Making a subfloor in a wooden house. Draft floor on wooden beams: purpose and design features, installation instructions How to lay a draft floor in a wooden house

27.06.2020

The draft floor, as a base, can be made in wooden and concrete houses. The pre-floor must be perfectly level. Installation of such a coating is a laborious process, and it is best to trust professionals.

Of course, the subfloor in wooden house you can do it yourself.

Before moving on to installation, we will analyze with you the types and purpose of subfloors.

Varieties of rough floors

Flooring directly on the logs. In this case, we use chipboard, OSB, plywood or boards, which in turn are laid on logs.

This type of subfloor is well suited for surfaces with low load-bearing characteristics, which allows you to distribute the load over the entire floor area. It is recommended to use such coatings as laminate, linoleum or parquet board.

Flooring directly under the joists. It is also called a double layer. The space from the log to the log is filled with waterproofing, thermal insulation, vapor barrier.

Draft floor directly on the bearing beams. This floor option should be laid when designing a house.

In order to reduce the step between the beams from 1.2-1.5 m, as is usually the case, to 0.6-1 m, then the beams will replace the logs. We refuse the extra layer. In terms of everything expendable materials, we get, and save about 30%.

Plus, we get an increase in the height of the room. But, in case you have already bought finished house, do not be upset, the subfloor boards can be thrown diagonally across the beams, this will ensure high strength of the floor surface.

Subfloor types:

A wet base is a screed (concrete base) under the space on which the wooden floor will be installed.

Since the concrete base is not level, an additional leveling layer will be required. It is possible to make a topcoat only after the complete drying of the rough base, approximately 7-8 days.

Dry is a log flooring. They are laid on the ground covered with sand. When installing a lag, use a ruler and a level. Unlike a concrete base, the floor on the logs is difficult to bring to a perfectly even state.

Protecting the subfloor from moisture

All components of the subfloor must be processed by special means against mold and rot. processing all wooden elements, carried out after drying - this is a very important point, the less moisture in the tree, the better and deeper it absorbs antiseptics.

Impregnation is done at least 2 times, do not forget about the cross sections of wood, they must be processed. It is not recommended to first lay the boards and then process them, because the ends will be open to mold and water vapor.

Natural ventilation of the underground, the most important organizational moment, when installing the subfloor. If it is not properly organized, then not a single antiseptic will help you, and after a while you will have to change the entire floor covering.

The vent is made at a height of 30-40 cm, and 90 cm from the corner wooden house so that the air does not stagnate.

From the protection of small rodents, a metal grill can be installed on the vents. For the winter, you can close the vents to keep the heat on the first floor, but be sure to open it with warming.

The preliminary floor should not be continuous. For flooring, you can use any material that can withstand this load.

Waterproofing is mainly used over the subfloor. But, it can also be used before, or crushed stone can act as a material.

Roofing material is used as waterproofing over the floor. On top of the waterproofing, we lay a layer of insulation (mineral wool, polystyrene).

After a layer of insulation, you can proceed with the installation of the finished floor, but professionals recommend over the layer of insulation, apply another layer of waterproofing, and then the final floor covering.

Laying a subfloor on a concrete base

The most important condition is that the screed is perfectly even.

There are two options for installing a subfloor on the surface of a concrete base:

Reiki is used when it is necessary to carry out communications, mount additional insulation or the screed has significant differences, more than 2-3 mm.

Between the slats and the screed we lay a layer of waterproofing, usually this is roofing material. We align the slats with linings and fasten with dowels. If necessary, we additionally insulate or install communications. Subsequently, we mount the floor with boards or slabs.

Remember that on one rail two plates will dock in the middle. The tiles are laid out as brickwork, thanks to this we get a uniform distribution of the load on the rails. We fix plates or boards with nails or self-tapping screws.

Laying a subfloor on a concrete base, used ideally flat surface. To obtain a flat surface, auxiliary compounds are used, usually a construction adhesive. The glue is applied in an even layer, the plates are laid one after the other.

The glue under the slab removes, all irregularities and the subfloor becomes a monolith with a concrete surface. Hats of nails and self-tapping screws are recessed using a screwdriver or a puncher. The holes from the hats are puttied with a special compound.

