How to Plaster a Wall – An In-depth Guide for Beginners

If you want to know how to plaster a wall, this article is for you.

Plastering is a key finishing process in any building construction or renovation. It plays a vital role in creating a smooth, hard surface on the interior and exterior walls and ceilings, preparing them for decoration. 

This process not only enhances the aesthetics of your home but also provides benefits such as improved insulation, soundproofing, and fire resistance. 

Proper plastering can also protect the structural integrity of your home by preventing dampness and other environmental damages.

Understanding the need for skills in plastering for a DIYer

Plastering might seem a simple and straightforward task, but it’s an art that requires precision, patience, and practice. 

For the DIY enthusiast, learning to plaster can be a cost-effective skill to have, saving you from hiring professional plasterers for minor repair or renovation works. 

However, keep in mind that it’s not just about slapping some plaster onto a wall. Achieving a smooth, even finish involves mastering the correct technique, understanding the materials you’re working with, and knowing how to troubleshoot common issues. 

It’s a skill that could elevate your DIY capabilities to a new level, giving you more control over your home improvement projects.

Plastering for beginners

This guide aims to provide beginners with an accessible entry point into the world of plastering. We will break down each step of the process, from choosing the right plastering tools and materials, to preparing your wall and applying the plaster. 

We’ll also discuss some common mistakes to avoid and provide tips to help you achieve a professional finish. However, it’s important to note that this guide is a starting point. Mastering the art of plastering takes time and practice, so don’t be discouraged if your initial attempts aren’t perfect. 

Essential Tools and Materials for Plastering

For a successful plastering job, you’ll need a collection of specific tools. These include:

Plastering Trowel

This is your primary tool for applying and smoothing plaster. They come in various sizes, but a 11 to 13-inch trowel is a good starting point for beginners.

Bucket Trowel

A smaller, square-edged tool, the bucket trowel helps you mix the plaster and scoop it out of the mixing bucket.

Mixing Bucket

A large, robust bucket is necessary to mix your plaster. It should be clean and free from any residual materials that could interfere with the plaster mixture.

Plasterer’s Hawk

This handheld tool is used for holding a portion of plaster before applying it to the wall with the trowel. It’s like a portable palette for your plaster.

Plastering Float

A smaller flat tool used for applying the first base layer of plaster.

Straight Edge

A long, flat piece of metal used to ensure the plastering is flat and level.

Corner Trowel

A handy tool for getting neat finishes around corners and angles.

Investing in high-quality tools can make the plastering process easier and contribute to a better finish.

Introduction to types of plaster

There are several types of plaster, but for beginners, we recommend starting with a multi-finish plaster, such as British Gypsum Thistle MultiFinish. This versatile plaster is suitable for use on a wide range of backgrounds, making it ideal for most plastering projects. It is easy to work with and provides a high-quality, smooth finish.

If you’re working on a larger area or a full room, you might consider using a backing plaster first (like British Gypsum Thistle HardWall) before applying a finishing plaster. 

It’s important to understand the specific instructions and drying times for the plaster you’re using, as these can vary between products.

Safety equipment

Your safety is paramount when undertaking any DIY task, including plastering. Essential safety gear includes:

Goggles

Protect your eyes from any plaster splashes or dust.

Gloves

Prevent skin irritation by wearing suitable gloves. Plaster can be harsh on skin over prolonged periods.

Dust Masks

Plaster can produce a lot of dust, especially when mixing. A mask can protect your lungs from inhaling these particles.

Safety Boots

Spilled plaster can make the floor slippery. Safety boots not only prevent slips but also protect your feet from any dropped tools.

Taking precautions and wearing the appropriate safety equipment will help ensure that your plastering project is not just successful, but safe too.

Understanding the Plastering Process

Explanation of key terms in plastering

Understanding the jargon can make the learning process easier. Here are some key terms you’ll come across in when plastering a wall:

Backing Coat: This is the first layer of plaster, applied directly onto the wall. Its primary purpose is to provide a stable and level surface for the finish coat.

Skimming: This term refers to the process of applying a thin layer of plaster (the finish coat) to create a smooth surface ready for painting or decorating.

Float: A float is a smaller trowel used for applying the initial layer of plaster. The process of applying this first layer is also often referred to as ‘floating’.

Rendering: This refers to applying a backing coat to an exterior wall.

Setting: The process of the plaster drying and hardening is known as ‘setting’. 

