Sewerage

Installing the log on a concrete base. Fastening a log to a concrete floor: types and techniques, necessary materials and tools, step-by-step instructions and expert advice

One of the most important elements of the floor structure is the lag system. It is from strength, choice the right step Between, the type of wood and the method of installation will depend on the operating conditions of the finish coating.

Choosing a beam for a log

Beams can have different cross-sections and moisture indicators

As already mentioned, it is the lags to the floor that perform one of the most important functions. Therefore, in order for the floor coverings to last a proper long time, it is necessary to choose the right one. construction material. It will be necessary to pay attention to many factors, otherwise, under loads, the bars can deform and cause damage to the finish.

Humidity. When choosing any wood building material, the first thing to consider is its moisture content. If the bars are not dry, they will not undergo strong linear changes during the drying process. Therefore, at the time of purchase, the timber should have a moisture content of no more than 16-18%. This moisture indicator is optimal, because the risks that the wood will absorb moisture or dry out are minimal. It is worth noting that both of these processes can cause deformations, only their directions will be different.
Type of wood. The lag system is designed to serve as a strong support for the finish coat, so it must be strong. Choice the highest grade optional, because 2 or 3 wood grades will do. The strength of the lag will be compensated big amount places of support, therefore the main thing is that the lumber does not have areas with mold and fungi. When using a leveling system, pay attention to the number and size of knots. They can become areas of fracture of the support.
Section. It will be possible to determine the shape of the section on the end side. It is necessary to choose the material that will have a clear rectangular shape. The optimal aspect ratio is 1:2 or 2:3, i.e. bars with a section of 50x100 mm and 100x150 mm, for example. In this case, the logs should fit on the edge. This position of the beam will be as resistant to vertical loads as possible. The choice of the beam section should be based on the step with which they will be laid and what layer of insulation is planned to be used.
Breed. The most common option is conifers, which have affordable prices and are great for supporting a finished floor. For example, pine or spruce are perfect for normal conditions, but where high humidity is expected, it is advised to use larch. It is more resistant to moisture and can provide a good service life.
Treatment. It is necessary to ask the sellers if their lumber has antiseptic treatment. If there is none, which often happens, then you will have to do it yourself without fail. In addition to the antiseptic, which will protect against mold and fungus, flame retardants are used to increase the refractory properties of the material.

Advice! You need to select lumber very carefully. It is best to select the samples you like from the warehouse yourself. So you can get rid of the likelihood that you will be slipped warped, which will be difficult to level, and you will have to plan a lot with a planer.

Choosing the right building material is only half the battle. It is worth dwelling on how logs are attached to wooden beams in a wooden house, on concrete floors and a strapping system.

Logs on supports in a wooden house

For logs, bars with a cross section of 50x100 mm are usually used. From this it is clear that they are not the only strengthening system. Therefore, beams are used in wooden houses on the floors, and on the ground floor and support pillars.

Supporting wooden support beams on poles

Installation of support poles

The support posts are made of brick with a wooden lining, which should not allow moisture coming from the post to rot the wood of the beam.

The installation site of the pillars is dug to a depth of 50-60 cm, a sand cushion is made. A layer of waterproofing is applied from sheets of roofing material, formwork is performed with a height above the ground of 30–40 cm.

After the concrete is poured and dried, bricks are laid on it one level at a time, which will also have a concrete structure inside. To do this, they leave in the process of pouring the concrete base under the pillars reinforcing wire to a height that will be necessary for the height of one pillar. The extra sections of the reinforcement are subsequently cut by the grinder.

Adjustable support for wooden floor beams

The step between the posts for one beam is within 60–100 cm, and between adjacent beams is 150–200 cm.

Attention! Floor coverings from boards are usually oriented in the direction of the sun's rays falling through the window. Therefore, it will be necessary to take this fact into account and orient the beams in the same direction as the finish floor.

beams

A layer of roofing material is laid on the prepared pillars. In addition, in the process of manufacturing the pillars, a wooden lath is installed on them as an overlay.

The beams will be based mainly on strip foundation, and the pillars should only serve as reinforcing elements and in no case should take on the brunt. Therefore, their level should not exceed the level of the foundation tape.

Fastening to wooden beams

Attaching logs to wooden beams will be as easy as shelling pears. As fasteners, it is advised to use squares. In this case, it is not necessary to fasten the logs on both sides. To save on fasteners for large squares, you can mount the corners in a checkerboard pattern.

