As the famous Ranevskaya liked to repeat, “the weaker sex are rotten boards.” Yes, the situation is actually one of the worst pleasant - a wooden floor has served you faithfully for decades, and at some point they begin to resemble ship planks: in some places they wobble, in others they bend, and in others they even break through... Going through the floor is as easy as shelling pears. But, even if you buy expensive and water-resistant wood, install more solid waterproofing and even hang a hygrometer, this will not save you from repeating the same situation in a few years if you make the same mistakes again during the arrangement. Therefore, let's learn how to solve such problems even before such labor-intensive repairs begin.
First, look at what happens if you don’t do everything wisely in time:
Let’s make a “diagnosis”: why did the floor turn to dust?
But let’s first learn how to “diagnose” rotten floors. So:
- The boards have turned to dust, but you don’t feel any obvious moisture? And does the wood look clean? This is not a rotten floor, but a floor that has been eaten by bark beetles. How to deal with them is in another section of our site.
- The boards are rotten, no moisture is felt, but there is some kind of plaque and something like white foam on the boards themselves? This is a fungus that does not always appear due to dampness; rather, it is introduced with already diseased boards.
- Do the boards turn to dust and even turn black in places? This is a sure sign that your floor is rotting, and it is rotting because of water. And water can get to it in a variety of ways, and this is not necessarily just groundwater from the basement. Everything here is much more complicated, and now we will gradually figure it all out.
- Are the boards rotten and the insulation soaked in water? Well, if moisture comes from the house (for example, the walls are to blame), then this will be noticeable first of all by the wet insulation. In this case, you need to work with the house - at least for the first time by installing a modern dehumidifier.
Have you determined what happened to the boards? Go ahead.
All about the rotting process of wooden floors
The source of rot for any wooden floor is water. Constant access of moisture and air to this material has a detrimental effect on it, especially frequent wet-dry cycles.
To determine the exact cause of rotting floors in the house, you should note the following factors:
- History of construction. What and from what, whether the blocks were dry, for example, how the foundation was waterproofed and what the roof was covered with.
- Weather. How often does it rain, and is there slush?
- Age of the house.
- How is air exchange organized? Eg, In order for the vents to work correctly, the diameter of each of them must be at least 25 cm.
- Were all standards observed when installing the floors?
The first signs of the beginning of floor rot are the swelling of the boards and “playing”. Already at this stage, the floors can be saved - without completely re-laying.
The most common sources of moisture in the underground are rising damp currents from the ground (especially if groundwater is located high) and too humid air from street ventilation. How to understand what exactly you have? Do this simple test:
- Close all vents well.
- Open a hatch in the underground or create a small hole near the wall to establish air communication between the room and the underground space.
- Place heaters in the underground so that the air temperature there becomes the same as in the room. Those. align it.
Now check whether the air in the underground remains as humid - if so, then the source is moisture from the soil. You can isolate it modern materials, laying them on the ground and covering the foundation from moisture. We also note that many of the types of oils that are coated with floorboards before installation also contribute to wood rotting.
The most common causes and solution to the problem
Let's look at the most common options that cause the floor to rot:
Option #1. The products don't do their job
There are too few vents in the house, up to 6, and they are located low to the ground. This makes airflow almost impossible and the environment becomes too humid over time. The joists and floors are rotting.
What to do: instead of insulation in the floor pie, lay a moisture-proof membrane that will control the movement of water. Next, organize a ventilation gap using counter slats across the beams. There should be a gap and ventilation slots on the ventilated baseboard. This way any possible moisture will be dried out. And, if the vents are not working enough, there should be some other ventilation under the floor. Usually this metal corner in the floor with holes - there is enough of it.
Option #2. The ground is too close
The wooden floor is laid on logs, and underneath there is earth, at a distance of up to 20 cm. Such a floor will deteriorate very quickly. And it’s precisely these kind of constructions that would-be builders often make in private homes – quickly and angrily, as they say. Sometimes, however, instead of earth you can find wet clay there, and the result is the same.
What to do: definitely redo the floor: waterproof it into a pie, raise the floor itself higher to regulate moisture, and protect it well from dampness. Another option is to put geofabric on this soil, and sand with good compaction on it. It will not conduct water upward, even if there were no geofabric (this is prevention) - just like the sand on the seashore is dry, but if you dig deeper, it is wet.
Here is an example of the joists being close to the ground, and they were raised during the process of replacing the floor:
Option #3. Hopelessly damp basement
It will be difficult to remove moisture from it, and it will still (even with good ventilation) reach the floor boards. High groundwater is especially dangerous for floors.
What to do: in this case, it is better to abandon it completely, foam the vents and completely cover it with clean river sand. Water each layer generously and compact it well. Lay plastic film and insulation on top of the sand cushion, then plywood, and then the floor itself. And, most importantly, remove the water as much as possible from the house itself - using external drainage. Usually even pipes around the house are enough, but sometimes people build small storage tanks nearby groundwater- deep holes. It’s not even difficult to pump water out of there.
Option number 4. Vapor barrier installed incorrectly
It often happens that a certain material is laid the way the floor was designed, and then the boards suddenly rot. This happens because the person laying the floor did not study the instructions for the vapor barrier itself - different manufacturers have very different requirements for its installation. So, materials of one brand should fit tightly to the insulation, while others should have a ventilation gap between them.
What to do: When changing the floor, you can use the same insulating material, but this time study thoroughly all the information about it. You can take a closer look at everything in this section of our website. And keep in mind that a vapor barrier can be done on the underside of the floor pie when the underground itself does not differ in temperature from the room. But if it is cold, then only the soil itself can be waterproofed, and good ventilation will need to be provided above.
In this photo instruction, the rotten floor in the bathhouse was due to incorrect application of the membrane, and now it has been completely replaced:
Option #5. Always wet insulation
The insulation gets wet, causing the joists and floor boards in contact with it to begin to rot.
What to do: remove the vapor barrier from the bottom of the insulation and attach a membrane in its place. If this does not help, remove this insulation altogether, and instead insulate the base and blind area, completely plugging all vents. There will be no more heat loss, and the problem will be completely solved. And the very first thing to do is determine where the floorboards began to pick up moisture. So, it can come from underground, or from the house itself.
Look at the example of how a rotten floor was replaced and its pie was correctly arranged:
Option number 6. There is a real swamp under the house
For example, today they are actively selling plots with a former swamp for private development. And problems with the floor – already in the first few years. No matter what you cover the floor with, moisture still gets to the boards, and they rot over time. There is only one way out: good vapor barrier below.
