Hello, friends! I have already told you how I discovered the possibilities of dry floor screed. Not so long ago I decided to introduce my cousin to technology: he is just doing repairs. When I told him that laying gypsum fiber board on the floor could be an alternative to dirty wet method, he didn’t really believe it at first. After all, people tend to stick to old methods, even if they are outdated. I had to explain the process step by step, but in the end the repair took significantly less time. If you also want to learn new methods, let's figure out the intricacies together.
The advantages of gypsum fiber floors include:
It’s worth noting right away that drywall can only be laid on the floor if the surface is perfectly flat. To level, you will need to use a screed; craftsmen advise using dry bedding, which may include sand, perlite or expanded clay. The most effective bedding is perlite because it has a very fine grind, which allows you to create the most uniform and dense layer on the base of the floor. The only disadvantage we can note is its expensive cost, so experts recommend adding sand (3:1) to it. Its good analogue is expanded clay; firstly, it has a more affordable price, and, secondly, excellent heat-insulating and sound-proofing properties.
First you need to cover the base with polyethylene film (preferably in 3 layers), it will serve as a barrier for the dry leveling mixture from negative impact moisture that will penetrate from below. It is very important to take into account here that the film is sold in rolls, so its width may not be enough; in this case, you need to put it in several strips (the edges should not be less than 20 cm), otherwise excess moisture will spoil all the loose components. If the floor has wooden base, That put You need better roofing felt or special bitumen paper.
A very important property plasterboard sheets is porosity (it makes the material absorb moisture very well), which leads to an increase in size, so a special technology has been developed that involves leaving small gaps between the sheet and the wall. They must be finished with waterproofing tape.
After the base is completely covered with film or paper, you can proceed to dry backfill. Here you need to take into account the area of the room; if it is small, then you need to fill the entire surface completely, but if the room has big sizes, then to facilitate the work and achieve the best result, you need to divide the floor into several sections using slats. The main thing at this stage is to achieve maximum evenness and smoothness of the dry elements.
To achieve maximum service life, gypsum fiber for floors must be subjected to an adaptation process, that is, left for 10-15 hours in the room where it will be used, therefore, they must be purchased and delivered in advance. This is very important, because during this time the sheets will get used not only to temperature conditions indoors, but also the humidity level.
In this case, you need to pay attention to the fact that the plasterboard floor must be made using special sheets intended specifically for floor coverings. If any questions arise, you should definitely consult with a specialist who will tell you which material is best suited and in what quantities.
You should proceed to installation only after all preparatory work has come to an end. To do this, you will need to purchase and prepare a drill, screwdriver and jigsaw in advance.
GVL floors should be installed starting from the doorway, because the leveling dry components at the door are not protected in any way and walking on them is strictly prohibited. Its own weight will leave deep pits on the surface, which will subsequently create voids in the floor covering, and they, in turn, will form the effect of “playing slabs,” which will not allow the floor lining to last long. Therefore, when laying slabs, it is necessary to adhere to the principle - from the door and deep into the room.
To connect plasterboard boards together, you need to use an adhesive composition, it is applied to the joints, after which they are connected. If there is uncertainty about the strength and uniformity of the gypsum plasterboard floor or there is a feeling that displacement may occur over time, they can be additionally fastened using self-tapping screws. In this case, the distance between adjacent screws should not exceed 20-30 cm, and the distance to the edges should be at least 3 cm, this is necessary for strong and reliable fixation of the plasterboard boards.
The whole range of work on laying gypsum fiber board on the floor can be done independently, but if possible, you can invite an assistant, with him the work will go faster (this is necessary if the repair needs to be completed in the shortest possible time) and more efficiently, because his presence will allow better control of the entire process work, both during the process of leveling and preparation, and during installation. It is worth noting the fact that 1 GVL for the floor weighs approximately 18 kg, so it is better to get a partner to transport and move it.
Thus, you need to install all the drywall on the floor, but here it is very important to constantly use a level so that the entire coating is smooth and of high quality, without slopes or gaps. This is very important, because it is better to immediately carry out everything according to the instructions than to redo all the work again; this will not only take a colossal amount of time and effort, but also money.
After the gypsum plasterboard floor has been completely laid, you will need to cut off the remaining waterproofing tape and proceed to further design. To carry out the final finishing, it is necessary to select the appropriate material; in this case, it is better to refuse parquet boards and use laminate or tiles (with a size of no more than 30x30 cm).
Plasterboard floor slabs will be an excellent solution for those who have decided to make major renovations in their apartment; they create an ideal flat surface, Beautiful aesthetic appearance and last for more than a decade.
Modern finishing work today cannot be imagined without gypsum fiber sheet (GVL). The popularity of this finishing material is due to a number of its advantages, such as environmental friendliness, strength, fire resistance, affordable cost, and simple installation. Laying gypsum fiber board on any surface, as well as tiling it, makes this surface perfectly flat, giving an aesthetic appearance to any room. Therefore this type finishing works received the most widespread use. The technology for working with GVL consists of several successive stages.
Preparing the premises includes work on dismantling existing equipment, removing furniture, dismantling old coverings (paint, whitewash, linoleum and other types). The working surface (walls or floor) should not have large defects in the form of cracks, crevices or voids. The screed must be strong and have no detachments. The surface must be level and clear.
If the floor is concrete, it is cleaned, leveled and covered with plastic film. If the floor is wooden, it is treated with an antiseptic. Wooden floors are susceptible to rotting processes and the formation of fungi and should be protected as much as possible. Next, the tree needs waterproofing. Therefore, roofing material should be laid on a wooden base, then reinforcing mesh and cement screed. Both ordinary film and bitumen mastic can serve as a waterproofing material.
GVL can be laid on both wooden and reinforced concrete structures, observing the features of each technology.
Tool for working with drywall.
After all the preparatory work has been carried out, the remnants of the old coating have been removed, cracks have been sealed, defects have been eliminated, the wall or floor has been treated with a primer, you should proceed to the stage of laying gypsum fiber board.
Laying gypsum fiber sheets on a wooden floor, wall or ceiling has its own characteristics. So, when laying on the floor, it is necessary to file the doorway due to the rise in floor level. In addition, it is better to first remove the wooden floor and make a screed. If it is not possible to remove a wooden floor, then prerequisite Rotten boards will be removed.