Logs on the beams

When using fastenings on beams, it is better to refrain from rigidly fixing the supporting lamellas to the wall. It is worth using a corner mount with the possibility of shrinkage of the supports and movement of the self-tapping screw. At the same time, a technological gap must be left between the wall and the lags.

Fastening the lag to the concrete base

Screw for fastening logs and rails

The use of beams and pillars on the concrete surface is eliminated, because the logs will be laid and attached directly to the concrete surface. You can do this task alone. The order of actions to be performed will be as follows:

On the concrete base it is necessary to lay a layer of waterproofing. Roofing material or ordinary polyethylene film can be used as a moisture-insulating material. In this case, the joints must be airtight, because they are glued with adhesive tape.
The choice of the lag laying step will directly depend on what finishing material will be used. For example, for floorboards with a section of 35–40 mm, a step of 60–70 cm can be used.
Using one log along the entire length of the room is not always possible. Therefore, it is necessary to carry out an even joint of the two parts so that the horizontal level at the junction coincides with the general level. To do this, they can use iron corners or special notches in a tenon-groove. If this is done across the entire width of the room, then it is better to carry out the lag connections in a checkerboard pattern so that subsequently the loads do not cause a kink and deformation in this area.
First of all, the extreme lags are fixed. They will serve as beacons for leveling the rest of the bars. To set two bars at large distances from each other, you must use a laser level.
Attach the logs to the concrete base, depending on what their height is. Thin bars are fixed through with dowels and spacers, which are placed in pre-prepared holes. BUT high supports- special corners.

As a topcoat over the bars, you can use plywood sheets that will serve as a subfloor for laminate or parquet.

Fastening the lag to the strapping of the timber

When performing a lag system, they usually use a strapping of beams, which perform a reinforcing function and allow the lags to be installed at the same level. In order to fix the logs to the strapping, they use a simple method - the corners and brackets are installed on self-tapping screws. At the same time, the latter are advised to put on slightly at an angle so that the logs cannot loosen during operation.

How to attach logs to the harness without using nails

The use of a strapping system is typical for frame houses and other types that do not have a rigid base, where an accurate and even connection is possible. When fasteners connect the bars with a concrete base, squeaks may subsequently occur, and fasteners only for strapping will not cause this.

There are many various ways fasteners, which must be used according to the situation.

On the video you can see how best to fix the wooden logs in the loggia in an adjustable way:

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No modern material does not fully replace the traditional wooden floor. True, its installation is fraught with some difficulties (the need for the correct selection of wood for the log, their strictly horizontal installation, careful fitting of the flooring boards), however wooden floor there is still no alternative in terms of environmental friendliness.

Wooden floors have always been highly valued. It is natural, attractive and safe.

It would seem that floorboards can be laid directly on a leveled screed, however, logs are necessary in order to sufficiently ensure normal ventilation of the floor and the most optimal heat exchange in the room. Of course, laying a perfectly even screed will simplify the task of installing a floor log, so the very first preparatory work when installing a wooden floor, there should be maximum leveling of the base.

Required materials, tools and fasteners

As for the question of how to fix the logs, it should be said that not every type of wood is suitable for their manufacture. best material for them are coniferous trees: spruce, fir, pine and larch. As a rule, a material with a cross section goes to the bars, in which the aspect ratio is 1: 1.5. In addition, before you start fastening the log, the boards and beams must be thoroughly dried. The wood moisture index should not exceed 20%. It should be noted that the installation of a wooden floor is advisable only in rooms with high ceilings.

For high-quality fastening of the log to the concrete base, a thorough approach to the choice of tools and fasteners is also needed. In the work it is necessary to use:

To install the log, you will need a hacksaw, a building level, a screwdriver, self-tapping screws, a construction pencil, etc.

tools for woodworking (planer, circular saw or hacksaw, drill, etc.);
screwdriver or screwdriver;
perforator (well, if there is a universal tool that can hammer, drill, and screw);
self-tapping screws with a section of 6 mm with plastic dowels (plugs should be driven into concrete by 6-8 mm, and the length of the fastener depends on the thickness of the bars) or anchor screws, whose dimensions depend to the same extent on the cross section of the bar.

The choice of fasteners depends on your preferences and the thickness of the wallet, but it must be said that the anchor fastening is much more reliable than the dowel, since the anchor shank, when screwed into the concrete body, bursts its sleeve and tightly fixes the fasteners. Nevertheless, it is often enough to use polypropylene dowels with self-tapping screws to fix the floor lag, since most coatings will not have to experience extreme mechanical stress.

