On Jan 24, 1:54 am, "Mel" wrote:
My glass greenhouse has been smashed and the frame bent out of shape in the
recent storms, so I need to replace it. Has anyone any experience with the
Norfolk greenhouses that use "semi-rigid sheet", which I assume is plastic?

No experience of that particular product, but I have used twin wall
plastic glazing in my greenhouse (which is fairly rigid - more so than
a thin single plastic sheet). And it does need an internal fixing point
or it will flex and flip out in the wind. This isn't too hard you need
a baton along the inside to lock it and a bolt with a washer on the
outside.

I also use the same twin wall material (as well as hardboard) for
instant repairs after the greenhouse sustains storm damage. Although it
was overwhelmed by the storm of Xmas 1996 it has alway served me well.

http://www.nezumi.demon.co.uk/garden/gizmos/gizmos.htm

I would also think about using stronger bracing aluminium struts on the
side of your greenhouse that faces into the prevailing wind. The
standard ones invariably buckle under extreme wind loading.

Regards,
Martin Brown