Many people have heard that floor leveling work usually involves pouring mortar onto the screed. But few people know that among construction technologies know-how appeared, dry screed.
New in the field of flooring - dry screed
The name itself suggests that when constructing such a screed, the use of water is completely eliminated. Now we will understand all the intricacies of this method of leveling the floor from start to finish.
- General concepts
- Tools needed for installation
- Preparation of the base and beacons
- Let's start making a screed
- Getting a flat floor
Common types of floor screeds have been successfully used in practice for decades. All work on leveling floors is carried out using sand, cement and the obligatory component of water. What else can you come up with and put into practice?
It turns out that it is possible, as the specialists of the Knauf company did, they were the ones who implemented their new project for leveling the floor. The technology is simple and accessible to almost everyone. The work uses gypsum fiber sheets (GVL), expanded clay sand as the basis of the entire screed. It remains to figure out in detail how to make a screed from these materials and weigh all the pros and cons, if any.
Preparing tools and material
So what do we need to make such a screed ourselves?
- First of all, partner, think about who could help you, because an assistant will not hurt when working. Taking into account the fact that the materials have their own weight, it will not be very convenient to carry heavy loads and stack sheets alone.
- Gypsum fiber sheets "GVL" from the manufacturer "Knauf", size 1200 by 600 mm. This special sheets reduced format, even one person can easily handle their installation. Technologically, we see two sheets glued together and offset to form a fold. They are also called Knauf dry floor elements.
- Expanded clay with a fine fraction, preferably 5 mm. In another way it is called expanded clay sand.
- Polyethylene film is spread on the floor before filling with expanded clay.
- Edge tape, PVA glue.
- Self-tapping screws for fastening GVL.
Now the tool for dry screed, which we will need in our work.
- Tape measure, pencil - so you can measure and mark
- A knife for cutting gypsum fiber board or a jigsaw - the sheets will have to be cut, you can use both tools
- Screwdriver – fasten sheet joints with self-tapping screws
- Narrow spatula
- Metal profile PN-27/28 will be used as beacons.
- Rule
Advice! We will not point out that a paint brush is a necessary element when installing a floor, but prepare that too. Later, the brush will help you sweep away the expanded clay crumbs from the joints before applying the glue.
Installation of beacons, starting to make the floor
We begin our work by laying polyethylene film throughout the room; this is required by the technology of laying dry screed. Be sure to make an overlap on the walls of at least 20 cm.
Afterwards you need to lay the edge tape, it should be between the screed and the plastic film. This required condition. The width of the tape should correspond to the thickness of the floor backfill with expanded clay.
Now it’s the turn of the lighthouses themselves, along which we will build expanded clay. At the same time, we will level the base on which the floor itself will rest. Thus, we additionally get the excellent quality that expanded clay provides.
In practice, the process of installing beacons is the same as when installing a cement-sand screed, with the only difference being that we will not attach the beacons to the floor. We will move the profile that we will use as slats and at the end of the work we will simply remove it without leaving it under the floor.
It is assumed that there are already marks for the height of the future floor, so we begin installing the profile. To make it easier to align the slats, it is convenient to stretch a fishing line or thread along the floor to the height of your beacons. The river will be located along the room from window to door, and the thread across from wall to wall.
The installation of the dry screed continues and now we need to sprinkle expanded clay on the lines under the lighthouse batten. They usually spill the width of the rule that will be used to tighten the expanded clay. We’ll place our profile in the resulting piles, be sure to sharp ends up so that the plane is on the expanded clay. Further along the thread we set the profile and, using a level and a rule, adjust the horizontal, even plane.
We have everything ready to start scattering expanded clay. Technologically, dry floor screed in an apartment is installed sequentially, so do not rush to pour out all the expanded clay at once. Spread the area between the beacons into several squares, so that later you can arrange the sheets without walking on the leveled expanded clay.
We take the rule in hand and begin to pull expanded clay sand along the lighthouses. In places where there is a shortage, add more and tighten again. You see how it is formed ready base floor, on which we will then lay our gypsum fiber board sheets.
Note! In practice, in order to walk on a finished expanded clay surface, GVL sheets measuring at least 50 by 50 cm are used. Islands are made from them that can be stepped on without damaging the surface. This way, you can get to the place you need in case of an emergency.