For the waterproofing device, roofing material is required.

In addition to the listed tools and fasteners, the log must be prepared for the device:

waterproofing agent (roofing material and similar rolled bituminous materials);
primer mixtures for processing screed and wood;
antiseptic compounds (you can always pick up multifunctional products in the store, which will significantly speed up the process of processing the bars).

You should stock up on pieces of plywood, chipboard or wood, which may be needed as linings for logs to the floor to level the plane.

Operating procedure

So tools and expendable materials prepared. You can start attaching the lags. Work is carried out in the following order:

Make sure the concrete screed is dry and prime it with a primer.
Lay a waterproofing layer on the screed. Its adjacent sheets should be laid with an overlap of 10 cm.
Glue the edges of the vapor barrier tapes with bituminous compound or adhesive tape (depending on the material of the water-repellent membrane).
Treat the bars with an antiseptic.
Cut the logs according to the dimensions of the room and spread them over the floor surface. It is desirable that only 1 beam is used for each log. Joints are allowed for large room sizes, when the length of the beam is not enough. The location of the joints on adjacent beams should not match. They must be spaced apart from each other by at least 0.5 m. There must be a support under the joints.
Put 2 extreme logs at opposite walls. Place the rest of the bars perpendicular to them. The distance between adjacent lags depends on the thickness of the flooring. The stride range ranges from 40cm to 100cm (more on that below).
Fasten the extreme lags. Using a hydraulic level and a chopping cord, set the end bars. Drill holes in them and in the concrete base, insert fasteners and fix the logs in concrete. The fastening step with self-tapping screws is from 50 to 80 cm, and the anchor screws are screwed in every 1 m.
Attach the cross joists to the floor. For better orientation, pull a cord between the extreme bars.

It is desirable that there are no linings under the bars, but with an uneven screed, they cannot be dispensed with. Make sure that the pads fit snugly into the space between the timber and the screed. If there is a bulge under the log on a concrete base, lightly trim the edge of the beam adjacent to this place with a planer or chisel.

Only when performing these procedures, the floor will not creak under your feet in the future.

Now back to the question of the step between the lags. Its dependence on the thickness of the floorboards is as follows:

floor thickness 2 cm - the distance between the lags is 30 cm;
for a board of 2.5 cm, the step is 40 cm;
for 3-centimeter boards, the distance between the bars will be 0.5 m;
for 35 mm, a 60 cm step is required;
40 mm boards are placed on logs, the distance between which is 0.7 m;
for 45 mm flooring, a step of 80 cm is provided;
under the floorboards with a thickness of 5 cm, the logs are attached at a distance of 1 m from each other.

Under the plywood floor, the distance between the lags is calculated a little differently. A pitch of 40 cm is enough for a 15 or 18 mm decking, and for 22 mm plywood, a spacing of 60 cm between the bars is suitable.

After mounting the bars, you can fill in expanded clay between them or lay another heat insulator. Until it's laid flooring, you can lay some communication lines. Before installing the floor on the logs, it is advisable to lay a vapor barrier film.

Laying beams on the ground

There are cases when the bars under the floor have to be laid not on a concrete base, but on the ground. To fix the logs in this way, it is necessary to clean the soil from the top layer and carefully compact it. It would be even better if the surface is covered with rubble. The backfill layer can be up to 5 cm. After leveling the rubble, waterproofing is laid on the ground.

On the walls of the building, it is necessary to mark the horizon along which the logs will be installed. Markings are made using a laser or water level and a chopping cord. First of all, bars are installed along 4 walls. Logs are placed on stands made of bricks, boards or other materials. All wood products must be treated with antiseptic compounds, and roofing material must be laid between the logs and supports. There should be a wooden spacer between the brick stand and the floorboard. Its thickness cannot be less than 25 mm. The distance between the extreme beams and the walls should be at least 2 cm. Threads can be pulled between opposite walls, which will serve as guidelines for mounting the beams.

Now the rest of the lags are attached. Their location should be perpendicular to the direction of the floorboards. It is recommended to lay the support bars transversely to the direction of lighting through the window opening. The step between the lags during their installation on the ground depends to the same extent on the thickness of the flooring, as well as when fastening to concrete. The cross section of the beam must correspond to the distance between the walls of the room (span):

for a 2-meter span, a beam of 110 x 60 mm is used;
if the walls are located 3 m apart, bars 150 x 80 mm are used;
4 m - 180 x 100 mm;
5 m - 200 x 150 mm;
6 m - 220 x 180 mm.

