Decorative plaster

Probably decorative stucco originated in ancient Greece . In part, examples of the first use of the material may be considered some examples of cave paintings . Not all drawings of cave people are made directly on the stone , the basis of some is a layer of clay and sand solution, leveling the surface and providing a convenient overlay of paint. This technique was used later, for example, to create frescoes , later transformed into one of the decoration methods.

In ancient Egypt, a painted textured coating was used to design the interior of the tombs . The seams between the blocks were filled with chalk composition with the addition of organic glue, polished , decorated with drawings, murals or counter-relief (slotted relief). In Mesopotamia , Ancient India and China , lime , clay and gypsum mortars were widely used to give more decorativeness to rough brick and stone walls. Ancient masters experimented with ingredients: added volcanic dust , wine , natural dyes . In India there was a “Pink City”, the walls of the buildings of which were covered with stucco with blood as a pigment .

The ancient Greek philosopher Theofrast was the first to describe recipes and technology for applying decorative plaster. Marble dust was added to the composition, and the surface after application imitated a cut of natural stone, at the same time, due to stone flour, it had greater strength . The new material helped to significantly reduce the load on the building structure , as it was easier to clad in natural stone.

The art of ancient Rome was eclectic , and eclecticism loves to imitate one material with another. Marble stucco that came from Greece was actively used in decorating facades , interiors , and patios . The decoration reproduced the pattern not only of the marble surface, but also of other decoration materials . Unlike stone slabs, she was not afraid of earthquakes - a frequent occurrence in that region. With the advent of concrete , plaster acquired a new pattern: larger particles were added, which allowed creating an expressive relief. Today, the coating has transformed into travertine and other structural plasters.

After the fall of the Roman Empire , its culture disappears, and with it the desire for “embellishment” and decorativeness. The interiors of the European Middle Ages are ascetic, minimalistic, gloomy. Plaster becomes a technical material: goes to putty gaps in the masonry and log houses , covering the filling of half-timbered walls. The most decorative use is similar to the Egyptian: substrate for painting. The revised technology of frescoes (painted with tempera paints on raw plaster) has found application in the modern decoration of walls and facades.

During the Renaissance, art received a new flourishing, samples of ancient Greek and Roman art , including architecture, became available, interest in them was growing. In the XV century, sgraffito technique appears and spreads. Colored plaster is applied in thin (2-5 mm) layers, while the color scheme can differ in layers both slightly and have a sharp contrast . Next, the picture is scratched, fragments of the coating are removed to the desired depth, thus creating a colored relief pattern. During the Late Renaissance (XIV century), the architect Andrea Palladio studied the ancient Roman decorative plaster, experimented with the recipe, and later developed the technology of imitation of natural stone, which was widely used in Venice and became known as “Venetian plaster”.

From there, the application technique, constantly evolving, falls into Europe , where it is actively used in the decoration of palaces and mansions in the Baroque , Rococo , and Classicism styles. To this day, you can see the interiors of that time, decorated with high-quality imitation of natural stone finishes ( marble , jasper , malachite , onyx , amber ), wood paneling.

Modern decorative plaster has incorporated all kinds of historical, national application methods and decoration methods. This is a whole class of materials that allows you to create different in appearance, performance, and finish coatings.

Decorative plasters are divided into the following types ^[1] :

• Colored plaster - ideal for decorating interior walls, door and window openings.
• Stone plaster - resembles masonry made of natural stone.
• Venetian plaster - in its appearance resembles real marble.
• Sgraffito - a type of plaster, which received this name due to the features of the application.
• Terrazite plaster - suitable for interior walls and facades.
• Silk plaster - designed for interior use. Non-combustible, does not accumulate static electricity . The material consists of natural or synthetic fibers , mineral fillers and various decorative additives. It is applied with a plastic spatula to surfaces plastered and coated with a primer or oil paint . It has various colors and textures, has no smell, when applied, a seamless coating is obtained, the material is elastic and does not crack when the walls “shrink”. The main disadvantage is poor moisture resistance, but when treated with moisture-proof varnish, it can also be used in rooms with high humidity ( kitchen , bathroom , etc.).

There are many options for classifying materials.

Depending on the type of binder, there may be:

• mineral;
• acrylic;
• silicone;
• silicate.

A mixture on a mineral binder ( lime , cement ) is environmentally friendly and economical. It is sold in the form of a powder, which is diluted in the right proportion with water before application. The color scheme is not wide, often light colors. The coating is gaining strength over time, it is permissible to use in damp rooms, but is afraid of vibration. Differs in resistance to ultraviolet.

Acrylic binder gives the plasticity of the mixture, which is sold ready to apply. Some compositions are allowed to be painted in bulk with pastes, tinted compositions are found. The mixture is flexible, which allows to achieve various decorative effects. The material is not afraid of water and vibration after drying, sudden changes in temperature, frost-resistant. As a result of exposure to UV rays, it can change color and become covered with cracks. However, the surface is not vapor permeable, therefore it is better to use it not on the entire plane of the walls of the room, but locally, for decorative accents.

