How to plaster a wall with cement plaster

Introduction

Cement plaster is most often used for rendering walls, even when there are multiple alternatives these days for facades. It’s for decorative purposes as old brick and concrete walls can be quite uneven, and some could be described as plain ugly. This traditional method of wall finishing serves both functional and aesthetic purposes, making it a popular choice in construction and renovation projects.

In addition to its decorative appeal, cement plaster offers various practical benefits. It can help with insulation, soundproofing, and moisture resistance, which are essential factors in both residential and commercial buildings. Understanding the versatility and advantages of cement plaster can empower homeowners and builders to make informed decisions regarding their wall finishes.

With cement plastering, you can level the walls a couple of inches with no problem; you need a few layers for that to work out. This layering process allows for adjustments in height and smoothness, making it easier to achieve a professional finish.

Before you begin, you need to decide on the product. Traditionally a sand and cement mix can be used or ready-made mixes from the hardware stores. I think ready-made is easier to use, but you can compare prices and estimate how much time it takes to make your mix. Opting for a ready-mix can save time and ensure consistency in your application, which is crucial for achieving a uniform finish.

Should you use a ready mix or mix the cement to the sand ratio for plaster yourself?

Cement plaster can be made by mixing the cement to the sand ratio for plaster with a shovel or by buying a ready-mixed bag where you add the right amount of water. Understanding the differences between these two approaches can influence your project’s outcome significantly.

For plaster, the cement-to-sand ratio could be something like 1:5. For rendering purposes, the scratch coat is harder, so it can be 1:3, then 1:4 for filling and 1:5 for the rendering layer. The idea is that the surface layer is the softest. This balance is essential for ensuring that the plaster adheres well and performs effectively over time. The proper mix not only affects the strength of the plaster but also how it behaves during application and curing.

So it will be harder if there is a lot of cement compared to sand. For plastering or rendering, you don’t want it to be too hard. Finding the right balance is a fundamental skill in plastering, as it can determine the longevity and appearance of the finish.

I’ve done outdoor rendering with a shovel, sand, cement, and a concrete mixer, and I’ve done it with ready mixes. I much prefer the ready-made ones, to be honest. The convenience of ready-mixed options not only makes the job easier but can also enhance the quality of the finished product.

If you work alone, it saves you some time. Working solo can be challenging, especially when handling heavy materials, so any time-saving methods are beneficial.

Whether you make the plaster mix yourself or use ready-made cement plastering bag mix like polymer and fiber modified, this article is for you. Before I moved up in my career, I used to do these a bit, so I decided to put up a short guide. It’s helpful to share personal experiences and insights, as they can provide valuable context for those new to plastering.

You can also cement interior plaster walls like you would be rendering outside. It’s not often preferred as sand is hard, and most want to work with more straightforward-to-handle products inside. However, cement plaster can offer a durable and aesthetically pleasing finish that can elevate the interior of any home.

But if you know your game, you can make durable decorative walls. Having the right knowledge and skills can transform the plastering process into a rewarding endeavor, leaving you with walls that not only look good but also stand the test of time.

If you’re considering alternatives to plastering a wall, there are also drywalls and other boards for exteriors, like cement boards. If you’re looking for how to smooth a wall without plastering or an alternative to plastering a ceiling, these can work out too. Each option has its own benefits and drawbacks, so weighing them carefully is crucial to achieving the desired results.

Now, to move on to cement plastering, or rendering, in other words. Understanding the following steps will help you gain confidence in your plastering abilities, ensuring a successful project outcome.

How to cement plaster a wall

Cement plastering a wall is a simple process, so it’s pretty easy to break into steps. By following a systematic approach, you can achieve a professional finish with minimal hassle.

We prepare the wall
Mix the plastering cement
Work out the number of layers
Finish the surface

How to prepare a wall for plastering

So how do we prepare a wall for cement plaster? Well, with no jokes in mind, it depends on the wall and what kind of surface it has. Proper preparation is key to ensuring that the plaster adheres well and that the finished surface looks smooth and professional.

Plastering old walls is a form of art. If it’s indoors, the walls will be only as hard as the surface they adhere to. Assessing the condition of the wall will help you determine the necessary steps for preparation.

It’s more than likely your surface is bricks or concrete, so if there is no paint, a brick surface is most often ready to go. With concrete, the cement glue on the surface of the concrete might need to be removed if it’s not done already. Cleaning the surface thoroughly will enhance adhesion, resulting in a more durable plaster finish.

