Greenhouse ridge cap: How to?

[Trent-Lion]

For my GH restoration project, in which I have put twinwall polycarbonate in an existing aluminum frame, I installed a flexible ready-made cap from Lowe's by screwing it in three overlapping sections to the aluminum cross-pieces, and, though functional, it looks like the devil: uneven and ugly. Sundance Supply offers two other options:

1. 15 mil Butyl Adhesive Roll Roof Flashing Tape from Carlisle Hardcast; I would want the 6 inch width with shiny aluminum foil backing. Sundance Supply says this will work at polycarbonate roof valleys, but I don't see why it wouldn't work at the ridge as well.
2. Go to a local sheet metal shop and have a cap made from aluminum (.019" minimum) or steel (30 gauge). Sundance says aluminum is easy to fasten and cut but flimsy. Steel is sturdy, harder to cut, and requires pre-drilling prior to fastening.

I would appreciate opinions as to how to cap this ridge. Thanks. T-L

[David Hill]

What about plastic guttering?

[David J Bockman]

Do you want it vented?

Dave

[Trent-Lion]

[David J Bockman]

Here is what I did on mine:

that I have twinwall polycarbonate roofing as well. I went to a local sheet metal shop that specializes in gutters and flashing, and bought a length of copper flashing (approximately 20'). I had them bend an oblique angle in it and carefully got it home without crimping it badly. I then used the same gasketed screws that you use when fastening the polycarb to the structure.

Dave