Concrete Cosmetics

Performing Repairs on Concrete Surfaces

When it comes time to repair concrete surfaces, specialized spackling compounds for cosmetic corrections become essential on every construction site and in prefabrication plants.

The use of spackles for concrete cosmetic work is not dependent on the class of concrete. Even high-quality exposed concrete surfaces may require precise corrections, such as when the natural raw materials used result in color differences in the concrete.

Over time, specialists in concrete cosmetics develop their own methods for carrying out cosmetic work. Since concrete cosmetic tasks vary widely, the tools used can also differ depending on the specific situation and requirements. It is important to understand that selecting the right tools and techniques is crucial to achieving the desired results when repairing concrete surfaces.

What to Use for Concrete Cosmetics?

Concrete spackles are invaluable tools for transforming defective surfaces into flawless exposed concrete. Defects such as chips, cracks, pores, shrinkage cavities, color differences, or stains can be easily and quickly turned into high-quality surfaces.

MC Concrete Cosmetics Spackle Range

The MC range of concrete cosmetic spackles includes two broad groups of products with various properties and colors. These spackles are characterized by:

• Optimal adhesion to concrete surfaces: Ensures the spackle firmly adheres to the substrate, creating a durable and aesthetic layer.
• Easy application: Simplifies the process of making cosmetic corrections.
• Resistance to frost and UV radiation: Maintains quality even under harsh weather conditions.
• Usability in extreme weather conditions: With appropriate additives, the spackles remain effective in the most challenging environments.

Color Range and Customization

The color palette of cosmetic spackles is comprehensive, and mixing different shades allows for achieving the desired tone. Additionally, with special additives, it is possible to create custom colors, offering flexibility in adapting spackles to specific concrete cosmetic projects. These spackles are indispensable for improving the appearance and quality of concrete surfaces.

MC-Powertop G

A coarse-grained spackle with extended workability time:

• Application temperature: From +15°C to +35°C.
• Suitable for small surfaces.
• Superficial corrective work: Ideal for minor surface adjustments.
• Repairs chips, edge damage, and similar defects.

MC-Powertop F

A fine-grained spackle with extended workability time, designed for precision work on high-quality exposed concrete surfaces:

• Application temperature: From +15°C to +35°C.
• Surface spackling: Ideal for small pores, shrinkage cavities, and cracks.
• Precise surface finishing: Ensures smooth and polished results for premium-quality exposed concrete.

MC-Powertop F Fine

A very fine-grained spackle for precision finishing of high-quality exposed concrete surfaces:

• Surface spackling: Ideal for addressing small pores, shrinkage cavities, and cracks.
• Precise surface finishing: Ensures flawless results on premium exposed concrete.

Application

Coarse-grained fillers are applied with a trowel and then spread using a steel float. The easiest and most precise application is achieved with the use of a rubber float.

When performing cosmetic work on concrete, it is recommended to wear protective glasses and gloves.

Smoothing

To achieve a thin and smooth surface, the filler should be smoothed with the MC-Top Sponge, which is dual-sided. Moisten the sponge with a small amount of water and wring it out thoroughly. Excess water can cause discoloration or smearing of the filler.

Curing

To achieve a perfect surface, freshly applied filler should be protected from rapid drying caused by sunlight, wind, or other atmospheric influences. Special attention should be given to protecting the surface from rain for at least 7 days.

Fine-Grain Spackling for Small Areas

Filling Pores and Shrinkage Cavities

The substrate should be slightly moistened as described earlier. MC-Powertop F filler is perfect for filling even the smallest pores and shrinkage cavities. A rubber float is ideal for applying the filler.

Fine-Grain Spackling for Large Areas

Surface Finishing

MC-Powertop F filler is used not only for smoothing and repairing concrete surfaces but also primarily for finishing large surfaces and leveling color differences.

For an even smoother surface, it is recommended to use the very fine-grained filler MC-Powertop F fine. Alternatively, the MC-Quicktop filler can also be used for smoothing.

To achieve optimal surface finishes when working with fine-grained fillers, the surface should be wiped with the MC-Top Sponge. This will result in even smoother and more aesthetically pleasing surfaces.

For dusty or insufficiently load-bearing substrates, it is advisable to use the primer MC-Estrifan Grund T 15. Apply the material in a single layer, or for very absorbent substrates, in multiple layers using a roller. After priming, you can proceed with the filling process.

Coarse-Grain Spackling for Small Areas

Filling Bug Holes by Trimming Excess Filler with a Trowel

The original contours of concrete elements can be restored by trimming the excess filler with a trowel. Ensure that the filler is slightly set before cutting.

Filling Holes and Anchor Points

Anchor holes should be pre-wetted before being filled with the mixed filler MC-Powertop G. Excess material should be trimmed with a trowel for a smooth finish.

Color and Texture Matching with Fine-Grained Fillers

For slightly dried concrete surfaces, fine-grained fillers can be used to optimally match the color and texture to the original concrete.