It is important to always leave a distance of approximately 1 to 2 cm between the walls and the floor. Do not forget to lay this distance with any insulation. If you plan to lay linoleum on top, then it must be sanded with special machines. Mainly the joints of the plates.

Price of work performed

Draft floor work for 1 sq.m. - an average of 150-200 rubles.
Finishing floor work for 1 sq.m. - an average of 150-200 rubles.
Completely rough floor, for 1 sq.m - an average of 1200-1500 rubles.
Completely finished floor, for 1 sq.m. - an average of 2400-2800 rubles.

The arrangement of a wooden floor is recognized as the most time-consuming, expensive and complex, since any structure made of wood should be protected from direct contact with concrete. Otherwise, the floors will become unusable in a short time, and they will need to be replaced. Using some impregnation, you can protect the tree from decay. Chemical methods protections are very effective and prevent the process of damage to the material. but wooden structure impregnated with chemicals cannot be considered environmentally friendly. Considering that it is because of this indicator that a tree is chosen, few people use chemistry. When laying on concrete, waterproofing is required over the entire area between the layers. fasten wood flooring follows using metal squares to create a gap between the bases and the joists.

Source 1poderevu.ru

The subfloor denotes certain bases, which by themselves form an ideal surface for laying the final floor. It is created to ensure the distribution of loads aimed at flooring.

In wooden structures, draft floors are made by three methods:

wooden on logs;
pouring concrete;
use of plywood flooring.

Source fondeco.ru

Wooden floors on logs

In a wooden house, the subfloor device does not differ from the installation of similar structures in a monolithic or brick structure. The only feature is how the lags are attached:

There is no need to attach lags to various wooden planks. Best Option- strengthen them to the basement or grillage of the foundation, retreating a couple of centimeters from all the walls. The distance from the support must be at least 11 cm on all sides of the lag.
Before laying the base, lay the strapping from below, which is made of a long and thin board. Logs are attached to it using metal anchors. They do not need to be rigidly strengthened with strapping. It should only be fixed so that they do not stagger while working on another layer of the floor. This design will have a few centimeters indent from the walls.

If the distance is less than 11 cm, then it is better to crash into the walls. But before that, it is necessary to make the initial laying on the base, then you should attach a choice of timber or logs. It is necessary to first measure the contour of the cutting site, then cut out in the tree the dimensions necessary for the groove, which will be required for the support function.

Important: it is recommended to add about 2cm to further widen the lag. It must be remembered that the laying of the log and beams is done on the grillage or plinth when the laying of the waterproofing layer is completed.

Source kamtehnopark.ru

The standard steps between two lags are 40-60 cm. However, when choosing, great emphasis is placed on the width of the insulation and the required load. Based on this, the choice of the lag section and the acting load is made. At small sizes sections should be approximately 15x10, with heavy loads - 15x20, with medium loads - 15x15 centimeters. In case of excessive load action, if the beams have a small section, it is desirable to provide section parameters of 30x40 cm.

Installation of subfloors on logs

When the installation is done, you will need to do the standard installation. It is carried out in several stages:

It is necessary to fix the cranial bars. They have small sections (approximately 4 by 4), they are fixed in the lower parts of the log from the side. Professionals recommend replacing the cranial bar with boards that will have more lags in width. They will need to be nailed either along or below the lags.
Boards should be laid. They need to be laid on the cranial bar, but not fastened. Considering that their main task is to fix the insulation, they are left to lie freely.
Waterproofing. Lay it on the subfloor. This is done to avoid additional load. The waterproofing is laid so that it goes onto the wall at the level where the floor will be in the future. It is recommended to use film insulation, and use a stapler for fastening.
Thermal insulation - laid on waterproofing.
Vapor barrier. Lay in the same way as waterproofing.
Ventilation. To create a ventilation gap, you only need to break through the counter rails along the lag on top of the vapor barrier.
Coating. At the final stage, it is proposed to use chipboard sheets, as well as boards. From the wall, the logs must be separated by a gap of 2 cm. They will then be placed heaters.

Source lineyka.net

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

Video description

Read more about floor insulation in a wooden house - in this video:

Rough plywood floors

The floor in a wooden house is one of the most reliable options, because it has a high hardness. Plywood is also used for flooring. If it is well sanded and varnished, it looks expensive. But in most cases, it is then covered with linoleum or parquet flooring.

