Knauf-Sevener is a modern dry mix made on a lime-cement basis. It is intended for indoor and outdoor use. Among the ingredients are special fibers, as well as polymer additives designed to provide high adhesion, water repellency and resistance to cracking.
general description
The process of making the described mixture is a combination of binders with adhesive additives, which provides increased strength of the finished layer and crack resistance, which is much higher than in the known solutions. Among the components there is a moisture-repellent additive that protects the thermal insulation layer or masonry from getting wet. Microclimate inside living quarters does not deteriorate, since "Knauf-Sevener" has a low resistance to diffusion of water vapor.
This mixture should be used when constructing systems external thermal insulation buildings for different purposes, when the insulation boards are glued to the base, they can be made of mineral wool as well as expanded polystyrene. Reinforced fiberglass mesh can be fixed on their surface, which is subsequently covered with decorative plasters.
For reference
It can be applied on solid, structured and cleaned mineral-based plaster substrates. A dispersion coating or based on artificial resins can be used as a rough surface.
Scope of use
Knauf-Sevener is used to repair cracked old ones and also as a solution for reinforcing mesh. The latter is laid on the hardened plaster during masonry work with mixed materials. The mixture can act as an adhesion plaster for porous and smooth concrete surfaces. Sometimes "Knauf-Sevener" is laid with a thin intermediate layer on concrete surfaces. In this case, you can use a mechanized or manual method. In the first case, continuously operating high-performance pumps are used.
Specifications
Professionals and DIYers may be interested in compressive strength and flexural strength, these parameters are 4.4 and 2.3 MPa. In the dry state, the mass reaches a density of 1400 kg / m 3, and the density coefficient is 0.52. Since the mixture is used as an insulating layer, you may be interested in its thermal conductivity, which is 0.87 W / m · ° С. The absorption coefficient is less than 0.5 kg / m² · h.
Material consumption information
Knauf-Sevener, specifications which are presented in the article may be useful to you if you plan to use it for renovation works... The composition will be consumed in a certain amount, which depends on various factors. When cladding insulating surfaces that are flat and covered with old plaster, 3.5 kg / m 2 will be consumed. If insulating boards are being lined, which are laid, then 6 kg / m 2 will be needed. The putty can be used as a protective layer, which is applied to the insulating boards, in this case 7 kg / m 2 will be needed. The average material consumption for plastering the old one will be 5 kg / m 2.
Feedback on the technology of use
"Knauf-Sevener", reviews of which are often the most positive, should be applied using a certain technology. According to users, you first need to prepare the base, then you can start mixing the solution. At the next stage, the application itself is carried out. If the work is carried out under special conditions, then fresh plaster must be protected from fast drying and impact low temperatures... As buyers emphasize, the decorative layer can be applied only after the plaster layer has completely dried.
Substrate preparation:
The substrate must be dry and sound. Brickwork, concrete foundations and mineral plasters must be cured for at least 28 days. Before applying the plaster-adhesive mixture, it is necessary to remove from the surface of the base crumbling elements, oil stains, snow, ice, frost and other contaminants that impede the adhesion of the material to the surface. To pre-level the surface and eliminate significant irregularities, it is recommended to use a suitable leveling plaster. To enhance the adhesion of the material to the base, treat the surface with an appropriate primer. The surface is ready for application only after the primer has completely dried. At work temperatures below + 5 ° C, priming is not performed. In this case, the base must be thoroughly cleaned with a brush.
When working with extruded polystyrene foam, before gluing and before applying the base plaster layer, the surface of the board must be roughened mechanically.
During the subsequent installation of the reinforced base plaster layer, thoroughly clean the surface of the heat-insulating boards from dust with a brush.
Solution preparation:
Before use, the dry mixture must be kept at a temperature above 0 ° C for at least 24 hours. Also, before starting work, all elements of the insulation system must be kept at positive temperatures. To prepare the solution, it is recommended to use water with a temperature of +10 to + 30 ° C. With constant stirring, pour the contents of the bag into a container with clean water based on 1 kg of dry mix 0.18-0.22 l pure water(for 1 bag of 25 kg - 4.5-5.5 liters of water) and stir until a homogeneous mass is formed. Mixing is done by a mechanized (professional mixer) or by hand... The solution must be kept for 3-5 minutes, then mixed again. After that, the solution is ready for use.