One of the installation options is as follows: GVL sheets should be laid on tile adhesive, secured with self-tapping screws around the perimeter, while adhering to the following parameters: sheet thickness 10-12.5 mm; self-tapping screws 30-40 mm; step between screws - 40 cm; The depth of fastening of screws is 2-3 mm. Fastening the sheets with self-tapping screws will eliminate cracks. After a day you can move on to the next stage.
Another option is to install gypsum fiber boards using metal guides (profiles). As an alternative, you can use a wooden frame made of slats, but the metal profile is more durable and reliable. The distance between the guide strips should be 40 cm. For structural strength, you can also use a plaster mesh secured with glue and staples. Features of frameless wall cladding with gypsum fiber sheets include maintaining a certain width of the gap between the sheets (5-7 mm), sealing the joints with a special gypsum putty, and using a special glue for gypsum plasterboard.
GVL cladding involves the use of paint, tiles. Speaking about tiled cladding, we can highlight general scheme work consisting of preparing tiles, marking the floor, preparing glue, laying tiles and grouting joints. First, you need to prime the sheets and, after complete drying, begin laying the tiles. By taking measurements of the width and length of the room, dividing by the size of the tiles, taking into account the width of the seam, you can calculate the number of whole tiles in each row. And the remainder, divided by two, will indicate the number of incomplete tiles. Wall and floor types tiles have varying degrees of strength and are selected taking into account the required surface.
Using a special marking cord, you need to connect the middles of long and short walls. The lines will intersect in the center of the floor. Marking the floor will avoid a large number of cut tiles near the walls. When laying tiles on the floor, the technology is followed either from the corner or from the middle of the room. It depends on the styling pattern. Laying diagonally does not avoid cutting the tiles. Laying along the walls should begin from the edge opposite the entrance to the room.
Glue (mastic or cement mortar) is evenly applied to the entire surface using a spatula and carefully leveled. Then a tile is placed on the floor (or other surface) and pressed down a little. You can use a rubber hammer to increase the strength of the fastening. A properly selected adhesive composition plays an important role, since the quality of fastening depends on it. It is recommended to prepare a tile adhesive solution in portions, in the required quantity for an area of 1 sq.m. In addition, you should monitor the level of the tiles as you work. You should not lay more than four rows of tiles on the floor at once and, if possible, take hour-long breaks to eliminate tension in the base. It is necessary to leave equal gaps between the seams, clearing them of glue. After two or three days, the seams are rubbed with a special solution. And after another 24 hours, the surface is thoroughly washed. When laying tiles on the wall, the seams are rubbed out within a day. It is recommended to ensure minimal humidity in the room for the entire period of operation.
It is unlikely that anyone will deny that a warm and high-quality floor is important for comfort. After all, we have to walk on it every day. Every day the use of GVL in floor finishing is gaining popularity, which has already become more popular than other methods of dry screed.
What is GVL? The answer is simple - it is a material for finishing a room, consisting of cellulose, additives and reinforced gypsum. It replaced, first of all, drywall. Its difference is that the material is homogeneous and does not have a cardboard covering; it is denser and therefore more durable.
What we are used to seeing under our feet in our homes is very rarely the floor in the understanding of building codes. If we look at them, we will see that the floor is a structure on which the life activity or work of people in the room takes place. It must dampen noise, be level, and provide sound and heat insulation.
Almost always floors are delivered in a rough finish. Therefore, even if the slab is covered with linoleum or other covering, such a surface does not fully perform its functions.
The floor must consist of three elements:
The use of gypsum fiber boards for screeding is becoming more and more popular, and this is explained by the fact that for a “dry” floor there are currently no alternatives with the same environmental friendliness and moisture resistance. Now GVL is also used in cases where water heating is installed.
If you need to arrange floor heating, then a “wet” screed is not always acceptable.
Let us note the reasons why it is better to create a warm water floor using a “dry” screed:
If there is an old covering on the floor, it must be removed. After this, they begin to process the cracks and irregularities using cement or special mounting mixtures, if they do not exceed 5 mm.
In cases where the floor has large differences, it makes sense to use bulk material - expanded clay. Next apply waterproofing material(polyethylene or special paper impregnated with bitumen), which is overlapped.
Then, during the installation process, insulating tape is glued. This is done, first of all, to reduce the risk of bloating and discrepancy between the sexes due to seasonal temperature changes. This sizing also has a soundproofing function.
The next step is insulation. The three main types of thermal insulators that are popular at the moment are bulk, fibrous and polystyrene foam materials.
After the procedures described above, they begin laying gypsum fiber boards, having previously glued them. If bulk methods are used as thermal insulation, installation begins from the door to prevent walking on the insulation. But if you start the installation process for one reason or another, you need a window, take care of placing “islands” of slabs along which you will move around the room.
If the slabs are laid in two layers, be sure to fasten them with self-tapping screws. After completing the laying of the layers, do not forget to seal the bonding points with putty material.
A mandatory element after installing the slabs is finishing the joints. Having previously primed the joints, apply reinforcement with the tape intended for this purpose.
In conclusion, we note that creating a level floor is an important step in renovating any room. Thanks to modern materials, it will be as durable as possible and adapted to laying the final coating. That is why GVL slabs so quickly gained popularity in the building materials market and deservedly justify it.
Modern technologies make it possible to simply and quickly perform dry screed, which involves the use of gypsum fiber sheets. Laying tiles on GVL, as the final stage of creating a high-quality floor, can decorate the interior of a bathroom, corridor, and kitchen. This floor has a good level of sound and heat insulation, does not allow moisture to pass through, and is resistant to high temperatures.
Gypsum fiber sheets are essentially advanced drywall. These materials have a number of similar characteristics, but the difference is that GVL is not glued with cardboard on both sides and has a number of advantages. In terms of composition, GVL consists of the same gypsum, which is additionally reinforced with cellulose components. Plus components are added to it that make the material fireproof and more moisture resistant compared to gypsum plasterboard.
Another plus is that gypsum fiber sheets are stronger than gypsum board. Therefore, they are recommended to be used when creating a flat floor using the dry screed method. If we're talking about When laying floors in the kitchen or bathroom, special moisture-resistant gypsum fiber sheets are used - GVLV.
