The concept of "rough floor" hides not just poorly processed boards, but a real "pie" of various materials, which together form a solid foundation for a finished floor. By the way, the subfloor does not have to be wooden; it can also be a concrete screed on the ground. The technology for arranging the subfloor includes a set of measures that provide hydro, heat and noise insulation of the base. In this article, we will look at how you can make a solid and reliable sub-floor, on which you can lay any finishing coating.
How to make a wooden sub-floor on the ground
In a country house, arranging the floor is a responsible and laborious task. A wooden floor on the ground can be made without restrictions. Even if you temporarily live in the house, when the heating is not working, the wooden floor serves for a long time without changes, since the underground is well ventilated through the vents in the foundation.
For wooden elements of the floor structure, it is necessary to select high-quality dried wood with a moisture content of no more than 12%. This is important, as a damp tree can "lead" during operation. For the rough floor in the house, conifers are chosen - spruce, pine, fir, larch. Resin-rich wood is less susceptible to rotting and the development of mold.
Also, wood for logs and subfloors must be treated with an antiseptic and fire retardant.
The underfloor of the wooden floor on the joists must be well ventilated. For this, air vents are made in the foundation, which are covered with a mesh with a cell of no more than 8 mm, so that mice do not get inside.
Base for wood floor
The construction of a wooden floor on the ground assumes that the floorboards will be laid on logs - longitudinal beams. Depending on the characteristics of the house, the logs can be laid on the support beams, a crown or on the support posts.
If the room is large enough, it will not be enough to fix the logs only with the ends on the beams, the structure will turn out to be fragile. Therefore, in the intervals between the walls, support posts are installed on which the logs will be laid. The step between the posts depends on the section of the lag. For example, if a beam of 150x150 mm is used as a lag, then the distance between the support posts should be no more than 80 cm.
How to make support pillars for logs:
- First, we make the markup where the lags will be located. We make notes on the support beams or the foundation of the house. Then we pull the cords through the entire underground. We pull the cords across the future lags at a distance of 80 cm or any other that is equal to the step between the posts. Support pillars will be located at the intersection of cords or ropes.
- In the places where we will make the support pillars, we dig a hole 40-60 cm deep, with sides 40 cm.
- At the bottom of the pit we tamp the soil, pour a 10 cm layer of sand, and then 10 cm of crushed stone. We carefully tamp each layer in turn. This will be our filling for the foundation of the column.
- We install a wooden formwork in the pit for pouring the foundation under a concrete post. If the supporting posts will be made of bricks, then the height of the foundation should be such that it rises 5-10 cm above the ground level. If the entire support post will be cast from concrete, then the height of the formwork should be such that the logs laid on the post are located horizontally.
- We insert a reinforcing frame inside the formwork, connected from steel rods of 6 - 8 mm in cross section.
- Pour concrete.
Important! If the entire post is poured from concrete, then it is necessary to control that the surface of the post is exactly horizontal and that all the posts are at the same level.
- After the concrete has completely dried, we cover the surface of the column with roofing material or glass insulation in 2 - 3 layers. Necessarily without sprinkling. We coat the surface and joints with mastic.
If you want to make support posts from bricks, then the masonry must be fastened with cement mortar. For a column with a height of less than 25 cm, the masonry should be 1.5 bricks, for a higher column, 2 bricks will be required.
After the concrete has dried, the formwork can be removed. For greater reliability, it is better to remove fertile soil from the underground. It must be removed to a depth of 20 cm. Instead of soil, it is advisable to add 10 cm of gravel and 10 cm of sand and carefully tamp with a vibrating plate.
Before starting the arrangement of the base, it is necessary to treat the beams, logs and sub-floor boards with an antiseptic. The logs can be laid immediately on the crown or foundation and on the support posts, or you can first install the support beams on the posts, and the logs from above across. Either option is correct. Only laying the logs across the beams provides a more stable and durable structure if the distance between the logs is very small, 40 - 60 cm.
The section of the lag must be selected taking into account the thickness of the heat-insulating material that will fit between them. For example, if the thickness of the insulation is 150 mm, then it is necessary to take a beam with a height of 180 mm. Always leave a ventilation gap of 30 mm.
The step between the lags is selected taking into account the thickness of the boards of the future floor. More detailed instructions can be found in the table below.
Table 1. Step lag.
Consider laying a lag on support posts:
- We lay the logs on the foundation crown (support beams, foundation) and support posts. We control their even arrangement, horizontal. A sound absorbing material can be placed on the surface of the support posts under the logs. But this is not necessary, since roofing felt or other waterproofing material, which covers the surface of the pillar, springs well and hides sounds.
- If, nevertheless, a sagging of the lag is noticed somewhere, it is necessary to put wooden blocks on the support posts under the lags and fix them firmly. If the beam sticks out somewhere, then it can be cut off with a plane.
Important! The maximum permissible deviation in the evenness of the location of the lag is 1 mm per 1 m.
