Decks, Patios, Porches and Docks - Beam Overhang Limit

I am planning a patio cover that consists of 2 4x6 posts ~15' apart (~10.5' out from the house) with a 4x8 beam sitting on top of the posts. Ideally, I would like the beam to be 20' long. Joists would attach to a ledger on the house and sit on the beam. Ideally, joists would be 18.5" apart and and the 1st and last joists would be 1' outside the posts. Then, the cover would be built with 2x4x20' separated 50%.

I will be using non-pressure treated Douglas Fir.

The 2x4x20's will overhang the last joists on each side by 18" which I believe is fine. However, is it ok for the 4x8x20' beam to overhang the 4x6 posts by 2.5' on each side? Also, is it ok to have joists sitting on the beam outside the posts? Finally, can the joists overhang 2.5' beyond the beam?

Thanks,

Darryl

Check with your local building department. Here is the latest deck code: http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf
Be safe, Gary