On Friday, 19 May 2017 16:34:21 UTC+1, Dave Plowman (News) wrote:
I have an outside door to the roof terrace here. A fairly recent one -
perhaps 30 years old. Just a basic wood frame with a single full sized
double glazed plain glass panel.

The door opens inwards and has leaked off and on since it was fitted. It's
rather exposed up there. I fitted fancy seals which helped - but notice
some of the rubber has started to perish, and the wood frame of the door
isn't that great either.

It's not a period feature, and security isn't an issue, so I'm considering
replacing it with a UPVC one which hopefully would have better seals.

The present door in set into a custom made window frame - pretty chunky as
it is load bearing. If I removed the door and the planted on stops, I'd be
left with a basic wood frame made out of 4x2" which is well braced by
horizontals for the window - of the same size.

I've a horror of double glazing firms that install things. Googling has
found several firms that will supply a door and frame made to size.

Any gotchas about a DIY install? I've done PVC windows and patio doors OK
some time ago.

Any glass in the doors & panels has to be carefully shimmed.
It stops the door from drooping after installation.