The use of logs shorter than the span when they are installed on the ground is highly undesirable.

Adjustable lags

Need to talk about modern means lag level adjustment. Manufacturers produce special racks that can change the height of the beams from 10 to 25 cm. Such devices are very useful when installing a wooden floor on an uneven base. They are threaded racks attached to the ceiling with dowels and nails. Changing the height of the beam is carried out by screwing or unscrewing the threaded rod, fixed in the desired position with a lock nut. Supports for timber can be inserted into holes drilled in its body. Often they are equipped with corners with holes through which self-tapping screws are screwed into the logs.

Despite the apparent complexity, setting the log is not so difficult. If you do not violate the installation technology, then the wooden floor within for long years will serve without the slightest creak and deflection of the floorboards.

The question is how to attach the lags to concrete floor, does not lose its relevance, since many homeowners prefer this particular method of device floor covering. Never mind, wooden house or brick, floors on logs will always have an advantage due to the ability to lay a heat and sound insulating layer. The main thing is to do all the work correctly in order to get a reliable base and a flat surface.

Preparatory stage

The surface of the rough concrete layer will never be perfectly flat. The advantage of the lag is that they make it possible to level out all the flaws of the concrete base. Some homeowners are hesitant about whether to fix the joists to the concrete floor or whether it is better to make a “floating” structure independent of the base. As an argument, the possible destruction of the screed is given, and a strong distortion of the structure in the case when the wood is wet.

The base made according to the technology will not crumble, otherwise it must be dismantled altogether. No one is safe from insufficiently dried wood, but the coating may swell in places from deformation, regardless of whether the bars are fixed or not. By the way, appearance wooden beams used as a lag does not play any role. From above, you still need to lay a floor covering, it will close all the flaws. The following points are important:

Wood should have a moisture content of no more than 20%.
The bars should be checked for curvature and sorted, if any.
In order to increase the service life, the wood should be impregnated with an antiseptic agent or, according to the old proven method, covered with drying oil.
The height of the bar must not be less than the thickness of the heat-insulating layer.

To exclude the occurrence of dust, a deep-penetrating primer must be applied to the subfloor, and then a waterproofing layer should be laid. There is different variants, optimal - lay a layer of roofing material with a careful sizing of the joints with your own hands. The easiest way is to cover the base with a polymer film overlap. Then the joints must be glued with special adhesive tape.

If you attach the logs incorrectly, then such an unpleasant phenomenon as a creak may appear. During operation, it is difficult to find it, but it is quite possible to avoid it during installation. Care must be taken to ensure that the vertical planes do not touch. wooden parts. During the application of a dynamic load in this place, the planes will rub against each other, making a creak.

It is unacceptable that the end of one lag rests on the second, it is necessary to leave a gap between them, and it is also impossible to fasten them with corners.

Mounting methods

To independently fix the logs on the concrete floor, you need to take such a tool:

perforator;
electric drill;
screwdriver;
standard set of locksmith tools: hammer, screwdriver, pliers, open-end wrenches;
measuring devices, building level.

To regulate the log in height (in order to bring them into one plane), you need to stock up on wooden spacers of different thicknesses. There are also special plastic kits that are very convenient for installation. The interval for laying the bars usually lies within 0.4-0.5 m, the distance from the wall is 30 mm. First, logs are laid near the walls, and then the rest are evenly distributed over the area of the room. Before fixing, they are brought out in one plane, using spacers. It is not necessary to screw the latter to the floor. After reconciliation, they begin to fix the lag.

For work, you can use 4 ways of fastening:

Using plastic dowels and screws.
On self-tapping screws by means of steel corners.
On anchors.
With the help of special regulating systems on dowels.

Fixing with self-tapping screws

The first method is the easiest, but it will not work in all situations. First, the timber is drilled to the size of the plastic dowel and a reciprocal hole is made in the concrete with a perforator. The dowel is hammered with a hammer, and then a self-tapping screw is screwed in or the dowel-nail is seated deep into the ceiling. In this case, the head of the screw should plunge into the hole by several centimeters. The interval between the attachment points is a fairly democratic value, it is allowed from 400 to 800 mm, but this should not be abused. You can't go wrong with a step of 0.5 m.

