How To Plaster A Wall

If you’re thinking about plastering, but don’t know where to start, our step-by-step DIY guide will give you everything you need to know about how to plaster a wall for a professional finish. DIY plastering doesn’t need to be a daunting task, but there are a few key elements that you need to know, such as what you’ll need and expert tips and advice to get the job done right.

There are many tips and techniques to achieve a quality finish when plastering a wall. Below we have listed some tips and best practices that you should be aware of to get the best results:

- Keep your tools wet and clean.
- Keep the room cool and well-ventilated to prevent the plaster from drying out too quickly. 
- Dampen the plaster if it’s drying too fast.
- You can practice your plaster application on a separate plasterboard to perfect the process.
- Always apply two coats of plaster.
- If you’re plastering around a corner, you can use beading to get a clean edge.
- When applying the plaster, firmly press the trowel at a 45-degree angle, flattening the trowel as the plaster reduces.

What You Will Need

Mortar is a mixture of sand and cement and once mixed, is a workable paste which hardens to bind bricks and building blocks such as stones and concrete masonry.

It is typically known to be thicker than other binding materials. This makes mortar a great option for building outdoor structures like walls, barbecues and structures made of bricks and blocks.

There are two ways that you can mix mortar; either with a cement mixer or by hand. Read on to find out what you will need for your project and how to mix mortar (using both methods) ready to use in your project.

What You Will Need

• Plasterers trowel

•  Hawk

• Plaster mix

• Dust sheet

• Dust mask

• Water spray bottle

• Paint brush

• Plasterers float

• 2 Buckets

• PVA glue

• Stirring rod or mixer

• Plasterers scratching tool (optional)

• Cloths or rags

Plastering Steps

Now that you have everything ready to begin plastering, it’s time to make a start. Our step-by-step guide will take you through how to prepare your walls for the plaster, how to correctly mix it and how to apply it for a professional-looking finish.

Step 1: Prepare the walls
Ensure that the wall is free from any debris including flaking paintwork, holes and loose plasterboard.  If you're plastering over new plasterboard joints make sure these are covered using scrim tape.

Note: We recommend that you use a dust sheet to protect your floor from any debris and spillages. 

Step 2: Apply the PVA
Now that your walls are ready to be plastered, the first step is to mix your PVA.  Generally, you should use a ratio of one part PVA and four parts water to dilute the glue. However, you should always check the instructions on the container as this can sometimes vary.

Apply the mixture using a quality brush, ensuring that the entire wall is covered. After the glue has become slightly sticky, the first layer of plaster is ready to be applied.

Step 3: Mix the plaster
Whilst you’re waiting for the PVA to become sticky, you should mix the plaster. Wearing a dust mask, add the plaster mix into cold water and mix until it has a creamy consistency without any lumps. 

Important: You should always mix the plaster into the water, never the other way around.

Step 4: Apply the plaster
Now that your plaster is mixed, it is time to begin applying it to the wall. You can practice your technique on a separate plasterboard before you start applying directly to the wall.

Using a trowel, apply small amounts of plaster to the hawk board. With the float, firmly push the plaster up the wall, gradually flattening the float at the end of each sweep. Applying pressure when using the float is the best method to ensure that you get a smooth finish and it prevents excess plaster from falling off the wall.

For best results, start from the bottom corner of the wall, working upwards and repeating the process until the wall is covered. 

Note: You should be aiming for a thickness of between 10-15mm for an undercoat layer, and around 3-5mm for a finishing coat.

Step 5: Smooth the wall
After 20 minutes the first layer of plaster should be slightly dried and ready to smooth over. Using a trowel, smooth out any imperfections such as bumps and the edges of the wall. If the plaster doesn’t smooth out, slightly wet the wall to make the plaster respond better to the trowel. As the edges of the wall can be difficult to perfectly plaster, you can use a wet brush to touch up the corners and edges.

Step 6: Scrape the plaster (optional)
Although scraping the first layer isn’t necessary, we do recommend that you do it to ensure that the second layer adheres correctly and doesn’t crack. Using either a plasterers scratching tool or an old fork, scrape the surface of the plaster to create texture. If you choose to skip this step, ensure that the first layer is wet before applying another layer.

Step 7: Apply the second coat of plaster
Now you are ready to apply your final coat of plaster, otherwise referred to as skimming. When skimming, the plaster mixture should be diluted with more water to form a thinner consistency – you should be aiming to plaster approximately a 2mm layer. 

Step 8: Finishing touches
Once your second layer has slightly dried, you should again smooth any imperfections. Do this by spraying water onto the surface and running the trowel across the wall using inward strokes. Like with the first coat, a wet brush can be used around the edges. Finish off by using a clean float to smooth the entire surface one last time.

Once the plaster has completely dried, use a sander to smooth the surface in preparation for painting and decorating. 

1. For larger DIY jobs, you may want to consider using a cement mixer. When using a cement mixer ensure it is on a firm, level ground and have someone around to help you with loading and unloading.

2. Using a shovel, load half of the sand, half the water, then half of the mortar cement into the mixer, avoiding build-up of any dry material on the blades of the drum.

3.  Add more water is necessary and mix for 3 to 5 minutes until the mixture is uniform in consistency and colour.

Hand Mixing Method

1. Hand mixing can be hard work, but satisfying if the correct procedure is followed. Always work on a hard, smooth surface, for example a sheet of plywood or in a wheelbarrow.

2. Using a shovel, add half of the sand and half of the mortar cement onto the flat surface or into the wheelbarrow and turn over the sand and cement until they are mixed together well.

3. Form a crater in the middle of the pile and add some water, then bring the dry material to the water and mix until the mixture is uniform in consistency and colour. Add more water to the mixture if necessary.

4. When you’ve finished using the mortar for your project, always clean your tools immediately and leave the area tidy.

 

FAQ's

How Many Bags Or Tubs Of Blue Circle Mortar Will I Need?
You can calculate the amount of Postcrete you will need by using this handy online calculator.

Where Can I Find More Information About Mortar?
For more information about the Mortar product itself, take a look at this detailed product data sheet.

Where Can I Find More Information Regarding Health & Safety When Using Mortar?
Before using this product, please refer to the product packaging for all health and safety information. You can also take a look at this detailed material safety data download.

Can I Recycle The Packaging?
Yes, all Blue Circle plastic packaging is made of recyclable material so is suitable for recycling and should be disposed of in the correct manner.

We hope you found this guide useful in learning how to mix mortar ready for your building projects. Hopefully you are now feeling confident enough to complete your project to a professional finish. For a video breakdown of the process, you can head to this step-by-step video demonstration.

If you found this post useful, please tag us in any social media posts of your projects using @BradfordsBuild on Facebook, @bradfords_building_supplies on Instagram, or bradfords-building-supplies-ltd on LinkedIn, so that we can see the finished result.

If you need further help or advice, please contact us or visit your local branch to speak to one of our experts.