H-Profile Polycarbonate Install Profiless: Items will yellow and get brittle. Best to use Aluminum Base & Cap System.
Polycarbonate H-Profile, 
See yellowing plastic parts
Used where sheet joining connector piece must be clear, sadly not in tune with sheet yellowing resistance.
H-Profile Constraints:
- Roof purlins or wall girts must be placed 2 ft. or less on-center.
- H-Profile offers minimal structural strength.
Drawbacks of Polycarbonate H-Profile:
- Often difficult to slide poly sheet into “H”. Do Not use on arch roofs.
- Sliding sheet into H-Profile on arched roof will be a nightmare.
- Less durable and less attractive than our aluminum systems.
- Not as watertight as aluminum. Especially over time as sun effects plastic.
- Service life less than the polycarbonate sheet. “H” will yellow.
Avoid Plastic Base & Cap Systems
Drawbacks of Plastic Base & Cap:
- Snap together & and holding features of these components not reliable.
- Do Not use on arch roofs.
- Less durable and less attractive than our aluminum systems.
- Not as watertight as aluminum. Especially over time as sun effects plastic.
- Service life much less than the polycarbonate sheet. “H” will yellow
Polycarbonate U-Profiles
Drawbacks Polycarbonate U-Profile:
- Does not fit tight on sheet, allowing bugs to enter cells.
- Vent tape required to keep bugs out. Now not a clear detail.
- Falling snow & ice will pull U-Profile off roof sheets.
- Less durable and less attractive than our aluminum system.
- Not as watertight as aluminum. Especially over time as sun effects plastic.
- Water may enter cell and start to move up the sheet.
- Service life less than the polycarbonate sheet. “U” will yellow.