The solution can be used within 1 hour after mixing with water. When the viscosity of the solution in the container increases (within the pot life), it must be thoroughly mixed without adding water.
To prepare the solution, use only clean containers, tools and water.
Execution of works:
Fastening insulation boards:
The adhesive solution can be applied to the surface of the insulation different ways... In case of unevenness of the base with a depth of more than 3 mm, the adhesive solution is applied to the surface of the insulation using a trowel along the perimeter of the slab in a continuous strip, as well as in the center pointwise. The width of the continuous strip is 3-4 cm, the thickness of the adhesive layer is about 20 mm. If the unevenness of the substrate is less than 3 mm, the adhesive solution is applied with a notched trowel or trowel evenly over the entire surface of the board.
Immediately after applying the adhesive, the board is applied to the surface and pressed firmly. The plate adjustment time is 15 minutes. Insulation plates are fastened in one plane, with a T-shaped bandaging of seams, close to one another. The gap between the plates is no more than 2-3 mm. Subsequent work on the installation of dowels and the device of the base layer can be done no earlier than in 2-3 days.
Arrangement of a reinforced base plaster layer:
Using a notched trowel or trowel, the plastering mortar is applied in a thin layer to the surface of the board and evenly spread. Reinforcing facade fiberglass mesh (with an overlap of at least 10 cm canvases) is laid on a freshly applied plaster layer, “embedded” into it and smoothed in such a way that the mesh is in the middle of the base layer.
During work and in the next two days, the temperature environment and the base must be at least -10 ° C. At temperatures below -10 ºС, all work should be carried out in the thermal circuit. During the hardening process, the surface must be protected from intense drying: do not allow direct sunlight, water and drafts. Application of decorative plaster, paints and varnishes and finishing with other decorative coatings is made no earlier than 7 days after the creation of the reinforced base layer.
Knauf Sevener- dry mix on a lime-cement basis for outdoor and internal works... Contains special fibers and polymer additives that provide the finished solution layer with high adhesion, crack resistance and water-repellent properties. A special combination of binders with adhesive additives and fibers provides sufficient adhesion and gives the plaster layer increased strength and significantly higher crack resistance compared to already known solutions. The water-repellent additive protects the insulation and masonry from getting wet and, due to the low resistance of water vapor diffusion, does not impair the residential microclimate. Knauf Sevener is used in the construction of external thermal insulation systems for buildings for gluing thermal insulation boards made of expanded polystyrene or mineral wool to ordinary bases and applying a protective layer reinforced with fiberglass mesh on their surface, followed by coating with decorative plasters Diamant-240 and 260, etc. Knauf Sevener can be applied on structured, durable, dust-free mineral plasters and the same surfaces with a dispersion coating or plaster coatings based on artificial resins (if necessary, after appropriate treatment).
Knauf Sevener can be used:
For the repair of old (cracked) plaster surfaces of building facades;
- as a solution for reinforcing mesh on hardened plaster when laying from mixed building materials;
- as an adhesion bridge plaster for surfaces of smooth and porous concrete, etc .;
- as a thin-layer intermediate layer of plaster for smooth concrete surfaces.
Knauf Sevener is applied manually and mechanically, for example, using continuously operating high-performance mortar mixing pumps, for example "G4" (G4), "G5" (G5), "Monojet" (PFT).
Consumption of materials
Depending on the type of work, the consumption of dry mix per 1 m2 is:
Facing with insulating plates on a flat surface old plaster~ 3.5 kg
Cladding with insulating masonry boards ~ 6 kg
Applying a protective layer to the surface of insulating boards ~ 7 kg
Plastering on a grid layer of old plaster ~ 5 kg
Preparation of the base
Conditions of work
The temperature of the surface of the base and the air in the room should not be lower than + 5 ° С.
Substrate surface preparation
Remove dust from concrete, masonry or old plaster.
- Check the old plaster for strength and adhesion to the substrate.
- To clear out potholes and to pre-plaster.
- Strengthen chalky and crumbling surfaces with Knauf-Tiefengrund primer.
Preparation of the solution
Mix the contents of the Knauf Sevene bag (30 kg) with 6.0 liters of water by hand or using a drill with a mixer attachment. Leave for 15 minutes and mix again. Adding any materials is not allowed. When working with plastering machines, for example, from PFT, set the dosage of water to about 320 liters and adjust the consistency of the mortar.
