At the moment we have a flat-roof porch. basically there are big
wooden joists that extend a couple of foot over the front door. On top
of these is some chipboard or plywood or something similar which has
felt on top of that. SWMBO would like this replaced with a sloping,
tiled, porch.

Since half of the frame is there already, I was thinking all we need
to do is fit a batten higher up the wall and another on the outside
edge of the flat roof and run wood diagonally between them and fill
with noggins. Is this more or less right?

If so, once I have a frame what about tiling. Never done that before.
Do I just nail it on? is it easy? Are tiles expensive? Where do I buy
them from?

I know you can get plastic sheets that I presume are cheap and
probably require less support. Of course they probably won't look as
nice. However, I think they are available in black. Has anyone seen
any in "real life"? Does it look smart or is it best left for
carports? We have got a flat roof carport, which I was as thinking of
doing the same... but that's another thread.

Thanks.