Knauf Sevener- dry mix on a limy-cement basis for external and internal works. It contains special fibers and polymer additives that provide the finished mortar layer with high adhesion, crack resistance and water-repellent properties. The special combination of binders with adhesive additives and fiber provides sufficient adhesion and gives the plaster layer increased strength and significantly higher crack resistance compared to already known mortars. The water-repellent additive protects the insulation and masonry from getting wet and, due to the low resistance to water vapor diffusion, does not worsen the residential microclimate. Knauf Sevener is used in the installation of external thermal insulation systems for buildings for gluing heat-insulating plates made of expanded polystyrene or mineral wool on ordinary bases and applying a protective layer reinforced with glass cloth mesh to 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 repairing old (cracked) plaster surfaces of building facades;
- as a mortar for reinforcing mesh on hardened plaster when laying from mixed building materials;
- as an adhesive 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 mechanized, for example, using continuously operating high-performance mortar-mixing pumps, for example, "G4" (G4), "G5" (G5), "Monojet" (Monojet) from PFT.

Consumption of materials

Depending on the type of work, the consumption of dry mix per 1 m2 is:
Cladding with insulating boards on a flat surface of old plaster ~ 3.5 kg
Cladding with insulating masonry boards ~ 6 kg
Application of a protective layer on the surface of insulating boards ~ 7 kg
Plastering on a grid of a layer of old plaster ~ 5 kg

Foundation preparation

Terms of work

The temperature of the surface of the base and the air in the room must be at least +5°C.

Substrate surface preparation

Remove dust from concrete, masonry or old plaster.
- Check the old plaster for strength and adhesion to the base.
- Clear potholes and pre-plaster.
- Strengthen chalked and crumbling surfaces with Knauf-Tiefengrund primer.

Solution preparation

Mix the contents of a bag of Knauf Sevene (30 kg) with 6.0 liters of water by hand or using a drill with a mixing attachment. Leave for 15 minutes and mix again. Adding any materials is not allowed. When working with plastering machines, for example, PFT, set the dosage of water to about 320 liters and adjust the consistency of the solution.

Application of Knauf Sevener

Cladding with insulating boards

Apply Knauf Sevener Mortar around the perimeter and also in the middle of the insulation board in dots or in a continuous zigzag strip. Strip width - approx. 5 cm, thickness approx. 2 cm. Place the insulation board on the wall and align it. Further work with the boards should be carried out after the mortar has hardened (~ after 48 hours).

Surface reinforcement 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 insulating boards with strips of reinforcing fiberglass mesh measuring ~ 30x50 cm. 10 cm, while the solution should cover the grid. If necessary, dowels are installed for additional fastening of the plates. Allow the reinforcing layer to harden and dry for 8 days before proceeding with the work.

repair mortar

To even out structural irregularities, apply Knauf-Sevener on cleaned or prepared surfaces of old plaster with a layer of up to 10 mm. If necessary, lay a reinforcing mesh.

Thin-layer plaster on concrete

Apply Knauf-Sevener 3.5 mm thick on 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 sagging.

Stucco-bridge

On a smooth surface of concrete, aerated concrete, etc. apply an intermediate connecting plaster layer KNAUF-Sevener up to 10 mm thick, smooth it over and apply the KNAUF-LUP-222 mortar after at least 3 days.

Plastering on the grid

On a dry layer of plaster, apply Knauf-Sevener over the entire surface with a layer of ~ 3 mm. Lay strips of reinforcing mesh ~30x50 cm in size diagonally relative to the corners of all openings. Lay reinforcing fiberglass mesh with an overlap of 10 cm over the entire surface. The next day, once again apply a layer of Knauf-Sevener mixture with a thickness of ~2.3 mm. After setting the solution, wipe the surface with a felt grater. For the manufacture of surfaces to be painted in the external insulation system, it is necessary to re-apply the Knauf-Sevener solution and lay a glass cloth mesh in it with the joints offset relative to the first layer. After acquiring the required hardness, once again apply a 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 washed immediately with water.