You can make a high-quality floor with your own hands. To do this, it is important to adhere to technology and have minimal installation experience. When starting to create a new floor, follow this procedure:
GVL slabs can also be placed on wet screed. But this process is more labor-intensive and is rarely used in ordinary houses and apartments.
Standard gypsum fiber sheet 10 millimeters thick
First, they get rid of the old covering and dismantle the old floor down to the concrete or wooden base. Removing the floor in the bathroom is more difficult, since you will have to dismantle the plumbing. After dismantling, remove the remnants of old glue, screed, dust and other things.
Since there are no perfectly flat subfloors, the next step will be screeding. If the dry screed method is used, install waterproofing before starting to fill the material. For example, a polyethylene coating, which is laid in several layers, especially at the joints. This will protect the base from moisture and provide waterproofing.
The ends of the walls are treated with edge film, after which they begin to fill in the expanded clay. Fine expanded clay can be easily leveled, so it is easier to make such a screed than a concrete screed.
After compacting the expanded clay, the installation of gypsum fiber boards begins. They are laid in two layers. There are ready-made slabs on the market that have folding at the ends. It is much easier to work with this type of GVL, so it will be the most preferable option. When laying the slabs, take care of high-quality gluing of the joints and each layer.
It is preferable to start laying from the corner closest to the entrance. The sheets are fixed in increments of 25-30 centimeters. After the base for the future laying of tiles has been installed, the joints are puttied, the edge film and excess waterproofing layer along the walls are cut off.
Before installing the tiles, the gypsum fiber sheets are primed. This will increase adhesion and improve the adhesion of the adhesive material. A day later they begin laying the tiles. For high-quality installation, you need to draw up a drawing in advance, calculate how many rows will be solid, and how many will be from cut fragments. It is allowed to start laying both from the corner and from the center of the room.
This is what the process of installing a quality floor looks like
After diluting the tile adhesive, apply it to the floor with a notched trowel. After this, lay the tiles, lightly pressing them onto the base. It is important to carefully check the process using a level so that the floor in the bathroom or kitchen remains level. Gaps are left between the tiles, which are easiest to level with special plastic crosses.
Apply glue in small areas, otherwise it will begin to set and harden even before the installation of the slabs.
In a bathroom where there are constant temperature changes, the seams at the joints are made about 10 millimeters thick. Control the level of the tiles along with the neighboring ones that were laid earlier! Clean the seams from excess glue that is released when pressing on each tile.
Once dry, it is very difficult to remove. After completing the work, the floor in the bathroom or kitchen is left to dry for at least three days. For three days, it is recommended to reduce the room humidity as much as possible. Therefore, it is not recommended to use the premises for their intended purpose at this time.
After grouting and cleaning the tiles, your floor is ready for use.
After three to four days, the seams are rubbed with a special solution. After removing the plastic spacers, apply the solution using a thin spatula. Excess mortar is removed from the tiles using a damp cloth.
On the market building materials and technologies, new products are constantly appearing. Not long ago, new sheet materials appeared, one of them is gypsum fiber sheets (gypsum fiber sheets). Its main advantages are solid strength, low price, and high level of moisture resistance. How to lay gypsum fiber board on the floor, what technologies to use, what to cut and fasten - more on all this below.
The abbreviation GVL stands for Gypsum Fiber Sheet. There are names like “gypsum fiber/gypsum fiber boards”. Plates, as a rule, are called materials of greater thickness and smaller size, although this is not a fact. Sometimes both terms are applied to the same material. Technical characteristics and requirements are standardized by GOST R 51829-2001, so the material is officially recognized. According to the standard, it can be used in the construction of private, public and production premises. Area of application: finishing and preparation for finishing walls, floors and ceilings. It is used for preliminary finishing, replacing “wet” processes - plaster, putty, pouring screed.
So GVL is one of the sheet finishing materials. Its composition includes cellulose fluffed into fibers, some additives that give the material certain properties (substances that increase the water resistance of the material are most often used). Gypsum is used as a binder. The components are mixed dry, and water is added to the finished mixture. The dough-like solution is used to form slabs that are fed into a press. After pressing, the sheet is brought to normal humidity (dried). Some companies (for example, Knauf) produce polished gypsum fiber boards. This kind of gypsum plasterboard for floors is too expensive, but for walls it is good because it does not need to be puttied before finishing.
Speaking specifically in relation to the floor, GVL is used for leveling under finishing floor coverings. It can be placed on joists or on a subfloor (solid or with cracks). Subject to certain conditions, installation on wooden floors and on screed (leveled, dry surface) is possible. Can be used in a floating floor as a dry screed material.
According to the type of edge, gypsum fiber boards come with a straight edge (marked PC) or a folded edge (FK). Rebate dimensions: width 2.8-3.2 mm, depth 1.7-2.3 mm. For the floor, you can use either type, but with a rebate there will be no through seams. This means that there is no need to seal joints. However, the cost of such material is much higher, so gypsum fiber board with a straight edge is more often used.
GVL with straight and folded edge - two main types As you know, gypsum is a hygroscopic substance. Therefore, conventional GVL in areas high humidity do not apply. There is a moisture-resistant modification for this. The letter “B” has been added to the front of the abbreviation. That is, VGVL is a moisture-resistant gypsum fiber sheet. It can be used in bathtubs, showers, etc. Outwardly, they do not differ from each other, so we are guided by the markings.
There is another type of gypsum fiber sheets - high density. Produced specifically for floors, marked GVL EP (floor element). Knauf has such a subtype. It costs a lot, but the geometry and strength characteristics are excellent. When using regular gypsum fiber board for a floor, as a rule, they take two sheets, which are laid with offset seams. This gives a sufficient level of strength. As floor elements, gypsum fiber boards are recommended to be used in one layer - their strength is sufficient even in this version.
According to GOST, gypsum fiber boards come in the following formats:
Deviation in width is no more than 3-4 mm, in length - 3 mm up to 2.5 m and 4 mm for longer slabs. Deviations in width are no more than 0.3 mm. The plan should be a rectangle. Permissible error (side bevel) - 4 mm.