- We fix the logs to the support pillars using fixing angles. From the side of the wood, we fix it with self-tapping screws 50 mm long, and from the side of the concrete column, we tighten the anchor.
- The first to lay the so-called "lighthouse logs", which are located at a distance of 2 m from each other. Further, we will be guided by them.
- By analogy, we put all the logs and check their even location.
After all the logs are fixed, you can proceed to the arrangement of heat and waterproofing.
Thermal insulation and waterproofing of a wooden floor
Waterproofing and thermal insulation materials are placed between the logs. To fix them, you need to equip the base. This can be done in several ways.
Method 1. From the bottom of the lag, you can nail sheets of moisture-resistant plywood. This design will be as reliable as possible. To do this, you will have to work from the underground, which is not always possible.
Method 2. In the lower part of the lag, you can nail cranial bars with a thickness of 20 mm, from above you can roll from the boards. This work is more painstaking, since you will have to cut a lot of boards with a section of 15 mm and a length equal to the step between the logs.
You can choose the method that you like best. The main thing is to get a fairly solid foundation.
- We lay a layer of waterproofing with an overlap of 15 - 20 cm, glue the joints with construction tape.
Important! Be sure to use a superdiffusion vapor-permeable membrane. We need the waterproofing material to release moisture from the room, but not let it inside from the side of the underground. Therefore, you cannot use ordinary plastic wrap.
- On top of the film, between the lags, we lay a heat-insulating material. We cut the rolled material with a width equal to the step between the lags plus 1 - 2 cm so that the material fits into the gap between the lags of the raspor.
Important! As a heater for a wooden floor, you can use mineral wool in rolls, slabs, basalt wool, you can blow out ecowool, sawdust. Styrofoam and extruded polystyrene foam must not be used. These materials are completely vapor tight, the wooden floor simply cannot breathe.
A ventilation gap of 2 - 3 cm must be left on top of the insulation.
Sub-floor laying
The sub-floor can now be laid in the house. There are several options for arranging rough flooring. As a material, you can use a floorboard with a thickness of 15 - 25 mm with minimal processing. You can also use a tongue-and-groove floorboard if finances permit. For subfloors, the price depends on the cost of the materials used. If you use a thick solid board, then there is no point in laying a sub-floor from a floor board. Or you can lay sheets of plywood, and on top you can lay the finishing flooring.
Subfloor from floorboard:
- We start laying from the wall. Cut off the spike and attach the board to the wall, leaving a 2 cm gap.
Important! The indent from the walls is required, since wood is a plastic material, gaining moisture, expands, and dries up, shrinks. The gap will provide an unobstructed opportunity for the wood to expand and shrink.
- We fix the board to the logs. From the side of the wall, screw the screws directly into the board, then this place will be hidden by the baseboard.
- From the side of the thorn, screw the screws into the thorn at an angle of 45 degrees.
- We move the next board close to the first. We insert into the groove of the first board.
- We screw a self-tapping screw into the groove of the second board, fixing it to the log.
- All subsequent boards are laid by analogy.
Important! If the boards are the same length as the room, then they can be laid exactly parallel to each other. If the boards are shorter than the room, then they must be stacked with an offset - apart.
The last board is fixed so that you can hide the caps of the screws under the skirting board. On this, the rough floor is ready. The main thing is to tightly fit the boards to each other. You can lay a floor covering on top.
How to make a wooden sub-floor on a concrete base
In apartments with concrete floors, you can also make a wooden floor. The logs are laid on a concrete base, but for this it must be flat. A height difference of several centimeters is unacceptable. Therefore, the option when wooden blocks are placed under the bending logs is not suitable. Over time, the linings will dry out and deform, from which they can easily fly out and the floor will begin to creak.
Substrate preparation: hydro and sound insulation
Before laying the logs on the concrete floor, the base must be leveled. To do this, fill in a cement-sand screed. Further work can be continued only after the concrete has completely dried, i.e. a month later.
On the surface of the concrete screed, we lay a waterproofing film with an overlap of 15 - 20 cm, glue the joints with tape.
We put noise-insulating pads under the logs. For this, you can use cork materials or polyethylene foam with a thickness of 1 - 4 mm. The lining under the logs is needed in order to dampen the impact noise.
Laying logs on concrete
It is advisable to use a bar with a length equal to the length of the room. If this is not possible, then you can take a shorter timber and connect it to the end. In this case, the joints should be staggered.
- We lay the logs on the prepared base.
- We check the horizontal position of the lag.
- We fix the logs to the floor using corners. Do not forget that the corners themselves are attached to the concrete floor with anchors.
- After laying and securing all the logs, we lay the insulation between the logs in the same way as in the case of the floor on the ground.
Do not forget to leave a ventilation gap of 2 - 3 cm.
Installation of the subfloor
On top of the lag we lay a rough floor. As mentioned above, it can be plywood, or maybe a floorboard.
Consider the option of arranging a subfloor made of plywood:
- We take a sheet of moisture-resistant plywood with a thickness of 22 mm.