Protect fresh plaster from frost and rapid drying. The decorative coating should be applied only after the Knauf-Sevener mortar has hardened and dried. Before applying Knauf Diamond-240 and 260 decorative plasters, prime the surface of Knauf-Sevener with Knauf-Isogrund primer.

Packing and storage Knauf Sevener

Knauf-Sevener is packaged in paper bags of 30 kg.

Stucco bags should be stored in dry rooms on wooden pallets. Pour the material from damaged bags into whole ones and use them first.

Shelf life in undamaged packaging is 6 months.

Expanded polystyrene (PPS) is a heat-insulating material, consisting of 98% air. Outwardly, it resembles foam, but other characteristics of these heaters are different. Expanded polystyrene plates are used for insulation and partial soundproofing 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 boards;
• does not support the development of mold and fungi;
• subject to the installation technology and operating rules, the service life of the material is up to 30 years.

Why plaster polystyrene foam insulation?

In the process of facade insulation, expanded polystyrene is mounted on the outside of the building. Insulation boards are glued to the walls using an adhesive solution for PPS, and then fixed with dish-shaped (mushroom) dowels. To protect and preserve the properties, the surface of the heat-insulating layer must be closed from ultraviolet radiation, temperature changes and other atmospheric influences (wind, precipitation, etc.). One of the best ways to protect polystyrene foam is. This type of coating is stronger and more durable than others, moreover, it has a large selection of options. Plaster is perfect for both protection and decoration of the facade.

How to plaster: the choice of mixture

For plastering PPS, it is impossible to use ordinary cement-sand mortars immediately. They quickly peel off the surface of the plates. Therefore, the first layer is applied with special plasters on expanded polystyrene. In addition to cement and fine sand, their composition includes glue and other additives that ensure a 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.

Glue plaster is intended for fastening PPS and some other types of heaters to various mineral bases.

Several popular brands of adhesive plasters for polystyrene foam:

1. Ceresit ST 85. Compressive strength (a parameter indicating the ability of a material to withstand destruction, mechanical stress) - 8 MPa. Frost resistance 100 freeze-thaw cycles.
2. Knauf Sevener. The plaster of this brand has all the characteristics of Ceresit ST 85, differs only in slightly lower compressive strength (7.5 MPa) and frost resistance (75 cycles).
3. Founds Caverplix C117. Plaster-adhesive mixtures of this series have high compressive strength - 10 MPa, frost resistance of 75 cycles. There are several special types of plaster in the series: winter, high-strength, reinforced, etc.
4. UNIS Hot glue for heaters. Its main characteristics: frost resistance of 100 cycles, high vapor permeability, suitable for machine application.
5. Plaster glue for expanded polystyrene Dali. It is based on cement. The mixture is elastic, has high compressive strength.

The presence of reinforcing microfibers in the composition of the plaster mixture does not eliminate the need to use a reinforcing mesh. Therefore, under the plaster on polystyrene foam, a fiberglass construction mesh is necessarily attached.

To create a base (not decorative) layer can be used ready cement-sand mixtures. They are available in almost every hardware store.

For self-preparation of the C-P solution, cement grade M400 or M500 is taken. Its ratio with sand will be from 1:4 to 1:5. River sand is cleaner, it does not contain clay impurities. But quarry sand has better grip because its edges are sharper.

Proportion Water/DSP = 0.8-1.2, depends on the moisture content of the sand.

For finishing the external walls of the building use special ones, for example:

When choosing a finishing decorative coating for expanded polystyrene, it should be taken into account that acrylic plasters are more resistant to atmospheric influences.

Plastering technology

Materials and tools, which will be needed for plastering polystyrene foam boards:

• primer for PPS;
• brush or roller;
• adhesive plaster mixture for PPS;
• cement-sand mortar;
• decorative plaster for PPS or paint;
• fiberglass reinforcing mesh with a density of 145-160 g/m2;
• plaster perforated corner;
• spatulas large and small (width 10 mm and 450 mm);
• construction grater or sandpaper;
• hacksaw or needle roller;
• solution container;
• mixer.