Plywood can be laid in one of two options:

On a cement base. It will be necessary to provide a horizontal and even base or use leveling stands.
Attach to the legs. The main thing is to correctly set the lags to ensure that the joint of the sheet hits them. The joists must be set in such a way that the top surface provides a straight line. They then remove the insulation and sound insulation.

Need to know! When laying plywood in 1 layer, it is necessary that it be at least 15mm thick, if there are 2 layers, the minimum thickness should be at least 9mm.

Source homius.ru

All debris and dust must be removed from the base prior to final laying. If possible, priming should also be done - primer treatment. Plywood must be fixed with glue, and the head of the self-tapping screw must be drowned.

Concrete floor

Like the draft and finishing floor in a wooden house, the concrete version is less common than the others. The concrete floor has one significant drawback - it is very cold. This problem can be solved with the help of thermal insulation material.

The advantages include durability and reliability. Compared to analogues, it is more even and durable. The concrete floor in a wooden house is also chosen because it is better preserved from destruction.

Source zamokok.ru

In a wooden house, a concrete floor is made in 11 stages:

Lay on the lags.
Lay on the ground.
A concrete screed is made on top of the wooden floor.
The floor horizon is set with marks (it is recommended to pull the cord for accuracy).
Stakes less than 11 cm should be hammered into the ground, so that later gravel can be poured over them. After that, it should be tamped and the pegs removed.
Next, the sand is poured.
Then a large polyethylene film is laid, creating an overlap on the walls. It will act as waterproofing.
Using slats, it is necessary to divide the room into equal strips. The width of each should be about 1 meter. The height of the installed rail must be equated with the height of the cord. The concrete is then poured onto the prepared surface.
Concrete is leveled along the rails.
Next, the concrete should be covered with a film and left to harden for several weeks. To avoid cracking, it is sometimes necessary to spray the mass with water.
After the expiration of the term, it is covered with a screed of cement and sand.

Materials for processing lags

Some environmental factors, such as dampness, should not affect the lags. Therefore, when providing a floor in a wooden house, it is necessary to protect them from certain factors.

Bioprotective compounds

The drug with a bioprotective composition protects the tree from mold, decay, blue discoloration, beetles and fungi. One application of such funds will provide protection for 27-32 years. You can buy them in the form of a concentrate. Sometimes a pigmenting substance is added to the composition, which makes it possible to control the quality of application.

Source centermira.ru

Bioprotective compounds are praised for:

environmental friendliness;
slight odor;
absence of allergens.

It is necessary to apply preparations before the installation of the floor in a wooden house has begun.

Indelible antiseptic

Great option if in the city high humidity. Also indicated for use in places with increased level precipitation, temperature changes, in baths and saunas. Working with antiseptics is simple and not too time consuming. Approximate consumption per 1 meter is about 400 grams. Surface application can be achieved after 4 coats. After completion of work, the color of the tree will become pistachio.

Folk methods

Folk remedies for processing lags:

Transformer oil. Due to deep penetration into the structure of the tree and embalming, this agent perfectly protects the material.
Resin. From bugs, fungi and decay, birch resin will perfectly help. Its only disadvantage is the vulnerability to fire.
Motor oil. Pros - low price, good protection. Cons - too strong smell, sometimes interfering for several months.

Source decorexpro.com

Before starting work, you should understand the layout of wooden floors, which consist of 4 “layers”:

Draft coating.
Heat and waterproofing layers.
Clean floor.
Finishing.

Therefore, when wondering what to make a finishing floor in a wooden house, you must first complete the first 2 stages mentioned above and start working on the finishing floor.

Source lesdomik.ru

To make a finishing floor yourself, you need to buy milled boards.

Need to know! The finished floor in a wooden house is laid 5 centimeters above the subfloor.

The floor structure of the first floor in a wooden house is being built in 3 stages:

Logs are laid - so that the boards can be laid perpendicular to them. The smallest thickness is 25mm.
The board must be fixed closer to the wall.
Next, you should use a hammer and a bar so that the boards are as close to each other as possible. With the help of a self-tapping screw, fasteners of each log are carried out through the comb.

