One of the finishing steps for walls is skim coat and putty application. Because they are often used together, skim coat and putty are often treated as the same material, with identical compositions and functions.
In reality, however, these two materials differ significantly. Putty conceals imperfections on walls, such as hairline cracks or holes. Meanwhile, skim coat smooths the wall’s surface and protects it from the elements.
To understand the differences between render and plaster, as well as their compositions, functions, and application methods on walls, read the following article!
What Is Skim Coat?
Skim coat is a layer of material applied after the plaster layer. Red bricks have irregular shapes and surfaces. Additionally, the textured nature of the adhesive mortar tends to make the walls uneven and rough.
Therefore, skim coat is applied as a finishing step after the bricks are installed to level and smooth the wall’s surface.
Applying skim coat also makes the walls denser and harder, giving them greater strength, shock resistance, and resilience against extreme weather.
The plaster mixture is made from a blend of cement (typically Portland cement) and water. You can also mix in additional binding agents, such as gypsum, to create a smoother mixture with a shorter drying time.
To ensure the plaster is properly applied and of good quality, check that the mixture is a consistent dark gray, produces a smooth, fine-pored surface, and is not gritty when applied to the wall.
What Is Wall Putty?
Putty is the final finishing material applied to walls before painting. Putty also ensures the walls are in optimal condition, free of cracks, scratches, and holes, so they are ready for painting.
Due to its composition, putty is generally white, making it suitable as a primer for painting. Putty covers the natural gray color of the cement skim coat and helps the paint look more vibrant, adhere better, and resist peeling.
Putty is made by mixing wood glue, fine chalk or calcium, and water. Typically, the ratio is 1 part wood glue to 2–3 parts fine chalk or calcium, mixed with enough water to form a paste.
Although the preparation process isn't difficult, many instant plaster innovations now only need to be mixed with water before use. Make sure your mixture has a smooth, paste-like texture and no lumps.
Differences Between Skim Coat and Wall Putty
The earlier discussion of skim coat and wall putty outlined the main differences between these two materials. Here are a few additional differences:
|
Skim Coat |
Putty |
|
|
Purpose |
To level and smooth walls |
To conceal wall imperfections |
|
Composition |
Portland cement and water |
Wood glue, calcium, and water |
|
Application |
Applied fairly thickly after the brick wall has been completed |
Applied thinly after the skim coat and before the finish coat of paint |
|
Durability |
Strong and durable, even when exposed to the elements |
Fairly prone to cracking and peeling due to moisture |
|
Appearance |
Rougher surface with a gray color |
Smooth surface with a white color |
How to Apply Skim Coat and Wall Putty
Skim coat and wall putty have different compositions, textures, and intended uses, so their application methods also differ. The process begins with the skim coat, followed by a layer of putty.
How to Apply Skim Coat to Walls
Before applying the skim coat mixture, make sure the surface is free of dust, dirt, and loose plaster fragments. Use a trowel to apply the skim coat, then use a sponge trowel to smooth it out.
Apply the skim coat to a thickness of approximately 1–3 mm and ensure the surface is even. Once the wall is smooth and even, let it dry completely. Protect the wall area from weather and water exposure.
Read also: Understand Differences Between Dry-Mix and Wet-Mix Concrete
How to Apply Wall Putty
Once the skim coat is completely dry and free of dust and debris, you can apply the wall putty. First, apply the wall putty to problem areas such as cracks, holes, or surfaces that need filling.
Once you've addressed all issues, apply the putty to the entire wall surface in a thin layer (skim coat). Then, let the putty dry completely. Before you start painting, sand the wall surface.
Skim coat and wall putty are used together as a wall finish. They complement each other, so you should not choose one over the other. By applying both, you will achieve a wall that is strong, smooth, and even from the skim coat, and neat and clean thanks to the putty.
To maximize the strength and durability of your walls through coating, choose high-quality cement such as Semen Merah Putih Watershield. This cement is not only for coating; it can also be used in various applications, including foundations, concrete slabs, cast-in-place concrete, bricklaying, and plastering.
Semen Merah Putih Watershield is designed to create sturdy, durable, low-maintenance buildings, supported by water-repellent technology that protects against seepage from three sources at once: the outside, the inside, and the ground.
We are ready to help you bring your dream house to life with the best materials and services. Contact us now for a consultation.
Read also: The Right Ratio of Cement and Sand for A Sturdy Building