Sheet marking displays all the data - moisture resistance, edge type and dimensions in millimeters. For example, GVL-PK 2000*1000*12.5 stands for ordinary (non-moisture resistant) gypsum fiber board with a straight edge. VGLV-FK - this means that the material is moisture resistant and the edge is folded.
Gypsum fiber sheets are classified as low-flammability materials. The cellulose is contained in gypsum, which does not burn or ignite. When in a flame, it does not support combustion. The classes according to the standards are:
A significant part of the characteristics of GVL is given within the framework - “from and to”. This is due to the fact that different cellulose and different percentages of its content can be used. If you are looking for a material with certain characteristics, view the materials from a specific batch. Each batch must be tested, all indicators are indicated in the accompanying documents. The characteristics of GVL are quite good, which, combined with a low price, makes them popular on the market. Here are the main technical characteristics:
VGLV is one of the most resistant to high humidity materials, which has no high cost. When water gets in or humidity increases, the stove absorbs it. As the humidity level drops, the moisture evaporates. This is not reflected in any way on the outside. That is, it is a durable, moisture-resistant material and can be used for interior decoration, even for wet rooms.
If we talk about the specific use of GVL on the floor, the material is not bad. Suitable for leveling, for laying along joists, can be placed on polystyrene foam, which increases thermal insulation characteristics. This is one of the most inexpensive sheet materials, which explains its popularity.
It is possible and necessary to use GVL on the floor, but you must strictly follow the recommendations. In general, gypsum fiber sheet does not have very high strength. The short cellulose fragments reinforce the plaster to some extent, but the material is still quite brittle. Properly laid, it can withstand heavy loads - up to 2 tons per square meter. But the key words are properly laid out.
GVL can be laid on either a continuous or discontinuous base. When laying on a solid base, it must be perfectly level. Requirements for the base - a difference of no more than 2 mm per 2 meters of length. Manufacturers insist on this and, if possible, it is better not to violate this recommendation.
In practice, it has been found that small smooth irregularities - an area of several square centimeters, a few millimeters in depth - are still acceptable. Manufacturers do not recommend it, but in practice it has been proven that GVL behaves more or less normally. The sheet may bend, repeating the shape of the notch. If there is linoleum, art vinyl or other on top soft covering, all this threatens is the appearance of a small unevenness. It is better not to leave even such recesses under parquet or laminate, as the locks may come apart and there may be an unpleasant squeak.
And, even under a soft coating, unevenness cannot be left everywhere. If they are located where the load is applied, it is better to eliminate them. For example, on the aisle or where there will be a table leg, chest of drawers, bed, closet. There shouldn't be any irregularities here.
Second point. When laying on a loose base or on logs, GVL is placed on the floor either with increased density (floor elements) or moisture-resistant in two layers. When laying in two layers, the sheets are cut so that the seams of one layer do not coincide with the seams of the other. This is fundamental and the recommendation should absolutely not be violated.
Third point. When laying GVL slabs on a hard, level floor (concrete), the ends are glued with PVA glue. When laying on a base that does not exclude movement (joists, for example), it is better to use elastic filler for the seams. One option is a sealant that remains flexible after drying. Apply it and immediately level the layer (you can use a gloved finger, for a better effect it can be moistened with water).
You can cut gypsum fiber board with a hacksaw; for faster results, use an angle grinder (grinder) with a wood disc (ø 125 mm). In a straight line, you can break it just like drywall. To do this, cut one side (front) of the sheet, place a rule under the cut, tap the hanging part with your palm, and break it. The fracture site is far from perfectly level, so cutting gypsum fiber board onto the floor is hardly worth it. The cut has to be leveled and polished, and this takes no less time, and sometimes more, than working with a hacksaw.
Self-tapping screws for GVL need special ones - with a sharp conical head The gypsum boards are secured to the floor with special self-tapping screws. They are called “by gypsum fiber”. They differ in that the cap has a sharper cone. This shape of the cap allows it to fit into a dense sheet without pre-drilling. The length of the screw must be at least 3 times the thickness of the slab. That's how you choose.
GVL on the floor along the joists is taken with increased density (from Knauf this is Super Floor) or two layers of ordinary moisture-resistant material are laid, spaced apart from the seams (they are shifted so that the seams do not coincide). In any case, there are two ways to make a gypsum fiber board floor using joists:
When laying gypsum fiber boards directly on logs, the pitch of the beams and the dimensions of the sheets should be selected so that the edges of the slabs rest on the beams. They are fastened with self-tapping screws, retreating at least 1.5 cm from the edge. The fasteners are installed in the intermediate beam (if there is a support under the sheet) with the same spacing. If necessary, the gaps between the logs are filled with heat-insulating or sound-proofing materials. Depending on the design of the floor, they are either installed vertically or placed on a leveled base.
This technique was developed by Knauf, and a high-density tongue-and-groove gypsum board was developed for it. This material is called Super Floor. The essence of the method is that expanded clay is poured onto the base (any, of any degree of curvature) small fraction(expanded clay sand). Expanded clay is leveled, and floor elements made of gypsum fiber board are placed on it. The finishing floor covering can be laid on this base. You can make your own insulated floor very quickly and conveniently. In addition, the technique does not create significant loads on the floor.
Instead of expanded clay sand, you can use regular construction dry sand. To mix different materials or different fractions are not allowed, because sooner or later they will shrink. And when laying gypsum fiber board on the floor it is required level base no failures. So it’s better not to allow drawdowns.
Concrete screed is a reliable foundation, but cold. If you don't heat it, the floor will be very cold. Residents of the first floors of high-rise buildings and private houses know this. The problem is solved by using a floating floor with improved thermal insulation characteristics. Eat traditional solution: put a layer of insulation and pour another layer of screed on top. But this is too heavy and will take a lot of time. You can make a dry screed - it's faster, easier and cheaper.
How to make a dry GVL screed on a concrete base? A layer of insulation is placed on the concrete, and sheet material is placed on top. It is better to use polyurethane foam or high-density polystyrene foam (at least 35 kg/m³) as insulation. Why not mineral wool? Because its thermal insulation characteristics are several times lower. This means that instead of 3-5 cm of polyurethane foam, 15-20 cm of cotton wool will be required. Few people would want to raise the floor to such a height.
