5 hours. Pre-wearing protective equipment.

Laying the subfloor in a wooden house is done using boards.

There are several methods for laying boards:

• In the grooves of the beams. Beams resemble the shape of the letter "H"
• Laying on the shoulders of the beams. In this embodiment, the beam is similar to the letter "T"
• Laying on cranial bars. The most common method, because the simplest. The bars are nailed to the edges of the beams, and boards are placed on them.

Instead of boards, slabs can also be used. He is able to withstand the load from the insulation.

On top of the boards, waterproofing, insulation, and at the end - vapor barrier are mounted. The draft floor is ready.

How is the draft floor arranged in a wooden house? How to do it yourself? Of what? There are many questions, but no fewer answers. If you are building your country house or if you decide to replace the old floor with a new one, then you are on the right track and have come to the right place where all your doubts will be dispelled.

Draft floor along the lags

The draft floor along the logs has long been popular - it is not difficult to make it, and you do not need any special skills. True, such a floor has one very significant drawback - it does not isolate impact noise well, since all connections are fixed rather rigidly. In addition, this type of subfloor is not recommended for bathrooms, toilets, baths and saunas, since the boards do not like moisture.

Logs are simply bars, of which the frame for leveling the floor consists. For logs, non-planed boards of the second and third grades from healthy coniferous and soft hardwood are most often used. But if we talk about a private house, then for the log you can use not quite ordinary bars, but logs, which will be much more reliable and durable.

But first you need to prepare these very logs. Since the surface of the logs is not even, you need to level it at least a little. To do this, it is necessary to “demolish” the upper part with an ax, that is, the one that will “hold” the boards of the finishing floor. You can not get carried away too much, you still won’t be able to achieve the perfect surface.

Logs should lie down in pre-prepared grooves cut in the upper crown of the walls, and the distance from the wall to the end of the log should be 2-3 mm. This is done so that they do not creak under your feet. Well, for safety (you never know what pests will get inside), it is worth treating the edges of the logs with an antiseptic or, in extreme cases, with ordinary bitumen. In addition to the grooves, the logs must have additional support, which can be brick pillars.

The lag step should be at least 60 cm, but if the boards are thick or you use logs instead of boards, then the distance between two adjacent lags can reach one meter, but no more.

Having laid the logs, you can proceed to the next step. You will need a bar with a section of 50x50, which will become a support for the subfloor. It must be screwed onto the screws from each side of the logs. Just keep in mind that by fixing it in three places, you risk your health - the beam can easily fall off - so you should screw the bars as securely as possible. Some cunning people buy ordinary 150x40 boards to save money, and then dissolve them into three parts. Thus, from one board, as many as three bars with a section of 50x40 are obtained, which are quite suitable for laying a subfloor on them.

Proper fixing of the bars for the subfloor

You need to fasten the bars along the log with the expectation that you will also use a heater. If the thickness of the insulation layer is 10 cm and the thickness of the draft board is 25 mm (for example), then the distance from the upper edge of the log to the bar should be 12.5 cm. With a greater thickness of the insulation, these figures will naturally change upwards.

The next step is laying the subfloor. Here you also have a small problem, which, fortunately, is quickly resolved. The fact is that the side surface of the logs has various flaws - somewhere a knot sticks out, and somewhere there is a hole, so you will not succeed in sawing the subfloor boards of the same length. You will have to cut each one separately. Well, if thick bars were used instead of logs, then in this case you can safely saw and saw.

The boards are laid directly on the bars that you screwed from the sides of the logs. They can be “planted” on nails, or you can also fasten them with self-tapping screws, just like bars. That's your business.

Laying subfloor boards on bars

Of course, you can walk on such a rough floor, but if your weight exceeds 80 kg, then the boards can easily break through and you will become a victim of your own stupidity. To prevent such incidents from happening, throw thicker boards directly on the logs and you can go about your business further without being exposed to any risk.

