The roof is thermoplastic polyolefin (TPO). I use Dawn dishwashing detergent and a brush like you'd use to scrub potatoes. Next time you are at your CW dealer ask them how they would service or replace the air conditioner, install covers over the roof vents, replace the TV antenna, replace seam sealant and caulking, or install a satellite TV dish without getting on the roof. I think he was feeding you a line.
TPO roofs are fairly comparable to EPDM (Ethylene Propylene Diene Monomer) rubber roofs, yet are smoother and shinier. TPO also has a less porous finish that will not absorb dirt and mold as easily as EPDM roofs. TPO doesn’t chalk up by oxidizing so you won’t have the unsightly streaks. TPO also tends to be significantly less slippery when wet. If you find it hard to keep your footing on the wet roof then you are most likely dealing with EPDM.
The process for RV roof maintenance doesn’t really change between EPDM and TPO. TPO traditionally has seams that are longer lasting and less prone to separation than EPDM. This makes it easier to maintain from that regard. This also means they are more expensive to repair given traditional rubber roof sealants may not work as TPO seams are heat welded and become harder to adhere to over time. They also tend not to be as porous and require as much cleaning to keep away stains. TPO can be cleaned and cared for in much the same way as the EPDM.
Dicor™ Ultra Sealant is best for TPO roofs. It is a two-part system (primer and sealant (Source: Dicor Ultra Sealant) :
1. Ultra-Sealant Primer, prepares the TPO surface for enhanced sealant bonding and is applied easily with a common paintbrush. No mixing. No measuring. Simply apply and let dry.
2. Ultra-Sealant, is then applied like any traditional sealant. It’s self-leveling and requires only a standard caulking gun. Simply gun it and you’ve done it. Due to its advanced chemistry, the Ultra Primer System has exceptional adhesion to vent caps, plumbing caps, exterior trim, and plastic components. For additional convenience, Ultra Sealant is engineered to stick to itself allowing you to reapply confidently for added assurance.
Also Rawhide, I compiled a Users' Manual for Axis & Vegas. There are tips inside the manual for maintaining the roof. Lots of checklists, troubleshooting guidance, and system operations and functions descriptions. Here is a link to download the manual: