Decks, Patios, Porches and Docks - Tricky Deck questions

I want to build a 12' x 18' deck attached on the 18' by ledger board to my house. It'll lag bolt onto the house beam as its just below door level.(just)There is a concrete pad there 13' x 15" which the deck will partially cover. If I use 2" x 8" construction with 5/4 x 5 deck boards it will clear the pad by a few inches, enough for drainage. I wanted to see whether I would be OK using 3 4" x 4" posts (very short posts) attached to the beam, (corners and 9' in), two resting on metal brackets floating on the pad and one on a pier block on grade. Or if I could support it better and still cope with the minimal clearance of the concrete pad? I called my city code guy as Alberta is pretty cold and he said 10' below grade concreted in posts or concete peirs would both be OK as it is only a foot above the ground. I can see it might be best to rip the concrete pad out and install 10' below grade posts but it seems excessive compared to the above plan. Any how suggestions welcome and a great site!

If code said go 10' to frost line Id do it. You dont want the deck going up and down all the time. Concret peirs about 6" out of the ground or on up so the deck would just set on them.

ED ;)