Work order:

1. Clean the styrofoam boards from dust and dirt
2. Apply a primer for PPS with a roller or brush.
3. With a hacksaw or a needle roller, make notches diagonally on the plates - “comb out” the insulation. This is necessary for better adhesion of materials.
4. Cut the reinforcing mesh into strips the length of the entire height of the wall (for one-story houses). If a multi-storey building is being plastered, then the length of the mesh is chosen based on the convenience of working with it.
5. Prepare the adhesive mixture in a volume of not more than one bucket. The solution must always be fresh.
6. Glue the plaster perforated corner on the corner. Instead, you can use a segment of the grid, bent in half.
7. Apply a layer of mortar 2-3 mm thick on the wall to fix the mesh. Its strips are overlapped. Therefore, the width of the adhesive mixture should be 10 cm less than the width of the mesh segment.
8. Press the mesh into the solution with a spatula. Move up and down and to the side. The grid must be completely covered with plaster mixture.
9. Apply a strip of adhesive solution under the next piece of mesh.
10. Glue the mesh segment in the same way as the previous one. Thus, cover the entire surface of the walls with a reinforcing mesh.
    

    Make sure that the mesh joints do not fall into the joints of the polystyrene boards.

11. After the first adhesive layer applied to the mesh has dried, rub it with a damp construction grater in a circular motion. Strive for perfect smoothness is not necessary. This will impair adhesion to the next layer of plaster mixture.
12. The walls are again treated with a deep penetration primer. Suitable Ceresit CT 17 or Knauf Isogrund.
13. After the soil has dried, they begin to plaster with a cement-sand mortar. I use the same tools - a large and a small spatula. The thickness of the second layer is 3-5 mm.
14. After the base layer has dried, rub the surface of the walls again with a moistened grater or sandpaper. If there are traces of circular movements, then you can rub straight a second time. Performing the last grout, you need to achieve the perfect result. This makes it easier to apply decorative trim.
15. Apply another layer of primer under the finishing layer of the polystyrene boards.
16. Paint dry plaster or cover with decorative plaster mixture.

Plastering of polystyrene boards is the best way to protect them from adverse weather conditions and create an attractive appearance of the walls of the building. The technology for applying plaster on polystyrene foam is quite simple, you just need to remember the main rule: you need to use a reinforcing mesh and attach it to the foam board using special adhesive mixtures. This will ensure the strength of the entire facade finish and create a base for a decorative coating.

We hope you found this article useful and interesting. 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.

Knauf Sevener plaster-adhesive mixture, bag 25kg

It is made from a cement-lime base with the addition of polymer additives and fibers, which provide the unique characteristics of this mixture. Knauf is one of the world leaders in the production of building mixtures and materials that are distinguished by true German quality, which is highly valued all over the world. Kanuf mixes are popular among domestic consumers, they have earned only positive feedback from builders and home craftsmen.

Advantages of the Knauf Sevener plaster-adhesive mixture:

Suitable for mineral-based substrates, dispersion coatings, synthetic resin plasters. It can serve as an intermediate layer for concrete bases.
It is a necessary adhesive for a heat-insulating layer consisting of mineral wool or expanded polystyrene. To keep the heat-insulating layer better, a reinforcing layer and fiberglass mesh are laid between the layers of plaster. In the future, with the complete drying of the applied mixture, additional finishing work can be applied, in particular, the application of decorative plaster.

Used to restore old plaster, uncoated or painted walls, provided that the paint is firmly attached.

The plaster-adhesive mixture is often used as a plaster-bridge in relation to porous concrete.

Fine sand, polymer additives and fibers, which is part of the Knauf Sevener adhesive mixture, endow the mixture with many useful qualities: hydrophobic properties, high adhesion, plasticity and crack resistance.

The plaster has increased strength, and water-repellent characteristics protect the insulating layer of mineral wool or polystyrene foam from getting wet.