One of the options sheet material for dry floor screed - gypsum fiber boards. GVL is ideal for flooring, as it itself has increased heat-insulating properties and also dampens sounds well. GVL flooring is a good base for laminate, linoleum, carpet and other coverings.
When laying gypsum fiber board on a rigid base, it should lie tightly. There should be no voids or protrusions underneath. That is, the concrete base must be level and smooth. GVL is laid on concrete. Fasten along the perimeter in increments of 50-60 cm, install clamps. In general, you can use a composition like Rotband based on gypsum. It will both fill/even out minor unevenness and keep the sheets in place.
If it is necessary to improve the thermal insulation characteristics, extruded polystyrene foam (EPS) or polystyrene foam is placed on the concrete floor. You can simply lay it down without attaching it. But to prevent the insulation boards from creaking, they must lie tightly. If there are small irregularities, they can be filled with the same glue. It is applied under the slab using a notched trowel. The height of the tooth depends on the irregularities that need to be leveled.
The thickness of the foam is selected based on the requirements and structure of the cake. If there are two layers, they are laid with the seams staggered (so that the seams do not coincide). So that they do not rub or creak, or move out of place during operation, they can be fastened together. For this use:
For floors, two layers of GVL are usually used. They are laid with seams spaced apart. The layers are fastened with self-tapping screws. The thickness of the gypsum plasterboard for the floor depends on the planned load. Typically, slabs of at least 12.5 mm thickness are used. If the geometry of the material is not ideal and there are differences in height, so as not to sand, you can use the same gypsum-based glue.
In principle, everything has already been said above. If the wooden floor is level, you can lay gypsum fiber boards without fear. It allows moisture to pass through normally, so the wood is not in danger of rotting. If the floor is uneven (which usually happens), it is best to dismantle it and lay the gypsum fiber board along the joists. Or make a subfloor. If this is not possible for some reason, GVL can also be placed on a wooden floor. There is a possibility - eliminate the unevenness with a plane, fill the cracks. If that doesn't work, there is an emergency option.
We take a primer for gypsum mixtures and cover the floor in several layers. All cracks should be filled with construction foam with good adhesion and leveled with the surrounding floor level. Gypsum plaster good quality dilute as for plaster (thick dough). We take a wide spatula and level the floor - apply plaster. In some places - to scrape, in others - until the unevenness is filled. Let's take a big rule and align everything to one level. When dry, apply two layers of GVL.
In order for the gypsum plasterboard tiles to hold well and for cracks to not appear, the base under the gypsum fiber must be absolutely flat and strong. If these are boards, there are no gaps, cracks or sagging. If the floor is made using joists, the thickness of the layers should be sufficient to prevent even the slightest deflection during loading and walking.
Installing GVL on the floor under tiles is a possible option Since tiles are usually laid in rooms with high humidity, additional waterproofing is required. It is recommended to use KNAUF-Flachendicht or other mastics and rubber paints.
When laying ceramic tiles on GVL, you need to use elastic glue for unstable or complex substrates. Make the layout so that the tile seam and the joint of the sheets do not coincide. It is desirable that the joint of the slabs be in the middle of the tile. With this approach, problems and cracks do not arise.
GVL (gypsum fiber sheets) is a finishing material for floor leveling, made of gypsum reinforced with reinforcing additives and fluffed cellulose fibers.
Has gained particular popularity thanks to its excellent technical and operational characteristics.
Figure 1. Construction of a GVL base
Gypsum fiber sheets have many advantages, the main one of which is environmental friendliness and Fire safety. The material is able to regulate the microclimate in the room, absorbing excess water when high humidity and giving it back in dry air.
Other benefits:
GVL is perfect for installing a heated floor system.
Along with its advantages, GVL is sensitive to humidity, so special attention should be paid to waterproofing measures.
This is a rather fragile material that requires care during transportation and installation.
When purchasing drywall, choose materials only from trusted manufacturers.
Professionals prefer KNAUF products due to High Quality And affordable price.
Gypsum fiber sheets are produced in the usual form - GVL, and moisture-resistant - GVLV, impregnated with hydrophobic primers.
They can be distinguished by markings on the sheets.
Marking example: GVLV-B-FK-1500*500*15 means:
Conventional sheets are used in dry residential areas where there is no risk of leaks. Moisture-resistant sheets are used in damp and unheated rooms.
Standard sizes of gypsum plasterboard for floors:
Figure 2. Standard sizes of GVL.
Prefabricated floor elements are produced standard sizes 1500*500 millimeters. The thickness of gypsum plasterboard for prefabricated floors is 200 millimeters. The sheets have folds for fastening the elements together.
Figure 3. Prefabricated floor elements.
Manufacturers also produce other sizes of slabs according to consumer orders.
By appearance and size, gypsum boards are similar to drywall. But unlike the latter, made in the form of a sandwich, when a layer of gypsum is sandwiched between two layers of cardboard, it has a homogeneous monolithic structure.
The sheets are sanded on one side and impregnated with a water-repellent primer.
Figure 4. GVL sheets.
The increased strength is due to reinforcing additives made from fluff cellulose, evenly distributed in the gypsum layer.
Gypsum fiber sheets can be cut with any tool; screws can be screwed into them and nails can be driven in. They do not crumble during processing, unlike drywall. They can be attached to decorative elements interior
When processing and cutting sheets, moisten the blade of a jigsaw or hacksaw with water to prevent the formation of gypsum dust.
Depending on the properties, gypsum boards are painted in different colors. For example, moisture resistant ones have green color.
Moisture-resistant gypsum fiber boards can only be distinguished by markings.
Gypsum fiber sheets are not flexible, unlike gypsum boards, so they are not used for the manufacture of curved structures.
They weigh more and cost more than drywall.
Gypsum fiber sheets can not only replace drywall, but also significantly expand the scope of application.
They can be used for various purposes:
Moisture-resistant gypsum plasterboard for flooring is well suited for finishing unheated and damp rooms, as it does not lose its properties in negative temperatures and high humidity.
When laying, the sheets should be positioned with an offset of 20 - 25 centimeters relative to each other, like brickwork, to obtain the most durable and long-lasting structure.
Figure 5. GVL layout diagram.
Important!
When laying gypsum fiber sheets on a concrete base or screed, wait until the concrete coating is completely dry.
It is necessary to remove folds from elements adjacent to the wall to prevent pushing through during operation.
