covering over the sideway on our end of terrace house

[kia cat]

we have a walled side entrance and would like to cover it over.
[1] the side wall has pillars, I'm guessing it's best to pack these out, so that there's a flush run?
[2] looking to collect any rain water that falls on it, so is the easiest way forward to build a sort of gully/ u shaped bit along the side wall and sit the guttering in that?
[3] what sort of fall from [a] the house wall to the side wall should I be aiming at and [b] on the guttering?
[4] we'd like to keep it light and airy so corrugated plastic or twinwall?

It's about a 12 foot [3.65m] run and 5' 9" [1.75m] approx wide. Thanks team, Happy Bank Holiday!

[The Builder]

What's on the other side of the wall? (The one that runs parallel to the house)

[kia cat]

Hi, The Builder, it's the pavement of the road I live in, we're sideways on to it, if you get my drift. The wall is flat on the outside [pavement side] topped off with concrete coping stones. Hope that helps

[The Builder]

OK, sit the roof timbers on top of the pavement wall. A fall of anything from 150mm or more is fine for twinwall. I guess 300mm (1') would look about right.
Fix a conventional fascia board and fix ordinary plastic guttering to that..... exactly the same as with a "conventional" roof. The guttering will have a stop-end at one end, and a 90degree return at the other, to get the water back into your yard.
Technically, you shouldn't overhang your guttering into the pavement space. It really all depends on width of pavement etc........ just use your common sense.
If you don't want to overhang, then simply site the guttering right on the top of the wall. If this wall is only 4", then run a timber lintel between your pillas on the inside of the outside wall. (To carry the roof timbers)

[The Builder]

^^pillars^^

[kia cat]

Thanks the Builder!