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Fastening metal lag to concrete without drilling. Fastening a log to a concrete floor: features and methods of fastening a log with self-tapping screws, anchors, corners

Timber joist flooring is a very practical and easy way to get a functional floor covering. In such a floor, you can install any base for the floor, lay heat and sound insulation, hide any engineering communications such as electrical wiring or a heating system.

It also creates conditions for freer air circulation in the room. In addition, a perfectly leveled surface is obtained on which any final design can be placed. decorative coating without the risk of deformation.

There is nothing difficult in installing such a coating, installation can be done on your own without the involvement of specialists, and hence additional costs. The price of this kind of work, taking into account the cost of all materials, will suit almost everyone. As a result, a structure is obtained that does not overload the foundation of the house or the ceiling between floors, but can itself withstand significant loads.

When considering this question, doubt will inevitably arise whether it will be possible to securely fasten together such different physical properties materials. In this material, we will consider fastening the lag to concrete floor.

What is the floor on the logs

The floor on the logs is a structure consisting of several functional elements:

  • bars;
  • fasteners;
  • Black flooring.

Proper installation involves rigid fastening of all elements relative to each other in order to avoid displacement, deformation and permanent creaking of the floors. True, opponents of this method argue that the rigid fastening of the beam destroys sound insulation and contributes to the destruction of the screed.

As for the first doubt, it can be easily dispelled by studying how the lag is laid. Indeed, a rigid connection can create sound transmission bridges. But at the same time, a special shock-absorbing layer is laid under the base of each beam, which has the property of sound absorption.

Some more noise is “eaten up” by the insulation laid in the cells. In addition, solid concrete conducts sounds quite poorly, unlike wood, so it is unlikely that the noise level will noticeably change after the repair.

Ideas about the possibility of destruction are also unfounded, since a well-made screed does not crumble when trying to fix the logs. If the screed began to fall apart even before trying to fix the logs, then it needs to be removed and the floor refilled, since such a base will not provide high-quality flooring.

Another argument in favor of rigid fastening is the inability to independently check how well the materials are dried. Floating (not bonded to other elements of the system) laying will save the maximum high level soundproofing. But insufficiently dried logs will eventually bend and distort the entire complex structure.

The floating floor gets a margin of safety literally under own pressure. In the lattice, assembled from the bars, a heater is installed, a rough flooring is laid on top. But still, it is better to give preference to rigid fixation of the log from the timber.

First of all, it is necessary to choose the highest quality materials. Coniferous trees are perfect for this task. It is necessary to ensure that its humidity is not more than 18%. After buying the bars, you should give them a little rest, leaving them to lie in the room where the floor is planned to be laid. During this time, the wood will get used to the new conditions. After that, the material must be treated with antiseptics and liquids that impede the combustion process.

After making sure that the tree is ready, you need to prepare the floor. It is cleaned of debris and dust, all cracks are sealed, bumps and protrusions are knocked off. Then you need to take care of waterproofing to protect the tree. Suitable special mastic, roll materials and even ordinary thick film.

It is required to lay substrates under the logs. You can make them yourself from thin pieces of wood, plywood or plastic, as well as buy ready-made materials at a hardware store. Make sure that these elements do not sag or deform, as gaps that are detrimental to wood can form because of this.

When laying, you need to make sure that the logs rise perpendicular to the sunlight falling from the window. Such laying will allow to achieve uniform heating of each beam, which will reduce the likelihood of material distortion.

If rather strong and thick sheets are chosen as a black coating, then the bars can be laid with a fairly large step. It must be assumed that the average width of the space between the lags is about half a meter, and the extreme bars are placed at a distance of a couple of centimeters from the walls.

The crate after assembly must be placed horizontally. If desired, you can level the floor with a cement-sand screed, but the design of the logs allows you to lay them on the floor without additional leveling. Instead of a screed, it is enough to put pre-prepared substrates in the right places.

Each support at the bottom must be padded with a piece of rigid material that is not subject to deformation (for example, linoleum). Soft materials will “fall through” over time and lead to squeaks and noises.

Among the necessary tools:

  • Perforator (or a drill with a special mode);
  • fasteners;
  • Tools for preparing timber and other elements.

Legs can be fixed in several ways. Each owner chooses the method that is clearer to him or more affordable for the budget. Can choose:

  • self-tapping screws;
  • anchors;
  • corners.

Self-tapping screws are the simplest and cheap way. It is enough to drill through holes in the bars and continue them into the bases. A dowel is inserted into the hole, inside which a self-tapping screw is screwed, which should go a few more centimeters into the base.

Anchors are, in essence, almost the same self-tapping screws, only with a much greater margin of safety. They not only firmly attract the floor, but also have resistance to tearing.

It is unlikely that the floor will ever be subjected to such loads, but the method, nevertheless, remains quite popular. Two or three anchors are enough for one room in the apartment. Their length ranges from 4.5 to 20 centimeters, it is better to choose those that go to the base of the floor by 5-6 centimeters.

