I am planning on building an arbor attached to the back of my house. The legnth is roughly 24 feet, depth 10 feet and height no higher that 10 feet overall. The plan is use a 2x8 ledger 4 - 4x4 posts spaced at 8 feet apart, a 4x6 beam (2 - 2x6's), 2x6 rafters 11feet long spaced at 16-18 inches, and a lattice of 2x2's spaced at roughly 1-1/2 inches for maximum shading. Three of the posts will be on a concrete pool deck, the fourth will have to buried in the soil or concrete support provided. I am planning on using pressure treated pine. Does this seem to be a reasonable design?
The design has flaws.
2x6's are too small, they will sink into the span. The support posts should have a footing, not just set on an existing pad.
You don't mention the house construction or how you will secure the ledger.