Strengthening polycarbonate greenhouse?

Yes, I know it's an issue that's been raised before but, being the dubious new owner of a shaky Chinese polycarb greenhouse, I'm racking my brains for the best way to strengthen it for winter. I'm planning to use silicone to fix in the flimsy twin-wall panels, and add extra cross-bracing - lots of it. Problem is, I can't find any suitable material at a reasonable price - each of the side and roof panels are 120 x 75cm, and cheapish metal strip from Wickes etc seems to only come in 1m lengths, so not long enough.

I'm sure you super-resourceful bunch have some bright ideas?

Many thanks in advance!

Pim.

Both, Spuds! Pipe sounds like it may be an idea for the walls, thanks!

Do you have a local steel stock holder . 15 or 20mm flat bar comes in 3m legnths and is not overly expensive

Steel would need treating to prevent rusting  but is a reasonable price. 

You could use Araldite 2 part epoxy resin (glue) for securing the panes and also attaching pipes to frame (rather that wooden blocks etc). Once cured it is very strong, just make sure you support things in place until that happens!