Removing Roof Plastic Coat
I have found a peel & stick product designed for such an application. It is called Eternabond and has three different types, white, black or polyester surfaces are available usually at rv part outlets. The polyester surface has to be coated with an acrylic coating. The white and black need no further coatings and will last longer than moast rv roofing materials.
All the old caulk should be removed and cleaned, (a small amount of spray brake partscleaner works well.) Remove the release film and applybeing carefull not to let it stick to itself. Apply firm presuure to the surface. Presuure is what makes it stick. It is a bio-degradable adhesive with no petrolium products. It virtually sticks to any suface except silica sand, so if your roof is an EPDM membrane, make sure you clean it well to remove anyexcess silica sand.
I believe their website is
www.eternabond.com
Gerry