7 Tips to Prevent Air Bubbles in Skim Coat

Ⅰ. Introduction

Skim coating is a popular technique to achieve smooth and flawless surfaces in interior wall finishing. However, one common challenge we face is forming air bubbles in the skim coat. In this article, we will share with you all the practical tips and effective techniques to successfully prevent the formation of air bubbles. So as to attain a smooth, bubble-free result for a truly professional appearance.


II. Skim coat applications

In many construction and repair projects, skim coats are frequently used to produce smooth, level, and visually acceptable surfaces. Skim coats are most frequently used for the following purposes:


1. Wall Finishing.

Skim coat is frequently used to finish walls, mainly concrete or plasterboard. It creates a smooth surface by hiding flaws, seams, or textural differences. The walls are prepared for painting, wallpapering, or other decorative treatments with skim coating.







2. Ceiling Repair and Refinishing.

Skim coat is frequently used to fix or cover surface flaws on ceilings, such as cracks or unevenness. It gives the ceiling a fresh, completed appearance and aids in restoring its appearance. Skim coating can also cover ceilings with texture for a sleek, contemporary look.





3. Surface Leveling and Smoothing.

When surfaces like concrete walls, floors, or countertops are damaged or uneven, a skim coat is applied to level and smooth them out. Removing flaws, roughness, or undulations helps create a level foundation for other treatments or installations.


4. Repairing Surface Imperfections.

Skim coat is a highly effective method for addressing and rectifying surface flaws, such as dents, scratches, or holes in walls or ceilings. The process involves the application of a thin layer of skim coat, which effectively fills these imperfections and delivers a seamless, polished surface that reinstates the affected area’s visual appeal and structural integrity.


5. Preparing Substrates for Tile or Flooring.

To prepare substrates, like concrete or plywood, for the installation of tile or flooring materials, a skim coat is utilized. It ensures the surface is level and smooth, improving the adhesion and functionality of the tile or flooring materials.





III. How to apply skim coat properly

To prevent air bubbles in skim coat application, follow these essential tips:


1. Prepare the surface.

Before applying the wall surface, you need to ensure it’s clean and dry. And all the previous coatings are removed. If there are any cracks or imperfections, it needs to be filled or fixed. A clean and well-prepared surface is the foundation for a smooth skim coat application.


2. Use the right tools and materials.

Invest in a quality tool and choose high-quality skim coat cement. That’s the precondition for a skim coat compound with good flow and self-levelling properties. Besides that, use a steel trowel with a rounded edge for smoothness and even spreading.





3. Mix the skim coat properly.

Follow the manufacturer’s guidelines to mix and prepare the skim coat compound. Do not over-mixing as additional air may bring in during mixing. Leave the ready-mixed compound for a few minutes before applying. It allows the remaining bubbles to rise to the surface.


4. Apply in thin layers only.

The mixture may still contain air bubbles hidden inside it. To minimize the risk, applying to skim coat in a thin and even layer is recommended. A thickness of 0.15cm to 0.3cm, preferably. Do not apply thick layers, as it entraps air and leads to uneven drying. Maintain a consistent pressure and angle to achieve an even application.


5. Eliminate air pockets.

During the skim coat application process, if you notice any air pockets or air bubbles. Use the trowel to push it out slowly and gently toward the edges. This approach ensures a bubble-free surface.


6. Minimize airflow.

During the skim coat drying process, minimize airflow in the room. Keep doors and windows closed, as air draft may disrupt the skim coat and cause air bubbles formation. Maintain the environment with stable humidity and temperature levels.


7. Sanding and finishing.

Once the skim coat is dry, double-check the surface for any remaining imperfections or bubbles. Sanding gently with fine-grit sandpaper to smooth out the surface. After that, apply an additional layer of skim coat if necessary; follow the same procedures.


Following these precautions can help you greatly reduce air bubbles in skim coat applications, resulting in a polished and professional finish.





IV. Advantages and disadvantages of skim coat

1. Advantages of Skim Coat


-Surface Improvement.

Skim coat is a technique to achieve a refined and visually appealing surface by concealing flaws, cracks, and uneven textures. It achieves a polished and professional look on walls and ceilings.



Skim coats can be applied to various surfaces, such as drywall, plasterboard, concrete, or wood. It is compatible with various materials. And it can be used for interior and exterior applications.



The skim coat provides a cost-effective solution compared to more extensive repairs or replacements. It enables the repair and enhancement of surfaces instead of full-scale renovation. And result in significant savings of both time and resources.


-Compatibility with Further Treatments.

A skim coat is a good foundation for future treatments like painting, wallpapering, or tiles. It improves the performance and adherence of subsequently applied coatings or coverings.



Skim coating takes only a short time, especially for small to medium-sized areas. Compared to more time-consuming alternatives, it may be applied effectively and dries reasonably quickly, allowing for quicker project completion.






2. Disadvantages of Skim Coat


Skill and Experience Required.

Skill and experience are necessary to produce a flawless skim coat finish. It can be difficult for beginners to use the correct application techniques. For example, managing thickness, removing air bubbles, and getting even coverage.



Skim coating can be time-consuming, especially when vast areas or significant surface repairs are involved. Surface preparation, application, and finishing procedures require meticulous attention to detail.


Drying and Curing Time.

Before further treatments or finishes can be applied, the skim coat needs enough time to dry and cure. This may extend the project’s completion date, particularly if more layers or repairs are required.


Limited Thickness.

The average thickness of a skim coat application is between 0.15cm and 0.3cm. It can not level significant imperfections or make extensive surface adjustments. Alternative techniques can be more suitable for large-scale repairs or significant levelling.


Potential for Surface Imperfections.

Even after meticulous application, skim coats might still have minor flaws like tiny bubbles, trowel marks, or microscopic texture variances. Some flaws can require more touch-ups or moderate sanding to get a flawless finish.



V. WOTAIchem High-quality Skim Coat Additives


Choosing high-quality skim coat additives ensures a smooth and flawless result. At WOTAIchem, our modified formulas help you to eliminate bubbles during the early stages of application.


Our cellulose ethers(HPMC/MHEC/HEC) are highly effective in improving your skim coat’s workability. They act as thickening agents, enhancing the consistency and adhesion of the skim coat to the substrate.



Additionally, our re-dispersible polymer powders are indispensable for enhancing the mechanical properties of the skim coat. By adding RDP powder, you improve strength, flexibility, and durability. Ensuring a long-lasting finish.


Last but not least, our defoamers prevent the formation of bubbles and foam during the application process. These additives reduce surface tension, allowing for a smooth, bubble-free skim coat.



You can trust WOTAIchem to provide the best solutions for all your skim coat applications. Contact WOTAIchem for highly quality construction additives today!

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Posted by Isabel

Hi, I've been in this industry for five years. I hope you enjoyed my blog. Welcome to leave a comment down below.

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