The lags will hold quite securely, but only if the gap between the bar and the base is small. It is also very inconvenient to work with lags whose height is 10 cm or more. In such scenarios, it will be more reliable to fix the bars with the help of steel corners. With one shelf, the part lies on the vertical plane of the log, the second - on the concrete surface. Fixation is carried out with short self-tapping screws to the tree and dowel-nails to the floor. Nevertheless, the main load should not fall on the fasteners, but on the gaskets, the task of the corners is to fix the beam.

Anchor mounting

Unlike previous types of fasteners, anchors not only rigidly fix the logs, but also attract the timber to the concrete surface. Wooden beams installed in this way will hold very securely, which is why anchors are used by the vast majority of craftsmen. In addition, such a powerful fastener up to some degree will restrain the deformation of the wood if it was not previously dried enough.

Thanks to this, the floor covering will not swell, but it can bend, but here it is necessary to provide for more frequent installation of gaskets.

For installation, the first step is to drill a hole through the lag. Then, opposite it, the second is performed, in concrete. Then everything is simple: an anchor bolt is inserted into both holes until it stops and is twisted with an open-end or box wrench. It is important not to overdo it here, a strong tightening will lead to a bend in the timber, especially when there is a gap under it. At this point, the finished floors will come out with a recess.

Before inserting the anchor, it is recommended to make a small indentation in the tree with a larger diameter drill - a hole for the bolt head. The elements are placed at intervals of 0.6-1 m, their length should be sufficient to go deep into the concrete by 60 mm. Bolts with a diameter of 10 mm are most often used.

Adjustable system

This type of fastener is a rectangular stand, attracted to the base with 4 dowels. In the middle of the stand there is a hairpin penetrating the beam through and through. Turning the nut under wooden beam you can fine-tune its height, and the top one can fix the log in the design position. As it is easy to understand, it is not difficult to install the system, it must be fixed to the floor with dowels, and a hole for the stud should be drilled in the beam.

The frequency of mounting the supports is determined by the cross section of the log, but it is not recommended to make an interval of more than 1 m. Such fastening of the log to the concrete floor is considered optimal, but is not used so often due to the high cost. At the end, the bars are covered with a rough wooden floor made of OSB boards or other material or sewn up with boards. The type of the entire floor covering depends on how well it will be possible to carry out these works, they must be approached responsibly.

Floors can be constructed using a variety of methods and materials. Floors on logs are considered popular, which can be arranged on any basis, including for floors on the ground. The main structural element is wooden logs, they are stacked in a certain order.

A heat insulator is mounted between the lags, communications can be laid. Then the rough sheathing is sewn on top. Commonly used plywood, chipboard, OSB, conventional wooden planks, which often act as a floor covering.

Floor on logs is one of the most popular. At the heart of such a floor are wooden bars of a certain size.

Installing a log for the floor can be carried out by various methods, it all depends on the need to level the surface, on other installation conditions. When laying, it is necessary to follow all the steps exactly, the wood will first have to be treated with an antiseptic and flame retardant to provide protection from insects and fire.

What are the benefits of lag?

The floor on the logs has certain advantages over other structures. It turns out not only durable, but also warm. Such a floor allows you to level the surface, arrange high-quality flooring for soil foundations in private homes. Among the advantages it should be noted:

Thermal insulation characteristics, such a floor avoids heat loss.
Lumber for work has an attractive price, they are much cheaper concrete screed, which requires some experience in the arrangement.
There is a minimum load on the foundation, this is significant for frame and dilapidated houses. Such floors are also suitable for wooden floors.
The floor can be installed at any level that is required.
The consumption of building materials is minimal, which has a positive effect on the budget.
The construction time is minimal, there is no need to wait for the solution to solidify, except for the floors on the ground, where the pouring is done under the supports.
An optimal microclimate is formed inside the room.
The floors on the logs can be done independently, no special experience is required.

During installation, you need to correctly determine in which direction the logs will stand. There are rules for installing a subfloor log. Finishing flooring is always carried out in parallel natural light, and the lags should go in the opposite direction. This should be foreseen in advance, so that later you do not have to fix everything.

If laying the floor is planned for rooms with a high intensity of passage, then the logs must be laid in the direction of travel in order to strengthen the structure and prevent it from loosening. It is important to immediately foresee how the floor boards will go, how the sheathing slabs will go if plywood is used. All fasteners of the finished floor must fall on the logs themselves in order to make the flooring durable.