- We lay a sheet of plywood on the logs and fix it to them with self-tapping screws in 15 cm increments.
- We arrange the plywood sheets in a checkerboard pattern. To do this, some of them will have to be cut.
- It is impossible that the joints of the plywood sheets are in one line.
Do not forget that there should be a gap of 2 - 3 cm between the wall and the subfloor. On top of the plywood base, you can lay the following floor coverings: laminate, linoleum, ceramic tiles, vinyl tiles, parquet, parquet board, solid board.
Installation of rough concrete floors on the ground
It is not always possible to pour a concrete floor in a private house on the ground. There are certain restrictions. Firstly, the groundwater at the site must be low enough - at the level of 4 - 5 m. Secondly, the soil must be stable, not mobile, otherwise the concrete floor may collapse. Thirdly, people must live in the house, or it would even be more correct to say that it must be heated during the cold season. If all the conditions are met, you can safely pour a concrete slab over the ground.
Earthworks and foundation preparation
First of all, it is necessary to outline the "zero" mark - the level of the future floor. You need to navigate along the bottom of the doorway. All walls must be marked so that in the future it is clear how long to pour concrete.
- The floor on the ground is a multilayer structure 30 - 35 cm thick.To equip it, remove the top layer of soil until the height from the zero mark to the bottom of the excavation is 30 - 35 cm.
Important! If the soil level is below 30 - 35 cm from the floor level, then it is necessary to level the soil surface, tamp it, add sand to the required level and also tamp it thoroughly.
- We tamp the foundation of the pit.
- Pour a 10 cm layer of crushed stone and tamp it carefully. If the thickness of the backfill is difficult to control, then we drive several pegs into the ground with the desired mark. After leveling and tamping, the pegs can be removed.
- Pour a 10 layer of sand, pour it with water and ram it too.
- On top we pour a small layer of crushed stone with a fraction of 40 - 50 mm.
- Sprinkle with sand, forming a thin layer, tamp it carefully.
Important! If suddenly sharp edges of crushed stone fractions are observed on the surface of the base, it is necessary to unfold the pebble and put it so that there are no sharp corners anywhere.
At all stages of the filling, it is necessary to monitor the horizontal position.
Waterproofing, thermal insulation, reinforcement
- We lay a waterproofing material on the surface of the base - a polyethylene film with a density of 200 microns, roofing material or glass insulation. The main thing is that the material is not damaged on the edges of the rubble.
- We put the waterproofing material on the walls up to a mark 2 cm above the floor level. We lay it with an overlap of 10 - 15 cm and glue it with tape.
- At this stage, you can lay a durable thermal insulation material. For example, extruded polystyrene foam or basalt wool in slabs, perlite or expanded clay are suitable. It is also possible to place the thermal insulation layer above, on top of the concrete base.
- The concrete floor must be reinforced. To do this, we use a metal mesh with 10 cm cells.
- We install the reinforcing mesh on supports 2 - 3 cm high so that the mesh is completely inside the concrete.
Installation of formwork and guides
To maintain the horizontal level of the floor, it is necessary to lay the so-called "beacons" or guides. For these purposes, you can use round and square steel pipes, wooden blocks. We place them in increments of no more than 1 m. We fix them with a thick cement mortar. Also, their height can be controlled by pouring more solution under the guides.
Between the guides, we install the formwork for pouring the floor. This is not necessary, but it makes the task of manually pouring the concrete floor much easier.
We treat the guides and formwork with oil or working off, so that after pouring they can be easily removed.
Rough floor screed - pouring concrete
It is necessary to pour the concrete floor in the house in one or two passes. If you take long breaks, then the foundation will turn out to be fragile.
- We start pouring concrete from the corner opposite the front door.
- Fill several cards at once, then level them with a shovel.
- We compact the concrete with a deep vibrator.
- Align the surface using a rule. Set the rule on the guides and pull it towards you. Excess solution is distributed among cards in which there is not enough solution.
- We take out the cards and fill the voids with concrete.
- When the entire floor is poured with concrete using this technology, it must be covered with plastic wrap and allowed to dry for a month.
For better drying of the concrete sub-floor, its surface must be moistened with water.
After the concrete is completely dry, the floor can be screed clean and the floor can be laid.
Making a rough floor with your own hands is a very important task, because a solid foundation is much more important than a finishing coating. For example, in an old house, you should not lay new flooring on top of an old sub-floor, unless it has been overhauled.
A sub-floor is a prepared base for a topcoat: laminate, linoleum, parquet. The sub floor is wood or concrete.
The advantages of a wooden floor:
- environmental friendliness;
- thermal insulation;
- good breathability.
The disadvantage of a rough wooden floor is that this structure does not resist high humidity very well. Therefore, wooden logs must not be installed in saunas and steam rooms.
Concrete screed also has its own advantages:
- durability;
- soundproofing;
- high strength;
- resistance to moisture, combustion and chemical attack;
- quick installation and affordable price.