What to do: arrange a special drainage with a separate pump under the floor, and another one - external, without a pump, just with water drainage. The problem will be solved.
A hole for targeted drainage of water in the base of the foundation can be made as follows: either using a reinforced concrete screed with a slope, or simply laying roofing felt with an overlap along the edges. In addition, if your underground is damp, under no circumstances should you put laminate or linoleum on a wooden floor. They simply will not allow moisture to pass through, and the floors will begin to rot. When laying a new floor instead of a rotten old one, be sure to treat the boards with an antiseptic at least twice.
Here's how to protect such a floor - this one also rotted from the swamp under the house:
Option No. 7. The floors were insulated too hard
Yes, all the warmth remains in the house, but under the floor will now freeze so much in cold weather that it will thaw all summer - and until the fall. Result: a huge amount of moisture.
What to do: review the insulation design and simplify it a little.
Option No. 8. Excessively humid air inside the house
Let's explain in more detail. If ventilation, namely the exchange of the walls of the house with external environment If it is arranged incorrectly, then in the warm season this is not yet felt. But at the very first fire, internal vaporization increases significantly (moisture is released from the walls and ceiling), warm air goes up, as we know from physics, cold goes down. And condensation forms on the floorboards, and precisely in the coldest place - on the insulation. Pay attention: do your walls get wet where external moisture could not get in? And for accuracy, buy a regular hygrometer and measure the humidity of the air inside the house in winter.
Another clear sign that the air in the house is currently very humid is frost on the walls during the first kindling.
What to do: if the phenomenon is temporary, then open two windows in the house, close the vents, and in this way expel the humid air to the street.
Option number 9. From old age
It happens that the floors rot even in a very old house. This is the property of wood.
What to do: just replace it. Just be careful when using the jack - if the house is made of wood. And carefully examine the logs - if possible, they should also be replaced.
This is what a competent complete replacement of a wooden floor due to rotting due to old age looks like:
Option No. 10. No ventilation gap between the floor and the wall
Those. the floors are made close to the walls, which in itself is a violation of all technologies. This design is especially vulnerable in a wooden house - it will be the first to begin to rot. lower crowns, and then the floor itself. The log house itself will not last long without intervention either.
What to do: completely change the floor plan and throw away the rotten boards (not all of them could have gone bad). It is advisable to replace everything with a good concrete floor, especially if we're talking about about the bathhouse. So, for a Russian steam room, use the following floor pie:
- Sand pillow.
- Crushed stone.
- The screed is 3 cm thick.
- Waterproofing film.
- EPPS.
- The same film.
- Reinforced screed 10 cm thick.
Why film? It is needed both below and above, because there will be a washing room or steam room above the floor, and this is especially wet areas. Secondly, it will not let cement laitance into the insulation during the process of pouring the screed.
Option No. 11. Only the beams rotted
If you find that only the beams are rotting and the floor is not touched, most likely the foundation freezes heavily during the cold season, and condensation accumulates on it from the inside. Beams are the first to be distributed, of course.
What to do: here it is necessary to dismantle the old beams. Next, where the boards come into contact with the base of the foundation or the walls of the house, waterproof them with rubemast or glass insulation in several layers.
Using a geomembrane as waterproofing under the floor should generally be done during construction, as an axiom. Glue its edges to the foundation with double-sided bitumen tape, and forget about underground dampness. If you change the lags, make them with slight slope to the side - so that the condensate that appears no longer lingers on them, but flows down. And for this water to escape, it is also advisable to make a drain under the foundation.
Option No. 12. The floors are rotten in the apartment
This is a sure sign that they lack ventilation.
What to do: organize required holes not difficult - you need one under the battery and one on the opposite side.
Products: necessity or evil?
By the way, recently underground spaces are increasingly being built without ventilation. Thus, the masters call this “a Russian tradition - first driving humid air underground, and then actively expelling it from there.” Therefore, today, more and more often, the foundation and floor are simply well insulated - and that’s all. This way the floor will never rot. What does this design solve?
Let's take a closer look at this point. For example, in the spring the air outside is much warmer than underground, and besides, it is also humid (the snow is melting). And this warm and moisture-saturated air penetrates through the vents under your floor and immediately settles in the form of condensation on the cold boards. And they spend a lot of time in this dampness - until the summer. Is it any wonder that wooden floors completely rot within a few years? And through the same vents, rodents sneak into the house in hordes in the fall. That is why today others are actively used Constructive decisions, and ventilation is carried out in a slightly different way - through the house itself.
Such an underground is called closed air-conditioned, i.e. mechanically ventilated. The fact of the matter is that if the temperature of the underground and the room does not differ much, then condensation on the floorboards will not occur. On the other hand, if your underground is and will be ventilated with vents, the movement of air from it through the floor must then be completely blocked.
These are the solutions to this problem - everything is actually very simple.
Wooden flooring is the undisputed leader among the floors of the twentieth century. It is absolutely natural, environmentally friendly, durable, creates coziness and comfort in the home, and the materials for it are publicly available. Most of the buildings of the last century: “Stalin”, “Khrushchev”, “Czech project”, all private houses and many others were equipped with wooden floors. Given the age of these objects, it is indisputable that it is time to renovate them. This article will tell you how to repair a wooden floor in a private house or apartment, and will also touch upon the repair of the floor in a wooden house and its design features.
Diagnostics and inspection of a wooden floor structure
Before you start repairing the floor, you must inspect it and find rotted or sagging boards, inspect the joists and beams to see if they have been eaten by a bark beetle. The result of the research will determine whether it is possible to do without partial renovation: screw it in here, trim it there, or you will have to do a major overhaul.
Even if the finished floor boards seem perfect to you, you still need to make sure that the subfloor is also in good condition. Let's try to find the rotten boards. To do this, tap the floorboards with a hammer. We will determine the condition of the boards by the sound. If the sound is dull, it means the board is rotten. And we determine the more accurate position by looking at the nails - they have rusted under the influence of the rotten board. If only the top boards become unusable, then they can be easily replaced. If the subfloor boards are rotten, it’s also not a problem; they can be cut out and replaced, having first checked the condition of the joists. But if the logs are rotten, you will have to disassemble the structure a little more, cut out the rotten piece of the log and nail new bars to it on both sides.
