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Person using measuring tape to measure metal external angle.

Overview

An important part of building a new wall is making a neat edge on your external corners. We'll show you how easy it is to adjust, attach and plaster an external angle to an external corner. 

Steps

1Check your wall is straight

Grab your level and place it against the edge of the wall. Check if there are any gaps between the wall and the level. If there are gaps, you will need to adjust the external angle to make sure the wall is straight.

Person snipping metal external angle.

2Cut the external angle

First measure the height of the wall and cut the external angle to suit on a 45-degree angle. Then gently squeeze the sides of the external angle together with your hands to account for any bends in the wall. 
Person using measuring tape to measure metal external angle.

3Attach the external angle using a staple gun

Position the external angle at least 10mm off the ground. This way if there is any movement on the floor the angle will not crack. Place the external angle against the straightest point of the corner, roughly in the centre. Position this firmly by placing pressure onto the middle of the angle, and pin into place with your staple gun. To check the angle is straight all the way down, place your straight edge alongside the angle, adding pressure. Once this is straight, staple the remainder of the angle into place.

Person stapling metal external angle to wall.

4Attach the external angle with a hammer

You can also pin the external angle into place using a hammer. Hold the external angle up to the corner, using your straight edge to determine if the angle is straight. Add pressure with your hand to the opposite side of the angle to hold this into place. Then place a nail through a circle on the outer edge of the external angle and hammer into the plasterboard. Repeat this in multiple spots along the angle until it's secure. 

Person hammering nail through hole in metal external angle piece.

5Mix up the plaster for your base coat

Now that your external angles are in position you can mix up your plaster for the base coat. In this case we have two externals, so we need to fill the bucket to at least three quarters to have enough. Once the plaster is mixed to the right consistency, you are ready to apply it to the wall.

Person mixing up plaster in bucket using scraper.

6Apply the base coat of plaster

Use your hawk and trowel to apply the plaster to the external corner. Start applying to the middle of the wall first, working downwards and taking any excess off the edges. When you reach the bottom, run the trowel to the top of the wall to smooth this out, making sure you have gone passed the architrave line. Then apply plaster from the top down to complete this side. Now start on the other side of the corner, applying the base coat from the bottom up. 

Person plastering over metal external angles attached to wall.

7Smooth the surface and apply the second coat

Once the first coat has dried, smooth the surface with your scraper to get it ready for the second coat. Apply the second coat of plaster to one side of the corner only and make it slightly wider than the first. This coat should be at least three quarters of the length of your trowel. Use the same processes for applying as the first coat. Leave the face side of the corner at this stage.   

8Apply plaster to the face of your wall

Now that you have applied a top coat to one side, you can apply a coat to the face using a slightly different technique. This time when you put the mud on, hold your trowel at a 45-degree angle away from the side that has already been troweled. 

Person scraping over plaster on wall and external angles to smooth it out.

9Apply the top coat

The process for applying the top coat is the same as the second coat. This time make the surface you apply slightly wider. Once the top coat is dry, you can sand it back and you are ready to paint. 

Plastered wall edge, with external angles just visible.
Health & Safety

Asbestos, lead-based paints and copper chromium arsenic (CCA) treated timber are health hazards you need to look out for when renovating older homes. These substances can easily be disturbed when renovating and exposure to them can cause a range of life-threatening diseases and conditions including cancer. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer or visit our Health & Safety page.

When following our advice in our D.I.Y. videos, make sure you use all equipment, including PPE, safely by following the manufacturer’s instructions. Check that the equipment is suitable for the task and that PPE fits properly. If you are unsure, hire an expert to do the job or talk to a Bunnings Team Member.