The disadvantage of the screed is its cold surface. Such a floor must be insulated.
Regardless of the choice of the floor, the technologies for the implementation of both structures are laborious and require careful work.
DIY floor made of wooden material
Making a wooden floor has its own technology:
- Wood preparation.
- Arrangement of the lathing.
- Insulation laying.
Second or third grade wood can be used as sub-floor beams. The sides of the beams on which the flooring will creep must be leveled.
Logs can be installed in two ways: on the floor or on the base.
According to the first method, it is necessary to lay the logs of the lower strapping and make grooves in them in those places where the logs of the upper strapping will creep. The depth of the grooves is equal to the width of the upper beams.
The harness must be securely installed. For this, brick posts are made, which will serve as a support for the lags.
The installation of the posts is carried out at the initial stage of the subfloor. This structure is also called "columnar foundation". The technology is as follows:
- Along the line of the location of the floors, holes are dug at the same distance from each other. The size of the holes: 20x20x40 mm.
- The bottom is covered with layers of gravel and sand, tamping well. Then the reinforcing mesh is laid.
- The pits are filled with sand-cement mortar. Cement, sand and water are taken respectively in the following parts: 1: 3: 0.5.
- Roofing material is laid on the frozen concrete.
- Brick pillars are being built.
The distance between the logs depends on the thickness of the wood material: the thinner the timber, the closer the logs are. The laid bars must be fastened together.
The lag device "on the base" involves the removal of the top layer of the soil and backfilling of the surface with fine gravel. Overlapping logs are laid on the resulting base, as in the previous version.
A waterproofing film is laid on the lower base, and a layer of insulation is laid on top.
At this stage, you need to decide on the finish coat. If this is a chipboard sheet material, then before laying it, it is recommended to perform a crate of transverse bars, which are fixed on the supports.
The flooring sheets are laid on the crate so that their joints are located in the center of the lintels.
Back to the table of contents
Sub-floor of a concrete structure
When pouring the subfloor, flaws and irregularities are allowed.
The purpose of the rough screed is to even out large surface differences in height and create a base for the final screed.
The step-by-step instruction looks like this:
- Determine the differences in irregularities and install beacons.
- Prepare the base.
- Prepare the cement mixture and pour the floor.
- Monitor the condition of the screed.
First, you need to clean the surface of debris and use a level to determine the height of the screed.
Piles of cement mixture of the required height serve as beacons, on which a metal profile is laid. The guides are fixed with a solution. The height of the profiles is the level of the future screed.
For good adhesion of the rough screed to the base, it must be prepared. To begin with, all large depressions and cracks need to be repaired with mortar. Next, the surface is primed to improve the adhesion of the concrete to the base surface.
All wires will be embedded in the tie. But before pouring, all communications must be wrapped with insulating material and fixed to the base with dowels.
Around the perimeter of the room, it is necessary to glue a damper tape, which compensates for the deformation of the screed.
To prepare the solution, cement and sand are taken in a ratio of 1: 3. Water is added to the mixture gradually, until a sour cream consistency is obtained. Roughly, the water consumption is 0.5 kg per 1 kg of cement-sand mixture.
Necessary tools for mortar preparation and screed filling:
- shovel shovel;
- mortar container or electric concrete mixer;
- buckets;
- overalls.
The solution is poured between the beacons and the rail-rule is distributed it. If voids are formed, then the mixture is reported to those places and again equalized.
The cement mixture must be prepared in small portions, as the mortar quickly hardens. It is recommended to fill the floor in one day so that the surface is homogeneous.
The screed may shrink when dry. To prevent this, it is necessary to take the following measures:
- For the first 3 days, you cannot walk on the screed.
- Exclude drafts and direct sunlight in the room.
- The next day after pouring, the screed must be covered with a film.
A good sub-floor is the key to a solid structure for the entire room. High-quality installation and strict adherence to technology will allow the foundation to serve for many decades.
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 sub-floor along the 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 timber is still low.
In floor construction, rough flooring can serve two purposes. The first is to serve as a basis for laying heat, hydro, and sound insulation materials. The second function is to serve as a support for the final 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 rough floor? Basically, it is possible, but in this case it is more difficult to achieve the required characteristics. If the requirements are not too high (summer house, 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 structure without a rough flooring requires more money. Why? Inexpensive materials are used for the subfloor. 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 focus is on "protective" characteristics. After all, the load falls on the floor structure and subfloor, not on these materials. And as a rule, they are relatively inexpensive.
All sub-bases can be divided into two large groups: dry and wet. All types of or are referred to as wet. But this is not about them. We will talk about dry ones, and on logs and beams.
Today there are more modern technologies, but the sub-floor on the logs remains the cheapest. This is the traditional version, which has been modified to accommodate today's demands for comfort and efficiency. But even with the changes, it is difficult to achieve those parameters that are considered the norm today. In particular, sound insulation, and even thermal insulation, cannot be perfect. You can only get closer to the norms. But the solution will not be the cheapest.
