Project Overview

Installing a timber awning window into a wall cavity is a pretty straightforward job once you understand the basics. We show you the steps involved in properly securing the window in place. You’ll also learn how to install a waterproof flashing barrier and use masonite packers to level the frame.
Continue to step-by-step instructions
This D.I.Y. Advice is part of a series How To Install an Awning Window

Step by Step Instructions

1 Install waterproof flashing onto the bottom of the timber awning window frame
2 Place the timber awning window in position
3 Mark up and drill pilot holes for the timber awning window frame
4 Level the timber awning window
5 Install the awning window
  • Step 1. Install waterproof flashing onto the bottom of the timber awning window frame

    Staple a strip of waterproof flashing onto the rear of the window frame so it can fold underneath and cover the base. Be sure to leave yourself plenty of overhang on either side. Staple that overhang tightly into position onto the sides of the window frame and trim any excess. This holds the flashing in place but leaves it loose at the front of the frame.
  • Step 2. Place the timber awning window in position

    Place the window into the wall opening. If it is a heavy window, get someone to help you with this step. Once the window is in place, hold it steady. Then send someone outside to firmly pull the flashing to make sure it is sitting clear at the front of the frame. 
  • Step 3. Mark up and drill pilot holes for the timber awning window frame

    Mark up and drill pilot holes near the top and bottom of the sides of the window frame. The holes should be about 40-50mm back from the window jamb and 50-75mm from the top and bottom of the frame. The width of the hole should match the width of the shank of the screw.
  • Step 4. Level the timber awning window

    Use your spirit level to check that the window is sitting level in the wall opening. If the window is not sitting exactly plumb, level it up with some masonite packers. Then use your ruler to make sure the frame is sitting flush with the internal walls.
  • Step 5. Install the awning window

    Place a packer in line with the top pilot hole, in between the frame and the wall. Then check that the side of the window is sitting plumb and flush with the internal wall. When you are sure everything is in place, drive screws through your pilot holes and into the frame of the house. To give your job the best finish, countersink your screws so they sit below the surface of the timber. That way you can cover them with putty before you paint.

Tools and Materials


  • Drill
  • Pencil
  • Ruler
  • Safety glasses
  • Safety gloves
  • Saw horse
  • Spirit level
  • Staple gun
  • Trimming knife


  • Awning window
  • Masonite packers
  • Plastic flashing
  • Timber screws
low water garden

Planning & Projects How to create a low-water garden ‘Dry’ or ‘low-water’ gardening is a real art and, when done right, will provide you with an inviting landscape that uses very little water.

Finished artificial green garden wall behind garden bench 02:05

Planning & Projects How to create a green wall using artificial hedge Green walls are all the rage at the moment, but buying and maintaining one can be costly. Why not have a go at creating your own using pieces of artificial hedge – it looks great and will last the distance. Here’s how.

reducing water

How To Save Water How to reduce water usage Whether indoor or outdoor, there are lots of ways to be smart about water usage. And there are some simple actions that can make a big difference to your water bill.

doorbell 02:04

Doors How to install a ring doorbell The Ring video doorbell is a wireless doorbell which allows you to see who is at your front door. Find out how to install the Ring video doorbell yourself.

a tree lit up with solar lights around it 01:46

Garden Lighting How to install solar lights in your garden Solar lights are a great way to illuminate your pathways and highlight your garden beds at night. Install them yourself with these easy steps.

how to organise your pantry 02:52

Shelving & Storage How to organise your pantry Create an organisational system in your pantry with these handy storage hints. Trust us – its life changing!

front door 01:31

How To Paint How to paint your front door Make an entrance every darn day of the week by painting your front door a bold, enticing colour!

how to hang pictures

Walls The best way to hang pictures on a wall Learn the tricks to hanging your wall decor so it looks good – and doesn’t damage the plasterboard. Create an effortless-looking display by taking the time to consider spacing, proportion, frame styles and colour palettes.

Health & Safety

Please make sure you use all equipment appropriately and safely when following the advice in these D.I.Y. videos. You need to be familiar with how to use equipment safely and follow the instructions that came with the equipment. If you are unsure, you may feel it is safest to consult an expert, such as the manufacturer or an expert Bunnings Team Member.

Grave health hazards are linked to asbestos, which may be in homes built up to 1990. Health hazards may result from exposure to lead-based paints in older materials and copper chromium arsenic (CCA) treated timber. 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. You can also use a simple test kit from Bunnings to indicate the presence of lead-based paint.
Top of the content