A ceiling and a roof can be different. You can leave the existing flat roof as your ceiling, and then construct a new flat roof further up.
But it's not impossible to leave it all as is and drain through the pitched roof from the flat roof. I recall doing a similar thing years ago - a false pitched roof around a square extension. It was not ideal, but I got the impression that the client really wanted to use the roof as a veranda after it had all been passed. IIRC, I forned a slot in the roof, as this would be better for access than a pipe or bridged channel.
Regarding that narrow gap between the garage and porch, even if it was just to be a cupboard, it would be much better than it is now. IMO.
Span across with a small lintel at ground level for the front wall, and form a suspended floor off the side garage and porch walls, so no need for foundations or digging.
Anyway, I'm still not sure waht the original question was?
BTW, that last image, has that been OK'd for butressing on each side of the window?
But it's not impossible to leave it all as is and drain through the pitched roof from the flat roof. I recall doing a similar thing years ago - a false pitched roof around a square extension. It was not ideal, but I got the impression that the client really wanted to use the roof as a veranda after it had all been passed. IIRC, I forned a slot in the roof, as this would be better for access than a pipe or bridged channel.
Regarding that narrow gap between the garage and porch, even if it was just to be a cupboard, it would be much better than it is now. IMO.
Span across with a small lintel at ground level for the front wall, and form a suspended floor off the side garage and porch walls, so no need for foundations or digging.
Anyway, I'm still not sure waht the original question was?
BTW, that last image, has that been OK'd for butressing on each side of the window?