On Fri, 3 Feb 2012 20:30:34 +0000, claire2965
wrote:

Not sure way I am going to use for the top, any suggestions.

Well, conventional reuse wisdom says to construct the frame of the
coldframe to accomodate the dimensions of whatever you're going to use
for the top. Old window panes are popular - already framed in wood or
sometimes aluminium). An alternative might be to head to the hardware
store and pick up some of the flourescent light fixture diffusers -
the 24x48 inch plastic stuff. You'd need to build a frame, and
really, I'd suggest providing some sort of intermediate supports in it
(i.e not one big floppy piece of plastic with a wood frame around it -
perhaps some intermediate wood crosspieces, or cut the plastic into
smaller pieces). I cannot speak to how many seasons it'll last out in
the elements, but since they're routinely in close proximity to
flourescent lights, they should have some UV protection.