Metal corners are fixed on the log with one side, and on the floor with the help of self-tapping screws or anchors on the other.

There is also such a solution to the issue as the acquisition of a regulated system. It will cost more than all the listed options, but the height of the structure can be adjusted almost perfectly. The system includes special plastic bases and self-tapping screws, which are screwed in at the right level, and then the excess is cut off from above.

At the final stage, it is desirable to lay a vapor barrier layer on top of the timber. And on top of the resulting result, plywood or boards are laid. The result is a perfectly even surface on which any decorative flooring can be laid.

Keep in mind that in wooden houses it is not worth attaching logs from a bar to the floor.

There are two main ways to prepare a suitable horizontal base for the laying of floor coverings currently in use: screed and subfloor laid on load-bearing beams. In order for the flooring to be durable, not to change its geometry under load and at the same time serve for a long time, it is necessary to correctly fix the lag to the concrete floor or other supporting structures that are provided for in a particular situation. The article will discuss the devices with which you can attach wooden rails, as well as how to use them, some of which can be viewed in the attached thematic video materials.

How to choose a beam for a lag?


Proper selection of lumber that will be used for the construction of flooring for laying finish coat, will guarantee the durability of the structure, and its ability to withstand the proposed loads without deformation of the surface. What should you pay attention to first of all?

  1. Humidity. The beam, which is usually used as a log, must be dry. Moisture content of wood, regardless of the species used, at the moment installation work should not exceed 18%. This is a natural moisture indicator for lumber. That is, the likelihood that moisture will occur or, on the contrary, further drying of the wood (both processes lead to deformation) with this moisture index is minimal.
  2. Type of wood. Logs, unlike beams, have more support points, the number of which can always be increased. So the type of wood does not play a special role. Grade 2 or 3 lumber is quite suitable. If a large knot or other defect affecting strength is found in the beam, it is enough to install an additional support in this place.
  3. Section. The main requirement is the shape of the butt. It is necessary that the cross section of the timber be rectangular, with an aspect ratio of ½ to 2/3. In this case, it will be correct to put the lag on the edge. In this position, the bar is maximally resistant to vertical load. The size of the section is selected so that its larger size allows you to lay a sufficient layer of insulation, and the smaller one allows you to easily lay and attach (taking into account the possible joining of fragments) a board, plywood or OSB. The strength of the lag can always be increased by installing additional supports.
  4. Type of wood. For a lag, they usually choose an inexpensive scaffolding conifers - suitable pine or even spruce. It is advisable to put larch bars where high humidity is expected.
  5. Treatment. The bars dried to the desired moisture content should be treated with protective impregnations. This will make the wood resistant to moisture, microorganisms and insects. If desired, it can be treated with flame retardants, which significantly reduce the combustibility of wood.

Important! Attention should be paid to the relief of the surface of the timber, to which the board or slab material will be attached. If there are irregularities on it, they should be removed with a planer. This must be done before installing the lag.

Properly selected and processed lumber is half the battle. Now let's look at how to properly attach the logs to the base, including concrete, in various situations.

Laying lag with slight floor insulation


This situation usually happens in apartments where the ceilings are low, so it makes sense to save space as much as possible. Moreover, there is a heated room below, so a small layer of insulation is enough, which is more needed as a sound insulator.

In this case, a small section of the lag is selected, which are laid directly on reinforced concrete slab or small regulators wooden coasters. There is no special need for waterproofing in such a situation. An exception is when the apartment is located on the ground floor above a damp basement. Then it makes sense to cover the concrete surface with a polymer film or treat it with bituminous mastic.

In this case, metal corners or anchors can be used as fasteners. There is no need to firmly attach the bars. Such a fixation of the lag is enough so that they do not move during the laying of plywood or boards. Professionals sometimes do not fix the guide bars at all if they are in a stable position, since the lag frame does not experience other loads during operation, except for vertical ones. An example of such a situation can be seen in the video below. The floor board or sheet material (plywood, OSB), when rigidly connected to the underlying supports, form a monolithic shield that does not have the possibility of lateral displacement.

How to fix the logs at a distance from the concrete floor?

This option for installing load-bearing beams is used if you want to lay a thick layer of insulation or simply raise the level of the floors. A similar situation arises when installing a wooden floor on a rough concrete base made on the ground, on loggias and balconies. This also happens in the living rooms of apartments, when, with large differences in the position of floor slabs, there is a desire to make the floor surface on the same level.


If necessary, a significant rise in the log above the plane of the plate or concrete screed most often, two devices are used to help adjust the position of the bars and attach them securely. These include:

  • screw adjustable supports;
  • metal brackets.