We check the embedded beams by piercing them with an awl
If in a private house there is emanation from the floor bad smell, and some elements are broken, which means there is rot somewhere. You will have to check all the elements: the finished floor, the rough floor, the joists, the beams, and the embedded crowns. The most difficult thing is that even rotten embedded beams can look perfect, especially if you examine them in a semi-dark underground. Therefore, we inspect all wooden elements from the outside of the building, from the inside, and from the underground. If no defects are found “by eye,” then we take an awl and try to pierce the embedded beams. We try to make piercing movements as often as possible. If we find a rotten section of the beam, we will have to cut it out and replace it. And if this is impossible, then we will raise the wooden house on a jack and replace the embedded beam completely.
Raising a wooden house with a jack
We pay close attention to the ends of the joists. They begin to rot more often and faster, taking over the rot from embedded beams that are not waterproofed or if the insulation has already worn out over time.
If, during an external inspection, minor defects are found in the form of cracks between the floorboards, the boards are “walking,” or the paint is peeling, then we will make do with a partial repair.
If the floor creaks, it is enough to go through it and replace some of the joists.
If the floor is too cold and allows moisture to pass through, it means that during construction they were in a hurry and skimped on materials, forgetting to insulate the floor. You will have to disassemble it and re-waterproof and insulate it.
Major renovation of a wooden floor
If you are the happy owner of a wooden floor that is 40 years old or more, do not entertain yourself with illusions; half measures will not do. Next we will look at how to make capital and other buildings. By the way, it’s quite possible to do all the work yourself. Although it is better to have a partner, it is also more convenient, faster, and more fun.
First of all, let's shoot flooring and baseboards. This can be linoleum, parquet, boards or cloth, depending on the design of the house. If tearing off linoleum or parquet is not so bad, then tearing off cloth and hardboard can be very difficult. During the Soviet shortage, when even nails the right size it was impossible to find, 5 mm hardboard could be nailed with 50 mm nails. It is quite possible that you will have to suffer. We throw away everything that is torn off; it will no longer be useful to us.
We undermine and cut out old floor boards
To dismantle the floorboards, we look for a wider gap. Using a crowbar or crowbar, or better yet both, we pry up the board and undermine it along its entire length. We pull out the nails. Thus, we remove all the floor boards, both finished and rough. The logs should appear before us in all their glory. Well, or what's left of them. Prepare for the worst. Most likely, you will see that the subfloor was simply hanging in the air above the soil and the remains of the rotted floors.
Important! It is quite possible that the logs were eaten by a bark beetle. After all, there were no special impregnations before. We'll definitely check this out.
If the logs still remain, we dismantle them by unscrewing them from the beams and support posts.
At this point, the dismantling of the old floor can be completed, and you can begin laying the new floor.
Scheme for replacing beams using a jack to raise a house
But if we are repairing a wooden house or bathhouse, in which the logs are supported and attached to embedded beams that are already rotten, then we cannot do without helpers and equipment. To work with support points, we will have to jack up the house and replace all the beams with new ones.
Installation of new joists
Before directly installing the logs, we need to decide whether we need to drain the basement or add foundation. If the subfloor is damp, draining the subfloor will significantly increase the time it takes to repair the floor.
If necessary, add foundation to crumbled areas.
We inspect the condition of the support columns for the logs: all structural elements must be in good condition. If there were none, for greater reliability of the structure we mount columns:
- We mark the places for attaching the lags on the embedded beams. We stretch the cord in the longitudinal and transverse directions, determining the angles of future posts.
- We remove the soil in the designated places. We compact it, lay down plastic film to waterproof the foundation, pour crushed stone, and compact it again.
- We install the reinforcing mesh 10 cm above the crushed stone.
- We install the formwork 10 cm above the ground level.
- We pour concrete. The foundation for the posts should protrude 5 cm above the ground. We wait until it dries, 2-3 days.
- We waterproof concrete.
- We lay the bricks in two rows on the cement mixture.
- We waterproof the bricks, install heat and sound insulation.
Scheme for installing joists on support posts
For the logs we buy rectangular timber. It is better if the height of the log is 2.5 times the width. But if you buy 200*200 mm timber, that’s also good. You can use coniferous wood: pine, if, fir. Humidity should be 18-20%.
Important! All wooden structures: beams, joists, floorboards are treated with antiseptics against bugs and fungi.
We lay the logs on the beams and support posts. We start with the “lighthouse logs”, the outermost ones from the walls. Then we retreat 2 m from them and lay more logs.
Important! Be sure to check the horizontal lag level. If in some place the lag protrudes beyond the level, cut off the excess with a plane. If the joist bends somewhere, we install a lining under it.
We lay all the joists and screw them to the beams with self-tapping screws. To secure the logs to the support posts, we use corners. We drill holes in advance so as not to split the lag. We secure it on the wood side with self-tapping screws and on the brick side with dowels.
Important! A deviation of the log level of 1 mm per 1 m is allowed.
Arrangement of the lower floor
We nail the bottom floor boards to the joists from below
We will need a “bottom” floor so that there is somewhere to lay the insulation. To do this, we take well-dried boards 20-30 mm thick.
It is more convenient and easier to fasten the lower floor boards across the joists, securing them directly to the beams.
To do this, all work will have to be done from the underground, maybe even while lying on the ground. We nail the boards or screw them to the joists with self-tapping screws.
Important! If for some reason you decide to lay the bottom floor boards along the joists, then you will have to nail bars to the joists, onto which the bottom boards will be attached.
Check the floor for cracks. If we find any, blow them out with foam.
We lay insulation between the joists
After the “bottom” floor is ready, we lay a layer of waterproofing and insulation. Since the space between the joists remains empty, we will lay the insulation mats in it: stone wool, mineral wool, basalt fiber or other material.
Arrangement of wooden flooring
We lay the finished floor on top of waterproofing and insulation
For the “top” or finished floor, we buy well-dried wood with a moisture content of no more than 12%. The thickness of the board should be about 40 mm. It is more convenient if the board is tongue-and-groove.
We begin laying the floor from the corner of the room farthest from the door. We lay the first board with a tongue and groove against the wall at a distance of 10-12 mm from it. We fasten the ridge to the beams and joists with self-tapping screws in such a way as to hide the head of the screw with the plinth. On the reverse side we screw the screws into the groove at an angle of 45°.
We insert all other boards into the groove with a comb, and screw them on the groove side with self-tapping screws.
