In article ,
Charlie Pridham wrote:

My feeling is if we can get hold of proper greenhouse mouldings it will
have a much longer useful life and require less upkeep than if we build
in wood.

Not necessarily. Well-made wooden structures will outlast UPVC or
most metals - inter alia, they are repairable if one part breaks, so
a single failure (combined with the original parts no longer being
available) doesn't mean demolition and rebuilding. It is essential
to use good-quality wood and, unless one of the extremely weather-
resistant woods, to paint it and maintain the paint.

Aluminiums vary, that I know, but I don't know which are durable and
which aren't. I have seen some that were completely rotten after a
couple of decades, even without exposure to salt spray, which you may
get. Steels, ditto, so GOOD galvanising or fancy stainless is needed
for a long life. And UPVC degrades with ultraviolet, at least.


Regards,
Nick Maclaren.