Low cost. The main element of this mixture is cement. The expense depends on the purpose of the appointment of Knauf Sevener. It varies from 3.5 kg for thin-layer plastering to 7.5 kg for attaching an insulating layer. All this makes Sevener a very inexpensive, high-quality and very necessary product at any construction site.

The solution is kneaded at a temperature not lower than 5 degrees Celsius, guided by the instructions regarding the proportions of water and dry mixture (usually for 5 liters of water - 25 kg Knauf Sevener). In the case of machine application, high-performance pumps are used.

The base is cleaned of oil stains, dirt and dust - everything that reduces adhesion (adhesion of the mixture to the base)

Existing potholes are pre-sealed with special Knauf mixtures. In any repair, it is advisable to choose the main and related material from the same manufacturer.

If application in several layers is required, then the next layer is applied only after the previous layer has dried.

After use, without waiting for the solution to dry, rinse tools and containers with water.

In the Synergy Build online store you can buy Knauf Sevener plaster-adhesive mixture at a low price. Our qualified specialists will assist you in calculating the required amount of material, for this you should call the numbers listed on the site. You can pay for the purchase using a bank card, through payment systems or in cash (for delivery by courier or pickup from the warehouse). Follow our promotions, where you can buy building materials even cheaper!

* The manufacturing company reserves the right to change the configuration and place of production of goods without notifying dealers! This information is not a public offer

Application area

Dry mix on a cement basis for external and internal works. It contains graded sand, special fibers and polymer additives that provide the finished mortar layer with high adhesion, crack resistance and water-repellent properties. The water-repellent additive protects the insulation and masonry from getting wet and, due to the low resistance to water vapor diffusion, does not worsen the residential microclimate. It is used when installing external thermal insulation systems for buildings for gluing heat-insulating plates made of expanded polystyrene or mineral wool on ordinary bases and applying a protective layer reinforced with glass cloth mesh to their surface, followed by coating with decorative Knauf-Diamant 260 plasters, 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 synthetic resins. (if necessary after appropriate processing). Can be used:

for the repair of old (cracked) plaster surfaces of building facades, including structural plasters, without or with a firmly adhering paint coating;

as a mortar for reinforcing mesh on hardened plaster when laying from mixed building materials;

as an adhesive bridge plaster for surfaces of smooth and porous concrete, etc.; as a thin-layer intermediate layer of plaster for smooth concrete surfaces. Can be applied manually and with plastering machines PFT G5, PFT G4, PFT Monojet.

The product is produced with constant internal and independent (GOST R certification) control.

Package

The Knauf-Sevener mixture is packed in paper bags of 25 kg.

Storage

Store bags with Knauf-Sevener dry mix in dry rooms on wooden pallets. Dispose of damaged bags and use first.

Shelf life in undamaged packaging is 12 months.

Consumption of materials

Depending on the type of work, the consumption of dry mix per 1 m 2 is:

Foundation preparation

Terms of work

The temperature of the substrate and the surrounding air must be at least +5°C.

Substrate surface preparation

Remove dust from concrete, masonry or old plaster, if necessary by rinsing with high pressure water. Check the old plaster for strength and adhesion to the base. Clean out the potholes and pre-plaster. The surfaces of leveling plasters must be dry before applying the Knauf-Sevener mortar. Strengthen chalked and crumbling surfaces with a Knauf-Tiefengrund primer.

Mortar preparation

Mix the contents of the bag (25 kg) with 5.0 liters of water by hand or using a drill with a mixing 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 water dosage to about 320 l and adjust the consistency of the mortar mixture by increasing or decreasing the water supply.

Protect fresh plaster from frost and rapid drying.

The decorative coating should be applied only after the Knauf-Sevener mortar has hardened and dried.

Before applying the decorative plaster KNAUF-Diamant 260, cover the surface of KNAUF-Sevener with a KNAUF-Isogrund primer.

Application

Cladding with insulating boards Apply Knauf-Sevener Mortar along the perimeter and also in the middle of the insulating board in dots or in a continuous zigzag strip. Strip width - approx. 5 cm, thickness approx. 2 cm. Place the insulation board on the wall and align it. Further work with the plates should be carried out after the mortar has hardened (after 48 hours).