Important! If the length of the flooring boards is less than the length of the room, then they will have to be laid “staggered”, i.e. offset by half a meter so that the joints of the ends in the row do not coincide.
We screw all the boards to all the joists without exception. If you bought non-grooved boards, then we use wedges and linings for installation.
Important! We alternate the direction of the growth rings in each row.
If we plan to leave the floor covering wooden, then the flooring must be sanded and covered with clear varnish or paint. If we are going to lay linoleum, then we level the finished floor with plywood or chipboard. And on top we lay linoleum, laminate or parquet.
The installation of a wooden floor in an apartment differs from the floor in a private house in that the logs are laid on concrete base, and not on the ground. Therefore, the technology for repairing such floors in an apartment will be slightly different.
First of all, we dismantle the old floor, remove the floor boards and dismantle the joists. We should see a concrete base underneath them. We thoroughly clean it of debris and dust.
The wooden floor joists in the apartment are laid on a concrete base. We clean it from dust and debris
Be sure to make the cement screed or screed with a self-leveling mixture. We prime the surface and lay waterproofing. You can use 200 micron polyethylene film, lay it in strips and glue the joints with tape.
We lay sound insulation on top of the waterproofing. You can use cork, fiberboard, roofing felt, rubber or polyethylene foam.
We lay the logs. We secure them with dowels.
Important! If we use timber less than the length of the room, then the installation should be done “staggered”.
We lay insulation between the joists. We lay floorboards on top.
How to fix creaking floorboards
Any wooden floor sooner or later begins to creak. Either this place is used too often, or the floorboards are simply dry, or the joists are split. There can be many reasons. And laying plywood on top may not solve the problem, but only delay its solution.
Floorboards squeak when they are loosely attached to the joists. There are several ways to eliminate the cause.
We drive a wedge between the floorboard and the joist from below
Method 1. If it is possible to access the floor from below, for example when the floor is the ceiling of a basement, then you can fix the floorboard from below. To do this, one person goes downstairs and the other walks on the creaky floor. Thus, a “creaky” board is determined. We find the place where a gap has formed between the board and the joist or beam, and drive a wooden wedge into it.
We fix the boards with screws at an angle
Method 2. If there is no access from below, then screw the screw in at an angle from above. To do this, we drill holes in all the joists and fasten the boards with screws. We putty the screw heads. And when the putty dries, we sand the surface.
Method 3. If the cause of the creaking is the friction of the boards against each other, then you need to walk along the floor and find the “causing” places. Then pour talc or graphite into the cracks between the floorboards or drive in wooden wedges.
How to fix sagging floorboards
Most often, the reason for sagging floorboards is that they were not laid sufficiently dry. Over time, the wood dried out, cracks appeared, and the boards began to “walk” and sag under the weight of a person or furniture. There are several ways to solve the problem.
We push the cord soaked in PVA glue between the floorboards
Method 1. We buy a thick braided synthetic cord (rope). We impregnate it with wood glue or PVA glue. We push the cord between the floorboards to the middle of the thickness of the board. We prepare putty from PVA glue and sawdust. We first sift the sawdust and remove bark fragments and debris. Stir the mixture until sour cream thickens. Fill the cracks with putty. After the glue dries, cut off the excess with a knife. After drying, after 1-2 days, the floor can be painted.
Filling the gaps between the floorboards with putty
Method 2. If the reason for the sagging of the floorboards is sparsely located logs, then we will fasten the floorboards together. We prepare round long wooden sticks or pieces of large diameter steel wire. Using a long drill, we drill holes in the floorboards at a large angle so that the hole passes through one floorboard and extends halfway into the adjacent one. We insert sticks into the hole. We begin to drill in a checkerboard pattern, first in one floorboard, then in the adjacent one. After all the sticks are inserted into the holes, fill the cracks as in the previous method.
Important! If the dowel sticks stick out from the holes, cut off the excess and putty.
How to partially replace floorboards
We pry up the board with a pry bar, leaning on the block
There are situations when only a few boards or even just one need to be replaced, and the rest are in good condition. What to do in this case:
- If it is necessary to replace not the entire board, but only the damaged area, we look for where the joist is located.
- We insert a crowbar into the gap and pry up the board.
- We raise it to a sufficient height to insert the fixing pad.
- We cut out the damaged area.
Important! The section must reach the middle of the lag at both ends. If you decide to remove the entire board, then cut out all sections until complete removal.
- We cut out a section of the board from new wood, using the old piece as a template.
- We lay a new fragment and secure it to the joists with self-tapping screws.
Important! If the flooring was made of tongue and groove boards, then the replacement technology is much more complicated.
Despite the fact that wood is a durable material, it must be good care. To avoid repairing your wooden floor too often, do not forget to treat the wood with antiseptics, which will prevent it from rotting and being eaten by bark beetles. From time to time check the fastening of the boards to see if they are loose. And cover the finished floor with a protective material, such as varnish.
Floor repair can include a whole range of work - this includes leveling and external finishing. Sometimes the question arises about raising the floor level in an apartment. This article will tell you how to do all the work correctly and not make mistakes.
Usually, during renovations in an apartment or house - especially an old one, where the ceilings are quite low - they try to make sure that the floors rise slightly during leveling. But in certain situations, the floor level may still need to be raised somewhat.
Quite often, the procedure for raising the floor is associated with the redevelopment of the room. For example, the floor can be raised onto a loggia in order to then remove part of the wall and increase the space of the room. Also, sometimes it is necessary to level the floors in the entire apartment and make them at the same level, and here, too, most likely, you will have to raise the base a little in some room.
IN neighboring rooms floors can have different heights, and they can differ either significantly or by just a few millimeters. It depends on the house itself and the type of room layout.
In a private house, raising the floor level may be necessary to lay an additional layer of thermal insulation if the previously laid one is not enough. To do this, you need to raise the base a few cm (about 10) in order to lay insulating material into the void.
In general, the procedure for raising the floor requires certain knowledge and considerable financial and labor costs. At the same time, work is not carried out in all rooms at once if the scope of work is expected to cover the entire living space. Raising the floor level is carried out in each room separately according to individual calculations.
Important! Before deciding how the floor will be raised, you should make calculations and find out what load the floors can withstand without damage and without damage.
All calculations are made taking into account the choice of finishing coating that has already been made, since the decision on how the floor will be raised will largely depend on its weight. Moreover, if in different rooms If a different type of coating is installed, then calculations are made individually for each of them.
