My mother would love a decked cast iron (or "cast iron effect" steel)
verandah outside her back lounge. It would need to be 2m above the ground
and have lots of cast iron mouldings in the most ghastly late-Victorian
Gothic monstrosity style possible, with swirly railings and a staircase down
to ground level. Any ideas as to where such stuff could be
obtained/manufactured?

The size of the main deck would be about 3.5m x 4m. I was thinking of a
layout like:

| HOUSE |
| |
+---------+ +-----+
| \ / |
|--| \ / |
|--| DECK |
|--| |
|--| |
|--| |
|--| |
|--#------#------#------|
^ |
| +-----

STAIRS

I would assume that there would be a few pillars on the south edge (#), with
an east/west beam and joists running north-south. The pillars would have
frilly capitals and the edges would have railings. Would a second beam be
needed halfway across the joists? What should the joists be made of? Steel?
Flitch beam? Wood?

Christian.