Photo of roofing meeting polycarbonate ----Quoting & Ordering 
Carlisle Hardcast Foil-Grip 3" x 100 ft. Adhesive Roll Flashing (shown above) has 15 mil Butyl Adhesive (facing down) and a Aluminum backing (that faces the sun). For wider than 3" areas simply overlay. Make sure polycarbonate is securely fastened to the structure with the screws we sell. To purchase see Hardware Section of our Online Order forms. See pdf version of tech & install data sheet.
 
Note: Photo above depicts what flashing tape can look like. The aluminum backing can tend to crinkle, so care must be taken when applying. Some choose to cover tape with painted metal flashing.
 
Reload Sundance Supply Site