Having finished laying the boards, you can begin to insulate the floor with heat-insulating materials. Fortunately, now they are “divorced” quite a few and it will not be difficult to choose the right one for the price and size. If necessary, the width of the insulation can always be adjusted with a construction knife with retractable breaking blades.

As you can see, the device of the subfloor on the logs is very simple, so you should not have any special problems during such work.

Dry screed subfloor

The first method is very common at the construction stage, but what if you bought a private house that is more than one year old and in which concrete floors are made instead of wooden floors? How to align them?

You can, of course, stop at a concrete screed or use the now popular self-leveling floors, or you can, the price of which is much lower.

So, to make a rough floor with your own hands in this way, you will need the following tools and materials:

• polyethylene film
• damper tape
• expanded clay
• plywood or chipboard, or GVL
• jigsaw
• screwdriver
• PVA glue
• self-tapping screws for
• ruler, marker, tape measure

Preparatory work

On a concrete base, you need to spread a plastic film, which will serve as a vapor barrier, while the overlap on the walls should be at least 10-15 cm. In those places where the pieces of the film are joined together, you must also make an overlap of 20 cm. So that the edges of the film do not diverge , it is necessary to seal the joints with stationery tape.

The next step is gluing damper tape around the entire perimeter of the room. The height of this tape should not be less than the thickness of the expanded clay layer, which you will fill up as the future base of the subfloor.

This is followed (you can do without them, but for greater confidence in an excellent result, it is better to use them anyway). Lighthouses are installed using a water level, and their height is adjusted using wooden blocks, by placing or removing which, you can achieve a perfectly flat plane.

Now you can fill in expanded clay and use a long metal rule to level it, guided by the beacons. You should not just immediately fill up the entire area of ​​\u200b\u200bthe room, it is better to lay exactly as much as you need to lay the first sheet of plywood, because walking on a flat floor is much more convenient than on quicksand. The minimum layer of expanded clay should be 2 cm, otherwise your subfloor will "dance" under your feet.

Expanded clay is poured onto a plastic film

Using the rule, we level the expanded clay, focusing on the beacons

Laying sheets on expanded clay

Having laid the first sheet, you will immediately begin to doubt whether everything has been done correctly, because standing on plywood or GVL with your feet and walking a little on it, you will feel how the sheet slowly begins to “sink” in expanded clay. This reasonable question always arises and absolutely for everyone who works with a dry screed for the first time. There is nothing to be afraid of, having laid the second and subsequent sheets, you can make sure that the screed really works, and the sheets lie flat and do not move anywhere.

We lay sheets of GVL (plywood, chipboard) on expanded clay

Important: try not to move the sheets of plywood or GVL strongly - their weight is almost 15-17 kg and the movement of such heavy plates can cause deformation of the expanded clay layer.

You can fasten the sheets with ordinary self-tapping screws, but you should not “plant” them too rarely - the most optimal distance between two self-tapping screws is 10-12 cm. Well, to make everything super reliable and super durable, pre-lubricate the joints of the sheets with PVA glue. It is recommended to apply it in waves and in a very small layer, because the structure will be additionally fastened with self-tapping screws.

How to apply glue

At the end of the laying of sheets, you can proceed to the "decoration", if, of course, I can say so. All joints must be puttied with a grout mixture, and after it dries, using grinding, level the surface.

If you are doing a dry screed in a bathroom or any other room with high air humidity, then you will have to treat the entire surface with special waterproofing compounds, for example, bituminous mastic or cement-based elastic mortar.

It is worth believing that now the question is: “How to make a subfloor?” you can safely remove it from the agenda and, without hesitation, begin to implement your plan. May good luck and success always accompany you!

Construction technologies are constantly changing. Modern methods are often more effective, but not always cheap. In particular, one of the most affordable flooring technologies is a subfloor along logs. Yes, it is not perfect, but so far this is the cheapest way to make a floor. In any case, in those regions where the price of wood is still low.

