Builders call the subfloor the foundation on top of which the finishing flooring is laid. When it comes to concrete floors, the arrangement of the subfloor means the installation of a dry or wet screed to level the surface. In wooden structures, this term is used by specialists to denote the lower part of a two-tiered ceiling.

Mounting a subfloor in a wooden house with your own hands will not be difficult if you have the skill to work on the installation of wooden structures. Overlappings in a wooden house are made two-layer, so that it is possible to lay heat-insulating material.

Insulated floors in a wooden house on the ground floor are an opportunity:

• reduce heat loss at home, thereby reducing heating costs during the cold season;
• exclude blowing through the cracks in the floor (drafts not only create discomfort, but are also dangerous to health).

A double floor with heat-insulating material in the middle of the structure is also mounted as a ceiling between the first floor and the attic (or second floor, residential attic). The insulation prevents heat from escaping through the roof and at the same time serves as a sound insulator if the upper room is used as a living room or workshop.

Construction of the subfloor of the first floor

The system consists of the following elements:

1. Logs.
2. Skull bars. Support for boardwalk, stuffed along the bottom edge of the log.
3. Subfloor flooring. It is made from boards or sheet wood material.
4. waterproofing layer. The heat insulator protects from moisture.
5. Insulation. Mounted between the lags.
6. Vapor barrier layer. Prevents the penetration of moisture into the insulation.
7. Counter rake. It is stuffed longitudinally along the logs or beams to create a ventilation gap - this prevents the top deck from rotting.
8. Flooring. It is mounted from planed boards or sheet material; a topcoat can be laid on top of it.

Before making a draft floor in a wooden house, ventilation of the space under the future lower flooring should be ensured. To do this, there must be air vents in the base. If they are not there, you will have to drill large holes in the corners of the base of the building.

Ventilation will protect the wood from which the ceiling is made from damage by the fungus. The products are tightened with a mesh so that rodents do not penetrate under the floor. If in winter snowdrifts sweep above the air ducts, a ventilation pipe should be brought up from the underground space, the upper cut of which should be protected by an umbrella from rain penetration.

Another important condition for the safety of the structure is the high-quality processing of lumber with a composition for fire and bioprotection. Processing is performed after the timber, board or other element is sized. This allows you to protect the ends of each element and prevent the appearance of foci of decay. Processing is carried out in two passes with a break for drying the first layer of the composition.

Also, the lower part of the wooden walls of the building from the inside should be treated with an antiseptic - all the structures that the laid subfloor will hide.

Installation lag

Lags are load-bearing structural elements. They are installed in increments of 400-600 mm - this parameter depends on the calculated loads and the section of the element. As a log, a bar with a section of 100x150 mm (for light loads), 150x150 mm (for medium loads), 150x200 mm (for high loads) is used.

If you have to use a beam of small section at high loads (or a board 50x150 mm, placed on the edge), the installation step of the lag is reduced to 300-400 mm.

The best option is laying the ends of the lag on the plinth or grillage. But for this, the width of the free part of the foundation base must be at least 120 mm. Strapping is in progress - boards of small thickness are laid on the free part of the grillage or plinth on top of the waterproofing layer so that the wood does not come into contact with capillary moisture rising through the porous concrete.

The ends of the logs are fixed on the strapping boards with the help of corners mounted on both sides of the timber. Logs cannot be rigidly fastened, since the tree changes its geometric dimensions with changes in temperature and humidity. Between the end of the log and the wall there should be a gap of 20-30 mm for such an expansion. This gap is usually filled with an elastic insulation, for example, mineral wool.

If the width of the free part of the foundation base is less than 100 mm, the logs are cut into the wall of the house. At the end of each element, a recess is made for the missing centimeters, taking into account 20 mm for the expansion of wood.

It is advisable to refuse a deep tie-in so as not to weaken the walls. In this case, support columns are erected next to the foundation so that they bear the main load that falls on the ends of the log.

Logs need a reliable support in the middle part, if the length of the run exceeds 2-2.5 m. Brick columns act as supports. To reduce the number of columns, a thick beam is laid on brick supports, on which all logs will rest. The total height of the supporting structure (post + beam) must exactly correspond to the height of the foundation with the laid board framing.

Under each cross beam, at least three brick pillars are required to create a reliable support. The columns are placed along one line, for each a pit is prepared with a depth of 400 mm and a section of 200x200 mm. A layer of gravel 100 mm is poured on the bottom and rammed, then a layer of sand 100 mm is also rammed.

A reinforcing mesh in the form of a square 150x150 mm is installed on the prepared "pillow" on small supports, the concrete mixture is poured. After the concrete has gained strength, the resulting foundation is waterproofed with roofing material and a column of bricks fastened with mortar is erected. Before laying the transverse beam or log (if the posts are mounted under the logs), a layer of waterproofing material is laid on the post.

Subfloor device in a wooden house

Properly installed logs form a horizontal plane - when performing, control the accuracy of the installation of each element with a level.