We mount the sheets and fasten them together
Now we have a couple of squares of ready-made evenly stretched expanded clay, on which the dry screed, our gypsum plasterboard sheets, will be laid. So, we lay the first sheet, first of all, do not forget to cut the fold from the side of the sheet adjacent to the wall. And this should be an internal fold, not visually visible to us.
During the process, try to move the sheet on the surface of the expanded clay as little as possible. Before laying the second sheet, and it should go in length, apply glue to the joint. Then place the sheet in the lock and fasten them together with self-tapping screws.
It is important to note that the sheets should be laid on the floor in staggered increments, like brickwork or laminate. Therefore, before laying the next row, measure the length of the room and find out how many whole sheets will be in the row and the size of the trim.
Laying the second row should begin with the remainder of the cutting of the first row. This way we use the material almost waste-free and achieve the runaway conditions we need.
Before applying glue to the lock, carefully check that there are no expanded clay crumbs; if they do get onto the fold, sweep them away with a previously prepared paint brush. After you have laid several sheets, the profile can be carefully pulled out and rearranged further. So, step by step, we install the sheets and get a flat floor; it immediately becomes clear why a floor screed is needed.
Summing up the work
If you did everything correctly, following the dry floor manufacturing technology, then your surface is completely ready for further use. This is distinctive feature this technology from others. We immediately receive a ready-made new floor. But do not forget that this is a rough surface on which you can later lay tiles, linoleum, and carpet.
Now that you have gone through all the stages of installing a dry floor, you can compare the labor costs if it were a DIY cement screed. Agree that the “super floor” is easier to install and cleaner during the work process.
Plus, you got a floor with an excellent soundproofing layer, and now the neighbors below will not bother you with noise. Probably the most important point This is because such a floor is very warm. Moreover, using this technology it is no longer necessary additional elements underfloor heating.
Unlike other types of screeds, you were freed from dampness and dirt during the work process. You didn't have to calculate the cement for the screed. All the reasons are positive in favor of your new floors.
Considering all the above facts, we can say that the ease of installation and further maintenance of such floors do not cause any difficulties. An even bigger advantage is that such floors can be dismantled if necessary. You just need to remember where you finished laying. Because it is from that place that it is advisable to begin dismantling if necessary.
The Knauf company, as a manufacturer, guarantees the strength of this floor and environmental friendliness, which is especially important today. After all, the composition of the floor screed that you used today does not contain harmful chemical substances. Which makes it even more in demand in the construction industry.
One of the simplest and quick ways To level the base of the floor, use a dry screed. This option is not suitable for industrial, commercial premises and offices, since its compression force is less than that of a traditional screed, but for arranging a floor or apartment - this is an excellent choice.
Depending on the method of installation, there are several types of dry screed:
- Using expanded clay. This is the most common method; first, a layer of waterproofing is applied to the surface; it can be rolled or in the form of a solution, after which expanded clay is poured in and gypsum fiber sheets are laid.
- Without the use of backfill. This method is recommended to be used if the differences in the height of the base are small, then the gypsum plasterboard is laid directly on the base, without the use of backfill.
- Application between the base and gypsum fiber sheets of modern porous fibrous or foam materials.
- Complex method. In this case, the above options are combined: first, a layer of waterproofing is laid, then a layer of expanded clay is poured in and covered with gypsum fiber sheets. At the next stage, a substrate is made; for this, porous or fibrous materials and cover it with GVL sheets with locks.
Before choosing this method of floor leveling, you need to know what advantages and disadvantages it has.
pros
- “wet” processes are not used during the work, so there is no dirt in the room, which will certainly be present during installation concrete screed, and this is very important, especially when work is carried out in an apartment;
- it is convenient to hide various engineering communications in the resulting cavities;
- This solution not only allows you to level the floor, but also improves its heat and sound insulation characteristics;
- light weight;
- long service life;
- no time is required for the solution to harden, so the finishing coating can be laid immediately after creating a dry screed;
Despite such a large number of advantages, it has of this type drawbacks and shortcomings.
Minuses
- relatively low mechanical strength
- higher cost.
Materials and tools
Before you begin work, you must purchase required amount materials and tools.
