Below you'll find some pictures of the completed project for the Manayunk garage reinforcement and deck. You'll see that we took care to ensure that the drainage membrane has a clear shot into the new gutter, keeping the rainwater off the garage roof. Just in case, we also covered the garage roof from inside with a masonry waterproofing sealant.
Since we spent all this time reinforcing the concrete garage roof, of course we didn't want to haphazardly drop a 300-square-foot deck on top of it. So before framing, we carefully measured and transfered the locations of the vertical steel columns below to the deck area above. Then we put masonry block footings for the deck directly on the locations of the steel columns, transferring all the weight of the deck to the columns and new footings below. Double 2x12 beams spanning the block footings provided the basis for the deck joists.
The adjoining neighbor was a little concerned about access, since we built over the existing passway, so we built gates on either side of the deck (with a nice little ramp for said neighbor).
We installed a garage light on a switch as well as an outlet in the garage (in case they want to vacuum their cars in the shade). We also put up a motion-detector light on the face of the deck, towards the parking lot, for a little security and to provide additional light as they approach or leave the garage.
A safe and solid deck and garage for many years to come. And, for those who are following, they had a beautiful baby girl.