In the construction of the floor, the rough flooring can perform two functions. The first is to serve as the basis for laying heat-, hydro-, sound-proof materials. The second function is to serve as a support for finishing flooring or floor screed under the floor covering. Moreover, insulating materials can also be used to improve performance.

One of the options for underfloor heating and tiles using

Is it possible to make a finishing floor without a draft? Basically, it is possible, but in this case it is more difficult to achieve the required characteristics. If the requirements are not too high (dacha, summer or guest house, technical building) and it is important to get only the necessary minimum, you can do without a subfloor.

If the requirements are high (for a residential or heated building), as a rule, a construction without a rough flooring requires more money. Why? For the subfloor, inexpensive materials are used. The main selection criterion is strength. They do not pay attention to the appearance and this allows the use of inexpensive materials. For example, unedged board (after appropriate processing), construction plywood, lean concrete slab. Other materials are laid on the rough base and claims to their strength are minimal. The main emphasis is on "protective" characteristics. After all, the load falls on the floor structure and rough flooring, and not on these materials. And they are usually relatively inexpensive.

All draft bases can be divided into two large groups: dry and wet. Wet include all types or. But this is not about them. We will talk about dry ones, and along the lags and beams.

To date, there are more modern technologies, but the subfloor on the logs remains the cheapest. This is a traditional version that has been modified to meet modern requirements for comfort and economy. But even with the changes, it is difficult to achieve those parameters that are considered the norm today. In particular, sound insulation, and thermal insulation cannot be ideal. You can only get closer to the norm. But the solution will not be the cheapest.

Ceilings on wooden beams

Beams in a floor structure are wooden or metal elements that rest on the foundation and serve to transfer the load. Since wood is still the cheapest tool for us, most often our beams are wooden. They are made from timber - solid, glued, or spliced ​​beams (from several boards) are used.

Beams can only rest on the foundation, they can have intermediate supports. In houses with a subfloor, piers serve as intermediate supports; in the absence of a subfloor, brick columns are folded or columns are made of reinforced concrete. Waterproofing is laid on these supports in two layers (roofing material or something like it, but not a film), and beams or logs are supported on the waterproofing.

Beams and logs - the difference

How are beams different from lag? In short, beams are load-bearing structures, but logs are not.

Beam - a linear element of load-bearing structures, based on both ends (unlike the console) and working mainly in bending. As a rule, the section of the beam is rectangular or square. In wooden houses, they are also made from hewn logs. The installation step of the beams and their cross section is considered during the development of the project. Logs are also prescribed, but they are not so critical, so their characteristics can be changed during the construction process.

The logs are not elements of the supporting structure and they are simply made of a thick board, which is often placed “standing up” - they are supported on a narrow part. With such an installation between the lags, it is convenient to lay the insulation - when choosing the installation step of the lag, the width of the insulation is also taken into account. The draft floor along the logs can also be with the location of the insulation on top. This type is called a floating floor, since the finish coating does not have direct contact with the base (in this case, with the rough flooring).

There are two important points. The first - when using mineral wool as a heater, it is necessary to measure the actual width of the roll or plates. It doesn't always match what is advertised. The second - the distance between the lags should be 3-4 cm less than the width of the insulation. Then it can be put in a thrust and it will be held due to the force of elasticity. This makes installation easier. But there is another advantage to this solution. Even if the insulation “bends” a little or dries out during operation, no gaps will appear between the cotton wool and the lag, as the material will straighten out.

When laying insulation, the main thing is not to leave gaps and minimize cold bridges

When using polystyrene foam, polystyrene foam, polyurethane foam as a heater, the step lag (and their cross section) is also better to choose. But in this case, "compress" it will not work. The plates are cut into pieces of a slightly smaller width than the distance between the lags, and the gaps are filled with mounting foam.

Lag installation step

The installation step depends on the board from which the lags are made:

• for a board with a thickness of 40 mm, the distance between the centers of the support is 80-90 cm;
• 50 mm - distance 100-110 cm;
• board thickness 60 mm - 120-130 cm.

The draft floor is the basis for the finishing floor, so it must be leveled to the horizon. The smoother the base, the less problems when laying other materials. Therefore, already when installing the lag, their edge is brought out at the same level.

One of the possible options

If the step of the beams is small - up to 80 cm, the rough flooring can be laid immediately, without a log (board 40 mm). With a large step of the beams, logs are laid across, and the flooring of the subfloor is laid on them.

A couple of comments about the wide board. If the budget is limited, you can save money by making prefabricated logs. Two boards 25 mm thick cost less than one board of the same length 50 mm wide. We buy two boards, put them one to the other, connect them with nails or self-tapping screws (preferably nails). We put fasteners on both sides in a checkerboard pattern. They put the logs “on edge”, so that they even surpass the board in strength - there is less chance of a crack appearing along the wood layer. There is one more nuance that will help to avoid the "torsion" of the prefabricated log: we arrange the boards so that the annual rings are located towards each other.

Floor structures on wooden beams

When constructing a subfloor, a board is more often used. Basically, it serves only as a basis for laying insulation. The load from the insulation is small, so you can not knock down the flooring tightly, but leave a gap of up to 1 cm. But such a sparse laying is suitable for materials with sufficient density. When using bulk thermal insulation, you will have to make a continuous crate.

With a large length of beams or lags, intermediate jumpers are also made for a more stable geometry

Draft floor along the lags under the screed (floating floor)

Can be done if necessary. The only question is that the beams can withstand the load. This is calculated separately. How good is this design? The fact that:

• The usual "cold" floor can be made warm. You can even make it heated (if the beams withstand).
• On top of the concrete slab, you can lay tiles, lay sheet material and lay coatings that are demanding on the base - laminate, PVC tiles, linoleum.

By the same principle, you can make a rough floor on wooden logs without cement. As a top layer, you can lay plywood, OSB and other sheet materials that you consider suitable in two layers. On such a base, again, you can lay tiles and any other type of finish.

What lags and board to use? It is possible / necessary to select, since the thickness of the board depends on the installation step of the lag:

• the distance between the lags is 80 cm (permissible up to 100 cm, but not under a screed or tile, under lighter coatings) - board 40 mm;
• installation step lag 50-60 cm, board 30-35 mm;
• for boards less than 30 mm, support is required with a distance of 35-40 cm (depending on the specific thickness).

The draft floor in this case may not be solid, but with gaps. Under a concrete slab, it is best to take extruded polystyrene foam, high-density polyurethane foam as a heater. You can foam glass (foam glass), but it is very expensive. These materials normally withstand the weight of a monolithic screed. By the way, since it fits on an unstable foundation.

How to ensure long-term operation

With this design of the floor on wooden beams, it is important to protect the subfloor board from decay as best as possible. If the subfloor is below, care must be taken to ensure that it is ventilated (ventilated) and that the humidity in the subfloor is as low as possible. We need a blind area around the house (better insulated), as well as a drainage system.

As an additional measure, a film with sand is used. A dense PVC film is spread on the ground in two layers - the joints are glued with adhesive tape, brought to the foundation and fixed there. A layer of sand is poured on top of the film (at least 5 cm, but more is better). The film does not let in most of the moisture (if it is intact and the joints are well glued), and the sand absorbs the excess, and then slowly dries out. The same method is also used using any other draft floor along the logs.

Draft floor from OSB (OSB). You can remove the rough flooring from the board and lay the slab in two layers

As already mentioned, the subfloor board can be edged or unedged. A prerequisite is operating humidity. Few people will lay chamber drying, but the board must be dry - at least 6-9 months of drying. If the floor of the first floor is laid, the material must be treated with protective compounds. Humidity in the underground will be high, so the quality of processing should be good. It is better to process several times. Chemistry for wood today is more than enough. You can select properties. If folk remedies are needed, this is processed oil.

