about to begin room addition
 

We're about to break ground on a room addition off the back of the house and I've got one "small" detail to figure beforehand.
It will be a 16x12 room with a concrete patio on 3 sides. 8' on the west, 3' on the south and 5' on the east. Plan is to have the roof overhang and completely cover the patio.
When pouring the slab, do I pour the patio at the same time?

I think you need footing and foundation under the walls, something like 18" below the level of the outside slab and there should be 6 to 8" of foundation showing from the outside deck to the floor level.