Laying should begin from the wall with the doorway, from right to left, with the cut side facing the wall.
The seams between the sheets must be at least 1-2 millimeters.
When installing a floor over a layer of thermal insulation made from loose mixtures more than ten centimeters thick, it is recommended to lay gypsum fiber sheets in three layers. In this case, the lower layers should consist of smaller parts, and the top one can be laid from large sheets, more than two meters long.
There are three main types of insulation under GVL:
Figure 6. Mineral wool for floor insulation in a wooden house.
A high-quality and reliable base for any finishing coating can be obtained by strictly following the technology and sequence of work:
Before starting work, we dismantle the old floor coverings, thermal insulation layers and destroyed screed down to the reinforced concrete floor slab. We remove construction debris and dust.
We seal the seams between the slabs with mortar. We expand the cracks in the concrete and seal them with repair compounds. We treat the surface with special penetrating primers for concrete.
We mark the backfill level and the top level of the screed using a laser or water level.
To do this, draw a horizon line along the entire perimeter of the premises. It can be located at a height of 50-100 centimeters from the ceiling.
We take measurements from the horizon line and determine the highest point of overlap.
From this point we mark the thickness of the backfill and transfer it to the walls around the perimeter of the room.
Similarly, we determine the screed height marks.
Transfer the marking lines for backfill and screed height to the walls using a painted tapping cord.
Figure 7. Marking the screed level.
Concrete floors are covered with polyethylene film with a density of 200 microns. We lay the canvases overlapping, overlapping each other by 20 - 25 centimeters and fastening them with tape. We place the film on the walls, 5-10 centimeters above the level of the screed and secure it with tape.
Along the perimeter of the premises we attach a damper tape made of foamed polyethylene, above the height of the screed, to mitigate deformation shrinkage and sound insulation of the walls from the floor.
Figure 8. Waterproofing the floor with a damper tape.
To install communications under a GVL coating, we put wires and cables into a protective corrugated pipe. The thermal insulation layer above the corrugation must be at least 20 millimeters.
To achieve a uniform layer, we install guide beacons from wooden slats or metal profiles. We check their horizontalness strictly according to the marks. We attach it to the base using cement or gypsum mortar.
Pour the dry mixture of expanded clay of different fractions in an even layer, leveling and compacting between the beacons. Pay special attention to junctions with walls and doorways.
Figure 9. Laying expanded clay along beacons.
Wear a respirator to prevent expanded clay dust from entering the respiratory tract.
After completing the work, remove the guides and fill the resulting voids with expanded clay.
To insulate the floor above an unheated basement, you can additionally insulate it with penoplex foam by first laying plasterboard sheets on the expanded clay.
We begin laying the gypsum fiber board from the corner farthest from the door.
We coat the folded edges with PVA glue and lay the sheets, additionally securing them with self-tapping screws, at least two centimeters long. We screw the screws with a screwdriver around the perimeter of each sheet, in increments of 15 centimeters, recessing the caps into the surface of the material.
Figure 10. Fastening gypsum fiber sheets with glue and screws.
We lay the second row of sheets on glue, with an offset of at least 20 centimeters, like brickwork. We secure the perimeter of each sheet with glue and screws.
The screw heads must be sunk into the slab to prevent damage to the final finish.
After installation of the gypsum fiber board is completed, the seams between the sheets and the recesses from the screws are sealed with putty.
Along the perimeter of the wall we cut off the protruding damper tape and waterproofing.
Figure 11. Layout of floors with gypsum fiber reinforced concrete over a concrete floor.
Work on finishing the floors can begin the very next day, after the glue and putty have dried.
A base made of gypsum fiber sheets is suitable for any final floor covering material.
When laying parquet, laminate or linoleum, you can additionally lay a special underlay.
Rigid gypsum fiber sheets are ideal for leveling wooden floors.
Before starting work, we check the condition of wooden structures.
If necessary, we replace elements damaged by rot and add joists.
Checking the horizontality of the floors building level. We correct the deviation by placing wedges or removing irregularities with a plane.
All wooden structures treated with antiseptic compounds.
We lay a vapor barrier made of waxed paper or glassine.
To prevent deformations around the perimeter, we attach a damper tape.
We lay thermal insulation made of mineral wool, laid tightly between the joists or fill it with a dry mixture of expanded clay.
We lay gypsum fiber sheets along the joists.
Figure 12. Laying gypsum fiber board on wooden joists.
We glue the sheets together along folds and secure them with self-tapping screws.
It is better to lay the second layer of gypsum board perpendicular to the first, on the glue.
We glue the top layer along the folds and fasten it with self-tapping screws, recessing the caps into the sheets.
We seal the seams and screw heads with putty, obtaining a rigid monolithic coating, ready for finishing.
When installing gypsum fiber board floors, it is necessary to strictly follow the sequence of work and installation rules in order to avoid possible defects:
By following our recommendations and observing the technology, you will be able to install the GVL base yourself or supervise the work of contractors. As a result, you get a durable, strong, perfectly flat base for any floor finish.
GVL (gypsum fiber sheet) is a finishing material made from gypsum, which is reinforced with the help of technological additives and dissolved cellulose. Home distinctive feature GVL is a homogeneous material structure that does not have a cardboard shell. GVL for floors have a higher density than plasterboard sheets, this adds strength. GVL differ in scope and characteristics (regular and moisture resistant).
It is advisable to lay gypsum fiber sheets only on a dry type of floor; a wet screed has too much moisture. If you lay gypsum fiber board on a wet screed, you must wait for it to dry completely in order to prevent moisture from penetrating to the floors below. Using sheets, the screed is done using a dry method, and after it you can immediately begin installing the finishing layer of the floor.
Gypsum fiber board is a compressed flooring material in which fluffed waste paper acts as reinforcement, and gypsum acts as a bonding element between parts of the sheets. This combination significantly strengthens the position of gypsum fiber board, especially in comparison with plasterboard and fiberboard, and in terms of moisture resistance it completely leaves its competitors behind. In addition to all the advantages, gypsum fiber boards do not burn and are made of environmentally friendly materials, which, of course, gives them an advantage when choosing finishing materials for the floor.