On a note! The load on the floors may not be calculated if the apartment is on the ground floor and there is no basement underneath. If basement is available, then you will have to calculate the load.
When calculating materials and permissible load, it can be assumed that the floor slab is concrete house capable of withstanding a load of about 400 kg/m2. And the density of reinforced concrete averages about 2700 kg/m 3.
Ways to raise the floor
There are 4 main methods of raising the floor. In general, they are all called screeds. Let's look at them in the table below.
Table. Methods for raising floors.
| Way | Short description |
|---|---|
| This is the most popular and familiar method to many. And the most durable even with intensive use. However, many builders do not like to use this method due to the long drying time. The cement-sand screed itself can be laid quickly, but after that it dries for about a month. And other work cannot be carried out during this period under any circumstances, otherwise all the work will go down the drain. It will be very difficult to correct the mistakes made. Also cement-sand screed- a rather difficult method of leveling the floor, and it puts a colossal load on the floors, which requires careful calculation and consideration of the amount of materials and the permissible height of the screed. |
| This special kind screeds, which are performed using special self-spreading building mixtures. It is usually used for additional leveling of the floor and if the level needs to be increased slightly. The type of mixture for pouring floors is selected depending on the conditions in which the floor will be used - a wet or dry room, in a heated or unheated room, etc. One of the main advantages of this method of raising the floor level is the high drying rate of the poured layer. However, it is important to remember that self-leveling floors are very demanding on the condition of the base - it must be well cleared of debris and leveled. Yes, and such mixtures are not cheap, but they require a lot of attention during the pouring process. |
| To raise the floor level, you can make floors from gypsum fiber - this is the so-called dry screed. GVL slabs laid on a leveled expanded clay bedding. In this case, installation occurs quickly, the process does not generate a large amount of dirt, floor design work can be continued almost immediately after laying the slabs, and this method of raising the floor significantly increases the thermal and sound insulation of the base. But GVL floors also have disadvantages - it is waterproof, and if the floor level rises significantly, you will have to use a lot of expanded clay bedding and over time, because of this, the floors may sag. |
| This method, like cement-sand screed, is considered one of the most popular and is considered traditional. It has become especially often used recently both for arranging floors in private houses and apartments. It makes it possible to raise the floor by a certain amount with particular precision and is ideal for laying laminate and parquet. The work is completed quite quickly, after completion it is time to install finishing coating you can start immediately. Using this method, the floor level can be raised to 15 cm or more, while the ceiling will not experience significant load. In the voids remaining between the joists, you can place various communications or make additional insulation floors But the lag system also has its drawbacks - if the work is done incorrectly, the floors may begin to creak or sag. |
How to raise the floor in a wooden house
In a wooden house, the floors can be raised using any of the above methods - there is no need to worry about the load on the floors, since there are none here. The best options are wooden joists or cement screed. And you should choose depending on which method the home owner likes best.
Important! When installing a floor in a wooden house, do not forget about high-quality insulation, as well as the mandatory waterproofing of the floors. Otherwise, the floors will quickly become unusable.
If in a private house the floors need to be raised to a considerable height, then you can combine both cement screed and logs. First, a concrete base is made, on which a wooden structure is then installed.
How to raise the floor level in an apartment?
In an apartment, raising the floor is done differently depending on where the work will be done. Kitchen, bedroom, bathroom or loggia - everywhere the floor level will rise in its own way.
Should be guided the following principles: if the floors rise to a level of up to 8 cm, then the screed is easiest to make using the wet method, that is, using a cement-sand mixture. In some cases, the ceiling can be additionally covered with expanded clay mixture. If the apartment is located above the first floor, then you can do without additional insulation.
On a note! A regular screed by itself will raise the height in the room by up to 5 cm, even without laying insulation or joists.
If it is planned to create a multi-level screed in the rooms, that is, a floor of a certain height will be made in each room, then calculations are made for each of them separately. Here it is optimal to use the method with logs, because with such a design it is most convenient to change the height.
Raising the floor in the bathroom or kitchen
The kitchen and bathroom are rooms where air humidity is quite high. Therefore, it is not recommended to use structures made of wood or plasterboard to raise the floor level. The best option is cement-sand screed or self-leveling floors.
A layer must be laid waterproofing materials. This could be roofing material or polyethylene film. It is also worth remembering that the floor level in the bathroom or toilet should not be exactly the same as in other rooms. The fact is that it is in these rooms that floods usually occur due to the presence of water pipes. And if the floor level here is the same as in other rooms, then if the apartment is flooded, water will get into other rooms. A small threshold or drop will allow the water to remain in the bathroom.
Important! If pipes are replaced, then all communications are changed before the screed is poured. Otherwise, you will have to carry out a number of additional works to create holes in the floor for laying pipes.
Raising the floor on a loggia or balcony
During construction, the floor level on a loggia or balcony is often lower than in other rooms. However, it is often raised in order to avoid tripping over the resulting threshold. Also, raising the floor level on the balcony and loggia is done if this part of the housing is planned to be combined with the room in which it is located.
When raising the floor level on the balcony, care should be taken to waterproof it. To do this, the base can be treated bitumen mastic or cover with film.
Raising the floor level in rooms
In rooms, you should choose the method of raising the floors according to your own preferences, the strength of the floors and the properties of the selected finishing coating. Since the area in residential premises is usually larger than in a bathroom or toilet, the mass of the cement screed here will be significant. Thus, in rooms it is easier to use a wooden joist system to raise the floor.
In general, the floor level usually rises to a maximum of 10 cm, and according to average indicators - only 2-3 cm. If the floors need to be raised as much as possible, it is also recommended to use a joist system. The voids between them can be filled with insulation or other materials so as not to “move through the air.” Ideally used as a filler mineral wool, Styrofoam.
So, the decision on choosing a method to raise the level is influenced by the following aspects.
- Budget for repairs. Some materials are more expensive, others are cheaper, and you need to calculate everything correctly possible options and choose the optimal one.
- Rationality of the work carried out. You don’t always have to choose a complex and time-consuming option; sometimes the simplest is enough - it will be enough to lift the floors without effort and at minimal cost.
- Labor costs. It is always worthwhile to adequately assess your time and effort that will have to be put into performing certain works.
Floor raising technology
Let's get acquainted with the technology of raising the floor using cement-sand screed.
