Hi I'm looking for the best way to attach trellis to the existing fence. I've done a little search but most vids just show what to do with the fence posts being higher.
Perhaps say what the trellis is made of and where on the fence you intend to attach it then someone can offer some advice.
Absent that, my answer is "with screws".
I don't know if it helps, but I have recently put up fencing for a customer. He had a brick wall and purchased 75mm posts for fence panels. The posts had 12mm threaded rods that were secured in the top of the brick using anchor fix resins.
There is no reason why you can't use stainless rods drilled in to the existing posts to extend them. So long as you seal the joints with something like an MS polymer and don't have water ingress, I can't see a problem.
Perhaps say what the trellis is made of and where on the fence you intend to attach it then someone can offer some advice.
Absent that, my answer is "with screws".
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local