General overview of the plastering process

Plastering is a multi-step process that involves the following key steps:

Preparation: This involves cleaning the wall surface, removing any loose material or old plaster, and applying a primer if necessary.

Mixing Plaster: Plaster comes as a dry powder that must be mixed with water to the correct consistency.

Applying the Backing Coat: Using a float, the backing plaster is applied to the wall.

Applying the Finish Coat: Once the backing coat is dry, a thinner layer of finishing plaster (the process known as skimming) is applied using a plastering trowel.

Polishing: After the finish coat has dried, it is polished to create a smooth surface ready for painting or decorating.

Differentiating between plastering new walls and replastering old walls

When plastering a new wall, you’ll usually start with applying a backing coat directly onto the bare brickwork or blockwork. This helps to level out the wall and provide a good base for the finish coat.

When replastering an old wall, however, the process is slightly different. 

Old, damaged plaster needs to be removed first, and the exposed wall must be cleaned and prepped before new plaster can be applied. In some cases, you may need to apply a special primer (known as a bonding agent) to help the new plaster adhere to the old wall surface.

The state of the wall can affect how the plaster adheres, so it’s essential to thoroughly prep the wall in both scenarios to ensure a smooth and durable finish.

Preparing the Wall for Plastering

Preparation is crucial when it comes to plastering. 

A clean, well-prepared wall is essential for ensuring that the plaster adheres correctly and sets smoothly. Properly prepping your wall can also help prevent future issues such as cracking, blistering, or the plaster coming away from the wall. 

Thus, the time and effort you put into this stage can significantly affect the quality of your finished wall.

Detailed steps on wall preparation

Here is a detailed breakdown of the steps involved in wall preparation:

Cleaning the Wall

First, use a brush to remove any dust, dirt or loose material from the wall. If there’s existing paint, it should be lightly sanded to provide a better surface for the plaster to adhere to. 

Removing Old Plaster

If you’re replastering an old wall, you’ll need to remove any damaged or loose plaster. This can be done using a hammer and chisel. Be careful to remove all the old plaster without damaging the underlying brickwork.

Checking for Damp

If there are any signs of dampness on the wall, these will need to be treated before you plaster. Damp can prevent the plaster from adhering correctly and cause it to fail in the future. 

Applying PVA Glue

Once your wall is clean and dry, apply a coat of PVA (polyvinyl acetate) glue. This acts as a primer, helping the plaster to stick to the wall. It should be diluted with water (usually at a ratio of 1:4 PVA to water) and applied using a brush or roller. Allow the PVA to become partially dry – it should be sticky to the touch – before applying the plaster.

Setting up Beads

If you’re plastering a wall with corners or edges, you’ll need to set up plastering beads. These are strips of metal or plastic that help you create clean, straight edges and corners. They should be fixed in place using small amounts of the plaster mix.

Covering Surroundings

Finally, before you begin plastering, make sure to cover the floor and any nearby furniture with dust sheets to protect them from splashes of plaster.

Each of these steps is critical in preparing your wall for plastering. By ensuring your wall is properly prepared, you’re setting yourself up for a successful plastering job.

Mixing the Plaster

Mixing plaster to the correct consistency is crucial to your plastering success. Here’s a simple step-by-step guide:

1. First, fill about a third of your mixing bucket with clean water. 

2. Slowly add the plaster powder to the water. It’s essential to add plaster to water, not the other way around, to prevent lumps from forming.

3. Stir the mixture gently with your bucket trowel, breaking up any clumps. Be careful not to stir too vigorously as this can create air bubbles in the plaster which will cause problems later.

4. Continue adding plaster and stirring until you have a smooth mix.

Tips for achieving the right consistency:

The aim is to achieve a consistency similar to thick custard or peanut butter. It should hold onto your trowel without dripping off, but still be soft enough to spread easily. If your mix is too thin, it will run off the wall and not adhere correctly. If it’s too thick, it will be difficult to work with and could leave a bumpy finish. 

A good rule of thumb is to add plaster until the mixture starts to pile up above the water level. Then, with some careful stirring, you should reach the desired consistency.

Importance of clean water and a clean mixing area

Using clean water and ensuring your mixing area is clean is vitally important. Any dirt or debris can affect the consistency of your plaster and cause problems when you start applying it to the wall. 

Similarly, old plaster or residue left in your bucket from previous mixes can cause your plaster to set too quickly, making it unworkable. Always thoroughly clean your tools and buckets before starting a new plastering project to give yourself the best chance of a smooth, professional finish.