Important! If there are plans to change the floor in the future, it is necessary to use a simple mounting option - all floorboards should be fixed from above to the logs using self-tapping screws.

Source ms.decorexpro.com

Conclusion

A high-quality and beautiful floor is the basis of comfort in the house. The floor is an interior decoration, but not only. During operation, it withstands the weight of people and furniture in the house, helps to save heat. For it to be so, he needs a solid foundation.

In the case of a house made of wood, this base will be the subfloor wooden lags. It is easy to make with your own hands, it is strong and durable.

The purpose of the subfloor

In a general sense, a subfloor is a flooring over a floor or beams at the base of a building that fits under the floor covering. For its manufacture, it is used various materials, most commonly wood. It can be OSB-board, plywood or cutting boards. In the case of non-residential buildings, lumber can be used without pre-treatment of the ends, as well as used.

The draft floor helps to solve three main tasks:

Additional thermal insulation.

One of the most popular subfloor designs is the joist design. It is easy to place a roll of insulating material in the space between the beams, which will significantly reduce heat loss.

Leveling the base for flooring.

It is difficult to create a beautiful floor on an uneven surface. This is solved with wood-based boards or plywood.

Increase bearing capacity gender.

A high-quality and reliable base will allow you to use any floor coverings without regard to their strength.

There are several subfloor options. The main difference between them is the material. Gender can be a time-tested concrete screed. It is a good choice for high humidity environments. concrete base suitable for a bathroom in the house, shower or bath.

If you need to prepare a flat base for linoleum, laminate or other material that is not very durable, it is enough to make a simple subfloor from plywood or OSB boards. It cannot boast of good thermal protection, therefore it is more suitable for non-residential premises.

Advice. The best choice for the residential part of the house is the draft floor wooden beams. This is a great option that is equally suitable for any room in a wooden house and not only.

Design features

At the heart of the floor on wooden logs are beams (). Are these bars made of wood or polymer materials, laid parallel to each other, which serve as a support for the sheet material. This is one of the most common options for creating a subfloor.

It is distinguished by:

sufficient ease of installation;
low cost of the material;
a significant increase in the strength of the floor;
uniform load distribution;
ease of installation of thermal insulation and noise protection.

It should be noted the versatility of this type of subfloor. Logs can be laid on the ground, wooden or concrete surfaces, of course, in all cases it is important to ensure maximum protection of the tree from moisture. The result of a properly performed work will be a dry ventilated underground, which will positively affect the characteristics of the floor and the structure as a whole.

Material selection

The reliability and durability of the floor directly depend on the quality of the material used. First of all, this applies to beams. For their manufacture, you will need a bar with a section of 50 x 50 mm or a board with a thickness of at least 50 mm, a width of 150 mm. The exact parameters are selected individually for each specific project.

An important detail of the floor on the logs are cranial bars - slats of small section (approximately 20 x 30 mm), which are attached to the beam along its length and serve to lay the material that supports thermal insulation. As such, OSB boards or plywood are most often used.

Timber and boards for draft floors must have sufficient strength and be resistant to decay. Structures are made of coniferous wood. Beams can be from any available wood, the most common option is pine.

In addition to timber, you will need sheet material to create a substrate for flooring, roll waterproofing, an antiseptic for impregnating wood and a heat insulator (mineral wool).

Floor on joists

Anyone can make a reliable and durable black floor in a wooden house with their own hands. House master. This is not a very difficult task, but in order to achieve the desired result, you will have to work hard. The work itself can be divided into two major stages. The first is the preparation and fastening of the lag, the second is the cutting and laying of sheet material.

Fastening

The first thing to do before starting work is to sketch out a floor plan and calculate the amount of material. It is necessary to calculate the number of beams and multiply by the length. It is important to choose the right laying step. It is calculated individually and depends on the area of the room, the material to be used in the second stage, its thickness and mechanical strength.

Advice. The device of the subfloor with insulation has its own specifics. When choosing a lag step, it is worth stopping at its standard value, namely 55–58 cm. This is due to the fact that the width of a standard sheet of mineral wool is 60 cm.

Before starting installation, it is necessary to impregnate the beams with an antiseptic. Professionals recommend processing wood in two stages, which will provide maximum protection for wood, and therefore the durability of the structure as a whole. If the ends of the log will lie on the foundation, it is imperative to lay two layers of roofing material or a modern analogue between the wood and concrete.

To fix the beams to the wall, you will need metal holders. Several of their modifications go on sale, it will not be difficult to choose the best option for each specific case. Fasteners are easy to install, it guarantees high reliability of the floor and its durability.

When mounting the logs, it is important to ensure that their upper faces lie in the same plane. For control, you can use a long, even rail, to make sure the surface is horizontal, you will need building level. Correcting a slight misalignment is easy; you need to put an adjusting pad under the sagging beam. It should be made of metal or plastic (the wood will soon sag, causing the floors to creak).

Mounting

Using a screwdriver or an electric drill with a nozzle, cranial bars are screwed along the lower edge of the log. Their task is to support plywood or wood board, which will serve as a support for mineral wool. Sheet material is cut, focusing on the step of the beams. Instead of plates, you can use cutting boards.

Advice. When cutting sheets for laying in the space between the lags, one should not strive for perfect accuracy, on the contrary, it is better to cut blanks 1–2 cm narrower. This compensates for the possible curvature of the bars themselves, and it is easy to close the gaps with mounting foam.

The assembled frame is covered with a vapor barrier. Can be bought expensive roll material membrane type or limit yourself to cheap plastic wrap. In any case, the isolation must be reliable. The film is attached construction stapler, the joints are glued with adhesive tape.

Lay the first layer of cotton wool. If a standard step is selected during the installation of the lag, there will be no problems. If necessary, the cotton wool is lightly tamped along the edges so that it fills the entire internal space. Next, lay the second layer. It is important to offset half or a third of the sheet.

The thickness of the insulation is chosen based on local climatic conditions. For middle lane 10 cm is enough, for the north of the country - at least 15 cm. Waterproofing is laid on top of the top layer. On the beams, it is additionally fixed with a stapler, the joints must be sealed with adhesive tape.

A rail 20–30 mm thick is stuffed over the log, it will provide good ventilation finishing floor, protect it from mold. The warm draft floor is almost ready. It remains only to lay the finishing floor boards or sheet material, which will serve as the basis for carpet, linoleum, laminate.

In order for the new floor to fully meet expectations, it is necessary to initially decide on the purpose of the room and the type of flooring, it is on its parameters that the width and thickness of the beams, their step depends. For the most part, a subfloor using OSB or plywood is seen as optimal. The technology of working with the material is not particularly difficult, and the result is a smooth and reliable coating.

Working with sheet material is really simple, but in order to avoid mistakes, you should follow a few simple recommendations:

regardless of the purpose of the room, use only waterproof boards;
joints should pass along the lags;
sheets should not be laid end-to-end, but with gaps of 2–3 mm between them and at least 5 mm from the wall, subsequently the joints are filled with foam;
for fastening the plates, it is necessary to use wood screws, the length of which is at least one and a half times the thickness of the plate.

Do not try to save on material. It is important not to forget that the reliability of the product consists of the quality of parts and components plus good work. In order to make good rough floors in a wooden house, you need to soberly assess your strengths.

Yes, this is not the most difficult thing, but you definitely cannot do without the initial skills of a builder and the ability to work with the material. Perhaps you should involve a specialist in the work, at least not be afraid to ask for advice.

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 gaps remain in it, then from below it will begin to flow cold air, 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 process installation work, should be evenly distributed over them.

How to make a draft floor in a wooden house

There are several options for its formation, but the “dry” method is more often used.

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.
Iron 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 soil shrinkage (change temperature regime and level groundwater 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 for milling machines raw 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 correct location 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 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: Correct installation 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?

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's not perfect, but so far it's the best cheap way make the 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 durability. On the appearance attention is not paid and this allows the use of inexpensive materials. For example, unedged board(after appropriate processing), construction plywood, a slab of lean concrete. 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 draft floor 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 moments. 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. Spread on the ground dense pvc film in two layers - glue the joints with adhesive tape, lead to the foundation and fix it 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 up. 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 processed 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 needed folk remedies is a 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.