How to fix logs to a concrete base

To fix the logs to the concrete base, you can use various methods. Previously, nails of the required size were used for this, but this method is not the best and most durable, such fasteners quickly fail. Today, the best method is to use galvanized metal corners and dowels.

The scheme of fastening the lag to the concrete base

Instructions for fixing the lag:

All metal corners are fastened with self-tapping screws. One plane of the corners is fixed to a wooden beam.
Self-tapping screws are screwed to a depth of 3-5 cm.
The lower plane is attached to the bar of the lower trim.
For brick supports, it is necessary to perform a layer of waterproofing, after which additionally make fasteners from dowels.

Instead of corners, you can use a special fastening in the form of a U-shaped part. It provides a strong fixation, especially if the bars have to be built up. This method is applicable for large rooms where additional fasteners are required.

The joints themselves for the lag can be arranged in this way:

Close to one another.
With the help of a notch. This docking method is the most effective, but it is necessary to carry out the cutting very carefully so that the docking points are tight.

If it is necessary to strengthen the docking, nails are used, they are stitched through the place of the fastener.

Additionally, you can use pieces of lumber, which can have a length of about 1 m. If the bars are mounted apart, then a step of 50 cm or more must be observed between the connection points.

Ground floor installation

Installing floors along the logs is not as difficult as it might seem at first glance. They differ the simplest design, they can be made for an apartment, a private house, a country cottage. Unlike concrete pouring, the weight of such a design is less, but the floor is in no way inferior in strength.

To install lags, you need to follow a fairly simple instruction:

Scheme of a wooden floor on logs on the ground

Look around first ground base, after which the soil is thoroughly compacted with a vibrator. If there is no such equipment, then the work can be carried out with a piece of logs of large diameter.
A layer of crushed stone is then poured onto the ground, it should be about 5 cm. Such a layer will serve as a base.
After that, it is necessary to build a formwork for each support separately. A preliminary layout of the supports is drawn up in accordance with the size of the room, the conditions for the construction of the entire structure. If the formwork is ready, then you can fill it.
Next, you need to build brick supports. At the same time, a layer of waterproofing must be provided between the supports themselves and the base. This will reliably protect the structure from moisture. Above the brick support, another layer of waterproofing should be made, a soundproof gasket should be mounted.
Next, put the logs for the floor. Pre-cut boards into pieces right size, after their surface is treated with an antiseptic and flame retardant. This will protect them from insect damage, mold, and make them more protected from fires.
The lags are fixed to the supports with special dowels, which ensure reliability and stability. After that, you can lay a special cranial bar, perform a primary plank flooring, you can use ordinary boards for it. After rolling, you can lay out another layer of waterproofing material.
Between the lags it is necessary to install a heat insulator. As such, it can be used various material. Manufacturers offer a wide variety of heaters suitable specifically for floors on logs. In this case, you can take expanded clay, other bulk materials, foam boards, mineral wool boards.
During insulation, it is necessary to ensure that no air gaps and cavities remain, as this will adversely affect the state of thermal insulation, heat losses will be observed.
After that, it is necessary to level the logs for the floor. The upper horizontal level is determined. All excess is cut off, the horizontal level of the coating is checked by the building level.
The finished floor is mounted from sheets of plywood or chipboard, any floor can be laid on them. Decoration Materials. During installation, you will have to ensure that a temperature gap of 2 mm remains between the plates, and 10 mm between the plates and the wall. For strength, plywood can be laid in 2 layers, the total thickness of the sheathing is from 12 mm to 20 mm, it all depends on the requirements for the floor. Between the casing and the insulation, it is necessary to leave a small ventilation gap.
After the floor sheathing is completed, it is necessary to check the horizontalness of the floor again, and then perform surface grinding. In order not to hurt grinder, should be recessed into the tree during fastening of the head of the screws. The last step is laying the flooring. The process depends entirely on what kind of material was chosen for work.

Should I use adjustable lags?

If the floor is not so flat, then its height can be easily adjusted with lags. For this, special fasteners are used that can withstand a significant load, up to about 5 tons per 1 m².

Adjusting elements can be made of metal or special plastic. These are threaded elements that can be given the required height. Logs are attached to such elements, the required height is set. Preliminary marking of the floor and walls is carried out, which determines the level of finishing.