Ground floor above ventilated subfloor

The overlap of the first floor over an unheated underground is different in that it must be well insulated. If you are not going to do floor heating, you need to make sure that it is comfortable even with working products. To do this, it is better to make two layers of insulation and place them in different directions.

In this design, the rough flooring is only a support for the first layer of insulation, so taking a thick board here does not make sense. Usually they take 25 mm, process it and use it for filing. In the construction shown in the figure, a cranial bar is nailed to the bottom of the beams. Usually its cross section is 25 * 25 mm. A rough roll board is placed on the cranial bar. The segments are short - the length is equal to the step between the lags. Substandard length can be taken on this flooring, but there is less waste if the length is a multiple of the lag step.

Waterproofing is laid on the boards. Please note that if mineral wool is used as a heater, the material must be vapor-permeable. It should make it possible to remove moisture from the insulation. If the insulation is foam, polystyrene foam, foamed glass, they themselves do not conduct steam and this layer is generally irrelevant.

The thickness of the insulation should be such that its upper edge is 2-3 cm below the edge of the beam. This is necessary to ensure the ventilation gap. Wood changes humidity and it is necessary to give this opportunity, leaving a ventilation gap.

A cross frame is laid across the beams. These are lags. Their height depends on the required thickness of the insulation, and the installation step depends on what kind of flooring you plan on top. The dependence of the board thickness on the lag step is described above. But it can be not only a board, but also any sheet material.

Waterproofing flooring at a distance of 2-3 cm from the surface of the insulation

A vapor barrier is laid on top of the insulation. This time, the material should retain both vapor and liquid. In the case of using mineral wool, it is better to use a membrane with one-sided vapor permeability (for example, or Izover, other brands). It must be laid so that steam can escape from the heater. This solution is better, as it makes it possible to maintain normal humidity in the floor cake.

There are also options with one layer of insulation (pictured above). This method is convenient if, according to thermal engineering calculations, the thickness of the insulation is not too large.

What is the rough floor made of on the logs

The draft floor can be made from boards (edged or unedged without bark) and any sheet material, including drywall. Sheet materials include:

Now we are not talking about the environmental safety of the listed materials. Here everyone makes his own decision. The point is that any of these materials can be put on logs. These materials fulfill their role as foundations. The thickness of each material depends on the installation step of the beams or lag. Once you decide on a specific material, it will not be difficult to choose the thickness.

Laying a subfloor is a rather laborious operation, but it is absolutely necessary. The device of the lower floor of the house serves as its basis and is connected with the foundation. The rough floor serves as an intermediate link between the foundation and the final finish, while performing a number of specific functions.

1. Draft floor as a structural element of the house

After tying the foundation, the first step is to install the lower floor of the house. On it you can carry out further work on the installation of walls. This is especially true for the construction of a frame house using frame-frame technology, and the laying of bricks, wall blocks from the inside requires a solid foundation under your feet. In addition, the lower ceiling performs a number of other functions, being a necessary element of the building.

Draft floor:

1. Carries out the distribution of all loads on the lower floor, such as the weight of load-bearing walls and partitions, all people, furniture, household appliances and appliances
2. Serves as the basis for the work on assembling the frame and erecting walls
3. Is the basis for the finishing floor
4. It is a component of the overall shell of the house, protecting it primarily from low temperatures

Obviously, all the listed functions of the subfloor impose special requirements on its installation, such as strength, surface evenness, resistance to atmospheric influences.

2. Types of floors

The main reason for installing different subfloor designs is the difference in the type of construction of the houses themselves. The house can be stone, block, built of logs or thick timber, frame. Under different types of houses, different types of foundations can be laid:

• slab
• Tape
• Columnar
• Pile screw

The deepening of the foundation and its strapping can also vary somewhat. However, there are some common features and features of subflooring for all types of structures. In many cases, the base for the subfloor is the strapping bars, which receive and transfer all loads from the floor directly to the foundation.