Coarse-Grain Spackling for Large Areas

Leveling Surfaces with Fiber-Reinforced Fillers

The mixed MC-Top Primer bonding layer should be carefully rubbed into the pre-wetted surface. A wide brush is ideal for this purpose. MC-Powertop G extra filler is applied to the fresh, matte-damp bonding layer.

• Application Thickness:
  • Single layer: 5 to 25 mm.
  • Double layer: Up to 50 mm.

Advantages of Fiber-Reinforced Fillers

Fillers such as MC-Powertop G extra and MC-Powertop G ultra are reinforced with special fibers, making them ideal for leveling large surfaces effectively and ensuring durability.

MC-Powertop G ultra Application

MC-Powertop G ultra is applied directly to a matte-damp substrate without the need for a bonding layer.

• Application Thickness:
  • Single layer: 6 to 40 mm.
  • Double layer: Up to 80 mm.

For a second layer:

• Apply directly if the first layer is partially set.
• If the first layer is fully dried, apply the MC-Top Primer bonding layer before adding the second layer.

Filling Gaps Between Prefabricated Elements

Filling Gaps

MC-Quicktop Uni is applied using a trowel or spatula in a layer up to 20 mm thick onto a dampened gap between prefabricated elements. Leave a slight excess of the filler and smooth it while still fresh.

• For a wallpaper-ready joint:
  Wait for the filler to set, then trim the excess with a trowel.
  Lightly sponge the filled gap with a damp MC-Top Sponge to ensure a smooth finish.
• Optional Additive:
  By adding a synthetic additive like Repacryl to the mixing water, you can significantly enhance the adhesion of the filler to the substrate.

Applying Cosmetic Slurry

Slurry Application

Pipe joints should be dampened and then coated with a slurry applied using the MC-Top Sponge. The slurry is prepared by mixing the synthetic additive Repacryl with MC-Quicktop filler.

Filling Corner Cavities (Without Load Bearing)

Bonding Layer and Application of Coarse-Grained Fillers

1. Bonding Layer
   Apply MC-Top Primer as a bonding layer to a damp, matte surface.
2. Filler Application
   While the bonding layer is still fresh, apply MC-Powertop G filler with a slight excess. This method is also effective for re-profiling damaged corners and edges.

   Trimming Corners

   The contours of concrete elements can be easily shaped by trimming the excess slightly hardened filler. Use a trowel or appropriate cutting tool to refine the edges and achieve the desired profile.

Reprofiling with Fine-Grained Fillers

1. Application of Fine-Grained Filler
   To achieve the quality of fair-faced concrete, apply a layer of fine-grained filler MC-Powertop F or MC-Quicktop on the slightly dried coarse-grained filler.
2. Smoothing the Surface
   For a smooth finish, lightly wipe the filler surface with an MC-Top Sponge.

Filling Corner Cavities (With Load Bearing)

Grinding

1. Early Grinding Capability
   Due to the very high initial strength of Reparoxyd SB/WG mortar, the surface can be ground just 30 minutes after application.
2. Adjusting Consistency
   By reducing the liquid components, Reparoxyd SB/WG mortar can be prepared in a consistency suitable for troweling.

Concrete Retouching on Spackled Surfaces

Concrete Retouching on Spackled Surfaces

1. Preparation
   Retouching is possible only after the fine-grained spackle has completely dried. First, mix the Repacryl hellgrau synthetic additive with water and spread it on the surface using a natural sponge.
2. Adjusting the Mixture
   Depending on the substrate, darken the mixture for each subsequent retouching step by adding Repacryl lichtgrau or betongrau.
3. Final Step of Retouching
   By adding MC-Powertop F fine spackle to the Repacryl-water mixture, you can reduce gloss. Gentle polishing provides an aesthetically uniform appearance to the concrete surface.

Concrete Retouching on Non-Spackled Surfaces

Retouching on non-spackled surfaces can also be performed as described above.

Concrete Retouching on Surfaces Exposed to External Factors

1. Hydrophobic Protection
   Once the retouch layer has completely dried, coat the surface with a hydrophobic agent, such as Nisiwa C, Nisiwa SN, Nisiwa L, or MC-Color Proof.
2. Ensuring Uniform Absorption
   Apply the hydrophobic layer over the entire sections of the surface to equalize absorption and protect the surface against external influences.

Joining Construction Elements with SX 481 E Spackle

Substrate Inspection

Before applying SX 481 E spackle, the substrate parameters must be checked.

• Tensile strength: Minimum of 1.5 MPa.
• Residual moisture: Must not exceed 4%.

Substrate Preparation

The substrate must meet the following requirements:

• Clean: Free from dust, grease, and any other materials that could hinder adhesion.
• Dry: Ensure no residual dampness remains.
• Stable: Must be load-bearing and free from loose elements.