The floors in the room where the work will be done are thoroughly cleaned of debris and leveled as much as possible. After this, using a building level, markings are applied to the wall, marking the level of laying the expanded clay mixture. Using a tape measure, measure the height from the rough base to the marked line. This is necessary to calculate the amount of mixture.
The area of the room is calculated. The required amount of material is purchased - expanded clay and sand concrete mixture M 300, as well as reinforcing mesh with a section of 6x6 cm.
Sand concrete - dry mix
A private home, like a human body, consists of a large number various systems, materials, liquids, beneficial and harmful microbes. He also has all sorts of ailments that appear and become apparent with age. Fortunately, most of them are easy to identify and treat. The wooden floor in the house is exposed to daily external influences. Time also leaves its traces on it: scratches and cracks appear, gaps between the boards grow, and the creaking of floorboards increasingly irritates the ear. These symptoms indicate an impending repair, which also involves leveling the wooden floor for a new coating.
When is it necessary to level a wooden floor?
Wooden floors have high performance characteristics. Having initially chosen natural wood, the home owner simplifies the task of future repairs. To prepare a wooden floor for new paint, laminate or parquet board, carpeting and linoleum, it is enough to first level the surface of the floorboards.
Sooner or later, even the best wooden floorboards begin to show signs of aging. There are many reasons for this phenomenon:
- Usage low-quality materials for flooring (poorly dried wood for making joists, damp floorboards). Over time, such materials contribute to swelling or sagging of the floor, disruption of the integrity of the coating, and squeaks when walking.
- Natural property of wood to bending when drying. It manifests itself as warping, the formation of unevenness along the length of the board, and, as a result, cracking of the coating.
- Mistakes when laying floors and its improper use. They contribute to damage to the coating, peeling of paint, formation of cracks and cracks, and sagging of boards.
The natural desire to correct the shortcomings that have arisen forces us to choose a method for solving the problem. Can be done redecorating paint coating or completely change the floors, it all depends on the actual condition of the floors and the available amount of finance.
There are many reasons, besides aging, for replacing or repairing a wooden floor:
- cracks;
- decay;
- recycling of wood by insects to the state of rot.
Any of the reasons requires repair or complete replacement of the plank covering. To identify defects and estimate the amount of work to be done, simply lift the boards and examine the joists on which they lie. The absence of traces of insect activity, as well as the dry and durable surface of the wood, allow you to confidently begin leveling the base, which does not require partial or complete replacement. If there are defects on the inside of the floorboards or joists, first eliminate the problem areas by replacing them with new wood, and only then proceed to leveling the floor.
The next reason for leveling the floor and the stage of assessing its condition is setting the deviation from the horizontal. It is made using a level or a precise laser tool, set according to the highest corner in the house. Afterwards, notes are made on the walls. The information obtained allows us to identify irregularities and determine the leveling method, for which today we use high-tech sheet materials made from wood and its components that differ a successful combination a number of properties.
Sometimes, at first glance at the wavy surface of the floor, sagging boards, tilted floorboards, it is not clear how to level a wooden floor without tearing off the boards, and whether this can be done at all. However, in most cases there is no reason for pessimism. Depending on the nature of damage to floor structural elements, apply various technologies restoration of the coating and its leveling:
- scraping with preliminary cleaning;
- putty or leveling using self-leveling solutions;
- laying leveling elements - for example, plywood or other similar materials can be used.
Materials for leveling floors on joists
Selection of materials to eliminate various irregularities and other defects wooden base depends on the leveling technology used, determined by a number of factors. The permissible level of deformation of the floor surface (height differences across the entire area) is dictated building codes and rules, and its value serves as the main guideline when choosing a technology:
- If there are small bulges and deflections within 1-2 mm over an area of 1 m2, there is no need to level the surface. This value is acceptable even for covering the floor with a material sensitive to unevenness such as linoleum.
Elimination methods:
- leveling the surface with a scraping machine;
- the use of industrial putties based on acrylic or a “folk” remedy - a mixture of PVA glue with sawdust.
- Height differences from 5 mm to 1 cm with uniform distribution over the floor surface for subsequent laying of coatings require leveling of the base.
For this purpose, the following technologies are used:
- leveling with sheet materials that can be attached directly to the floor;
- elimination of unevenness and defects using self-leveling floor mixtures.
The most common sheet materials are plywood, OSB boards or chipboard.
The use of fiberboard is unacceptable, since over time this material follows the shape of the floor, and all irregularities appear on the surface.
Plywood
Optimally suited for fast and high-quality work:
- use of natural veneer of coniferous and hardwood species for the production;
- the surface is flat and smooth;
- has a pleasant, barely perceptible smell of wood;
- simply sawn and treated with protective agents;
- the strength of the sheets is combined with flexibility;
- convenient format - you can cut sheets of the desired size with a minimum amount of waste;
- simple and affordable installation.
In areas used for permanent residence, it is recommended to use FBA and FK brands, which are intended for rooms with low humidity and are suitable for interior work(bedroom, living room). The FSF brand is more resistant to moisture and can be used both outside and indoors (corridor, kitchen).
Another way of classification is by variety. The following are quite suitable for leveling and installing a subfloor:
- 2nd grade – smooth surface, small cracks, scratches, traces of glue are acceptable;
- 3rd grade – the number of possible defects is slightly greater than in 2nd grade.
For the purposes of leveling and installing a clean floor you will need:
- E – elite variety, has no defects;
- 1st grade - no visible defects, but small chips and tiny cracks are allowed.
In premises intended for temporary residence (dachas, makeshift buildings), grade 4 can also be used, despite the existing defects, the strength of plywood of this grade is quite high.
Manufacturers also produce sanded (marked Ш1 and Ш2) and unsanded (marked НШ) plywood. To lay plywood on a wooden floor, you should choose one that has been sanded on one side (Ш1) and fasten its unsanded side to the floor. When choosing a material, you should focus on the ratio of cost and quality.
The next leveling material behind plywood in the popularity rankings is better known as OSB. The characteristics are similar to those of plywood. It differs in the manufacturing method - instead of natural wood veneer, natural wood shavings are used.
Advantages of the material:
- environmentally friendly (natural resins are used);
- no surface defects;
- not subject to delamination;
- light weight;
- variety of sizes;
- adequate cost.
Manufacturers produce boards of four grades: from OSB1 to OSB4 (as moisture resistance and strength increase). Another variety found on the market is a tongue-and-groove slab, which has a connecting groove for a tighter joint. Laying OSB on a wooden floor for the purpose of leveling is carried out using tongue-and-groove boards of the OSB3 brand.
