I am looking to extend my 4x4 corner posts on a deck to build a Pergola over top of the deck. I also plan on sleeving those 4x4's with a composite sleeve for the full length from the 4x4. So the extensions need to be flush, so plates and other things protuding cannot be sticking out of the sides.
So what is my best and strongest option to join these 4x4s?
This is my preliminary Pergola design. The deck where I'm adding the pergola is not huge. It is basically a 10x12 Pergola design.
Please note the 2 posts on the left side away from the large square deck section. That is the old deck section that I sleeved the old posts. As alignment wasn't perfect, the post in the center is actually a "floppy post" to make the steps more aesthetic on each side of the steps. But with the composite sleeves make them look like 6x6's and adds structure to the 4x4 posts.