You will need the following supplies:
- waterproofing material, it can be a film or a solution. The film is laid in such a way that there is an overlap of 10-15 cm on the walls. If it is not possible to cover the room with a whole piece, then when connecting two canvases, you need to overlap them by about 15-20 cm;
- dry backfill(expanded clay) to fill square meter flooring with a layer thickness of 10 mm, you will need 0.01 cubic meter of the specified material;
- edge tape , its length should be equal to the perimeter of the room, minus the doorways;
- glue, PVA is used to glue sheets together;
- profile for beacons necessary in order to level the expanded clay, it must be laid in increments of 0.5 to 1 m;
- GVL, you can use chipboard, OSB, moisture-resistant plywood, asbestos sheets for this, but they are used much less frequently;
- self-tapping screws, you will need 8-12 of them per sheet.
From tools you will need a jigsaw, a screwdriver, a water or laser level and a tape measure.
More often Expanded clay is used as backfill, and there should be no sand or dust in it, buy only clean material, but besides this, they can be used and other materials:
- vermiculite– this is a material of natural origin, it is light in weight, only expanded vermiculite should be used for screeding;
- perlite– volcanic material, it is processed at high temperature, which allows moisture to be completely removed; perlite sand can be used as backfill;
- compevit– this is expanded clay from the Vipol company, the granule size is about 4 mm, such backfill does not sag or deform during the use of the floor.
Knauf dry screed technology and device
Knauf floors represent hollow-core, quick-installed dry screeds, which can be laid on both concrete and wooden surfaces. Superpol KNAUF can be laid in rooms with high humidity, but waterproofing must be done correctly.
Dry mixtures for floor screed KNAUFdivided into the following types:
- Alpha - used on a flat surface;
- Beta - laid on flat surfaces, but using a backing made of porous-fiber materials;
- Vega - placed on a leveling layer of dry backfill;
- Gamma - laid on dry backfill and porous-fibrous materials.
Important! Regardless of the type used, KNAUF dry floor screed can be used at a room temperature of at least 10°C and a humidity of about 60-70%.
Step-by-step instruction
Preparing the base
First you need remove the old screed, there is no need to perfectly level the surface, but if there are cracks, their need to be repaired using a solution. After that remove all debris and treat the floor with a primer. Conduct marking zero level , for which a water or laser level is used.
Steam-waterproofing
For organizing a vapor barrier layer, a film is laid on the floor, while the overlap of the canvases between each other and on the walls should be 10-15 cm, all seams are properly taped with construction tape.
Attention! Moisture is destructive for a dry screed, and if you treat the stage of laying waterproofing irresponsibly, then the sheets will subsequently swell, which will lead to damage to the floor covering.
Installation of beacons
According to the level of the future screed in increments of 50-70 cm lay out beacons, which are U-shaped profiles, it is best to use plaster or alabaster to fix them, as they harden quickly. After installing the beacons, fall asleepdry mix for screed, it can be quartz or silica sand, expanded clay screening, expanded perlite sand, fine-grained slag, and using the rule they level it along the installed beacons; this should be done just above their level.
Usually a layer of backfill 3-5 cm thick is sufficient, but if it exceeds 6 cm, then it is necessary to strengthen the screed with an additional layer of slabs.
If the surface of the base is perfectly flat, then the backfill can be omitted, and instead, sheets of extruded polystyrene foam are laid, which should fit tightly to each other; they can significantly increase the thermal insulation characteristics of the dry screed.
Now you can move on tolaying dry screed(gypsum fiber sheets). The folds on the first sheets are cut off so that later a double layer of gypsum fiber board can be laid. The sheets are stacked offset, according to the principle brickwork, they are fastened together using self-tapping screws, usually their length is 19 mm, but longer ones can be taken. Self-tapping screws are screwed along the folds in increments of 10-15 cm.
- Although such a coating has big amount advantages, it also has certain disadvantages. Most often, when installing a dry screed with your own hands, home masters do a grave mistake– do not cut off the fold of the first sheets adjacent to the wall, and this leads to the fact that in such places the floor begins to sag over time.
- If you leave the beacons after backfilling, then after some time the expanded clay gives, albeit a small, sediment, while the beacons remain in place, which leads to problems with the coating. It is recommended to either remove the beacons after leveling the backfill layer, or pour a layer of it slightly above the level of the beacons.
- Necessarily pay attention to the quality of expanded clay, if there is dust or sand in it, then over time such a floor will begin to creak. Buy better bulk material, so you can visually check its cleanliness. The material must be well dried if it has high humidity, then over time this will lead to deformation of the sheets.
