Winnebago Fiberglass Roof

Our old RV Seen Here was about as leak free up top as one could get having a seamless double-wall honey-comb body. It had just one 9" diameter hole in the roof for a little pop-up vent and it never leaked.

But being naive 25 year olds with a first motor home, we were ignorant when special ordering that unit. The optional front cab-over windows didn't need to be. We thought they would be fun to have but they were nothing but trouble for the first year until I replaced them with a second set that I handled myself differently. Oh how painful that was. We kept the plexi-glass blocked with a back-packing sleeping pad for insulation & privacy, and piled up blankets & pillows all the time for safety since the kids liked to hang out there while in transit......please don't be hard on me over that last comment. It was different time under different laws.

Dakzuki wrote:


Aluminum comes with its own set of issues. You have to be careful about how everything is constructed or you can set yourself up for galvanic corrosion which will rot holes in your lovely roof. I've seen pics posted of it on RVNet.

In 1995 I bought a new Four Winds Class C that came with an aluminum roof. Within the first year the cabover developed pin holes. The aluminum roof was replaced with a rubber roof under warranty. I kept that MH for almost 10 years and never had any further issues with the roof.

mlts22 wrote:
If I had my way (which is fairly expensive), I would go with an anodized aluminum roof, add the usual stuff on top (A/C flange, vents, skylights, satellite dish, solar panel mounts, etc.) then cover it with an elastomer epoxy spray that not just covers the roof and a few inches down the sides, but is used around the tail-light fixtures. That way, if a tree branch gouges a chunk of coating off, the aluminum will still provide decent leak protection.

Aluminum comes with its own set of issues. You have to be careful about how everything is constructed or you can set yourself up for galvanic corrosion which will rot holes in your lovely roof. I've seen pics posted of it on RVNet.

pnichols wrote:



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.

They are now using adhesives to glue the bracketry to fiberglass roofs without drilling for fasteners.

If I had my way (which is fairly expensive), I would go with an anodized aluminum roof, add the usual stuff on top (A/C flange, vents, skylights, satellite dish, solar panel mounts, etc.) then cover it with an elastomer epoxy spray that not just covers the roof and a few inches down the sides, but is used around the tail-light fixtures. That way, if a tree branch gouges a chunk of coating off, the aluminum will still provide decent leak protection.

pnichols wrote:



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.

the last couple of family vehicles that I drive all had an opening for a sun/moon roof and aerials mounted. none of them has leaked.
bumpy

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! :(

TPO and EPDM roofs suffer from the same problem... seams that are right on areas that are blasted by water. A fiberglass roof rolled over the sides (as pointed above) won't have water at high speeds (60+mph when on the road) hitting directly on places where it can come into the rig.

With the caulked seams of a TPO or EPDM roof, your motorhome essentially has an expiration date stamped on it due to water getting past caulk and rotting areas like the cabover. The only real defense against certain conversion to scrap by a rubber roof is a spray on elastomer epoxy like rvroof.com or Rhino Lining's, and those dealers are very few and far between.

As for ron.dittmar's suggestions, I would add a 1.5 in there. A one piece aluminum roof that is cupped over the sides by at least 2-3 inches. A friend of mine has a rig that has that, and his trailer has seen virtually every type of weather that can be thrown at it, and no leaks yet.

In my opinion, motor home roof materials rated best to least.

#1 - Seamless body & roof combination, 100% gel-coat, very thick fiberglass
#2 - Gel-coat very thick fiberglass roof "hat" (I have not seen used in many years)
#3 - Thin Fiberglass sheet stock, rolled over the sides of the rig
#4 - TPO sheet stock, a plastic material
#5 - Rubber sheet stock

Also important is a crowned roof. A flat roof sags over time. You want to prevent water puddles which generally form around the heavy a/c unit. Puddled water also freezes which can be hard on the roofing material.

Rubber & TPO roofs could be more favorable but they are most commonly used in flat-roof designs.

A gel-coat thick fiberglass roof would best to survive a very bad hail storm.

And the problem with my statement is what? All you have to do is research leaks and eternabond tape 90% of all people with RV's have to fix roofs with eternabond tape because of high failure of rubber roof because of water leaking in. I bet the company is making a good profit The tape gives a 15 year warranty the rubber roof is lucky to get 10. Make you think maybe you should coat the whole roof with the stuff LOL. My buddy's winnie has 14 year on his and still look's like new and never had a leak.