Overlapping 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, most often our beams are made of wood. They are made from a bar - solid, glued, or use spliced beams (from several boards).
Beams can only rest on the foundation, they can have intermediate supports. In houses with an underfloor, piers serve as intermediate supports; in the absence of an underfloor, brick posts are folded or posts are made of reinforced concrete. On these supports, waterproofing is laid 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 lags? In short, beams are a supporting structure, but logs are not.
A beam is a linear element of load-bearing structures that rests on both ends (as opposed to a cantilever) and works primarily in bending. As a rule, the cross-section of the beam is rectangular or square. In wooden houses, they also make from hewn logs. The step of installing the beams and their section is considered when developing the project. Lags are also prescribed, but they are not so critical, so their characteristics can be changed during the construction process.
Lags are not elements of the supporting structure and they are made simply from a thick board, which is often placed "standing" - supported on a narrow part. With such an installation, it is convenient to lay insulation between the lags - when choosing the step of installing the lags, the width of the insulation is also taken into account. A rough floor along the logs can also be with the location of the insulation on top. This type is called a floating floor, since the finishing coating does not have direct contact with the base (in this case, with the subfloor).
There are two important points. First, when using mineral wool as a heater, it is necessary to measure the real width of the roll or slabs. It does not always coincide with the declared one. Second - the distance between the lags should be 3-4 cm less than the width of the insulation. Then it can be placed in a position and it will be held due to the elastic force. This makes installation easier. But there is one more plus of this decision. Even if the insulation "sticks" a little or dries up during operation, gaps between the cotton wool and the lag will not appear, since the material will straighten.
When laying insulation, the main thing is not to leave gaps and minimize cold bridges When using polystyrene, expanded polystyrene, polyurethane foam as a heater, the lag step (and their cross section) is also better to select. But in this case it will not be possible to "squeeze" it. Plates are cut into pieces of slightly smaller width than the distance between the lags, and the cracks are filled with polyurethane foam.
Lag installation step
The installation step depends on the board from which the logs 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 subfloor is the basis for the finishing, so it must be leveled to the horizon. The smoother the base, the less problems with laying the rest of the materials. Therefore, already when installing the lag, their edge is brought out at the same level.
One of the possible options If the pitch of the beams is small - up to 80 cm, the rough flooring can be laid immediately, without logs (40 mm board). With a large step of the beams, logs are laid across, and the subfloor is laid on them.
A couple of comments about the wide board. If your budget is tight, you can save money by making prefabricated lags. Two 25mm boards cost less than one 50mm wide board of the same length. We buy two boards, put them one to the other, connect them with nails or self-tapping screws (preferably nails). We put the fasteners on both sides in a checkerboard pattern. They put the logs "on the edge", so that they even surpass the board in strength - there is less chance of a crack in the wood layer. There is one more nuance that will help to avoid the "twisting" of the prefabricated log: we arrange the boards so that the annual rings are located towards each other.
Floor structures on wooden beams
When arranging a rough floor, a board is 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 installation 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. Sub-floor on the joists under the screed (floating floor)
You can do it if necessary. The only question is whether the beams can withstand the load. This is calculated separately. Why is this design good? The fact that:
- A normal “cold” floor can be made warm. You can even make it heated (if the beams can 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 using wooden logs without cement. As a top layer, you can lay plywood, OSB and other sheet materials in two layers, which you deem suitable. Again, tiles and any other type of topcoat can be laid on such a base.
What logs and board to use? It is possible / necessary to select, since the thickness of the board depends on the step of installing the lag:
- the distance between the lags is 80 cm (up to 100 cm is permissible, but not under a screed or tile, under lighter coatings) - 40 mm board;
- installation step lag 50-60 cm, board 30-35 mm;
- for a board less than 30 mm, support is required with a distance of 35-40 cm (depending on the specific thickness).
In this case, the subfloor may not be solid, but with gaps. For a concrete slab, it is best to take extruded polystyrene foam, high density polyurethane foam as a heater. Foamed glass (foam glass) is possible, but it is very expensive. These materials will normally support the weight of a monolithic screed. By the way, since it fits on an unstable base.
How to ensure long-term operation
With this kind of wooden beams, it is important to protect the subfloor board from rotting as much as possible. If the bottom is a subfloor, you need to make sure that it is ventilated (air vents) and that the humidity in the subfloor is as low as possible. Need a blind area around the house (better insulated), as well as a drainage system.
A sand film is used as an additional measure. A dense PVC film is spread on the ground in two layers - the joints are glued with tape, put on 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 adsorbs the excess, and then dries out slowly. The same method is used using any other subfloor along the logs.
