[JRTJH]

This is my "opinion" and I suppose everyone has one..... So, take it for the value you pay for it:

EPDM is a extremely durable "rubber roof compound" that has been used on RV's for more than 20 years. It is relatively heavy (when compared to TPO) and in the "industry search for lighter weight materials" TPO was chosen to replace the heavier EPDM. Along with that, lighter frame rails, lighter flooring, lighter windows, lighter <fill in the blank> all started showing up in RV's.

Is TPO as durable as EPDM? That question has been answered by the industry with the inclusion of a "pro-rated 12 year warranty" to the original owner, not transferrable and pro-rated after the second year. They "advertise a 12 year warranty (just like EPDM) but it's only been in use since around 2013, so nobody knows whether it'll last 12 years or not (I'm not one to believe the lab testing data as real world use)...

Who wins? With the pro rated warranty, if at 8 or 9 years, your TPO roof fails, you pay the manufacturer 90% of the cost of the replacement membrane, so they get paid more than their cost for materials (profit continues for them) and you're responsible for all labor charges. So they really have nothing to lose and a guarantee that you'll return to buy more (if you use the warranty)....

Win/Win for them, maybe a durable roof for us, maybe not, depends on whether their lab tests were properly done and we don't drive under a low hanging tree limb..... In which case, they win again, because they're "off the hook" for the rest of the warranty, just as they're "off the hook" if you trade RV's before the 12 years as the warranty is not transferrable.....

So, to answer your question, EPDM "seemed to be" more durable, at least in my experience, and I'm not impressed with TPO, just like I'm not impressed with Styrofoam laminated floors and in many cases walls..... Lighter, cheaper and "just as durable" don't always go hand in hand.......