Suppose your wall has old rendering/plastering. In that case, I’d most likely remove it and clean the surface with a power washer if you’re working outside or an industrial vacuum cleaner if working inside. This step is vital to ensure that any debris or loose material does not interfere with the new application.

That will remove the dust from the surface pores, making the cement a suitable ground to adhere to. We must remember that cement is the glue that holds everything together; if it can’t adhere to the surface, you’re wasting time and money, and we don’t like that. Consistent results depend on meticulous preparation.

Here is a guide for removing plaster from those surfaces. This guide provides detailed instructions for effectively stripping old plaster, ensuring a clean and suitable substrate for new plastering.

Plaster cement and how it is made

This part is as essential as doing the groundwork for the plastering. Understanding the composition of your plaster mix is crucial for achieving the desired results.

Cement plaster mix is made out of sand, cement, and water to simplify it. That’s why it’s usable both inside and outside, and it’s durable against the weather. Once it cures, it makes a tough surface. This durability is especially important for external applications, where weather conditions can take a toll on the material.

Like when mixing concrete, it’s essential to use clean water, sand, and cement. If the ingredients are not pure, it will produce a weaker mix. Using high-quality materials will contribute to the overall strength and integrity of the plaster.

Also, you can’t mix more water when the mix starts to cure. The cement to water ratio will weaken, and you will have significantly weaker parts in your wall. This is a common mistake that can lead to cracks and failures in the plaster over time.

I like to think of the wall as almost like a living being. If there are parts that are greatly different, it’s more than likely the first part to crack. After that, water gets in, and erosion begins. Regular maintenance and monitoring can help prevent these issues from escalating.

The cement-plaster mix ratio can be different from one surface to another. If you do it yourself, 1:4-5 cement to sand will do it for bricks as it’s close to mortar mix, and 1:4 would be for outdoor work. The less cement you have, the softer it will be. Adjusting the ratios based on the specific needs of your project will yield the best results.

For me, it has been infrequent to mix it myself. Only building facades that are done traditionally have been done like that. Most of the time, the render mix has been delivered on ready-mixed bags. That’s also the easiest to get for households. The convenience of ready-mixed options cannot be overstated, especially for DIY enthusiasts.

Cement plaster is a surface I’d not be sanding, which is out of the picture in this guide. So let us move on to how to plaster a wall with sand and cement then. It’s essential to follow the correct application techniques to ensure a long-lasting finish.

Cement plastering work can be done indoors and outdoors

How to apply the cement plastering

Cement plastering work is different from plastering in a way that the wall will have to be good when you do the final layer. I mean, you have to get the surface level and smooth. Achieving a flawless finish requires attention to detail and patience.

So it involves spreading the cement plaster and using the float to make it smoother. The right technique can greatly influence the final appearance of the plaster.

For thin plastering/rendering, you can do only 2 layers. For a wall that needs a thicker layer, 3 layers might be needed. Understanding the requirements of your specific project will help you determine the appropriate number of layers.

Cement plaster for the scratch coat

This is the coat made with the hardest mix. 1:3 or something close to that. The scratch coat serves as the foundation for the subsequent layers, ensuring that they adhere properly and maintain structural integrity.

It has more cement, so it’s harder but, on the other hand, adheres better on the surface. We leave it rough surface because we want the second layer to adhere well to it. Creating a textured surface allows for a stronger bond between the layers.

It should not be “higher” than the intended surface of the finished product. Careful application during this stage is crucial to avoid unnecessary adjustments later on.

So high points we flat out with our chosen tool like a trowel. There are tools like a stucco sprayer that can make this part easier. Using the appropriate tools can significantly improve the efficiency and quality of your work.

Professional tools are quite expensive, so think about renting as an option. Renting tools can be a cost-effective solution for DIY enthusiasts who may not need them for regular use. Old school workers used to throw this layer into the wall, but most people lacked that skill. Learning the right techniques is essential for achieving professional results.

Cement plaster for the second coat

This is the coat that makes the wall level. It’s also more difficult to achieve, so the steps are below. If precision is not maintained, the final appearance of the wall may be compromised.