Sub-floor from OSB (OSB). You can remove the rough flooring from the board and lay the slab in two layers As already mentioned, the sub-floor board can be edged or unedged. A prerequisite is working humidity. Few people will use chamber drying, but the board must be dry - at least 6-9 months of drying. If the overlap of the first floor is being laid, the material must be treated with protective compounds. The humidity in the underground will be increased, so the processing quality should be good. Better to process multiple times. There is more than enough chemistry for wood today. You can select by properties. If you need folk remedies, this is processed oil.
Ground floor above the ventilated subfloor
The overlap of the first floor above the unheated underground floor is distinguished by the fact 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 air vents. To do this, it is better to make two layers of insulation and arrange them in different directions.
In this design, the rough flooring is only a support for the first layer of insulation, so it makes no sense to take a thick board here. Usually they take 25 mm, process it and use it for hemming. In the structure shown in the figure, a cranial block is nailed to the bottom of the beams. Usually its cross section is 25 * 25 mm. A roughing board is placed on the cranial block. The segments are short - the length is equal to the step between the lags. On this flooring, you can take substandard lengths, but less waste if the length is a multiple of the lag step.
Waterproofing is laid on the roll-up boards. Please note that if mineral wool is used as insulation, the material must be vapor-permeable. It should make it possible to remove moisture from the insulation. If the insulation is polystyrene, expanded polystyrene, 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 provide a ventilation gap. Wood changes moisture content 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 thickness of the board 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 Steam waterproofing 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, there is one or Izover, other brands). It must be laid so that steam can escape from the insulation. This solution is better because it makes it possible to maintain normal humidity in the floor cake.
There are also options with one layer of insulation (in the picture above). This method is convenient if, according to thermal engineering calculations, the thickness of the insulation is not too large.
What is the subfloor made of along the logs
The subfloor 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 a decision for himself. The point is that any of these materials can be placed on logs. These materials fulfill their role as a foundation. The thickness of each material depends on the pitch of the beams or lags. After deciding on a specific material, it will not be difficult to choose a thickness.
The builders call the rough floor the base, on top of which the finishing flooring is laid. When it comes to concrete floors, setting up a sub-floor means installing a dry or wet screed to level the surface. In wooden structures, this term experts designate the lower part of a two-tier floor.
It will not be difficult to assemble a subfloor in a wooden house with your own hands if you have the skill to work on the installation of wooden structures. Overlappings in a wooden house are made in two layers, 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 in 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 floor between the first floor and the attic (or the second floor, residential attic). 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 sub-floor of the first floor
The system consists of the following elements:
- Lags.
- Skull bars. Boardwalk support, padded along the bottom edge of the log.
- Sub-flooring. It is made of planks or sheet wood material.
- Waterproofing layer. Protects heat insulator from moisture.
- Insulation. It is mounted between the lags.
- Vapor barrier layer. Prevents moisture penetration into the insulation.
- Counter-rail. It is stuffed along logs or beams longitudinally to create a ventilation gap - this prevents rotting of the upper deck.
- Flooring. It is assembled from curved boards or sheet material; a topcoat can be laid on top of it.
Before making a subfloor in a wooden house, ventilation of the space under the future lower flooring should be ensured. For 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 overlap is made from damage by fungus. The air is covered with a net so that rodents do not penetrate under the floor. If in winter snowdrifts are swept above the air vents, a ventilation pipe should be brought up from the underground space, the upper cut of which should be protected by an umbrella from the penetration of precipitation.
Another important condition for the safety of the structure is the high-quality processing of lumber with a composition for fire-biological protection. Processing is carried out after the timber, board or other element has been adjusted to size. 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 structures that will be hidden by the laid sub-floor.
Installation lag
Lags are load-bearing structural elements. They are installed with a step of 400-600 mm - this parameter depends on the design loads and the section of the element. A beam with a section of 100x150 mm (at low loads), 150x150 mm (at medium loads), 150x200 mm (at high loads) is used as a lag.
If you have to use a small section beam at high loads (or a 50x150 mm board placed on the edge), the lag installation step is reduced to 300-400 mm.
The best option is to lay the ends of the lags on a base or grillage. But for this, the width of the free part of the foundation must be at least 120 mm. Strapping is in progress - boards of small thickness are laid on the free part of the grillage or basement 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 using corners mounted on both sides of the timber. The logs cannot be rigidly fastened, since the tree changes its geometric dimensions with changes in temperature and humidity. There should be a gap of 20-30 mm between the end of the log and the wall 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 is less than 100 mm, the joists 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 the wood.
It is advisable to refuse a deep cut-in so as not to weaken the walls. In this case, next to the foundation, support columns are erected so that the main load that falls on the ends of the lag lies on them.
Logs need reliable support in the middle part if the length of the run exceeds 2-2.5 m. Brick posts act as supports. To reduce the number of posts, a thick beam is laid on the brick supports, on which all the logs will rest. The total height of the support structure (post + beam) must exactly match the height of the foundation with the plank strapping laid.
At least three brick pillars must be installed under each crossbeam to create 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 100 mm layer of gravel is poured onto the bottom and rammed, then a 100 mm layer of sand is rammed in the same way.
