I haven't seen your plans so I may be speaking outa turn here. If you have a wooden deck like on a second level, and a porch or something under it that you would like to use when its raining, "Trex" decking, makes a product called "Rain escape". Its a product that goes inbetween the floor joists of the upper deck and causes the rain water to drain into a catch basin and then dumps into a gutter. Its cool. Don't know if you have a use for that or not though.
The other thing I was gonna tell you is this: remember the last 10% of the job, is 90% of the work!