Application of Knauf Sevener
Cladding with insulating boards
Apply Knauf Sevener mortar around the perimeter and in the middle of the insulation board in dots or in a continuous zigzag strip. Band width - approx. 5 cm, thickness approx. 2 cm. Place the insulation board on the wall and align. Further work with the slabs should be carried out after the solution has hardened (~ after 48 hours).
Reinforcement of the surface of insulating boards
Apply KNAUF-Sevener mortar 5 mm thick, level with a rule. Install protective corners on the outer corners. Diagonally, at the corners of all openings, reinforce the surface of the insulation boards with strips of reinforcing fiberglass mesh measuring ~ 30x50 cm. Lay the reinforcing mesh over the entire surface in fresh mortar with an overlap of approx. 10 cm, while the solution should cover the mesh. If necessary, dowels are installed for additional fastening slabs. Allow the reinforcing layer to harden and dry for 8 days before continuing work.
Repair mortar
To smooth out structural irregularities, apply Knauf-Sevener to cleaned or prepared surfaces of old plaster with a layer of up to 10 mm. Install reinforcing mesh if necessary.
Thin-layer plaster for concrete
Apply KNAUF-Sevener with a thickness of 3.5 mm to a dust-free concrete surface and smooth it out. In the process of setting the mortar, when a certain surface hardness is reached, remove the formed nodules.
Plaster bridge
On a smooth surface of concrete, aerated concrete, etc. apply an intermediate connecting plaster layer of KNAUF-Sevener up to 10 mm thick, smooth and apply the KNAUF-LUP-222 mortar after at least 3 days.
Plastering on a grid
Apply Knauf-Sevener on a dry layer of plaster over the entire surface with a layer of ~ 3 mm. Lay strips of reinforcing mesh with a size of ~ 30x50 cm diagonally relative to the corners of all openings. Lay reinforcing fiberglass mesh over the entire surface with an overlap of 10 cm.On the next day, apply a layer of KNAUF-Sevener mixture ~ 2.3 mm thick. After the mortar has set, rub the surface with a felt float. For the manufacture of painted surfaces in the external insulation system, it is necessary to reapply the KNAUF-Sevener solution and lay in it a fiberglass mesh with a displacement of the joints relative to the first layer. After acquiring the required hardness, apply again the KNAUF-Sevener solution with a thickness of ~ 2.3 mm to this layer and, upon reaching the appropriate hardness, process it with a felt or sponge float. At the end of the work, the tools must be immediately rinsed with water.
Protect fresh plaster from frost and quick drying. Apply a decorative coating only after the KNAUF-Sevener solution has hardened and dried. Before applying decorative plasters Knauf Diamant-240 and 260, coat the surface of Knauf-Sevener with a primer KNAUF-Izogrund.
Packaging and storage Knauf Sevener
Knauf-Sevener is packed in paper bags of 30 kg.
Store the bags with plaster mixture in dry rooms on wooden pallets. Pour the material from the damaged bags into the whole and use it first.
Shelf life in undamaged packaging is 6 months.
Expanded polystyrene (PPS) is a heat-insulating material, which is 98% air. Outwardly, it resembles foam, but other characteristics of these heaters are different. Expanded polystyrene plates are used for insulation and partial sound insulation of walls.
Advantages of expanded polystyrene:
- high degree of thermal insulation;
- vapor permeability;
- moisture resistance;
- strength;
- does not react with cement, which makes it possible to plaster PPS slabs;
- does not support the development of mold and mildew;
- subject to the installation technology and operating rules, the service life of the material is up to 30 years.
Why plastering polystyrene foam insulation?
In the process of warming the facades, expanded polystyrene is mounted on the outside of the building. Insulation plates are glued to the walls using an adhesive solution for PPS, and then fixed with disc (mushroom) dowels. To protect and preserve the properties, the surface of the heat-insulating layer must be covered from ultraviolet radiation, temperature drops and other atmospheric influences(wind, precipitation, etc.). One of better ways protective finish styrofoam is. This type of coating is stronger and more durable than others, and it also has big choice execution options. Plaster is perfect for both protecting and decorating the facade.
How to plaster: the choice of mixture
For plastering of EPS, it is impossible to use ordinary cement-sand mortars right away. They will peel off quickly from the surface of the slabs. Therefore, the first layer is applied special plasters on expanded polystyrene. In addition to cement and fine sand, they contain glue and other additives that ensure strong adhesion of the mixture to the walls. After applying the foam adhesive, it is already possible to create a base plaster layer using a cement-sand mixture.
