Decorative plaster “bark beetle”: application method, expert advice

Recommendation points

• Classification: purpose and composition
• Foundation preparation
• Mix preparation
• Applying a decorative layer

Decorative coatings with a volumetric texture usually look more attractive than a smooth surface. In addition to the aesthetic properties, practical qualities are also of great importance – the rough texture and complex pattern of chiaroscuro conceal small defects. This type includes plaster “bark beetle”.

Classification: purpose and composition

This type of plaster has a traditional field of application – facade decoration and interior work. The composition of the material largely depends on the specialization.

Finishing of large surfaces with plaster “bark beetle” most often takes place using coarse filler grains. A distinct relief texture and wide grooves look spectacular at a great distance, so this size of the fraction of stone chips is typical for facade plaster mixes.

The fine fraction of the filler leaves fine traces, therefore it is usually included in compositions intended for interior use.

It is the stone chips that give the bark beetle effect – rolling under a trowel while smoothing the surface, it leaves furrows. And the drawing depends on the direction of movement. The main condition is that the grain size in the entire volume of the mixture should be the same and equal to the thickness of the decorative layer (this is another reason that coarse grain is used for facade decoration). The size of the fraction is usually in the range of 1.5-5 mm.

The strength of the plaster depends on the nature of the stone chips and the binder. The softest stone is marble. Its stone chips have relatively low mechanical strength, but good adhesion to mineral and polymer binders. It is more often used in compositions for interior decoration..

Quartz and granite chips have medium adhesion to binders, but their strength is one of the highest among natural finishing materials (equal to 7 and 6 points on the Mohs scale, respectively). Therefore, they are more often used for facade plaster “bark beetle”.

In terms of binding materials, these building compounds do not differ from ordinary plaster: mineral, polymer-cement, polymer (acrylic, styrene-acrylic, styrene-butadiene, silicone), silicate, etc..

It is mineral plasters and mixtures based on acrylic binders that are most widely used. First of all, due to the availability and fairly high performance properties.

Foundation preparation

Despite the masking properties of the “bark beetle” plaster, it must be applied to the prepared surface.

Important! In order for the crumb to roll in a uniform top layer in thickness, the base must be even..

This can be achieved in several ways:

• base leveling layer of ordinary plaster (spray plus primer);
• walls pre-leveled with plasterboard or dry plaster;
• plastered walls and partitions made of aerated concrete blocks, tongue-and-groove gypsum blocks or gypsum plasterboard structures.

Advice.Before leveling, the surface of the wall must be inspected. Fill cracks, find out the reason for their appearance and, if necessary, strengthen with special compounds (so that they do not expand).

If there are foci of infection by fungus and mold, treat these areas. Remove crumbling areas of old plaster to the base.

If the walls were painted, then before leveling with a base layer of plaster, the paint must be cleaned, making the surface rough.

Mix preparation

Some manufacturers offer ready-to-use solutions tinted in bulk.

Important! The solution colored at the production stage in different batches will always have a different shade. This also applies to any paints, pigments and finishing materials (wallpaper, tiles, etc.). But it is also impossible to mix several cans of the finished mixture in one container (there are restrictions on the time of use).

Advice.For finishing large surfaces, experts recommend choosing dry white mixtures. Prepare them before use, and paint the entire surface at the final stage of finishing. And do it as expected, in three stages: primer plus two coats of paint.

In principle, it is possible to make do-it-yourself plaster “bark beetle”. There are at least two main ways:

1. Based on ready-made dry mixes of finishing plaster, adding screenings or stone chips of a certain size to them.
2. Take any suitable formulation of mineral improved plaster. Prepare it by mixing individual ingredients and stone chips with a calibrated fraction.

Applying a decorative layer

In terms of time, the application method itself is traditional – it is necessary to process the entire surface of the wall in one step. And this is at least from corner to corner or in the intervals between other clear boundaries with complex finishing with different materials.

Therefore, professionals advise to work together: the first applies the solution, the second evens the layer to the thickness of the fraction caliber.

Then, when the plaster has set a little and does not stick so much, one creates a pattern on the surface with a plastic scraper, the other prepares a new portion of the solution.

The direction and nature of the movement of the scraper is set by the drawing. It can be chaotic or circular movements, a wave, horizontal or vertical lines. Some craftsmen prefer uniform alternations of approximately the same sections or stripes..

Advice.In addition to painting the entire volumetric surface with a long-nap roller, the method of applying a finishing layer of paint of a different color with a semi-dry short-nap roller is practiced. This method emphasizes the texture of the “bark beetle”, creating an original two-color pattern.