Originally Posted by harry

On 24 July, 05:34, MrsTrellis
wrote:
Hello. *I'm new to this forum, but am a longstanding gardening
enthusiast.

I have experienced a problem with the installation of twin-wall
polycarbonate panels in my small greenhouse, and I wondered if anyone
else has the same problem. *I was spurred on by Bunny Guinness’s article
in The Telegraph, 10 Nov 2009, extolling the virtues of twin-wall
polycarbonate panels to replace horticultural glass. *During Spring this
year, there were suddenly several suppliers selling polycarbonate online
at very tempting prices. *I plunged in and bought new panels, together
with the aluminium tape and breather tape for sealing top and bottom cut
ends respectively. *I replaced all the roof panels of my greenhouse, and
all seemed well. *However, less than 3 months later, the breather tape
has come unstuck on all panels, allowing debris and mould to start
moving up, inside the channels.

The supplier denies hearing of anyone else having this problem. *Please
can anyone throw any light on why this breather, ‘anti-dust’ tape has
failed to do its job?

--
MrsTrellis

The purpose of the breather tape is to allow the air in the panels to
expand & contract but to keep insects out & drain any condensation
out. This tape is not weather proof it is intended to go beneath a
plastic trim.
I too had this problem. I got round it by fitting weatherpoof tape to
the bottom edge and sticking a few pinholes in it.Seems to be OK at
the moment.
I had plastic trims but the snow just slides downand pushes them off.