Most finishes can only be installed on a leveled floor, which requires additional preparation. Not all of them have good thermal and sound insulation. As finishing coating You can use a dry version of the floor screed, made on the basis of gypsum fiber board, which will become a good substrate for almost all materials, and a rough floor covering and good insulation.
GVL can also be laid on structures made of wood and reinforced concrete. To do this, it is necessary to lay waterproofing material on the base, on which the final assembly of the screed sheets will take place.
With this approach, sound-heat-insulating components, such as polystyrene foam boards, can also be included in the layers. The sheets can easily be used to cover a heated floor system, because any type of heated floor can easily be accommodated in the free space under the sheet. Installation is carried out using a dry method, which of course will save money and time on work. Thanks to GVL, the basic version of the floor is as smooth as possible and already insulated. If you choose this flooring technology, be prepared to purchase small sheets with a width of 1.5 * 1 m and a thickness of 1-1.2 cm.
GVL sheets are laid in two layers, or floor slabs already glued by the manufacturer are used, which are equipped with folds at the ends, which is a much better option.
Before installing the slabs, it is necessary to insulate the floor with expanded clay, which will help to level the coating well. A vapor barrier placed under expanded clay can be a polyethylene film with a thickness of 200 microns, but depending on the type of ceiling, you can replace the film with roofing felt or glassine.
Before starting work, the area of the entire room must be fixed with a thickness of 1 cm, which will simultaneously absorb the noise of tools and prevent significant deformation due to temperature fluctuations.
After laying the tape, you need to cut off its extra centimeters along the upper edge of the edge of the planned floor. Next, a vapor barrier substrate is placed on the polyethylene flooring, and each strip must be laid overlapping the previous one.
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Expanded clay is distributed over the surface covered with a film with a fractionation of no more than 0.5 cm, while the guides must be set according to the level and leveling bedding, after which the floor is leveled using the rule.
After filling the expanded clay with a tamper, if the layer thickness is more than 10 cm, this work must be done especially carefully. When compacting, you should pay special attention to areas near walls, doors and in the corners of the room.
Laying the first layer of gypsum fiber board for the floor begins from the corner closest to the entrance, after which PVA glue or a special adhesive mastic is applied to it. After applying the fastening substance, a second layer is applied, always in the opposite direction. The technology of such installation provides that during installation upper layers GVL, their fragments will need to be connected with fasteners and glued along the folds.
The step with which the sheets will be fixed should not be more than 30 cm. If you purchased sheets with a thickness greater than 1 cm, the length of the screw for fastening must be at least 1.9 cm, but in the case of installing plates with a thickness of 1.2 cm, you will need self-tapping screws with a length of 2.3 cm.
When installing the basic version of the floor, you must ensure that when gluing the gypsum fiber boards, you immediately remove any remaining glue that will protrude near the walls and at the joints. If you plan to lay carpet or laminate on the sheets, then the joints and remaining seams must be puttied.
After laying, fixing and puttying the second layer, the floor surface should be primed. When purchasing a primer, make sure that the technical specifications show compatibility with the adhesive material that will be used when laying the screed.
Sheets are cut only after laying their last row, i.e. at the wall opposite the installation start point. This is necessary for high-quality work, the result of which will be a large spread of seams (more than 25 cm), but it is worth making sure that the seam width of the first layer does not exceed 1-2 mm.
Factory-glued floors should be laid in the same way as small-format slabs, so the process will be completed faster. The sheets must be joined using folds coated with glue. The folds themselves, adjacent to the wall, must be cut after laying, while simultaneously fastening the tiles.
If the leveling bedding is 10 cm or more thick, subfloors are made from gypsum plasterboard in three layers. In the uppermost layer, the size of the working material can be 2.5 * 1.2 m.
If gypsum fiber sheets act as protection for a heated floor, then the assembly of a dry type screed begins with the installation of polystyrene foam boards.
Laying polystyrene foam boards. When creating basic heated floors using bedding, the insulation is laid out directly on the bedding itself (or on the film).
Dry screed made from gypsum fiber sheets can be of three types.
Prefabricated base floors placed on a leveling expanded clay bedding 2 cm high, which are recommended for installation on an insulated base without height differences.
A rough version of the floor on the surface with foam insulation, the thickness of which is 2-3 cm, it can be used if the floor requires insulation, and the base itself has slight unevenness.
A prefabricated version of the screed on slabs of expanded polystyrene, laid on a bedding of expanded clay, with a thickness of 2 cm, which is suitable for uneven floors, which also need to be insulated.
The prefabricated screed must have the following components.
A vapor and waterproofing layer that separates ceilings and other parts of a multilayer floor. If the floor is reinforced concrete, a polyethylene film will be an ideal separator; if the floor is wooden, glassine is used.
Compensating and soundproofing gasket in the form of an edge strip, which can be secured with screws or glue. The gasket is fixed immediately before installing the prefabricated screed in the room, and the gaskets themselves can be isolon, foam, or basalt wool and other materials.
A leveling layer, which is made using one of the above methods. GVL slabs, two- or single-layer, fastened with screws or glue.
Only small format slabs with dimensions of 1.5 * 1 m, with a thickness of 10 mm are suitable for the floor, and in the markets there is also a gypsum fiber board thickness of 12 mm and a width of 1.2 mm, which is not so often used for flooring. The sheets are laid in two layers, therefore, you need to purchase them twice the size of the room area. Remember that GVL comes in wall and floor types, as well as moisture-resistant and ordinary, moisture-resistant ones are sold with a moisture-repellent mixture.
If during the process of laying the floor you also need to insulate it, then you need to know that insulators can be of three types.
Fibrous - glass and mineral wool, which look like cotton candy, but instead of melted sugar it contains the same granite or glass. If the choice fell on the fiber type of flooring, then it is better to look for foreign products, because domestic goods cannot be installed in living rooms.
Expanded polystyrene - similar to polystyrene foam, they have heat-saving qualities and last a long time, but at the same time they are expensive and flammable.
Backfill - expanded clay, crushed stone, slag pumice, which provide poor insulation, but are inexpensive.
Screed made of gypsum fiber sheets (GVL) is an established technology for creating a leveling layer for floors. The GVL base is durable, reliable, suitable for any floor covering - you can lay laminate, linoleum, carpet, ceramics and... Creating floors from gypsum fiber sheets is a much less labor-intensive process than laying screed using the wet method.