Applying the First (Scratch) Coat

Step-by-step process of applying the first coat of plaster:

Loading the Hawk: Place a good amount of your mixed plaster onto the hawk. Then, with a swift and smooth motion, transfer a smaller amount from the hawk to your trowel.

Applying the Plaster: Hold the trowel at a slight angle against the wall, and spread the plaster across in a smooth motion. Your aim is to apply a uniform layer of about 2mm thickness.

Moving Up the Wall: Start applying from the bottom and work your way up. This approach helps catch any falling plaster, ensuring that it doesn’t mess up your finished work.

Cover the Entire Wall: Repeat the process until the entire wall is covered. Don’t worry about getting it perfectly smooth at this point; the goal is to get a reasonably flat and even layer onto the wall.

Scoring the Plaster: Once the entire wall is covered and the plaster starts to set (but is still slightly soft), take your plastering comb and lightly score the entire surface. This process creates a key for the second layer to grip onto.

Tips on achieving a flat and smooth surface

Keep your Trowel Clean: Regularly clean off any dried plaster from your trowel. This can be done by scraping it against the edge of your hawk or mixing bucket. Any dried bits can cause lines and grooves in your plasterwork.

Check for High Spots: Hold your trowel flat against the wall and look for any gaps between the trowel and the plaster. These are high spots and should be smoothed down.

Use a Straight Edge: If you’re working on a large wall, it can be helpful to use a straight edge or a long spirit level to check the flatness of your wall. This can help spot any bulges or hollows that need addressing.

Don’t Rush: Let the plaster start to harden slightly before you start to flatten and smooth it. If you try to work it too soon, you’ll just move the plaster around, and it won’t have a chance to stick to the wall properly.

The first coat doesn’t need to be perfect. You’re looking for a good, flat base upon which you can apply your finish coat. Any minor imperfections can be addressed in the next step of the process.

Applying the Second (Finish) Coat

Detailed process of applying the finish coat:

Preparing the Plaster: The finish coat plaster should be mixed to a slightly thinner consistency than the first coat. Remember to add the plaster to the water, not the other way around, to avoid creating lumps.

Loading the Hawk and Trowel: Just like with the first coat, load your plaster onto the hawk and then onto your trowel.

Applying the Plaster: Begin applying the finish coat of plaster, starting from the bottom of the wall and working your way up. Hold your trowel at an angle and press firmly to spread the plaster smoothly and evenly. This coat should be approximately 2mm thick, just like the first coat.

Smooth Out the Plaster: Once you’ve covered the wall, go back over it with your trowel, smoothing out any lines or ridges. The more time you spend on this step, the smoother your final wall will be.

Final Polishing: After the plaster has begun to dry but is still slightly damp, polish the wall using a clean, wet trowel. Apply a firm pressure and smooth, sweeping strokes. This will help achieve a professional, smooth finish.

Techniques for ensuring a smooth and professional finish

Clean Tools: Make sure your tools are clean throughout the process. Dried plaster on your trowel can cause marks and scratches on your finish.

Work Quickly but Carefully: Plaster can begin to set quickly, so it’s important to work efficiently. However, don’t rush. Taking your time to get a smooth, even layer is crucial for a professional finish.

Check Your Work: Regularly check your work by placing your trowel flat against the wall and looking for gaps where light comes through. These are areas where the plaster is not flat and will need additional smoothing.

Keep Plaster Moist: If your plaster is drying too quickly, mist it lightly with water using a spray bottle. This can help prevent cracking and give you more time to achieve a smooth finish.

Polish the Wall: The final key to a smooth finish is to polish the wall with a clean, slightly damp trowel. Use long, sweeping strokes and apply firm pressure.

The aim is to achieve a uniform, smooth finish. It may take some practice, but with patience and persistence, you can plaster a wall to a professional standard.

Drying and Polishing the Plastered Wall

The drying time for plaster can vary depending on the type of plaster used, the thickness of the plaster, the conditions in the room, and the material of the underlying wall. However, as a general rule, you should allow at least one week for the plaster to dry fully. 

Keep in mind that plaster needs to dry naturally, so resist the urge to speed up the process using heaters or dehumidifiers, as this can lead to cracking. Instead, promote good air circulation by keeping windows open.

It’s important to make sure the plaster is completely dry before painting or decorating. You can tell if it’s dry as the colour will change from a dark pink to a light, even pink all over. 