In accordance with their functions, the draft floors are several layers responsible for each of them:

1. The base of the floor is either soil or floor elements
2. The underlying layer is a layer of gravel, sand, slag, expanded clay, etc.
3. Base for coating (screed) - monolithic leveling layer
4. Layer of hydro and thermal insulation
5. The floor covering itself

Draft floors are divided into three main types:

• By lags
• By the beams
• On the ground

The difference between the types of subfloor is in the way it is laid, as can be seen from the name.

3. Preparation for installation of the subfloor

If the foundation of the house does not provide for a basement, then the ground serves as the basis for laying the subfloor. It must be prepared accordingly for the device of the subfloor.

Grass, various construction debris and vegetable soil are removed. An important point: you need to dry clay and loamy soils as best as possible, so they can contain a lot of moisture in the base. It is also impossible to use soils with an admixture of snow and ice.

The site is then carefully leveled. If necessary, soil can be added to the pits. After adding the soil, it is distributed in an even layer and tamped with manual or mechanical rammers.

4. Laying the subfloor along the logs

The device of the floor along the lags is a fairly popular way.

In this case, a wooden frame is made, which is laid on a strapping beam or other specially made supports. The logs themselves are a bar or a thick board, sometimes placed on edge.

In this case, the height of the floor should be insignificant - so that there is no danger of failure to a great depth. The distance from the floor to the log should not be more than 25-30 cm.

With a significant width of the room, the logs will have a large length, and it is not enough to lay them only on the external strapping beam. In this case, additional supports are placed under the logs. There are several ways to arrange supports for logs.

The base is concreted and a thick board is laid on it, which serves as a crate for installing a log. This method is especially well suited for a low base above the ground. If the distance under the floor is large 15-20 cm and the floor is not concreted, posts are installed under the boards of the lower crate, in increments of about 80 cm. The posts can be installed in this way:

1. Holes come off, slightly wider than the cross section of the columns (35-40 cm)
2. They are concreted so that the upper base protrudes slightly above the ground.
3. Brick columns are laid out.

Usually it is enough to lay out the columns in two bricks in two layers, perpendicular to one another. You can completely make columns out of concrete, but then you will need to build a high formwork.

The height of all columns must be displayed in one plane. This is controlled already when laying the foundations for them. If necessary, the height of the columns is adjusted with various substrates: wooden spacers are installed between the surface of the boards and the logs, the dimensions of which are about 20-25 cm long, 10-15 cm wide, and about 3 cm thick. They adjust the horizontal plane of the log. For fine adjustments, thin sheets of plywood are usually used.

On top of the posts, you need to lay a layer of waterproofing, for example, from roofing material.

The distance between the lags should not exceed 0.5 m. A small gap must be left near the walls, taking into account the deformation of the wood.

On top of the log for the finishing floor, you can fix plates made of durable material - OSB or thick plywood. It is recommended to do this "out of the box", that is, the subsequent layer of plywood or OSB is slightly shifted relative to the previous one.

If necessary, the cavities between the lags can be filled with insulation. It can be expanded clay or mineral wool - depending on the degree of necessary insulation of the house.

5. Floor on adjustable joists

Recently, it has acquired a method of installing a log on adjustable stands. These are plastic screw supports, strong enough and light. They are equipped with a square section stand, which is placed on a rigid base and a height-adjustable screw. With their use, you can quickly equip the subfloor, moreover, it will not come into contact with the base, it will be well ventilated, and therefore the need for waterproofing disappears.

The order of installation of such lags is as follows:

1. Holes are drilled in the log boards - in increments of 50-80cm
2. Lag is installed in the right place
3. The support is attached to the base
4. Racks are twisted to the required level

6. Subfloor flooring on beams

The next way to lay the subfloor is to install it on the beams. Here the main structural element is a wooden beam. It is made from a rectangular bar. To determine the cross section of the beam, all load characteristics on the base of the ground floor premises are taken into account. In order not to use a heavy thick timber that is physically difficult to work with, you can use double boards or boards mounted on an edge. A good option would be to use hewn logs.

