On Tue, 20 Jan 2004 08:10:44 -0500, Dwight Sipler wrote:

C wrote:

Small vent holes near the top of each fogged channel would help. I'd
put the holes on the inside surface, that which is away from the
weather. The vents holes would allow trapped moisture a way to escape.
The holes would not need to be any wider than 1/32 or 1/16", I would
think. It's worth trying on one panel before committing to all of them.



When I put up my twinwall polycarbonate panels the manufacturer
recommended that the bottom of the panels be left open and the top be
sealed. This prevents air convection through the panels (decreasing their
insulation properties) while allowing moisture to get out through the
bottom. Sealing the panels can be done either with caulk or with tape. The
aluminium tape is weather resistant and will last a lot longer than
something like duct tape (which has about a 2-month lifetime in sunlight).

In practice, there are times when moisture collects in the channels, but
the next sunny day clears it out.

If the caulk in the original poster's installation is too thick to remove
or if it is still unsightly after attempts at removal, you could cut of an
inch or two of the bottom of the panel and install a baseboard (on the
inside of the panel).

If you opt for the vent hole approach, I would put the holes at the
bottom, just above the caulk (or maybe even through it), so that they
could also act as a drain in the event that a large quantity of condensate
forms in the channels.


I was thinking the top because heated air rises thus evacuating more
quickly. I doubt whether minute holes in the panels will affect their
insulation properites to any noticeable extent. The original poster's
outdoor temps were not so bad. There is still plenty of air trapped in
the panels to insulate.