ron.dittmer wrote:
#2 - Gel-coat very thick fiberglass roof "hat" (I have not seen used in many years)
I'd sure like to see something in writing from Winnebago stating that the above is in fact NOT what they're using for their Class C roofs!
Our Itasca's one-piece heavily crowned fiberglass roof with ~3 inch rolled edges full length along both sides sure feels mighty strong when I'm up there (I weigh ~230 lbs.) ... with no hint of depression, sinking, or give from my knees pressing down on it's surface. Also, looking at the material's cross-sectional thickness along it's edges ... it appears as thick as fiberglass boat hulls that I've looked at up close.
Regarding the invincibility of the aluminum roof used on a very few Class C motorhomes (is Lazy Daze the only one?) ... I've heard that the rare/freak large-ball hail storm permanently dents them ... which certainly makes sense as a possibility that would/could happen. I wouldn't want this to happen if I had an aluminum RV roof. Also, I see no reason why an aluminum roof isn't just as prone to leaking around vents, antenna mounts, air conditioner openings, roof access openings, and bathroom shower bubbles as any other RV roof type is -> from sealant failure over time.
Of course, even the the #1 best roof type from Ron's list can leak from sealant failure at all the openings I list above.
There's just no engineering way around it. No roof with openings in it - one piece or otherwise - is going to remain as leak-free as the one-piece roofs with no openings in them like is on the family vehicles that we all drive.
By the way, all of those solar panels that folks have mounted on their RV roofs using brackets with through-holes in the roof are of course opening up a whole additional source of leaks as sealants fail over time. Some of those solar panel bracket holes are difficult to get at for future resealing too ... especially so when you have more than one solar panel mounted with their edges right close to each other.
That good old solar ultra-violet ray distruction thing sure can be very insidious for us RV owners! :(