For a concrete floor, dowels are used, and for a wooden floor, self-tapping screws are used that can withstand the necessary loads. After that, all excess is cut off. The logs are attached at the required height, if required, a heat insulator is poured in to make the floor more comfortable and the microclimate more pleasant.

Plywood or chipboard is laid on top, after which you can proceed with the installation of the flooring.

Laying a wooden floor on a concrete base is a common way to create a warm, well-ventilated structure that can serve as a finishing coat when using tongue-and-groove boards or be an excellent base for a finish. facing material. At the stage of manufacturing such a floor, the question arises: what is the best way to fix the lag to the concrete floor? This will be discussed in today's material.

Despite the fact that the advantages of creating a flooring with lags rigidly fixed to the base are obvious, there are opponents of this method, who argue that in this way it is possible to damage the integrity and violate the sound insulation of the room due to the formation of acoustic bridges at the installation sites of the fasteners.

If the screed is destroyed during drilling, then this indicates its poor quality and should serve as a signal to dismantle it completely and fill in a new one. A well-made screed does not change its integrity when drilling holes in it with a drill.

Regarding sound insulation: a rigid structure transmits sound waves, but given that insulation material is laid between the lags, which dampens sound, this statement can be considered controversial. In addition, concrete is much denser than wood, and therefore the sound that is transmitted through the acoustic bridge to the concrete base will not reach the neighbors from below.

One of the nuances of wooden flooring along the logs is the possibility of a creak, which becomes audible even to the neighbors below. This occurs when the structural elements (beams, logs and fasteners) are displaced relative to each other. With a rigid fixation of the lag to the concrete base, these troubles can be avoided.

Important! If the logs are not rigidly fixed, and their moisture content, declared by the seller, is not true, then soon, due to the wood warping process, the floor structure will begin to deform and shift.

Proponents of the rejection of rigid fastening of the log prefer floating floor structures when the flooring is not fixed to the supporting structures. In this case, it is necessary to carefully approach the choice of lag material. The stability of the floating structure will be given by a special fastening of the bars to each other - in the form of a lattice, in the voids of which the insulation material is placed.

The process of creating high-quality flooring along the logs depends on the right material. Coniferous wood is most preferable, as it resists moisture better, contains natural antiseptics in its composition, and therefore is resistant to the formation of fungus, and also belongs to durable types of wood.
The moisture content of the timber should not exceed 18%. Before laying the timber, it must undergo an acclimatization period of several days and get used to the microclimatic conditions in the room where it will be used. If during these days some logs begin to show signs of warping, then they are rejected and not used in the floor construction.
Before laying, the logs are treated with an antiseptic and fire retardant. It is better to do this before installation, because it is more convenient to process the whole product.
It is important to pay attention to the choice of the direction of laying the log relative to the sun's rays - the bars are laid across to ensure their uniform heating. Where the strength of the flooring is important (in rooms with high traffic), the logs are placed across the movement.
The distance between the lags is selected in accordance with the thickness of the rough flooring. The larger it is, the greater the distance between the lags (40 - 50 cm). The distance from the wall to the beam should be 2 - 3 cm.

Materials and tools

Work on laying the floor on the logs does not require specialized equipment and tools. You will need to prepare:

Perforator drill.
Screwdrivers or screwdriver, hammer.
Measuring tools - tape measure, level, pencil.
Fasteners, depending on the method of fastening.
Wood processing in the course of work is carried out using a planer, hacksaw or circular saw.

Need to purchase waterproofing material taking into account the overlap on the walls along the perimeter of the room is not lower than 15 - 20 cm.

You should not take to heart the assurances of lumber sellers that the more expensive and higher the grade of wood, the more reliable and durable the logs made from it will be. For flooring, you can completely do with spruce, fir or pine.
You can safely purchase wood of grade B and BC, provided that its moisture content does not exceed 18%. Minor external defects and the shade of the material can be ignored.
The main condition is the absence of traces of insect pests (bark beetle) and mold on the surface of the wood - even its minimum amount should be a signal to refuse to purchase wood from this batch.
The choice of the beam section occurs in accordance with the chosen thickness of the flooring and the upcoming loads.

Mounting methods

There are several of the most common ways of attaching a lag to concrete. Each of them has its own characteristics.