Gypsum fiber sheets are made from a mixture of gypsum and cellulose wool with various additives. Cellulose threads inside the sheet reinforce the material, giving it elasticity, eliminating the excessive fragility of gypsum. As a result, gypsum fiber board sheets, compared to gypsum plaster, are much more bending and viscous; the material is supplied without a shell and does not crumble. Volume weight is 1.25 T/m3, which is more than plasterboard. But this is 2 times less than that of cement-sand screed - 2.5 T/m3.
GVL sheets are produced various sizes. Standard - 1500x1200 mm - the same as plasterboard, but with a thickness of 10 mm. But there may be small-format sheets -1000x1200mm, or other sizes of plates for various purposes. For example, Knauf produces a so-called prefabricated gypsum fiber board floor - slabs of reduced size, but much thicker, weighing up to 18 kg, with the expectation that the material can be laid by one worker.
GVL sheets can be with a regular straight edge or with a fold. Special sheets for creating floors are made with a wide rebate of up to 10 cm, which allows them to be fastened together into one surface using PVA glue and screws.
Typically, dry screeds lying on a continuous bedding or elastic layer of insulation (mineral wool, expanded polystyrene) are created with a thickness of 2 cm. That is, two or three layers of gypsum fiber board are laid with the obligatory displacement of the seams between the layers.
The use of gypsum fiber board in one layer is allowed provided that the bedding is accurately leveled and compacted, and a material with its own significant elastic bending resistance is used as a floor covering - laminate, plank flooring, parquet, parquet boards.
From the consumer’s point of view, a foundation created using gypsum fiber board laid on a layer of insulation or simply sand bedding is not much different from concrete screed. It is hard and smooth, suitable for laying any coating. 
But the installation of the floors itself is carried out without wet processes - cheaper and faster. In addition, the possibility of laying GVL with a thickness of up to 30 mm saves internal space compared to a cement-baked screed on a layer of insulation. And also the weight of a GVL screed can be several times less than a cement-sand screed, which is important for apartments when creating floors on the ceiling.
Dry screed makes it possible to simply create floors using a layer of insulation and/or sound insulation on the ceiling. Laying GVL on a layer of leveling sand bedding and mineral wool slabs 30 - 40 mm thick is a classic example of creating a floating floor with high noise insulation.
In addition, there are advantages of production process in creating the subfloor.
But GVL can only be used if there is the most reliable vapor barrier from a moisture source. Gypsum can easily become saturated with water, at the same time soften and increase in volume, and become distorted. So the moistened base may swell. Therefore, usually they do not risk using GVL in showers, swimming pools, bathrooms - where moisture can penetrate from the side of the room, even with complete waterproofing.
The same is true above the underground in the house - if ventilation is poor and the vapor barrier is damaged, the plaster can become moistened to the point wet soil under the house and problems will begin. GVL, like plasterboard, is not used in basements, boiler rooms, and in some industrial premises... 
Even when laid on concrete slabs ceilings, for plasterboard, gypsum plasterboard, it is recommended to introduce a layer of vapor barrier under the insulation and gypsum plasterboard into the floor structure. And in apartments there is also a layer of waterproofing on top of GVL for protection in case of flooding...
Gypsum fiber sheets do not allow the ingress of water, dew, or high humidity, therefore all work on installing gypsum fiber board floors is carried out last - after completion of testing of heating and water supply systems, after wet finishing processes on walls and ceilings, and even at temperatures above +10 degrees and humidity up to 60%.
The concrete base is covered with a layer of vapor barrier - polyethylene with a thickness of at least 0.2 mm, while the overlap of the film strips should not be less than 200 mm, and it is also wrapped on the walls above the level of the finished floor. 
A damper tape or polystyrene foam 1 cm thick is placed along the walls above the finished floor level. The goal is to create a compensation gap for thermal expansion between the floating base and the walls, to reduce impact noise transmitted to the walls.
The next stage of creating a GVL floor is leveling bedding. In the future, it should not sag or become denser, i.e. no precedents should be created for gypsum coating deflection. It is recommended to use fine-grained expanded clay in a layer of up to 100 mm. If the layer is larger, then it is necessary to use 3 layers of 10 mm GVL. 
On the bedding, long guide beacons are installed in one plane throughout the room. To do this, a continuous line of the backfill level is drawn on the walls using a water level or a laser builder. Leveling of the bedding is carried out only along beacons installed at the same level. Otherwise, the floors will simply not be even.
Typically, the bedding is leveled over the entire room at once, and the installation of gypsum fiber board begins from the far corner. Therefore, to move around the room where the GVL floor is being created, slabs randomly laid on the bedding are used.
GVL is laid in rows, and the seams in the rows are ligated. The seam offset is at least 20 cm. This is easy to do by starting each subsequent row by trimming the gypsum fiber board from the previous row. In addition to shifting the seams in the rows, there is almost complete saving of material. 
Cutting the material can be done with a jigsaw with a special file. And the fastening of individual panels to each other on the rebate is done with PVA glue and screws, which are screwed in every 20 - 30 cm along the rebate along its center line.
There may be small gaps between the sheets. If the coating is not hard (carpet, linoleum), then all gaps are puttied.
If thin gypsum fiber board sheets (10 mm) without folds are used to create floors, then they are laid in 2 - 3 layers. In this case, each layer is glued to the previous one. PVA glue is applied with a notched trowel onto the laid bottom layer, and the top layer is always laid with the seams overlapping with the bottom layer. Those. the middle of the top sheet should be where there is an intersection of the seams between bottom sheets. Thus, a continuous connected base is obtained, where elastic resistance to bending and fracture is provided by all layers simultaneously, like a solid slab. 
On elastic bases made of insulation (dense foam plastic, extruded polystyrene foam, mineral wool floor slabs), thin gypsum fiber board sheets must be laid in at least 3 layers under flexible floor coverings to achieve sufficient base rigidity.
As you can see, the work of laying dry gypsum fiber screed can be completed in the shortest possible time. For example, two workers can lay special seam sheets for flooring in one day on an area of up to 70 square meters, i.e. completely in small house. It is also not difficult to make floors from gypsum fiber sheets with your own hands.