To obtain a flat surface, screed the floor: dry or wet. Each option has its advantages, but also many disadvantages. Traditionally, many craftsmen prefer the “wet” method, which involves pouring a semi-liquid mixture. Its disadvantages include labor intensity, a large amount of dirt, and it will take at least 2-3 weeks to dry. The cement layer creates additional load on the floor.
An excellent alternative to the “wet” method is the “dry” method. It allows you to get the perfect foundation with less time and effort. In the future, it can be used for laying parquet, linoleum, carpet, and tiles. This technology is becoming increasingly popular. Doing a dry floor screed with your own hands is not difficult.
The name “dry floor screed” indicates that no water is used in its implementation. The classic “wet” version involves the use of a semi-liquid mixture of sand, cement and water. Due to the force of gravity, which forces the liquid to be evenly distributed over the volume it occupies, a perfectly flat surface is ensured. It would seem that you could come up with something better? However, specialists managed to create a fundamental new technology, the implementation of which is accessible to the average person.
The floor, made on the basis of dry screed, is a multi-layer structure. The first layer is dry backfill, then gypsum fiber sheets (GVL). This dry-pressed floor screed creates excellent sound insulation and retains heat well. It will take no more than 2 days to create it, depending on the volume of work. The only limitation for doing dry floor screed with your own hands is wet rooms. Absorbing moisture from the air, expanded clay or other filler loses its shape and swells. As a result, the floor is no longer level and the finish is deformed.
Manufacturers offer several options for dry mix for floor screed. They differ in the complexity of preparation and purpose. They are selected taking into account the characteristics of the base:
- Alpha - suitable for smooth floors;
- Beta - for a flat base covered with a layer of porous or sound insulating material;
- Vega - laid on a leveling, soundproofing layer;
- Gamma - intended for laying on a leveling layer of backfill, after laying thermal insulation materials with a layer of gypsum boards.
The finished screed is somewhat reminiscent of a layer cake. It can be laid on a concrete or even wooden base. You can safely lay communications inside it. It is perfect for installing heated floors and has a positive effect on its energy efficiency.
Dry floor screed technology
Before starting work directly, you will need to prepare materials: waterproofing film, expanded clay, gypsum fiber board, profiles for beacons. The sheets are fastened with self-tapping screws and additionally fixed with construction adhesive. Dry floor screed is carried out in stages.
Preparatory stage. The arrangement of the floor begins after completion of the installation of plumbing, adjustment of pipes, electrical networks, and completion of other work. Before laying a new coating, old materials should be removed. Then level the base and seal cement mixture cracks, protrusions, chips. When the “dirty” stage has been completed, you need to carefully sweep away the resulting debris and collect dust. Mark the height of the screed on the walls.
Stage two - laying insulation. The technology of dry floor screed includes the installation of a waterproofing layer of polyethylene or glassine. It is better to use the whole canvas. If laying is carried out in pieces, they should overlap each other with an overlap of at least 20 cm. The film is placed on the wall to the floor level (minimum 6 cm). Insulation is chosen taking into account the characteristics of the ceiling:
- concrete - take polyethylene with a thickness of 200-250 microns;
- wood - it is better to use glassine or moisture-proofing paper impregnated with bitumen.
The purpose of the moisture-proofing layer is to protect the backfill from swelling when absorbing water or steam.
When performing dry floor screed with your own hands, you should not forget about sound insulation. It is made of glass wool, polypropylene foam or mineral wool, gluing the tape around the perimeter of the walls. Such a strip will protect against extraneous noise; it prevents the floor from deforming due to thermal expansion.
Stage three – placing beacons. Without using tools, it is simply impossible to lay it evenly loose mixture. There is no point in hoping that you will be able to level it later: every pass on the viscous base leaves footprints. No complex equipment is needed, profiles are enough U-shaped. They are turned upward with a sharp edge, leveled, and secured with self-tapping screws. Expanded clay will then be poured between them.
The main stage is arranging the floor. First of all, pour the mixture, trying to create a homogeneous layer. It is made from expanded clay, fine-grained slag, quartz sand or purchase a ready-made mixture. The amount of backfill is determined by the unevenness of the floor. The thickness of the layer on average reaches 4 cm, it is not recommended to make it more than 6 cm. Sheets are laid on the prepared floor and secured to each other. The sheet should not be pressed into the sand, nor should it be moved. Laying of gypsum fiber boards on the backfilled surface begins from the door. If the sheets go on top of the insulating material, they move away from opposite wall to door.