Surface reinforcement of insulating boards:

Apply mortar mixture Knauf-Sevener 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 insulating boards with strips of reinforcing fiberglass mesh measuring 30x50 cm. 10 cm. If necessary, dowels are installed for additional fastening of the plates. Allow the reinforcing layer to harden and dry for 8 days before proceeding with the work. repair mortar

To even out structural irregularities, apply Knauf-Sevener on cleaned or prepared surfaces of old plaster with a layer of up to 10 mm. If necessary, lay a reinforcing mesh.

Thin-layer plaster on concrete: Apply Knauf-Sevener 3-5 mm thick on a dust-free concrete surface and smooth. In the process of setting the mortar mixture, when a certain surface hardness is reached, remove the formed sags. Stucco-bridge

On a smooth surface of concrete, aerated concrete, etc. apply an intermediate connecting plaster layer of Knauf-Sevener with a thickness of up to 10 mm, smooth it over and apply the Knauf-Lup 222 mortar after at least 3 days.

Reinforcing the surface of plasters Apply Knauf-Sevener on the dry layer of plaster over the entire surface with a layer of 3 mm. Lay strips of reinforcing mesh 30x50 cm in size diagonally relative to the corners of all openings. Lay reinforcing fiberglass mesh with an overlap of 10 cm over the entire surface. The next day, once again apply a layer of Knauf-Sevener mixture 2-3 mm thick. After setting the solution, wipe the surface with a felt grater. Additional reinforcement In the case of the manufacture of worn surfaces for painting in the external insulation system, it is necessary to re-apply Knauf-Sevener and lay a fiberglass mesh in it with the joints offset relative to the first layer. After acquiring the required rigidity, apply Knauf-Sevener 2-3 mm thick again on this layer and, upon reaching the appropriate rigidity, process it with a felt or sponge float.

At the end of the work, the tools must be washed immediately with water.

Mechanisms

Plastering machines PFT G5,

PFT G4, PFT Monojet.

Screw pair D4-3.

Rotoquirl stirrer.

Equipment and tools

Plaster mixer (N > 800W)

plastic tank

Stainless steel trowel

Falcon stucco

Rule (h-profile) aluminum

Felt or sponge grater

Notched metal spatula

Metal lattice grater (Rabbo)

System TN-FACADE Decor 1 - outer wall; 2 - hardening primer (if necessary); 3 - glue for heat-insulating plates; 4 - stone wool insulation Technofas Cottage; 5 - dish-shaped facade dowel; 6 - basic plaster-adhesive reinforcing layer; 7 - fiberglass mesh; 8 - quartz primer; 9 - decorative plaster; 10 - facade paint (if necessary). Photo: TECHNONICOL

Most of the major manufacturers of thermal insulation materials and building mixtures offer efficient systems for thermal insulation of building facades. One of the most popular in private housing construction consists of (expanded polystyrene or mineral wool), which are attached to the walls with special glue and dowels. The outer layer of the fixed insulation is first protected with a plaster-adhesive composition reinforced with a special fiberglass mesh, after which a decorative coating is applied.

Living in a house insulated in this way is comfortable. The cost of heating and air conditioning is reduced, and the facade acquires a new original look.

Maintenance-free service life of the system is at least 25 years. In its multilayer construction, there are practically no rigid bonds that could become cold bridges. Heat losses through dowels are so insignificant that they are not taken into account in thermal engineering calculations.

Types of adhesive mixtures

Universal glue

Polyurethane adhesive Fastfix (Penoplex) (pack. 750 ml - 300 rubles). Polyurethane adhesive Ceresit CT 84 (Henkel) (pack 850 ml - 550 rubles). Glue-foam for expanded polystyrene (TECHNONICOL) (pack. 750 ml - 326 rubles). Photo: Penoplex, Henkel, TECHNONICOL

It seems to an inexperienced buyer that mixtures of two types are needed for a facade insulation system. The first is adhesive, for fixing insulation boards on the wall surface. The second is plaster and glue, to create a base layer under. Having studied the assortment, he understands that there are special adhesive and plaster-adhesive mixtures on the market, designed for a specific type of insulation (expanded polystyrene or mineral wool), and universal. If the craftsmen do not have time to complete the construction work with the onset of cold weather, then you will have to use the "winter" modifications of these compositions.