With big walls, we choose a high and low point from the side of the wall.
Then we use a plumb bob or another tool to check how straight the wall is. You can even use a spirit level if the wall is small enough.
For the high and low points, we make a small patch of plaster to the level we want the second coat to be.
Repeat this process with the width of the tool you use to screed.
Let the patches be until the next day.
Fill the space between the high and low patch points with plaster.
Level it vertically in between patches.
Let it be until the next day.
Use those vertical plaster benches to fill the in-betweens and screed them with your chosen tool.
Use a big wooden or plastic float and float the surface with a circling motion.
Water the surface for three days for the cement to cure as hard as possible.

First, do the patches to the wanted surface level, and screed vertically to get a vertical guiding bench. After you have as many of these as you need, do the middle parts screening horizontally. Unlike the picture, there should be no gaps in the result as it should be a level surface.

Cement plaster for the finish

The floated cement plaster wall finish can be done in multiple ways. If you want texture, go wild and do it with different methods, like spraying with a hopper gun or making marks with a notched trowel. Experimenting with textures can add personality to your walls and make them unique.

If you want it smooth, you need to float it. You can’t float the cement plaster straight when you spread it; it needs to start to cure a bit. Timing is critical during this phase to ensure a smooth finish.

When you can touch it without leaving deep finger marks, or it starts to turn grey, it’s time to take a hard wooden float and start circles with it on the wall. This technique can create a polished look that enhances the overall aesthetic of the plastered surface.

If the cement plaster starts to roll with the float, it’s too soon. You should be able to press it gently while you float without it rolling with a wooden or plastic float. Patience during this stage will pay off in the form of a flawless finish.

Other floats work the same, but you might need to water the wall or ceiling with something like a pump sprayer/garden sprayer to get the surface moist for floating. Keeping the surface damp is vital for achieving the best results during the finishing process.

How to plaster a damaged wall for minor fixes

Now, this is included for those that need to do minor fixing. Repairing damaged walls can be a straightforward process if approached correctly.

How to plaster a hole in the wall? If the hole is big, you don’t. You get a rough patching compound or make it whole like it was built. Assessing the damage accurately will help you determine the best repair method.

The fix must be close to the hardness of the surrounding wall. If the patch is made with too hard a compound, it will crack and pop off the surface. Ensuring that your repair materials match the existing wall’s properties is crucial for long-term success.

For small holes, everything goes. Small repairs can often be handled with ease, especially if you have the right materials on hand.

You can’t do fine plastering before you fix the damage on your wall. Small and big holes will need to be fixed with cement compounds made for that purpose, like polymer fiber cement mixes if it’s concrete. Choosing the right repair material is essential for achieving a seamless finish.

If it’s a brick wall, get some bricks and mortar for big holes. Try to fix it so that it’s level with the rest of the bricks, so you don’t need to grind it level. Proper alignment during repairs will minimize the amount of finishing required later.

When you’re done with the fixes, it’s like plastering any of the following walls. Here is also a guide on fixing holes in plaster walls. This guide will provide you with step-by-step instructions for addressing various types of wall damage effectively.

Additional Tips for Successful Cement Plastering

In addition to the steps outlined above, here are some extra tips to ensure your cement plastering project is a success:

Weather Conditions: Before starting your project, check the weather. Avoid plastering in extreme temperatures or during rainy conditions, as they can affect the curing process.
Safety Precautions: Always wear protective gear, including gloves, goggles, and a mask, to protect yourself from dust and debris.
Practice Patience: Rushing the process can lead to mistakes. Allow ample time for each layer to cure before applying the next.
Seek Help When Needed: If you’re unsure about any part of the plastering process, don’t hesitate to consult with professionals or seek guidance from experienced individuals.
Finishing Touches: After achieving your desired plaster finish, consider applying a sealant to enhance durability and resistance to moisture.

By incorporating these tips and following the guidance provided in this article, you can achieve a beautiful and long-lasting cement plaster finish that enhances the overall appearance and functionality of your walls.

Conclusion

I hope this clears up how to plaster a wall with cement plaster. The ceilings work the same way; you have to work upwards. Ensuring that you follow the proper techniques will make the process more manageable and yield better results.

I like working with the polymer fiber cement renders as they can fill a bit, don’t crack that easily because of the fiber, and make a fine-looking floated surface. These modern materials can enhance the quality of your work and provide additional benefits over traditional methods.

Other mixes work as well; good workers won’t blame the product but update their skills to match them. Continuous learning and adaptation in the field can lead to impressive results and a more fulfilling plastering experience.