The sheet material is laid offset (like bricks) to provide strength and stability to the floor.
The sheets are fastened with self-tapping screws along the perimeter, placing them every 15-20 cm. Additionally, the sheets can be secured with glue. Irregularities are sealed with putty, then sanded. The surface of the sheets is covered with bitumen insulation. Now you can start finishing. Although it is better to give the floor 2-3 days to “rest.”
Advantages and disadvantages
Dry floor screed has earned its popularity due to its many inherent advantages. The main thing is that it does not need to be dried. After installation is completed, you do not have to wait 45 days, as is the case with a concrete base. The very next day you can lay linoleum, lay tiles or lay parquet board. Another important advantage is the low weight of the coating. The additional load it creates on the floor is minimal. The time it will take to complete it depends only on the area of the room and the efficiency of the performer. This layered “pie” improves sound and thermal insulation.
To complete the picture, it is necessary to note the disadvantages of dry floor screed. There are few of them, but they exist. This coating is not recommended for unheated premises, bathrooms, showers. A traditional or semi-dry screed is suitable for them. Having understood the pros and cons, you can safely get to work. For residential premises this option is ideal. Its minor shortcomings are more than compensated for by the simplicity and efficiency of installation. Even one person can do it. Only when laying gypsum fiber boards is it better to use the help of another person, since it is inconvenient to handle them alone.
How to make a dry floor screed
When starting a repair, each master decides the question: what can be done independently, and what work will require the involvement of specialists? Dry floor screeding is completely doable with your own hands. The technology is simple and does not require the use of complex equipment. If you carefully study the order of execution, there will be no difficulties. Here it is important to adhere to the accepted rules and use materials recommended for dry floor screed.
A common mistake made by craftsmen is to neglect the gasket. damper tape. Its absence will make itself felt immediately after the floor begins to be used: creaks and sounds will prevent you from enjoying the new renovation. The tape can be glued to PVA, double-sided tape or fasten directly to polyethylene with a stapler.
Another important question: what to choose as backfill? There is no strict requirement - sand, expanded clay or slag. These materials have similar characteristics: they do not burn, retain heat, and do not shrink. The thickness of the layer should be at least 3, but not more than 6 cm. If the floor is flat, you can do without it altogether. Then, instead of backfill, slabs of extruded polystyrene foam are used.
When starting to install a dry floor screed made from gypsum fiber board sheets, it is important to avoid directly walking on the backfill. Therefore, the sheets begin to be placed immediately from the door. When one sheet is laid, the floor still “moves” under your feet. There is no need to be upset: each subsequent sheet gives the structure the required stability.
Installation work can be carried out at any time of the year. The main thing is to follow the technology exactly, laying out “layers” of waterproofing film, a leveling layer, surrounded by a damper tape, and sheet material as the basis for the finishing coating.
Dry floor screed is a relatively simple and efficient technology leveling the floor for the finishing coating. Why might this method be of interest? First of all, for its versatility and “purity”. Further, we can highlight the low cost (comparable to the traditional type of screed), ease of installation and speed of implementation. The low weight of the dry cake is also important if there are load restrictions on the floors.
IN this review discussed in detail: dry screed technology, basic recommendations for its design and necessary materials and tools for work.
Dry screed - the essence of the method
To understand how dry screed differs from traditional “liquid” and semi-dry screed, let’s briefly consider their components and construction method:
- Regular and has water, sand, cement and plasticizers. The prepared solution is evenly distributed over the prepared surface and, if a semi-dry composition is used, rubbed down. The labor intensity of manufacturing such a floor is high. Besides, further use coverage is possible after several days.
- Dry screed is less labor intensive. Sheet materials (gypsum fiber board, chipboard or plywood) are laid on the prepared base. Multilayer structures are glued and fastened with self-tapping screws. This floor can be immediately used for further finishing.
A dilemma may arise when analyzing material costs. If the speed of installation does not matter to you, and all the work will be done by yourself, then a traditional screed will be a cheaper option.
To complete the picture and help in acceptance optimal solution When installing a floor, it would be a good idea to familiarize yourself with the main advantages and disadvantages of the dry method.