Adhesive plaster is intended for attaching PPS and some other types of insulation to various mineral substrates.
Several popular brands of adhesive plasters for expanded polystyrene:
- Ceresite ST 85. Compressive strength (parameter indicating the material's ability to withstand fracture, mechanical stress) - 8 MPa. Frost resistance 100 freeze-thaw cycles.
- Knauf Sevener. Plaster of this brand has all the characteristics of Ceresit ST 85, differs only by slightly lower compressive strength (7.5 MPa) and frost resistance (75 cycles).
- Founding Coverlix S117. Plaster and adhesive mixtures of this series have high compressive strength - 10 MPa, frost resistance 75 cycles. There are several special types plasters: winter, high-strength, reinforced, etc.
- UNIS Warmglue for heaters. Its main characteristics are: frost resistance 100 cycles, high vapor permeability, suitable for machine application.
- Adhesive plaster for Dali expanded polystyrene. It is based on cement. The mixture is elastic, has increased compressive strength.
The presence of reinforcing microfibers in the plaster mix does not eliminate the need to use a reinforcing mesh. Therefore, under the plaster on expanded polystyrene, a building mesh made of fiberglass must be attached.
To create a base (non-decorative) layer can be used ready cement-sand mixture... They are in almost every hardware store.
For self-cooking C-P solution take cement grade M400 or M500. Its ratio with sand will be from 1: 4 to 1: 5. River sand is cleaner, there are no clay impurities in it. But quarry sand has better grip because its edges are sharper.
The proportion of Water / DSP = 0.8-1.2, depends on the moisture content of the sand.
For finishing external walls buildings use special ones, for example:
Choosing the finish decorative coating for expanded polystyrene, it must be taken into account that acrylic plasters more resistant to weathering.
Plastering technology
Materials and tools that will be needed for plastering expanded polystyrene plates:
- primer for PPP;
- brush or roller;
- adhesive plaster mix for PPS;
- cement-sand mortar;
- decorative plaster for PPP or paint;
- fiberglass reinforcement mesh with a density of 145-160 g / m2;
- perforated plaster corner;
- small and large spatulas (width 10 mm and 450 mm);
- construction grater or sandpaper;
- hacksaw or needle roller;
- container for solution;
- mixer.
Work order:
- Remove dust and dirt from expanded polystyrene plates
- Apply with a roller or brush a primer for PPP.
- Make diagonal notches on the plates with a hacksaw or a needle roller - "comb out" the insulation. This is necessary for better adhesion of materials.
- Cut the reinforcement mesh into strips along the entire height of the wall (for one-story houses). If plastered multi-storey building, then the length of the mesh is chosen based on the convenience of working with it.
- Prepare a glue mixture in a volume of no more than one bucket. The solution must always be fresh.
- Glue the perforated plaster corner to the corner. Instead, you can use a section of the mesh folded in half.
- Apply on the wall a layer of mortar 2 - 3 mm thick to fix the mesh. Its stripes are glued with an overlap. Therefore, the width of the adhesive mixture should be 10 cm less than the width of the mesh section.
- Press the mesh into the mortar with a spatula. Move from top to bottom and to the side. The mesh must be completely covered with plaster mixture.
- Apply a strip of adhesive underneath the next section of mesh.
- Glue the mesh section in the same way as the previous one. Thus, cover the entire surface of the walls with a reinforcing mesh.
Make sure that the joints of the mesh do not fall on the joints of the expanded polystyrene boards.
- After the first adhesive layer on the mesh has dried, wipe it with a damp construction float in a circular motion. It is not necessary to strive for perfect smoothness. This will impair adhesion to the the next layer plaster mix.
- The walls are again treated with a deep penetration primer. Ceresit CT 17 or Knauf Izogrund will do.
- After the soil has dried, they proceed to plastering cement-sand mortar... I use the same tools - a large and small spatula. The thickness of the second layer is 3-5 mm.
- After the base layer has dried, wipe the wall surface again with a moistened float or sandpaper. If traces of circular movements remain, then you can wipe the second time with straight lines. When performing the last grout, it is necessary to achieve perfect result... This will make it easier to apply decorative finishes.
- Under finishing layer apply another layer of primer to finish the expanded polystyrene boards.