Fastening the lag with self-tapping screws

This method of fixing the lag, although it is the simplest, is not suitable in every case. The process is simple:

A hole is drilled in the concrete base for a plastic dowel.
A hole for a self-tapping screw is also drilled in a wooden element.
The dowel is placed in a concrete hole, hammered, and the log is fixed by immersing the head of the self-tapping screw into the wood body by several millimeters.

The step that is taken when attaching the lag in this way is at least 50 cm.

Table 1. Installation of a wooden floor with a lag fastened to self-tapping screws

Illustration	Description
	Explicit defects on the concrete surface are sealed with mortar or mounting foam.
	The concrete base is dedusted and debris is removed from this surface with a vacuum cleaner.
	The floor is primed with a solution with antiseptic additives.
	Logs are pre-treated with antiseptics and fire retardants.
	Logs are laid in increments of 50 cm.
	Plastic wedges are placed under the log and with their help the element is set to the desired height.
	The height of the lag is controlled using a building corner or tape measure and a laser level.
	Drill a hole for the screw.
	Screw in a self-tapping screw.
	The wedges must be fixed in a predetermined position with foam.

	Lay a layer of vapor barrier.
	Fix OSB boards.

Fastening the lag with anchor bolts

Fixing the log with anchors is a durable and reliable method. Additional structural rigidity is provided by pulling the beam to the surface of the base.

The anchor is a more powerful fastener than a dowel, it is able to withstand high loads. When installing such a floor, you can be calm in its reliable fixation to the concrete base. According to the technology of work, fastening a beam to an anchor is similar to fixing to self-tapping screws. Preliminarily, holes of the required diameter are drilled in the base and lags. A hole is made in the wood so that the bolt head can be hidden.

The number of fasteners is calculated taking into account the fact that an average of 4 anchors will be required to fix one beam. The bolt in the locking element, inserted into the hole in the concrete, is carried out through the wood. The length of the anchor bolts varies from 45 to 200 mm. When choosing it, 6 cm is added to the thickness of the timber for penetration into concrete. Recommended Diameter anchor bolt is 10 mm.

The popularity of anchoring is due to a more rigid fixation. wooden structure. With this fastener, you can rely on the containment of wood before the deformation process, if it has not been dried sufficiently.

Table 2. Anchor installation

Illustration	Description
	After the anchors are driven into the concrete base, using a 13 wrench, you will need to stretch each anchor nut to secure it more securely. In this case, do not apply too much force so as not to break the thread.
	After that, a bottom nut is screwed onto each anchor and a washer is installed on which the lag itself will be laid. The nut is installed with the reverse side and screwed in, guided by the markings on the wall.
	Throw a puck on top.
	In the lags, a hole is drilled under the anchor's head and under its body, taking into account the spacing of the anchors.
	The lags are baited on the anchor.
	Screw the top fixing cap of the anchor.
	The nut is tightened in accordance with the level value.
	The excess fastener is cut off with a grinder.
	Insulation is laid in the space between the lags.
	Sheets of plywood are fixed to the lags.

Fastening the lag with the help of corners

If the height of the lag exceeds 10 cm, then metal corners are used for their fastening. The corner shelf is fixed to the concrete base with dowel-nails, and to the log - with self-tapping screws. In this case, the corner is used to fix the position of the wooden element, and the load is distributed to the spacers.

Table 3. Lag installation

Illustration	Description
	Before attaching the corner to the log, drill a hole for the self-tapping screw. For the strength of the connection, the self-tapping screw is immersed in the wood at an angle.
	A hole is drilled in the concrete floor for the dowel.
	The dowel is immersed in the hole and the self-tapping screw is screwed in.
	A beam is introduced under the logs, which will fix the logs at the required height and ensure ventilation of the structure.
	The bars are also fixed with corners to the floor.
	Wooden flooring is made of grooved boards.
	To fix the board at an angle, drill a hole for a self-tapping screw.
	The board is fixed with a self-tapping screw immersed in the groove at an angle of 45 degrees.

Adjustable lags

Adjustable log system is the most in a simple way devices of a flat boardwalk in a room with a concrete base having a significant height difference. Anchors in this design are replaced by plastic posts, which are attached to concrete with dowels. The convenience of using plastic racks lies in the fact that you can adjust their height and the level of the lag location using special rotating bolts. Excess racks protruding above the surface of the log after adjustment are cut off.

Modern manufacturers offer universal racks that allow you to make perfectly even boardwalk in a room with a large height difference, regardless of the section of the beams. Installation takes place as follows. The supports are installed on a concrete base.