Pros and cons of dry screed
Any construction material or the technology has certain advantages and disadvantages. Let's consider the positive and negative sides dry screeds:
| Advantages of dry screed | Disadvantages of dry screed |
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Materials and tools for dry floor screed
The role of materials and tools when carrying out any construction work great. Trying to save money or experiment, you will end up with a floor that is not best quality. At the same time, the installation process will be delayed due to unnecessary manipulations and adjustments. Accordingly, so that the work goes well and the mood is not spoiled, choose only those materials and tools that are recommended for dry screed.
Let's start with the materials and consider them in order (from top to bottom):
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Sheet materials: GVL ( gypsum fiber sheet), plywood, OSB, chipboard. Let's take a closer look at GVL. For dry floors, small-format sheets measuring 1.5 × 1 m and 10 mm thick are produced. It is very convenient to work with such material, which cannot be said about the standard format of sheets with a width of 1.2 meters and a length of 2.5 meters or more (such sheets are very heavy). When purchasing sheet material, remember that the structure will consist of two connected layers. Therefore, to calculate the amount of GVL, multiply the area of the room by two. Also on sale are gypsum fiber floor elements - glued panels with a protrusion (rebate) and a recess. This option the most acceptable due to ease of installation. During the joining process, the elements must be glued together. Additional fixation is made with special self-tapping screws. |
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The next piece of the pie is the insulator. It is necessary for thermal insulation and sound insulation. There are three types of heat insulators:
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It is recommended to use overlapping polyethylene film as a waterproofing layer on a concrete base. The edges of the film must be raised above the insulation layer to full protection heat insulator. On wooden bases, instead of plastic film, bitumen or paraffin paper is laid. Such materials insulate the layers and allow the wood to breathe. |
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An edge (damper) tape is attached around the perimeter of the room. It serves as additional sound insulation and creates an expansion joint during cyclic expansion of materials. |
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During the work you will need following tools and accessories:
- Level and rule for controlling the plane and preparing the insulating layer.
- When using dry backfill, for the correct formation of the layer, it will be necessary to install beacons (pipes, profiles or factory beacons) on the solution.
- Tape measure, stationery knife, marker (pencil) - for cutting sheets of gypsum fiber board, EPS or mineral wool.
- Screwdriver and screws for connecting floor elements.
- A spatula and brush are useful for applying glue to gypsum fiber board sheets.
Preparing the base for the screed
The first thing you need to do before starting installation is to prepare the base of the floor. This stage includes dismantling the old floor covering and removing uneven surfaces and construction debris from the concrete (wooden) surface.
The concrete floor must be examined for cracks, potholes and other defects. All gaps, holes and large cracks between the floor and walls must be sealed with a mortar of grade M 150 (or higher). Using ready-made mixtures pay attention to their name - the mixture must be masonry or assembly.
After filling the uneven areas and completely drying the areas with cement mortar, the surface is thoroughly swept for further installation waterproofing material.
Dry screed waterproofing device
Considering that concrete plates or wooden floors are not able to fully resist the penetration of moisture from the underlying premises, the only way protecting the dry screed cake from dampness is insulation protective films and roll materials.
As a waterproofing material on concrete foundations It is recommended to use polyethylene film with a thickness of 0.2 mm.
Waterproofing dry screed The film must be laid in strips with an overlap of 15 - 20 cm. The film must go onto the wall. To further seal the layer, the strips at the joints can be glued with adhesive tape (scotch tape).
In the case of a wooden base, it is better to replace the plastic film with a more breathable material. The best option there will be bitumen or paraffin paper.
After laying the film (glassine) around the perimeter of the room, a damper tape is installed. The main purpose of this strip is to compensate for the thermal expansion of dry screed elements. Also, the damper tape will partially perform a soundproofing function, absorbing noise from the floor to the walls.
Backfilling (laying) of insulator
Depending on the required heat and sound insulation parameters, an underlying layer is created from fine-grained expanded clay, expanded polystyrene, mineral wool or a combination of the materials considered.
It is worth noting that when using polystyrene foam or mineral wool as an insulator, the base must be ideal in plane and level. If there are significant differences and unevenness, it is recommended to first level the base with a backfill insulator (sand, expanded clay).
When using expanded clay as the main insulator for a dry screed, you should consider:
- The minimum backfill thickness is 20 mm.
- The maximum thickness depends on the specific floor design.
- The use of coarse expanded clay is not permissible. It significantly reduces the area of contact with the upper sheet material, which in turn can lead to pushing and deformation of gypsum fiber sheets.
- Leveling the backfill layer is impossible without installing beacons.