The load on the beams is calculated from a number of parameters that we mentioned above. It is believed that the total load from the weight of furniture, fittings, etc. can be about 400 kg per 1 m2 of floor area.

Span length, m	Installation step, m
	0.6 m	1.0 m
3	75x200mm	100x175mm
4	100x200mm	125x200mm
5	125x200mm	150x225mm
6	150x225mm	175x200mm
7	150x300mm	200x275mm

The beams are mounted parallel to each other. With a room width of more than 6 meters, additional supports must be installed under the beams. These can be columns, the installation of which was described above.

Beams are fastened directly to the walls. A hole is cut in the wall corresponding to the section of the beam, and the beam is laid into it with its end. To isolate from external influences, this hole is laid with tow. The installation depth of the beams in the walls depends on the section of the beams. The thinner the beams, the deeper they should go into the holes (up to 100-150mm).

Often, the transverse beams for the subfloor are elements of the lower piping of the foundation.

7. Laying the floor on the ground

In many cases, especially if the floor height is low, it is laid using the “on the ground” method. In this case, you do not have to spend a lot of expensive lumber.

Let's consider this method in detail. It consists of several stages:

1. Base Leveling
2. Backfilling with a layer of sand 10-15 cm at a humidity of 7-10%
3. Sand compaction
4. Adding crushed stone and gravel with a thickness of 8-20 cm at a moisture content of 5-7%
5. Laying adobe-crushed stone or adobe-gravel layer with a thickness of about 10 cm
6. Compaction of this layer and the appearance of moisture on the surface
7. Pouring concrete mixture

As a result, after hardening, we will get a flat solid surface on which you can immediately lay the finishing floor. The layers of the subfloor for better fastening and solidity of the screed are usually reinforced with reinforcing mesh. Thermal insulation of such a floor is conveniently carried out with expanded polystyrene plates.

8. Device of couplers

The top layer of the subfloor on the ground is called the screed. Screeds are made from cement-sand mortars. The main purpose of the screed is to create a perfectly flat surface for laying the finished floor. To bring the plane, so-called beacons are installed. These are, as a rule, slats with a thickness selected for the creation of a plane. The mixture is applied to the floor and accelerated to the height of the rails.

The junction of the screed to the walls and partitions must be laid with waterproofing. The surface during the laying process is continuously leveled, as the concrete tends to settle.

Work on the creation of screeds must be carried out in the warm season, with an optimum air temperature of at least 15 degrees. On top of the main screed, it is recommended to apply a self-leveling layer (its thickness is about 5-10 mm) using the bulk method. To do this, there are many different mixtures on sale.

The final stage of the screed device is its primer and waterproofing. The surface before applying primers is cleaned and primed without gaps.

9. Conclusion

The device of draft floors is a rather laborious process that requires compliance with all technologies, accuracy and well-known craftsmanship. In the simplest cases, you can do it yourself, but it’s better to turn to professionals - the structural strength of the building, the evenness of the surface and its suitability for finishing, as well as sufficient insulation and waterproofing of the whole house, largely depend on the installation of the floor.

Specialists of the company "K-DOM" are ready to perform work on flooring, both rough and finish, in compliance with all requirements. Works can be performed both separately and as part of the construction of turnkey cottages.

The load from the building falls on its foundation. The structure that precedes the finishing coat and serves as the basis for the insulation is the “subfloor”. The temperature regime of your room depends on how it is installed. If cracks remain in it, then cold air will begin to flow from below, dampness and the smell of rot will appear in the house.

Description

When choosing a material for the load-bearing beams of the floor structure as a whole, consider the area of ​​\u200b\u200bthe room for which it will be intended. The larger it is, the thicker they are. This factor is explained by the fact that the finish coating and all the materials that are involved in the installation process must be evenly distributed on them.