- Paint over dried plaster or cover with decorative plaster mixture.
Plastering of expanded polystyrene boards - optimal way to protect them from adverse weather conditions and create an attractive appearance walls of the building. The technology for applying plaster to expanded polystyrene is quite simple, you just need to remember the main rule: you need to use a reinforcing mesh and fix it on the EPS using special adhesive mixtures. This will ensure the durability of the entire facade finish and create the basis for the decorative coating.
We hope this article was useful and interesting to you. You can read about working with other types of plaster on the pages of our website. Leave your questions and comments below. We will definitely answer them.
Both among professionals and among novice finishers, Knauf plaster mixes are especially popular due to their quality, ease of application and a large assortment, which allows you to choose the right composition for any type of work. One of them, Sevener plaster, will be described in great detail in this article.
Knauf Sevener plaster-adhesive mixture is made on the basis of cement (see). It also includes fractional sand, special fibers and modifying additives that give it high plasticity, water-repellent properties, crack resistance and other positive qualities.
Advantages of the Sevener mix
Like everyone else plaster mix Knauf, this stuff is different high quality... And its special properties are given by its constituent components, mixed in optimal proportions.
So:
- Special fibers in combination with polymers and water-repellent additives endow this product with resistance to cracking and the ability to repel water, which protects the base and the insulation glued to it from the aggressive effects of moisture, prevents dampness in the room;
- Sand of a certain fraction in combination with adhesive additives and binders gives it maximum strength, good adhesion to the base, plasticity.
Sevener Knauf plaster-adhesive mixture is distinguished by its economical consumption: depending on the type of work for which it is used, it is 3.5-7 kg / m 2. That is, one bag of 25 kg can be enough for finishing more than 7 sq.m. surface. Considering that the price of packaging is just over 400 rubles, the costs of repair and construction work are low.
Specifications
Application
Thanks to its unique properties, Knauf Sevener plaster-adhesive mixture can be used with equal success both for external (see) and for internal work.
Use cases
Already from the name it is clear that this building mixture is versatile and can be used both as a plaster and as an adhesive.
It is intended for the following types of work:
- Repair of old plaster of building facades, including structural surfaces and covered with varnish-and-paint compounds, provided that they do not crumble and are firmly adhered to the substrate;
- Application of thin-layer intermediate plaster on smooth concrete and structured surfaces of mineral plaster, on coatings based on artificial resins and surfaces with dispersion coating;
- Arrangement of an adhesion plaster bridge on surfaces made of porous or smooth concrete;
- Bonding thermal insulation boards made of mineral wool or expanded polystyrene to the base when installing external thermal insulation systems;
- Installation of a protective layer over thermal insulation boards.
Note. The coating created with the Severin mixture is an ideal base for subsequent finishing with materials such as the Goldband Knauf plastering mixture or decorative Knauf plaster Diamond.
Depending on the method of application, the consumption of the dry mixture for square meter surface. For example, Severin Knauf plaster mix for gluing insulation to a flat surface is diluted at the rate of 3.5 kg / m 2, and if heat-insulating plates masonry is revetted, it will already be required 6 kg.
Likewise, for plastering even surfaces of the material, less (5 kg) is required than for applying a layer on an old one. structural plaster(6-7 kg). The maximum consumption is obtained when creating a reinforced protective layer on the surface of the insulation.
Application features
Regardless of the type of work for which the Knauf Sevener plaster mixture will be used, the base must be carefully prepared, cleaning it from crumbling particles, dirt and dust.
Then the solution is prepared, instructions for its preparation are on the package. Typically, 5 liters of water is required to mix 25 kg of dry mix.
For reference. Ready mix can be applied both manually and mechanically, for which continuously operating mortar mixing pumps are used.
When applied with your own hands, the amount of the prepared solution should be such that it can be completely worked out in 2 hours. After this time has elapsed, it will begin to lose its properties.
Work should be done when positive values air temperature and protect the freshly applied plaster from frost, direct sunlight and drying out too quickly.
Before continuing to work and applying leveling or decorative Knauf plaster mixtures to the surface, it is necessary to wait for it to dry completely and cover Primer Knauf Isogrund.
Conclusion
We deliberately did not begin to describe in detail the process of working with this plaster: you will get acquainted with it by watching the video in this article. By choosing this material, you will be satisfied with the quality of the result.