Silicone-based decorative plaster is also sold in the form of a finished mixture with a rich color scheme. After drying, it is characterized by high strength, is not even afraid of shock, does not fade in the sun, is moisture and frost resistant , tolerant of temperature extremes. But the use of silicone in the base leads to a rise in the cost of the material.

Silicate is made on the basis of liquid glass. Sales form: dry mix and ready-made pasta. Of decorative plasters, the highest indicators of resistance to mechanical damage in mixtures based on silicates. However, the coating is cracked by vibration. It is not afraid of water, ultraviolet radiation, fire, dirt, and prevents mold . But it has a poor range, does not allow tinting, it is better to use it in the design of facades because of the possibility of releasing toxic compounds .

There are mixtures on a combined binder. So, for example, acrylic-silicone combine the advantages of both types, while compensating for the disadvantages: elastic, resistant to mechanical damage and ultraviolet rays , moisture-proof and vapor-permeable .

According to the size of the filler, the plasters are divided into:

• fine texture
• fine-grained,
• secondary,
• coarse.

The main filler is stone chips, polymer granules of various shapes or acrylic “ chips ”. The appearance of the surface as a result depends on their size. It can be a smooth, polishable surface, or grainy, loose, or even resembling porous sandstone.

Depending on the type of surface obtained, they are divided into:

• structural
• textured
• Venetian.

Structural, as the name implies, has the same characteristics throughout the thickness of the coating. This is usually a ready-to-use dense, granular mixture tinted in bulk. It is applied in a layer up to 1 cm, then a deep relief is created on the surface using spatulas and textured rollers.

Mosaic medium refers to medium and large-structured structural plaster: a mixture of pebbles of different colors on an acrylic binder. Mixtures with a filler are made not of stone chips, but of polymer granules. It is sold in the form of ready-made pasta of a certain range, some manufacturers offer the service of selecting the composition, which allows you to choose the shade necessary for the buyer. They do not require further coloring, they are highly decorative and vandal resistant .

Textured plaster contains small fillers, which allows you to simulate various textures. These are dry mixes, or ready-made pastes, characterized by homogeneity, elasticity. They are painted in bulk, or after drying. A less dense consistency and high elasticity allow you to apply thin (about 1-2 mm) layers, use a variety of tools (not only spatulas and rollers, but also sponges, brushes, stencils, stamps), all kinds of techniques to simulate surfaces. You can create the illusion of a wooden surface, genuine leather, or suede, waves, concrete, textiles, crumpled paper, etc. After application, it requires protection with waxes or varnishes.

Venetian plaster imitates a cut of a natural stone. The fine-texture mixture is supplied both in finished form and in powder form, and is dyed in bulk. The finest layers, depending on the desired effect, are applied in one direction or randomly. As a result of the imposition of translucent layers (up to 9), a unique pattern arises. An additional drawing of the veins is possible. With its help, you can simulate metal. The finished coating is glossy and polished, and then waxed for protection and greater smoothness.

There are various application techniques, the choice depends on the decoration idea.

The relief is created using:

• trowel
• straight and uneven spatulas,
• mastekhin,
• textured and conventional rollers with foam, fur coats,
• stencils
• sponges
• brushes of different stiffness,
• stamps
• materials at hand: e.g. paper, polyethylene, textured leaves,
• hand sculpting.

Depending on the chosen tool and technique, the final coating has a small repeating pattern, or acts as an art object and accent in the interior.

The composition is tinted in bulk or stained after complete stabilization. To paint the finished coating, paints are used (for silicate plaster - silicate , in other cases, water-dispersion). The color additionally emphasizes the relief, which increases decorativeness.

Further decoration is:

• applying glazing compositions;
• applying compositions that give the surface texture ( craquelure , fluorescence , imitation of rough stone, wet surface);
• coating with sheets of gold leaf or silver;
• partial toning of the protruding parts.

If the composition and operating conditions require it, at the end of work the surface is covered with a protective varnish or wax.

The exposed surface of the plaster lends itself to abrasion and scratches. Thin relief protrusions can be chipped off under mechanical action. Wall varnish creates a strong transparent protective film that surrounds the protrusions of the texture, protects the plaster from external influences and gives the surface a matte or mirror finish.

• Stucco in the encyclopedia.
• Types of decorative plaster for interior wall decoration: selection tips and 40 photo examples (Russian) ( HTML ). www.ivd.ru. Date of treatment September 7, 2019.

Normative literature

GOST

• GOST R 55818-2018 // Decorative plaster compositions on a polymer basis for facade heat-insulating composite systems with external plaster layers. Specifications ..
• GOST R 54358-2017 // Decorative stucco compositions on a cement binder for facade heat-insulating composite systems with external stucco layers. Technical conditions

Technical Literature

• Bochkareva T. M. , Zakharov A. V. , Ponomarev A. B. Section 1 “Plaster works”. § 1.3 “Decorative plaster” // Classical and new technologies for finishing coatings / Reviewers: Yuzefovich A.N., Ofrichter V.G. - Textbook. allowance. - Perm : GOU VPO PSTU , 2007. - P. 15-26. - 224 p. - ISBN 978-5-88151-679-6 .