How to Plaster a Corner?

Plastering a corner can seem challenging, but with the right tools, materials, and techniques, it’s entirely achievable for DIY enthusiasts and professionals. 

This guide will provide everything you need, from essential tools like trowels and corner beads to step-by-step instructions for preparing the surface, installing corner beads, and applying the basecoat and skimcoat plaster. 

We’ll cover different bead types and how to choose the right one, ensuring you get sharp, durable edges that last. You’ll also find tips to avoid common issues like uneven plaster thickness and bead movement. 

Mastering these techniques will create smooth, professional-looking corners that enhance any room. Whether working on plasterboard or concrete, this guide will help you perfect your plastering skills and achieve a flawless finish every time.

Let’s get straight to the point.

Plastering a corner requires the right tools, materials, and techniques to achieve a clean, durable finish. The process involves preparing the surface, installing corner beads, and applying basecoat and skim-coat plaster layers. 

Depending on the project’s needs, different corner bead types, such as steel, thin coat, and mesh wings, are used. Proper installation techniques, including adhesive and mechanical methods, ensure the bead stays secure. 

We also cover tips for avoiding common issues like drying shrinkage and uneven plaster. Following these steps and maintenance tips, you can create professional-looking, long-lasting corners in your plastering projects.

Tools And Materials Needed For Plastering A Corner

Tools

• Trowel
• Straight edge
• Hawk
• Tape measure
• Tin snips
• Hammer
• Nails
• Safety gear (gloves, glasses)
• Stapler
• Sanding block
• Bucket
• Ladder

Materials

• Angle beads (corner beads)
• Basecoat plaster
• Skim coat plaster
• PVC edge beads (optional)

Step-By-Step Guide To Plastering A Corner

1. Preparing The Surface

Before applying the plaster, ensure the wall surface is clean and flat. Remove any loose debris or existing plaster that could affect the adhesion of the new layer.

2. Choosing The Right Corner Bead

Corner or angle beads are crucial for creating a crisp and durable corner. They come in different materials and designs:

• Steel Corner Beads: Ideal for internal plastering; they resist corrosion.
• Thin Coat Corner Beads: Have perforated wings on both sides for a secure fit.
• Mesh Wings Beads: Best for use with skim plaster as they provide better adhesion.

Choose the bead-based on your project needs. It should be 2.4m long and no more than 3mm deep to match the plaster thickness.

3. Installing The Corner Bead

Option 1: Adhesive Method

1. Measure and Cut: Cut the bead to the required length using tin snips.
2. Apply Plaster: Mix a thick plaster paste and apply it in small blobs at regular intervals (about 4 cm apart) along the corner.
3. Set the Bead: Press the corner bead firmly into the plaster, using a spirit level to ensure it is straight.
4. Remove Excess Plaster: Clean any excess plaster with a trowel, leaving a smooth surface.

Option 2: Mechanical Fastening

1. Align the Bead: Position the bead along the corner, ensuring it is level.
2. Secure with Nails or Screws: Use nails or screws to attach the bead to the corner, making sure they are evenly spaced.
3. Staple Method (if applicable): You can staple the bead in place using a powerful staple gun, though this method is rare.

4. Applying The Basecoat

Once the bead is securely in place, it’s time to apply the basecoat plaster:

1. Mix the Plaster: Prepare the basecoat plaster according to the manufacturer’s instructions.
2. Apply Evenly: Use a trowel to spread the basecoat evenly over the corner bead, ensuring the plaster is pressed firmly.
3. Smooth the Surface: Use a straight edge to smooth out any irregularities and to ensure the plaster is level.

5. Applying The Skim Coat

The skim coat provides the final finish to the plastered corner:

1. Mix the Skim Plaster: Create a smooth plaster mix suitable for a thin layer.
2. Apply the Skim Coat: Spread the plaster over the basecoat, bringing it to a precise contact with the corner bead.
3. Finish with a Trowel: Trowels smooth the surface, ensuring a clean, crisp edge.

6. Finishing Touches

1. Allow to Dry: Let the plaster dry completely before any additional work.
2. Sand if Needed: Lightly sand the area to remove any minor imperfections.
3. Final Inspection: Check the corner for straightness and consistency before painting or decorating.

Tips For Effective Corner Plastering

• Use a Spirit Level: Regularly check the alignment of your corner bead to avoid crooked edges.
• Maintain a Clean Trowel: A clean tool will help achieve a smooth finish.
• Plaster in Layers: Build up thin layers rather than applying a thick coat all at once.

Common Issues And Solutions

1. Drying Shrinkage

• Solution: Use a proper mix ratio and allow each layer of plaster to dry fully before adding the next layer.

2. Corner Bead Movement

• Solution: Avoid using nails if they don’t hold well; use plaster as the adhesive for a more secure bond.

3. Uneven Plaster Thickness

• Solution: Check your work frequently with a straight edge to ensure even application.

Understanding The Role Of Angle Beads

Angle beads, also known as corner beads, play an important role in plastering by:

• Reinforcing Corners: They provide extra strength to prevent chips and cracks.
• Ensuring Straight Edges: The beads act as a guide for achieving sharp, clean corners.
• Improving Durability: Angle beads help absorb impacts, reducing the risk of damage.

Types of Angle Beads

• Galvanised Steel Beads: Suitable for indoor use as they resist rust in dry conditions.
• Stainless Steel Beads: Recommended for external applications due to their higher 

corrosion resistance.

Plastering Techniques For Different Surfaces

1. Plastering On Brick And Concrete Walls

Attach angle beads to bricks or concrete using a skim plaster mix. Apply the plaster at intervals, press the bead firmly into place, and smooth it out with a trowel.

2. Plasterboard Corners

Edge beads are often used for plasterboard. These beads have a smaller hook facing the plasterboard’s front, providing a tight grip and easier alignment.

Maintenance Tips For Plastered Corners

• Regular Inspection: Check corners periodically for any signs of damage.
• Prompt Repairs: Fix minor chips and cracks early to prevent them from spreading.
• Avoid Damp Areas: Protect external plastered surfaces from moisture to prolong their lifespan.

Conclusion

Plastering a corner might seem challenging initially, but it becomes much more manageable with the right tools, materials, and techniques. Using corner beads ensures a sharp, durable finish that looks professional and withstands wear and tear. 

Whether you’re working with clay plaster or other materials, preparing and installing the corner bead properly will save you time and effort in the long run. 

These techniques will improve your skills and ensure your plastered corners remain strong and beautiful for years.

Frequently Asked Questions About Plasterer

What Causes Ripples in Plaster?

The plaster tends to ripple if it is being applied too thick. Make sure the plaster is not mixed up too thick – when you pull the whisk out, it wants to have soft peaks of about 25mm or so in height.

Does Plaster Absorb Sound?

By absorbing sound waves, acoustical plaster makes conversation clearer, even in harsh situations, by reducing reverberation time.

What Is Barium Plaster?

Barium plaster is used as a final coat for surfaces of X-Ray rooms to protect the person working in and around X-Ray rooms. It is essentially made from Barium sulphate.

Can I Screw Directly Into Plaster?

Screws are your ultimate option for hanging things on plaster walls without a picture rail. Screwing into the plaster with a 1 1/4″ drywall screw can get the job done for lighter items. For heavy items, you can opt screws with masonry anchors.

What Is Browning in Plastering?

Browning plaster

This undercoat plaster is used as a base for paint and other decorative endeavours. It is very similar to bonding plaster but is most useful with more absorbent surfaces. Furthermore, they can be used to ‘build up’ walls and are useful in construction.