My ideas on "extending" these posts to 8 foot to hold a shade cover. I plan to cut out a 4X4 notch in the deck by the highest corner post and then run a 4x4 beside it all the way down to the concrete footing. A non-structural 4X4 will be placed on top of the existing post, giving the appearance of a 4 X 8 post. At the other 5 posts locations (4 corners, 2 middle posts on the 20 foot length), I had not planned on extending thru to the footing, but rather place on the deck and lag bolt to existing "short" 4X4 post. The "cover" will be made of "king post" trusses, made of 2 X 6 treated lumber set 24 inches on center, finally vinyl lattice will be sandwiched in a 2 x 2 frame and attached to the trusses. Plan on using hurricane clips or simpson connectors at all major connections.
City building department inspected the deck last summer but inspector told me no new permit would be required as long as the cover was for shade, not solid.
I am only looking at about $500 worth of material at my local discount building supply, but first contractor's estimate came in at $4500. Not sure if I failed to explain it, he is really overbuilding it or he's afraid of the job.
Appreciate any feedback on potential pitfalls.