Chipboard (chipboard)
A less durable and moisture-resistant analogue of OSB. Low grade wood and wood processing waste are used in production. Quality, strength and resistance to moisture are determined only by the quality of pressing of the boards and the binder.
Benefits include:
- good sound insulation performance;
- excellent thermal insulation properties;
- ease of laying the material;
- low cost.
Chipboard – best option leveling layer for parquet and synthetic coverings for rooms with low humidity levels.
Pay attention to the specifics of how to level a wooden floor in a private house or apartment if measurements show subsidence and uneven differences of more than 1 cm, but less than 8 cm. Only using joist leveling technology.
Unlike laying leveling materials directly onto the surface of the floorboard, in this case required preliminary preparation. First, a base of logs (wooden blocks) is calculated and installed, which makes it possible to compensate for height differences and form flat plane for subsequent installation of a leveling layer of suitable sheet material on it.
Selecting the thickness of the material for leveling
Another parameter of sheet materials that needs to be taken into account when selecting is their thickness. Factors that influence the choice of material thickness:
- type of base for installation;
- type of finishing coating;
The thickness of plywood for a wooden floor with slight “waviness” should be at least 8-10 mm. If parquet or laminate is to be laid as a finished floor, it is worth increasing the thickness to 10-16 mm. For carpet and linoleum, the thickness is increased to 16-18 mm. Installation of heavy furniture or equipment in an apartment or house will require a thickness of up to 21 mm.
Technology for laying plywood on a wooden floor
The first step towards flat floor– preparing a wooden floor for laying plywood.
If necessary, wobbly boards should be fixed and creaking noise when walking reduced or eliminated. It is best to secure the boards with screws (self-tapping screws). Each nail that secures the old floor boards must be sunk 1-2 mm into the wood.
The next step is to perform calculations for correct installation and cutting plywood sheets.
What needs to be taken into account in the calculations:
- the type of base on which the plywood will be laid - an old floor or a sheathing of logs;
- installation of sheets according to the principle brickwork– with an offset of half a sheet;
- linear dimensions of the room;
- gaps for thermal expansion of the material are 1-1.5 cm from each wall and 3-4 mm between sheets of plywood.
If installation is carried out on top of floor boards, it is recommended to cut the plywood sheets into 4 equal parts, which will facilitate the work, allow you to detect internal defects (delamination), and replace them with undamaged sheets.
In the case of laying sheets on the sheathing, cutting the sheets should be carried out taking into account the sheathing pitch so that the joints of the sheets fall on the center of the joist. Depending on the thickness of the sheets, the lathing pitch is 30 or 40 cm.
Before cutting the sheets, based on the calculations made, a laying diagram is drawn up and the sheets are numbered. This allows you to calculate the number of standard pieces of plywood (quarter sheets), as well as the number and sizes of pieces for cutting.
Before cutting and laying plywood, it is important to keep it indoors for several days, stacking it or placing it on its edge. The curing period depends on the temperature difference between the warehouse from which the plywood was brought and the room in which it will be installed. The greater the difference, the longer you should wait.
After cutting the sheets, you can begin to attach them. It is convenient to start installing sheets from the corner of the room that is closest to the right angle (90 degrees). It is worth using a construction angle to compare the values of each angle.
Self-tapping screws are used as fasteners, the length of which should be 3 times the thickness of the plywood. Before installation begins, perform the following operations:
- in places where screws are attached, holes are drilled in plywood with a diameter 2 mm smaller than the diameter of the working part of the screw;
- countersink holes to fit the diameter of the screw head;
- the fastening pitch between the screws is chosen to be 30-40 cm;
- make an indent from the edge of the sheet of at least 2 cm.
A plywood underlay can be laid on a wooden floor if additional thermal and sound insulation is required. The installation is completed by installing each sheet in its place in accordance with the diagram and securing it with screws.
Scraping – labor-intensive and efficient leveling
If there are no plans to use the flooring after leveling, it is recommended to do the latter using the mechanical scraping technique.
Step-by-step instruction Leveling a wooden floor with a scraping unit looks like this:
- Clearing the room of furniture. If it is not possible to remove the structure, it is covered plastic film.
- Removing from the plank floor all nails and fasteners that could negatively affect the sanding apparatus, rendering it inoperable.
- Equipping with thick gloves, headphones and a respirator to protect your ears and hands from strong vibrations and noise from the machine, and your respiratory tract from fine wood dust.
- Start the scraping process from the far corner of the room. The first layer is removed carefully, moving around the room like a snake.
- Clogging all cracks and holes in the floor with putty that matches the color of the coating.
- Repeated sanding of the floor after the putty has dried.
- Remove accumulated dust with a powerful vacuum cleaner.
- Wiping surfaces with a lint-free cloth soaked in a degreaser.
- Varnishing a plank floor.
Theoretically, scraping can be done manually. However, a special scraping machine will significantly speed up the process. In this case, we are not talking about units, but tens or even hundreds of times, depending on the area of the room. In addition, manual scraping cannot boast high quality, which means it will not correspond to the expected result.
Wooden flooring, despite the emergence of many other modern options, remains at the top of popularity. It is widely used not only in old houses, but also in new buildings, as it is warm and durable. However, over time, under the influence of many factors, it may begin to sag on one or more sides. And as a result of this, serious level differences occur.
On such a surface, the furniture stands crookedly, and the doors in the cabinets do not close due to the resulting distortions. Creaking floorboards become inevitable. In addition, gaps form between the boards, which negatively affects the appearance floor, and on its insulating qualities. Therefore, sooner or later, all owners have a question about how to install a wooden floor, making it more stable, warmer, more comfortable for walking and more beautiful in appearance.
Basic ways to level a wooden floor
Dismantling and reassembling plank flooring is a complex, lengthy, labor-intensive and dirty process, which can be difficult to decide on. However, it is often impossible to do without it - if the floor boards are rotten, sagging, or there are signs of mold or mildew on them. In this case, there is nowhere to go - a complete replacement is required. wooden flooring. If the boards are strong, well connected to each other, but there is a serious difference in the horizontal plane or in certain areas of the floor, then you can do without opening the boardwalk. Under favorable circumstances, superficial leveling measures are used.
Depending on the nature of the irregularities that appeared on the wooden floor during the period of its operation, the method of their removal is selected.
There are several methods applicable to leveling board coverings:
- Looping.