Installation of facade thermal insulation systems begins after completion of internal wet work and drying of the building, as well as installation of window and door blocks.

Works with the plaster-adhesive mixture are carried out at air and base temperatures from 5 to 30 °C. Photo: ShutterStock/Fotodom.ru

Taking into account all the nuances of the construction process, from the unevenness of the base to the timing of the work, and the exact calculation of the amount of consumables seems to be an impossible task. However, leading manufacturers of dry mixes have taken these circumstances into account. In order not to suffer with the choice and calculation of the volume of required dry mixes, they suggest choosing one - universal. In fact, it is glue and plaster rolled into one. The composition equally successfully fixes expanded polystyrene and mineral wool boards to the base and forms a reliable and durable base layer.

How to prepare a mixture

The cement-based plaster-adhesive mixture contains sand of different fractions, reinforcing fibers and polymer additives. The distributed adhesive solution provides sufficient adhesion to the base, and the base layer is strong, resistant to cracking, with good water-repellent properties.

The manufacturer guarantees the useful qualities of the mixture only if it is properly prepared. In a large container (at least 25 liters), pour the amount of clean water at room temperature indicated on the package. Then, the plaster-adhesive composition is gradually added to the water, constantly mixing the mass with a mixer or a drill with a special nozzle so that lumps do not form. Moreover, they act only in this sequence, and not vice versa. Mixer rotation speed should not exceed 400-800 rpm (as recommended on the package), otherwise the mixture may delaminate. After a technological pause (5 min), which is necessary for the maturation of the solution, it is stirred again. If in the course of work it becomes thicker, the consistency is restored by repeated mixing. Do not add water to the mixture.

At the corners of window and door openings, thermal insulation slabs should not form continuous horizontal or vertical joints. In these places, plates with an angular cutout are installed. Moreover, they are positioned so that the joints of the seams with adjacent elements are at a distance of at least 150 mm from the corner of the opening. Photo: Saint-Gobain

Polyurethane adhesive

Polyurethane adhesive in a bottle is an effective means of fastening thermal insulation boards made of extruded and foamed polystyrene foam. The composition has high adhesion to plastered bases, as well as surfaces made of metal, brick, wood, stone and various concretes. Glue in a cylinder does not take up much space, it is easy to deliver to the site. It is convenient and easy to use, does not require any special skills. There are no dusty and dirty preparatory works required when mixing dry plaster-cement mixtures with water. The only limitation is that the insulation material is only polystyrene foam.

The reinforcing mesh should never be laid directly on the thermal insulation layer. It should be inside the plaster-adhesive layer and in the correct position not be visible on its surface.

Compared to dry mixes, bottled adhesives reduce transportation and storage costs, reduce the time and laboriousness of installation work. The material is very economical: one bottle is enough to fix 6–12 m² of slabs. Photo: Henkel

How to apply glue

Cement adhesive mortar is applied to the surface of the insulation boards in different ways, depending on the unevenness of the base. Beacon is used for wall irregularities of 5 mm or more. The mixture is distributed around the perimeter of the plate and laid out with several beacons in the center. Solid is used on surfaces with irregularities up to 5 mm, acting with a notched trowel. In both cases, the surface of the mineral wool insulation is pre-primed with a thin layer of the same adhesive solution. After installing the element, excess glue that goes beyond its contour is removed.

After installing the plate in the design position, the adhesive contact area must be at least 40% of the bonded surface. Photo: KNAUF

To create a protective reinforced layer, the glued insulation is covered with a plaster-adhesive composition 2–3 mm thick. Then the fiberglass cloths are sunk into it and the mixture is again applied up to 3 mm thick, smoothing it so that the mesh is not visible. Surface irregularities are leveled with an abrasive float in a day.