The beacon installation process includes the following steps:
- Determination of the upper backfill level.
- Using a level (preferably a laser), marking lines on the walls around the perimeter of the room.
- Focusing on these lines using big rule you need to place the beacons on the solution. The process is controlled by the level.
- The pitch of the beacons should be 20 - 30 cm less than the length of the rule used. For example, if the width of the room is 2.5 meters, and the two-meter rule is used for work, then you can get by with two beacons located at a distance of 1.7 meters from the walls.
You can completely abandon traditional lighthouses. However, for an unprepared person, alternative methods may seem complicated.
Beacons from the rules for dry screed Let's consider one of the ways:
- We begin to pour expanded clay along one of the walls.
- With help long rule(2 -2.5 meters) inverted flat, we form a plane along the line marked on the wall. We leave the rule on this plane and additionally check the level.
- We form the next strip - an expanded clay beacon - after 1 - 1.5 meters (depending on the working rule) and also lay a long rule on it.
- The space between the beacons is gradually filled with expanded clay and leveled using a short working rule.
- The short rule is that the fry additionally needs to cut out notches. The depth of the excavation should be equal to the thickness of the expanded clay rule laid flat on the beacon.
Installation of sheet material
After filling the expanded clay or laying another insulator, you can proceed to the last stage of installing a dry screed. Let's look at the main features and recommendations.
Installation of dry screed elements Laying gypsum fiber sheets should begin from the doorway into the room. To ensure a reliable connection between the layers, glue is applied to the bottom gypsum fiber sheet. Upper layer GVL is laid with provision of ligation of seams. Excess glue protruding from the seams must be removed with a spatula.
The top and bottom layers of sheets are fastened together with special screws (self-tapping screws) for gypsum fiber boards with an anti-corrosion coating.
After installing all the sheets of dry screed, all excess damper tape and film must be cut off, and the junction of the floor and the walls must be filled with sealant.
Dry screed Knauf
Knauf dry flooring consists of gypsum fiber slabs (floor element) 2 centimeters thick and a ready-made backfill of expanded clay chips (fraction size 1-4 millimeters). Double gypsum plasterboards with a seam connection simplify installation and make it possible to produce a floor that meets all modern requirements for strength and safety.
The main advantages of using dual Knauf sheets for screed device:
- The design of the dry screed due to its low weight is applicable in multi-storey buildings without additional reinforcement of floors.
- This floor has maximum acoustic and thermal insulation.
- The Knauf screed is quickly and easily installed.
- The strength of the structure reaches 500 kilograms per square meter.
- Laying the floor covering can be done immediately after installing the dry floor.
- There are no wet processes.
- Expanded clay and Knauf floor elements are environmentally friendly and fireproof materials.
Video on the topic
To level the floor tiles, linoleum or laminate is used various technologies. Dry floor screed allows you to create solid foundation under Decoration Materials in more short time compared to the traditional method of leveling the floor surface using cement-sand mortar. When using this technology, there is no need to pause work to dry the materials.
The “dry method” allows you to prepare the base in one day and immediately begin finishing works. In addition, the materials used in this technology are much lighter cement-sand mortars, so the floor on which the screed is located is not overloaded. As a result, it becomes possible to make a screed of any thickness and hide communications without damaging the building in which the floor is leveled using this technology.
This method of floor leveling appeared about 40 years ago, but was not very popular.
Thanks to modern materials, produced under the Knauf brand, builders now have the opportunity to create foundations for floor coverings, which meet high requirements when carrying out European-quality repairs.
The composition of such a screed includes pure expanded clay of a fine fraction, which does not contain waste and by-products from production.
Pure expanded clay of fine fraction Gvl (gypsum fiber sheet) Knauf, which has precise dimensions and special folds used for joining. To prevent moisture from being supplied by expanded clay from the ceiling, waterproofing is installed.
When installing any screed, it is necessary to prepare the base. If there are cracks in the room where work will be done on the concrete or tiled floor, they should be repaired. The joints of the slabs and the junctions of the walls are also treated with mortar, if necessary.
Prepare the base Before starting the screed installation, it is necessary to install all communication pipelines, heated floors and electrical wiring, if any, in the room. If you have no experience in installing communications, you can watch the video on our website and do this work yourself. After completing this stage of work, they begin installing moisture insulation.
On concrete floors Polyethylene film with a thickness of at least 250 microns is used as a vapor barrier material. Wooden floors isolated with glassine. Vapor barrier material is spread on the ceiling in a continuous layer.
