Since aluminum...
Remove the black tar (that previous owner applied)
Clean roof with appropriate cleaner (varsol or ???)
If existing Aluminum is good, then apply liquid Rubber on it. re:
- Click Here 1 - or
- Click Here 2 - Note: Before buying, do call EDPM company to confirm if RV EDPM (in orange can) or normal EDPM (in blue can) should be used on existing Aluminum material.
Is re-skin with new aluminum or simply cleaning and coating with EDPM better? Not too sure. I'd probably go with new vents / new covers, then coat with EDPM liquid rubber.