In article ,
Martin Brown wrote:
On 26/04/2013 22:36, Janet wrote:

I agree. I don't see those poorly supported polycarbonate panels
standing up to coastal weather , either.

Ventilation seems to be an optional extra - which is a nonsense. Seems
like these are greenhouses specifically designed for non-gardeners.

Why buy steel (which rusts) when all the other manufacturers use
aluminium, which doesn't.

You could at least in pricinple have a much stronger large steel
structure for the same price as aluminium. And steel is less likely to
cripple under extreme wind loading. I would recommend replacing some of
the struts on the prevailing wind side with thicker material.

Plus the fact that aluminium corrodes much faster than steel
when it does, and one of the things that it handles very badly
is salt. The reason that most aluminium structures survive
is that they are exposed to air, and aluminium develops a
protective oxide layer. It will corrode very fast if there is
any location/joint/etc. where water can get in but which is
enclosed enough to be effectively anaerobic, especially if the
(whatever) is held together with steel bolts or screws.


Regards,
Nick Maclaren.