gray wrote:

Apart from cost and weight, surely doubled glazed greenhouses must be
economically viable. Especially if you heat a greenhouse over winter like
me.

Any thoughts or recommendations ???

Use 1cm gap twinwall polycarbonate intended for home conservatories.
Better insulation, lighter and much easier to handle and work with than
glass.

(also excellent for instant storm damage repair if you keep a couple of
pieces ready to go)

You can gradually replace glass with twinwall polycarbonate provided you make
sure that the replacement sheets cannot ever jump out. Start from the top
down - heat rises. The 5mm grade will bend horribly under severe storms so
not recommened but even that will outlast glass if it is properly anchored
in.

I wish I had converted more of my greenhouse to polycarb before the winter
storm of Xmas '97.

Regards,
Martin Brown