- Local alignment of a specific area.
- Self-leveling compounds.
- Alignment with lags.
- Leveling with pads.
To determine which method would be better suited for a certain case, it is first necessary to measure the differences in the floor surface using a laser or a conventional building level with a length of at least 2000 mm. Permissible value unevenness that can be tolerated (unless, of course, creaks appear) should not exceed 2 mm per linear meter of base.
What to do if the floor is smooth, but begins to creak?
There is definitely something wrong with him. It is necessary to conduct an audit to identify the cause of the appearance unpleasant sounds. Well, then - by applying certain techniques, which are described in detail in a special article on our portal.
How to do the leveling yourself?
Local leveling of the floor surface
It happens that irregularities are local in nature, that is, they are located only in certain areas of the floor. Leveling boards protruding above the main plane can be done using a plane or a hand sander. Of course, in these areas you should inspect the heads of fasteners - nails or screws. They should not interfere with leveling, that is, if necessary, either deepen them into the thickness of the board, or even temporarily unscrew them.
If, on the contrary, small concave areas have formed on the floor, then they are raised to general level surfaces. This process can be done using oil or acrylic wood putty, or a self-made composition of small sawdust and PVA glue.
The repair compound is applied to the depression and spread over the surface using a spatula. With this alignment, the edges of the recess, located at the same level as the main plane of the floor, will serve as beacons for this alignment. After the putty mass has dried, it is cleaned with a grinding machine.
The methods discussed above are good only in cases where the board covering is being prepared for painting or under covering it with plywood sheets. If the floors are being prepared for varnishing while preserving the natural color and texture of the wood, then you will have to sand the entire surface.
Wood floor scraping
The scraping method is used in cases where it is necessary to free the floors from the old coating or the top darkened or damaged layer of wood. In addition, if the deformation of the surface and its differences in height are no more than 10 mm, then the floors can also be leveled using a scraping machine. This method is quite noisy, but fast, since in a short time it allows you to renew the plank covering, preparing it for further finishing.
It’s not difficult to carry out this process yourself, but the equipment is expensive, and hardly anyone will purchase it for a one-time task. Therefore, if you decide to level and clean the floor yourself, it is best to rent the device for a certain period.
When choosing this processing method, you should take into account the thickness of the floorboard. And also that after leveling, the height from the surface to the connecting lock of the tongue-and-groove board should be at least 4÷5 mm. That is, you will have to act very carefully and carefully.
To carry out scraping, in addition to the scraping machine, it is necessary to prepare the following auxiliary materials and devices:
- Set abrasive attachments with grain of different fractions - circles and ribbons. Don't buy too much Supplies. The best option would be to consult with specialists when renting a car, explaining the characteristics of the board covering. In addition, you can purchase several nozzles with different numbers and test them in practice experimentally.
- Disposable sawdust bags.
- Facilities personal protection- gloves, respirator and construction glasses.
Before starting work, it is necessary to inspect the surface of the boardwalk. It must be dry and clean. The gap between the floorboards should be no more than 5 mm. In addition, metal elements such as nail heads or self-tapping screws should not come to the surface. They should be deepened into the wood 1.5÷2 mm below the thickness of the layer expected to be removed.
The scraping machine must be prepared for work by first installing attachments with large grains on it and adjusting the clamping force of the device using a special screw.
The first stage of cleaning is carried out along the fibers. You need to move slowly, without sudden jerks, but also without long periods of downtime in one place. The car should run smoothly.
Having cleaned one strip of coating, the next one should be started by moving the device by ⅔, that is, by ⅓ capturing the previous one, just processed. As the abrasive layer of the nozzle wears out, it must be replaced with a new one.
Having treated the entire surface of the floor with a coarse-grain nozzle, you can proceed to sanding the boardwalk, installing an abrasive belt with a fraction of at least P240. This attachment will help make your floors perfectly smooth.
Next, the wood is treated with an antiseptic primer or tinting stain. After which the surface is puttied, cleaned and covered with varnish, wax, oil or painted in the chosen color.
If the differences in the surface are more significant, then to level it you will have to resort to more labor-intensive methods.
Leveling planks with dry screed
Necessary materials
This method of leveling the surface is suitable for both plank flooring and. When choosing this method of tidying up the floor, it is necessary to take into account the height of the ceiling of the room and the magnitude of the differences in the surface.
To arrange a dry screed you will need the following materials:
- Dry expanded clay, perlite or silicate-slag mixture of fine fraction, specially designed for dry screed. An excellent option for this material would be the composition of the Knauf company. Good reviews The material of the Belarusian production “Kompevit” also deserves.
Standard backfill packaging is bags with a capacity of 40 liters. Calculation required quantity is based on the floor area and the thickness of the proposed leveling backfill. The thickness cannot be less than 20 (or better - 30) mm. It is undesirable to make it more than 60, maximum 80 mm. If on base floor there is a significant level imbalance from the horizontal, then this is also taken into account.
- Covering sheet material- This ready-made elements floors (EP) made of gypsum fiber boards. Such EPs are equipped with specially designed locking lamellas, which speed up installation and make the coating neat. In addition to this material, waterproof plywood or particle boards. However, the best option Still, there will be gypsum fiber EP, which have optimal characteristics for flooring:
— Thickness 20 mm. (Two layers of 10 mm each. The layers are placed and connected with an offset, which is what forms the interlocking connection 50 mm wide).
— Standard linear dimensions of the EP are 600×1200.
Other floor elements are also on sale, in particular with dimensions of 500×1500×20 mm, that is, with an aspect ratio of 1:3.
Floor elements are purchased depending on the area of the room. A 15% reserve is made, since, firstly, there will be waste during cutting. And secondly, on those elements that will be laid away from the walls, the locking lamella must be cut off from the side adjacent to the wall.
- Damper tape for installation along the wall around the perimeter of the entire room. Purchased according to the length of the perimeter of the room with a small margin.
- Waterproofing material for laying on the surface of the base for backfilling. For wooden floors, glassine, thick paper impregnated with bitumen, or roofing felt are best. You can also use polyethylene film with a thickness of at least 200 microns. Purchased based on floor area with a 15% margin.
- Metal profile for placing temporary beacons.
- Glue for mutual fixation of plates along the lines of interlocking connections. High-quality PVA glue is quite suitable.
- Self-tapping screws. The optimal one is special self-tapping screws for GVL (GVVL), which are distinguished by a double-start thread and have a self-drilling head.