On the prepared "pillow", a reinforcing mesh in the form of a square 150x150 mm is installed on small props, a concrete mixture is poured. After the concrete gains strength, the resulting foundation is waterproofed with roofing felt and a column is erected from bricks fastened with mortar. Before laying a transverse beam or a lag (if the posts are mounted under the lags), a layer of waterproofing material is placed on the post.
Subfloor device in a wooden house
Correctly installed lags form a horizontal plane - when performing, control the accuracy of 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 decking tabs.
Subfloors are lower flooring that is laid on top of the cranial planks. 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 fastened.
Installation of a sub-floor in a wooden house involves laying a 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 with a width of at least 120 mm. The edges of the material should go against the walls - the excess is subsequently cut off.
The next stage is the installation of thermal insulation between the logs. When choosing how to insulate your house, pay attention to the operational parameters of slab or roll materials. Mineral insulation materials and foamed polymer boards are popular. If the thickness of the heat insulator exceeds the height of the log, bars of suitable thickness are packed 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 polystyrene or polyurethane foam boards are cut to size, the joints are sealed with polyurethane foam.
If a mineral wool insulation is chosen, a vapor barrier must be installed. It does not allow moisture to accumulate in the fibrous heat insulator, since 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 plastic film or a special membrane) is attached to the logs with a stapler. Its edges can be fastened to the rolled edges of the waterproofing material using reinforced tape. The same adhesive tape is used to glue the joints of canvases laid with an overlap of 100-150 mm.
Laying the sub-floor is continued by installing counter-rails along the joists. They are used to create a ventilation gap under the top deck. This will reduce the risk of fungal growth and development.
The upper deck of a wooden floor is assembled from high-quality boards or sheet material - plywood, wood-based panels. Fastening is carried out on self-tapping screws, since the nails loosen over time and come out, the plank base begins to creak.
After installing the flooring, the sub-floor is considered ready.
Conclusion
Step-by-step instructions help you figure out how to make a rough floor in a wooden house. Ideally, this issue is worked out at the stage of preparing a building project. For example, support beams passing through two adjacent rooms and an internal partition are designed in advance.
When developing a foundation project, it is worthwhile to provide for the optimal width of the grillage, taking into account the width of the building structures, so that in the future you do not have to cut the logs into the wall.
A competently assembled sub-floor will give home comfort and warmth, increase the thermal efficiency of the house and help save money on its operation.
Many novice builders who have just started building their home are already considering what kind of linoleum or laminate they will lay in the future room.
And soon, the question arises before them - How and on what, to lay this linoleum. Of course, we all understand that first you need to make the so-called subfloor - the basis on which, in the future, you can lay any floor covering you like. But how to make the floor “from scratch” correctly, so that it is reliable, even and, most importantly, warm. You will find the answer in this article.
To make a rough floor with your own hands, you do not need any professional skills or special tools. The main thing that you need is good physical strength and a head on your shoulders, as well as some very common tool. But more on that later, first you need to decide what building material you will need to purchase for the construction of the subfloor. The choice of materials for the floor in the construction market is now huge, but we will consider the most common option - no less reliable and at the same time not expensive.
We use the following timber:
- a wooden beam with dimensions of 100 by 150 mm (or 150 by 200 mm) and a length of 6000 mm;
- a wooden block with dimensions of 50 by 50 mm (or 60 by 60 mm) and a length of 3000 mm;
- planed boards 50 mm thick and 6000 mm long;
- OSB sheets with dimensions of 1250 x 2500 mm and a minimum thickness of 12 mm.
As a heater, it is advisable to use basalt insulation (in a simple way, glass wool). To protect lumber from mold and decay, you need to purchase a special solution (antiseptic). You may also need cement mortar during the construction of the floor. Now we will consider all the lumber used separately, as well as what role they play in the subfloor.
Used lumber.
Wooden beams, with dimensions of 100 x 150 mm, are used as load-bearing logs, on which, in the future, the entire floor in the room will rest. 
Bars with dimensions of 50 by 50 mm are intended for placing insulation in the floor. 
The cost of a bar, on average, is about 6,500 rubles per cubic meter. To calculate the total cubic capacity of all bars, you need to calculate the volume of one bar and multiply by the required number of bars. The volume of any bar is considered as the volume of a parallelepiped.
Choosing the right board
The board plays an important role, therefore, it is better to use planed larch as the base of the subfloor. The cost of one cube of such a board is about the same as that of the beams. Cubature is considered similarly. 
All of the listed lumber should be made mainly of coniferous trees, for example larch, it is less afraid of moisture and dampness, which means it will last longer. By the way, the whole of St. Petersburg, which is already more than 300 years old, was built from it!
When buying beams and boards, you will need to take into account that the drier the lumber, the better and more expensive it is. After all, the dried boards will no longer warp and will not go (by helicopter), for example, during the heating of a house. Therefore, we choose sawn timber based on the following criteria:
- the lower the humidity level, the better, you can take it straight from the dryer;
- timber or board should be flat, surfaces without significant defects, cracks and delamination.
