Welcome to the Bunnings Workshop community @Baron. It's fantastic to have you join us, and many thanks for your question about Colorbond fence extensions.
@ProjectPete uses plate 250mm brackets (flat steel hammered into the top of the posts) to connect the 300mm uprights (shape of the channel/post) onto the existing posts.
Using COLORBOND Steel 340mm Fencing Post Extensions is another approach. They are available in our stores and don't require the use of a joining bracket. They fit over the existing posts and are then screwed into position. You'll just need to check whether they are compatible with your fence posts.
If you'd like to contact @ProjectPete, you can do so through Workshops' private message function. However, hopefully, he'll respond to our tags and reply here. I'll also reach out to Pete to see where he got the extensions and plate brackets for his How-To article. I'll let you know when I have an answer.
@ProjectPete has used extensions from the manufacturer of his particular Colorbond fence. Since several profiles of posts exist, you'd need to contact the supplier of your specific fence and order the extension kit through them. The kits are not interchangeable between different brands. Do you happen to know the brand of fence you have? Perhaps Pete might then be able to point you in the right direction.
Would it be possible for you to post a photo of your finished project? I'm sure our members are keen to see how you made your fence extensions.
Here are some photos of my fence extension. It takes a bit of manipulation to get the 2 - 3 x3 x 1.15mm angles into the top of the posts. I have cut the post extensions using an angle grinder from the standard 2.4 m posts. I made them 340mm long and and cut standard infill sheets to 330mm, that left me very little waste. Of course you can make the extension posts and sheets to suit your requirement or leave out the bottom rail if you want a slat or lattice infill sheet. I made a total of 6 extensions for a total cost of $350, all materials bought from Bunnings.
I did 6 extensions for a total cost of $350.
Thank you so much for posting those fencing extension photos. What an amazingly creative solution to extending your fence using Australian Handyman Supplies 30 x 30 x 1.15mm x 2.4m Galvanised Pressed, Angle. I wouldn't have it thought possible because of the shape of the post. This is a good alternative to extending Colorbond steel fences.
Again, thank you for sharing your fence extension technique.