Use polyethylene film The joints must be at least 15 cm; when laying the material, they can be taped. The film or glassine should extend onto the walls. After all work is completed, excess material is cut off. Detailed description This process can be watched on video on the Internet.
In order to prevent sound from the floor from being transmitted to the walls along the perimeter of the entire room in which the floor is being dry-screed, sound insulation is done - a tape made of polyethylene foam is installed.
Polyethylene foam tape This material will absorb sound waves generated by walking on the floor and prevent them from being transmitted to the walls. And vice versa - from the walls to the floor. A 20 cm wide tape is glued to the walls using liquid nails.
Installation tools - screwdriver - required for screwing screws into gypsum plasterboard;
- jigsaw – needed for cutting gypsum fiber board sheets;
- rule - serves to create guides and level the expanded clay;
- laser level - will help you find the zero mark and make a level floor;
- shovel - use it to level expanded clay;
- stationery knife - necessary for cutting insulation.
If you don’t have power tools, you can rent them on the construction market.
For dry screed, it is preferable to choose expanded clay fractions from 1 to 5 mm, because this material is not flammable, retains heat well and has low shrinkage.
Expanded clay Do-it-yourself dry floor screeding is done using laser level. Using it, the zero mark is found - this is the level of the finished floor. Next, pour expanded clay paths onto the base.
Having placed the rule on them, use a tape measure or ruler to measure the same distances from the laser beam to the rule. Thus, the rule will be set by level. It serves as a guide rail.
Guide rail function When choosing materials, you should give preference to manufacturers who have a good reputation.
At a distance from the first guide rail, which is no greater than the length of the rule, a second guide is installed. The space between the guides is filled with expanded clay. Next, using one more rule, the backfill is leveled. As a rule, the expanded clay layer is aligned along the guides.
Leveling the expanded clay In places where there is a shortage of expanded clay, it is necessary to add backfill and level it again. You can see exactly how to do this in the video, which is located at the end of the article.
GVL sheets Knauf In order not to spoil the even layer of backfill, when installing sheets, place a piece of plywood or other durable sheet material on it.
Lay a piece of plywood Knauf sheets are also suitable for these purposes.
Before installing the first sheet, the joining seam is cut off from it on those sides on which it will be adjacent to the wall. This can be done using a jigsaw or a hacksaw with a fine tooth.
Cut off the joining seam Such an event is necessary so that the dry backfill does not fill the voids in the folds and the Knauf element does not fail.
When working, you must follow safety precautions. When working with the tool, you must wear protective gloves and goggles.
The first Knauf sheet is placed close to the walls, the folds are coated with PVA glue and the next fragment of the floor is laid.
Coat the folds with PVA glue For everyone GVL sheets The folds that lie near the walls must be cut off.
After connecting two floor fragments, their joints must be secured with screws. A screwdriver is used for these purposes. The distance between fasteners should be no more than 10 cm.
To secure Knauf sheets use special screws for gypsum fiber boards.
Special screws for gypsum fiber boards They have a double thread and a specially shaped head. When tightened, these screws go deep into the surface of the sheet and do not interfere with further finishing of the floor.
When installing sheets, they are placed with a running start. In such a way that cross-shaped joints do not form. Once the installation of all floor elements has been completed, it is necessary to cut off the soundproofing tape and film that protrudes above the surface of the sheets.
After dry screeding the floor with your own hands is completed, you can begin finishing work. There is no need to pause for the expanded clay to shrink, so this method of leveling the floor is the most effective. Detailed steps works can be viewed on video.
Cost of materials
To make a high-quality screed, you should buy high-quality raw materials from trusted manufacturers, for example, Knauf. Such backfill can be purchased for 225–300 rubles per bag.
Sheets for screed cost 250–310 rubles. These floor elements have dimensions of 1200-600-20 mm and 1250-500-23 mm.
250 micron polyethylene film costs depending on the width of the sleeve. On average - from 35 to 75 rubles.
Edge tape (damper), which is used as sound insulation, costs from 245 rubles per roll of 30 meters. Tapes vary in width and thickness, so the price may vary depending on these parameters.
Video
In this video you will learn about installing a dry subfloor screed from KNAUF supersheets.
Thanks to this material you will receive a lot of useful information.
Photo source: consultinfo.net, rovpol.ru