Screw fasteners have an extended support platform that is connected to a vertical threaded pin. The lag is attached on top with nuts. By screwing in / out of the screw, it is possible to accurately and conveniently adjust the position of the bars, exposing them in the same horizontal line.

Important! Screw supports are the most expensive devices for installing load-bearing bars. They are usually used when installing floor structures over large areas.

The brackets are U-shaped and come in different heights. First, they are attached to a concrete base along a line with a calculated step. Then a beam is inserted into them and fixed with self-tapping screws on both sides or a through bolt.

Atypical situations

Sometimes in houses of old construction, when trying to replace the wooden floor with a new modern design, one has to deal with atypical floor slabs. In these cases, you have to come up with non-standard ways of laying and fastening the lag. One such situation is described in detail in the following video. As you can see, in addition to the standard methods of fixing the bearing bars, you can come up with many more methods. In fact, it does not matter how the lags are attached, the main thing is that they are correctly located in the horizontal plane and withstand vertical loads.

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 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:

  1. Thermal insulation characteristics, such a floor avoids heat loss.
  2. Lumber for work is distinguished by an attractive price, they are much cheaper than a concrete screed, which requires some experience in arranging.
  3. There is a minimum load on the foundation, this is significant for frame and dilapidated houses. Such floors are also suitable for wooden floors.
  4. The floor can be installed at any level that is required.
  5. The consumption of building materials is minimal, which has a positive effect on the budget.
  6. 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.
  7. An optimal microclimate is formed inside the room.
  8. 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 the laying of 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:

  1. All metal corners are fastened with self-tapping screws. One plane of the corners is fixed to a wooden beam.
  2. Self-tapping screws are screwed to a depth of 3-5 cm.
  3. The lower plane is attached to the bar of the lower trim.
  4. 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:

  1. Close to one another.
  2. 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 structure 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
  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. 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.
  11. 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.

Now there are many technologies that make it possible to make a high-quality and solid foundation during the construction or repair of both a private house and an apartment. The options can be very different - from inexpensive flooring materials to an expensive "warm floor" system, but in some cases it is impossible to do without fixing the log to the concrete floor. This allows not only to additionally insulate the space between the base and the coating, but also to correct the unevenness of the concrete using wooden beams.

Logs are boards or bars made of wood (less commonly, polymeric materials) that create a solid structure for flooring. They may differ in shape, size, method of installation and installation, but are used in the same way.

Application

A new floor level can be fixed on any basis. The boards are easy to install, relatively cheap, and allow the use of all available types of insulation and insulation, which reduces the overall cost of construction. They are used for:

  • creating a ventilated space under the finished coating;
  • improved heat and sound insulation;
  • obtaining a flat horizontal surface;
  • distribution of the load of the building on its lower sections.

Usually, two methods are used to fix the bars - adjustable or non-adjustable. Which one to choose, only the owner of the house decides, since both methods have their advantages and disadvantages.

For any type of fastener, the future location of the floor is marked first. It can be carried out both on the base itself and on the walls, marking the level. Then one of two options for installing lags is selected.

Unregulated Method

The base surface is cleared and waterproofing is laid, the layer thickness of which should not be more than 10 cm, otherwise it will be necessary to lay bars for supports, which will not only increase the budget, but also complicate the process. Then a wooden sole for boards is laid out all over the floor. After that, the laying of wooden logs begins with corners to the concrete base.

Stands for boards are attached with nails. But there is another option here - fastening the lag with anchors to the floor. To do this, the same hole is made in the bar as in concrete. The diameter of suitable anchors is 10 mm. This is the most popular method, its only drawback may be the bumps that occur due to the bending board. Only after the installation is completed, sound and heat insulation is laid in the remaining empty space.

Adjustable method

It makes sense to do this option only with obvious irregularities in the base. Instead of anchors, plastic racks are used, screwed into the floor boards, after which they are fixed to the concrete with dowels.

There is a lag design that does not require anchoring to the floor, which is best used only when choosing an adjustable method. To install it, be sure to lay a film over the insulation. Usually used logs covered with plywood.

Fixing the lag to concrete with your own hands is a completely doable task. The main thing in this matter is to choose the right materials and follow the rules. technological process. This will guarantee a reliable floor and the absence of its displacement in the future.

The question of how to attach the logs to the concrete floor does not lose its relevance, since many homeowners prefer this particular method of flooring. 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 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 log 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:

  1. Wood should have a moisture content of no more than 20%.
  2. The bars should be checked for curvature and sorted, if any.
  3. 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.
  4. The height of the bar must not be less than the thickness of the heat-insulating layer.

To exclude the occurrence of dust, it is necessary to apply a deep-penetrating primer to the subfloor, and then lay a waterproofing layer. 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:

  1. Using plastic dowels and screws.
  2. On self-tapping screws by means of steel corners.
  3. On anchors.
  4. 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: it is inserted into both holes until it stops anchor bolt and twisted open-ended 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.