Cranial bars with a section of 40x40 mm or 50x50 mm are attached to the lower part of the lag. If it is possible to dissolve the boards, it is cheaper to buy boards with a section of 40x150 mm and get three suitable bars from each. They are fastened with nails and form ledges for the flooring.

Draft floors are the bottom flooring, which is laid on top of the cranial bars. For its installation, moisture-resistant plywood or OSB boards are used, but boards of small width are more often used. They are cut to size so that the elements fit in a continuous layer without gaps. This flooring should not be fixed.

Installation of a subfloor in a wooden house involves laying waterproofing roll material. A special membrane or dense polyethylene film is used. The material should envelop all the logs, the joints of the panels are glued with reinforced tape, overlapping at least 120 mm wide. The edges of the material should go to the walls - the excess is subsequently cut off.

The next stage is the laying of thermal insulation between the lags. When choosing how to insulate your home, pay attention to the operational parameters of plate or roll materials. Mineral wool insulation and foam polymer boards are popular. If the thickness of the heat insulator exceeds the height of the log, bars of suitable thickness are stuffed on them.

Mineral wool slabs are cut with a margin of a couple of centimeters in width and length and installed in a spacer. Rigid slabs of foam or polyurethane foam are cut to size, the joints are sealed with mounting foam.

If mineral wool insulation is chosen, a vapor barrier must be installed. It does not allow moisture to accumulate in the fibrous heat insulator, as this drastically reduces the effectiveness of insulation.

It is important to ensure the tightness of the vapor barrier around the perimeter and at the joints of the sheets. The material (dense polyethylene film or a special membrane) is attached to the logs with a stapler. Its edges can be fastened to the wrapped edges of the waterproofing material using reinforced tape. The same tape is used to glue the joints of canvases laid with an overlap of 100-150 mm.

Laying the subfloor continues with the installation of counter rails along the logs. They are needed to create a ventilation gap under the top deck. This will reduce the risk of the appearance and development of the fungus.

The top flooring of a wooden floor is mounted from high-quality boards or sheet material - plywood, wood boards. Fastening is carried out on self-tapping screws, since the nails loosen and crawl out over time, the plank base begins to creak.

After installation of the flooring, the subfloor is considered ready.

Conclusion

Step-by-step instructions help you figure out how to make a subfloor in a wooden house. Ideally, this issue is worked out at the stage of preparing the building project. For example, support beams passing through two adjacent rooms and an internal partition are designed in advance.

When developing a project for a foundation base, it is worth considering the optimal width of the grillage, taking into account the width of building structures, so that in the future you do not have to cut logs into the wall.

A well-mounted subfloor will give home comfort and warmth, increase the thermal efficiency of the house and help save on its operation.

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.

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 mix

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.

Later, insulating material is placed on the first base, in the gap between the lags. Only after that do the top flooring from the boards. If you understand, then this process is not particularly difficult.

However, in order to make a draft floor with your own hands, you will need to familiarize yourself with the methodology for its installation in more detail, having read the description of each stage.

lags

The following fact can be considered a separate bonus. A well-executed rough base can significantly increase the life of the final decorative floor covering. For this reason, it is highly desirable for this technology. It is quite possible to carry out familiar and simple procedures with your own hands. Compared to analogues, for example, flooring, the recommended design will have a much lower cost.

Does the subfloor made of wood have any flaws?

There are few of them, but they are available:

• Do not use the double wood decking in rooms where high humidity is expected.
• This design is not only strong, but also quite rigid. For this reason, it can dampen various impact noises quite poorly.

A detailed description in the article of various will help the novice master to assemble the subfloor at home on his own. Based on the above, you can get a clear idea of ​​the sequence and correctness of the necessary construction activities.

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 draft floor in a wooden house can be done with your own hands.

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 all consumables, we also save about 30%.

Plus, we get an increase in the height of the room. But, in the case when you bought a ready-made house, you should 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 treated with special agents against mold and rot. The processing of all wooden elements is 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 of a 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 are used when it is necessary to carry out communications, install additional insulation or a 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. We lay out the slabs like brickwork, thanks to this we get an even distribution of the load on the slats. We fix plates or boards with nails or self-tapping screws.

Laying a subfloor on a concrete base, used on a perfectly 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 adhesive 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.

All photos from the article

In any room, flooring is an important step; wooden houses are no exception to this rule. And it is not necessary to be limited only to a wooden floor, it is quite possible to use ordinary concrete.

What can be the floor in a wooden house

When it comes to what to make the floor in a wooden house, the first thing that comes to mind is a wooden floor.

However, this is far from the only option; in the general case, it is possible to single out such flooring methods as:

• wooden - the most common construction in wooden houses. A rough floor is laid on top of the log, then a finishing floor, and only then - a floor covering. Since the floor thickness is decent, insulation can be placed in the space between the lags, so that heat and sound insulation will be at its best;

• concrete, in this case, several options are possible. You can simply remove the old logs and pour concrete on top of the ground (after pouring a layer of heat insulator and leveling it). And you can make a thin one, though it’s impossible to arrange a thick layer (a big load on the logs), you may also need to strengthen the log, all the work can be done by yourself.