How to Polish and Finish the Plastered Wall

Final Troweling: Once the plaster has started to set but is still slightly soft (typically around 20-30 minutes after application), use a clean, slightly wet trowel to give the wall a final pass. Hold the trowel at a slight angle and apply firm pressure to smooth out any small imperfections.

Polishing: After the wall is completely dry, you can give it a final polish to achieve an ultra-smooth finish. This involves going over the wall with a polishing trowel or a damp sponge, using a circular motion. This can help to eliminate any last minor imperfections and give the wall a professional-grade finish.

Sealing the Wall: Once your wall is dry and polished, you’ll want to seal it before decorating. This can be done using a suitable size paintbrush and a mist coat, which is a mix of watered-down emulsion paint (one part paint to four parts water is a typical mix).

This sealing layer is essential as it prevents the new plaster from sucking moisture out of the decorative paint, ensuring a nice, even colour. Allow the mist coat to dry thoroughly before applying your topcoat.

The drying and finishing stages are just as crucial as the application. Taking the time to let your plaster dry naturally and spending time on the finishing touches can really pay off in the end, leaving you with a beautifully smooth, professional-looking wall.

Common Mistakes and How to Avoid Them

Here are some examples of typical beginner mistakes:

Poor Consistency: Many beginners struggle with getting the right consistency for their plaster mix. Too thick, and it won’t spread easily; too thin, and it can run off the wall. Achieving the right consistency – similar to thick custard or peanut butter – comes with practice.

Rushing the Process: Plastering is a task that can’t be rushed. Many beginners make the mistake of trying to work too quickly, leading to a poor finish. It’s important to remember that good plasterwork is all about patience and attention to detail.

Not Preparing the Wall Properly: The preparation stage is crucial, yet many novices skip over this, leading to poor plaster adhesion and a rough finish. The wall needs to be clean, free from loose material, and primed with a PVA sealant before plastering.

Overworking the Plaster: Another common mistake is overworking the plaster after it’s been applied. Once the plaster starts to set, it’s important to leave it alone. Continually fiddling with it can lead to marks and grooves that are difficult to smooth out.

Tips on how to prevent and fix these mistakes:

Practice Mixing: Spend some time practicing mixing plaster before you start your project. This will help you get a feel for the right consistency and how to achieve it. 

Plan Your Time: Make sure you have plenty of time to complete your plastering without feeling rushed. Remember, you can’t speed up the setting process, so be prepared to wait for the plaster to dry naturally.

Thorough Preparation: Don’t skimp on the preparation stage. Spend time cleaning and priming the wall before you start plastering. It’s also worth checking for damp, as this can cause problems later on.

Let the Plaster Set: Once you’ve applied the plaster, let it do its thing. Resist the urge to keep touching it or trying to smooth it out. Once it starts to set, you can give it a final smooth over with a clean trowel.

Learn from Mistakes: Everyone makes mistakes, especially when learning a new skill. If something does go wrong, try to learn from it. Understand what caused the problem and how to avoid it in the future. With practice and patience, you’ll soon be plastering like a pro.

Plastering is as much an art as it is a skill. Don’t be discouraged if you don’t get it perfect the first time. Practice makes perfect, and every mistake is a learning opportunity.

Recap of the Plastering Process

Throughout this guide, we have covered the important steps involved in plastering a wall for beginners. This started from understanding the importance and benefits of plastering, the tools, and materials required, and the steps involved in the plastering process.

We delved into the nitty-gritty of wall preparation, how to mix plaster to achieve the right consistency, and the detailed application process of both the first (scratch) coat and the second (finish) coat. 

After application, we covered the crucial drying and polishing process, as well as common mistakes that beginners often make and how to avoid them.

Practice Makes Perfect

Plastering may seem daunting initially, especially for first-timers, but it is essential to remember that like all DIY skills, it gets easier and better with time and practice. It is a very handy skill to have and can save you a lot of money in the long run. 

Don’t be discouraged if you don’t get it right the first time. There’s a learning curve involved, and everyone has been there at some point. What matters most is persistence and a willingness to learn and improve.

Remember that perfection isn’t achieved overnight; even experienced plasterers weren’t masters on their first day. With the tips and knowledge provided in this guide, you’re well on your way to mastering the art of plastering. 

So, go ahead and give it a try on your next DIY project. With every wall you plaster, you’re honing your skills, and before you know it, you’ll be plastering like a pro.