How to make a draft floor in a wooden house

There are several options for its formation, but more often they use the "dry" method.

The draft floor is formed according to the following principles:

• According to the lags.
• "Prefabricated", using a dry screed.
• "Adjustable" (on plywood and chipboard).

"Prefabricated" subfloor

"Adjustable" subfloor

If the boards are laid on logs, then they are laid on the following base:

• Beams.
• Reinforced concrete slab.

The adjustable floor is formed on the following grounds:

• Logs.
• Plywood.

What do you need to know?

It is laid on the floor main floor, using less hard woods. These include coniferous varieties. These are the following types:

• Cutting board.
• croaker

In order to achieve the expected results from the installation done, you need to know the following:

• The basis of the entire floor structure is a beam, which is laid on a waterproofing layer (two layers of roofing material).
• A rolled protective material or 2 layers of high-density polyethylene is spread on it.
• Logs are attached to the timber, which serve as a frame for mounting. They are not brought to the walls, leaving a gap of up to 30 mm. This distance will be insurance against possible shrinkage of the soil (changes in temperature and groundwater levels in the soil) and natural fluctuations in the moisture content of the log during its operation.
• The artificially created free area between the wall must be filled with mineral wool.
• The whole tree must be treated with antiseptics and fire retardants. If ready-to-use materials are purchased, then the cuts made must be protected from moisture and bark beetles.

Do-it-yourself draft floor in a wooden house

For work, a board with a thickness of 15 to 20 mm is used. Properly prepared on milling machines, the source material will create grooves and shoulders on its side. This option will eliminate the work with a hammer and nails, which will speed up the assembly process and the tightness of the connection. The rigidity of the structure will not create a creak.

The thickness of the board for the subfloor affects the distance (step) between the lags. The larger it is, the wider this gap. For example:

• With a board thickness of 40 mm, the step between the lags can reach one meter.
• With a thickness of 35 cm, the step between the lags should not exceed 850 cm.
• With a thickness of less than 35 cm, the step between the lags should not exceed 60 cm.

Of great importance is the correct location of the foundation pillars. They are located around the perimeter and in the central part of the building.

The thickness of the log is directly related to the step of placing the foundation pillars, since the main beam is attached to them.

The following ratios between the dimensions of the lag and the pitch of the foundation pillars, expressed in centimeters, should be observed:

• Logs 40 thick with a step no more than 900.
• Logs with a thickness of 50 at a step of 1100.
• Logs with a thickness of 60 at a step of 1300.

Subfloor installation using plywood

The sequence of work is as follows.

• Beams are placed on a layer of waterproofing.
• Roll material is laid on them, providing protection from moisture.
• The lags are fastening.
• They are lined with a plywood sheet 10 mm thick or moisture resistant boards (MDS, VAT).
• The seams of the connection are closed with construction tape or sealant is poured.
• Close the subfloor with a layer of vapor barrier.

For insulation from condensate from the side of the room, the following materials are used:

• cement mortar.
• Thick cellophane in 2 layers.
• Roll foamed polyethylene based on foil (lay foil to the room) and other materials.

An air barrier must remain between the vapor barrier and the floorboarding. Through the holes in the foundation (air), the subfloor must be ventilated.

Before applying, isolate pipes and meters with construction tape. Apply in layers using a brush, roller or rubber trowel. Pay special attention to hard-to-reach places. After the first layer, self-adhesive tape must be applied to all joints and joints. The second layer will close it. The composition should be partially applied to the wall (its lower part).

There are other materials for such work. Roll foil insulation can be used, which will simultaneously contribute to noise isolation and heat preservation in the room. They are overlapped with a metal part towards the room.

Video: Proper installation of the subfloor

Conclusion

This type of "dry subfloor" can serve as the basis for the formation of the main coating. In some cases, for laying a parquet board or laminate, the finished structure is covered with a layer of waterproof plasterboard.

Video: How to make a subfloor from plywood?