OSB sheets (plates)
These so-called OSBs are used to complete the sub-floor. Subsequently, OSB panels will serve as the final base for the flooring. Translated into Russian, OSB is translated as OSB - oriented strand board. The material itself is a board pressed from sawdust. 
Over the past 5 years, OSB boards have become increasingly used in the decoration of walls, floors and are considered a fairly good basis for almost all types of finishing materials.
The main advantages of OSB boards:
- high moisture resistance;
- high mechanical strength;
- the material is easy to install.
One OSB sheet with dimensions of 1250 by 2500 mm and a thickness of 12 mm will cost you about 700 rubles. Many Russian manufacturers sell OSB boards for less than 500 rubles apiece. You should not lean towards a cheaper option, it is cheap OSB panels that have received bad reviews due to their low level of environmental safety.
We figured out the materials, now we will find out what tool you need for the sub-floor device. Prepare or buy the following tool to make your job as easy as possible:
- hammer;
- electric jigsaw;
- hacksaw or electric saw;
- roulette;
- level 1.5 meters long;
- stationery knife;
- nails 50-100 mm long.
Stages of construction of the subfloor
Let's first figure out how to properly position the lags. Before we figure out the correct location of the lag, let's go back a little to the past. It is advisable to take care of the floor arrangement even before the construction of the main walls of the house, that is, immediately after the preparation of the foundation. After all, then it will be impossible to fix something in the location of the lag.
First, we treat all the beams (for the first floor) with a special solution (antiseptic) against mold and decay. The fact is that the logs are located near the ground, under the house and will always be exposed to a humid environment. 
After laying the beams, check that they do not touch the ground (the distance from the bottom of the beam to the ground should be at least 20 cm). That is why all the space inside the foundation is always cleared in advance.
So, we place the beams perpendicular to the direction of the longest side of the future room with a step of 80-100 cm. The more often you take the step, the less the floor will stagger and play, but this will require more building materials, and, accordingly, costs.
We place all the beams "ribs" in order to increase the rigidity of the floor and make it as high as possible from the ground level. Agree a room on the ground floor with too low windows is not the best option. We place all the logs strictly in a horizontal position, checking them with a level from the edges, in the middle and between adjacent beams. If necessary, the edge of the timber can be lifted with cement mortar.
The beams should rest on the edges of almost the entire width of the foundation, and their ends are smeared with cement mortar or closed from the street. It is not necessary to specially fasten the logs to the foundation - we just lay them, but so that they adhere firmly to the surface of the foundation and do not stagger.
All boards, even before the walls are erected, should preferably be laid out on logs and covered with the same solution against mold. You can also adjust them to size and cut a little too long boards, so that later, indoors, it would be more convenient to work with them. 
Finally, we make the base of the floor after the walls have been erected. We measure all the boards so that there is a 3-5 mm gap between the wall and the board at the end. This gap is necessary so that the board does not rest against the walls during the shrinkage of the house. We lay the boards perpendicular to the direction of the log.
We nail each board with "weaving" nails, after one - two logs. Do not hammer three nails into each bar - this will not win you anything. Boards should also not be pressed strongly against each other. The first board lays down with a distance of 3-5 mm from the wall, the last one is adjusted to size. You may need to trim the last board and cut it lengthwise.
For floor insulation we use bars and basalt insulation. To insulate the floor, it is necessary to build a semblance of a frame in the form of a lattice of 50 by 50 mm beams. In the cells of this frame, you will lay insulation with a thickness of 50-60 mm. Insulation in our case comes with slabs, but if you don't like that, you can insulate with soft cotton wool, just keep in mind that for the same soundproofing effect as from plates, you will need twice as much soft cotton wool. For example, if you open a wooden floor in a Soviet apartment, you will see a similar grating, and in rare cases, even with insulation. 
The bars must be distributed with a step equal to: the width of the OSB board divided by two, that is, approximately 620-630 mm. Bars are also laid across, here you determine the step at your discretion.
Try to set all the bars to a horizontal level. This can be achieved with small wooden wedges. Wedges will not be difficult to make yourself.
Important! We nail the bars to the boards, as in the previous case.
We lay the insulation in small rectangles, cutting out the required size with a clerical knife.
Important! When working with insulation, be sure to wear glasses and a mask.
A small digression.
There is another pretty good way to insulate the floor. Although it is used mainly for insulating the floor of the second floor, it is also suitable for the first floor. Here, the insulation fits into the space between the logs. In order for the insulation to hold, boards 80-100 cm long are nailed to the logs from below, you must admit it is not very convenient. Moreover, the boards should be tried to be nailed tightly to each other so that the insulation does not crumble over time and does not fall to the ground inside the foundation. However, in this case, you will be able to install the insulation with a thicker layer, and the floor will be better insulated as a result. With this method of insulation, the device of bars 50 by 50 mm will not be necessary.