How to Skim Coat a Wall in 5 Steps + Mixing Techniques

Skim coating is a process of covering the wall pores, making the wall smoother and neater. Skim coating is important to make the wall ready to be painted or finished. If the mixture or application technique of the plaster is incorrect, the coating can crack or be uneven. In addition, using the right type of cement is also very crucial in making the skim coat strong and durable.

Then, what is a skim coating, and how to skim coat a wall correctly? Read the explanation below to find the answer!

What Is a Skim Coating?

Skim coating is a thin layer made of cement and an additional mixture applied on the wall surface after plastering. This layer aims to smoothen the wall so that it is ready to be painted or finished with another coating. Skim coats not only beautify the wall but also ensure that the finishing is optimal and long-lasting.

Aside from aesthetic purposes, the skim coat protects the wall from humid conditions and fungus. A wall with no skim coating is prone to cracking, flaking, and mold growth; thus, affecting its strength and durability.

The skim coating makes the wall stronger, neater, and protected from various environmental-caused problems. This process is crucial to ensure that the wall is optimally durable.

How to Skim Coat a Wall

There are some steps you must do to skim-coat a wall. Below is a detailed explanation of how to skim coat a wall:

1. Prepare the Materials and Tools

First, you must prepare cement and water as well as tools like a plastering trowel to even the coat, sandpaper to smoothen the dried surface, render float to ensure the wall is flat, and a small basket to mix the cement and water.

2. Clean the Wall Surface

Before skim-coating the wall, you must clean the wall surface of dust, mold, and other dirt. This process is important to make the coating easier and smoother. If you feel like the wall is too dry, you can wet it with water first. This is because a too dry wall can absorb the coating, making it dry faster and prone to cracking. Thus, make sure the wall is damp enough to be coated for maximal results.

3. Make the Coating Mixture

To make a coating mixture, you can prepare 13–15 liters of water and 40 kg of cement with a ratio of 1:3 between water and cement. The size of the coating mixture can be adjusted to your needs. After the ingredients are mixed, stir the mixture with a hand mixer until smooth and no lumps.

4. Skim Coat the Wall

Now that you already have the coating mixture, you can take the plastering trowel and put the mixture on the trowel. Next, you can apply it to the plastered wall. Spread the coating to make it flat. It is recommended to apply the coat to 1–3 mm thickness because the thin coating is prone to cracking.

5. Smoothen with Sandpaper

Once the coating dries, you can smoothen the lumping or uneven part with sandpaper. Note: Sandpaper the uneven part only and not the whole wall.

Sandpapering aims to flatten the hard or sticking out part. You must use smooth sandpaper to prevent damaging the coating. After smoothening it, the coating will be flatter and ready to be finished with paint.

Proper Mixing Techniques for Skim Coating

To skim-coat the wall, you can use several mixing techniques to prevent the wall from cracking. Below are some methods you must pay attention to:

1. Mixture Proportion

To make the coating mixture, you will use two main materials which are cement and water. Both materials must be mixed in a correct proportion to make a maximal result. Usually, the mixture proportion can be seen in the cement package.

The right skim-coating mixture has a balanced consistency which is not too watery or thick. The texture will be as smooth as a paste. Moreover, make sure to use high-quality materials, especially cement.

2. Mixing Process

The mixing process is crucial to prevent the coating from cracking. You can begin by pouring the instant cement into the basket according to the desired amount. Then, add water based on the procedure explained in the cement package. Make sure to mix the cement and water thoroughly with no lump.

Once the mixture is ready, set the mixture for 5–10 minutes rest until becoming more stable. This process gives time for the mixture to be ready to use with maximum results. After being left to rest, the skim coat mixture is ready to be applied to plaster the walls.

3. Adding Additive

To increase the durability of the skim coat so that it does not crack easily, you can add additives to the coating mixture. These additives are usually already contained in instant cement widely sold on the market, so you do not need to bother looking for additional ingredients. Additives function to increase the strength and flexibility of the coating, making it more resistant to environmental factors, such as temperature and humidity that can cause cracks.

By using instant cement containing additives, the coating process will be more perfect, the coating will be stronger, and the risk of damage due to cracked walls can be minimized.

How to Measure Skim Coat

To measure the skim coat materials needed, you can determine the area of the wall by multiplying the length and the width of the wall. Then, you can find out that every meter square requires around 3.25 kg of coating.

For example, if the area of the wall is 20 meters square, the skim-coat mixture would be: 20 m2 x 3.25 kg = 56 kg. Thus, to skim-coat the wall, you need 65 kg of coating mixture. This calculation can be used to calculate the coating requirements according to the area of the wall to be coated.

Those are information about skim coats and how to mix them properly. To get optimal results, it is crucial to use high-quality skim coat materials and mix them according to the right measure.

Regarding this, you can opt for Semen Merah Putih Watershield. This cement has water-repellent technology protecting the concrete structure from damaging water seepage. Semen Merah Putih Watershield is proper for skim coating, casting, and plastering to ensure that the building structure stays strong and durable against extreme weather.

So, to get high-quality and long-lasting results, choose Semen Merah Putih Watershield as the main material. Contact us to get more information and make sure to use the best material for your building!