Mary Fisher wrote:
Hi, I may (or may not) be able to get hold of some double glazed units
fairly cheap, probably old upvc windows. Is there any reason why I
can't use these to "knock-up" a conservatory? I'm not sure how I'd
make up the frame (steel posts?) or do the roof (polycarb with the
upvc edging stuff?)

Don't know where you are but many councils planning people don't allow
polycarb roofs anymore.