Has anyone glassed the front / rear end cap seams??

Your analogy with a boat is very wrong!

If you were to invert your fiberglass roof and try and make a boat out of it, you would break into pieces at the first wave.

If you inverted a boat and try and make a roof out of it, you would tip the RV over at the first corner.

Boat construction is heavyweight fiberglassing - RV roof construction is extreme lightweight fiberglassing.

As others have said, the seams allow some flex and cheaper manufacturing and lighter weight. If you were to glass them then you would introduce additional stresses that may result in a cracked roof down the road.

Try it by all means, it would be an interesting experiment.

Tioga George had all of the seams on his class C fiberglassed in Mexico in 2007. http://blog.vagabonders-supreme.net/search?q=fiberglass It looks like it's held up very well.

If you could fiberglass the front and rear caps, across the top and down BOTH sides, then you may have something similar to a boat hull. By just fiberglassing the top, it may allow the front and rear cap to flex/shift too much and crack the connection. I would clean both surfaces very well, and just use Eternabond tape, which should be good for another five years, before doing it again.

ccxnola wrote:
Tom,
I agree that is what we have been told by the RV makers, but...is it because it is easier and cheaper to do it that way?? I know there are many very good fibrelass boat hulls that take a beating in the ocean - and they are one-piece hulls, not a bunch of panels stuck together. Is there an engineer among us for some enlightenment??

If your roof front and rear caps were layed up as a single laminate and co cured together you would not have a problem. For example if the laminate was 1/4 thick like a boat hull the individual layers of fiber glass an resin would be over lapped by at least 1/2 in and the overlaps would be staggered. When cured their strength would be as if they were one continuous layer of fiber glass and resin. Resin has very little strength other than to stiffen the fiber glass cloth so it can carry the load. Also polyester and epoxy resin have very little elongation before it fails. It is brittle. You would be covering the the seams with resin any movement of the joints caused by vibrations going down the road would have to go right through the resin over lap. I would feel safer with an elastomeric material like Eternabond over the joints. Just picture a 1/4 thick fiberglass laminate 12 ins by 1 in and try to flex it. It will flex forever with out cracking. Now picture the same laminate with a 1/2 over lap in the middle joining the two pieces together the same amount of flexing will cause a failure in the resin bond line. Hope this helps.

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A multi-part roof panel with front and rear end caps are used because they are cheaper to manufacture , cheaper to assemble on the line , and require less skilled labor .

An RV is subject to hurricane force winds every time it moves !

There are several companies that use 1 or 2 piece molds with reenforced inserts to manufacture the shell for their products that are waterproof and durable .

Airplanes and yachts both use seamless curves and adhesives in critical components .

I think it would be a cost effective upgrade .

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We had a Damon Escaper 36' 5th wheel that had an all fiberglass roof as well as wall and front and back caps. Made to look like nearly all one piece. Unless you somehow punched a hole in the roof, they was no way it was going to leak. I don't understand why they are all not built that way. Cars and trucks have solid roofs that don't leak, so why shouldn't campers have the same setup. Leaks seems to be one of most discussed and damaging problems with campers, when it seems it would be fairly simple to build them of reinforced fiberglass with a gel coat and just eliminate all leaking problems so we could get back to worrying about the torgue on the lug nuts or something else.

Tom,
I agree that is what we have been told by the RV makers, but...is it because it is easier and cheaper to do it that way?? I know there are many very good fibrelass boat hulls that take a beating in the ocean - and they are one-piece hulls, not a bunch of panels stuck together. Is there an engineer among us for some enlightenment??

I think the caps, roof and sidewalls are separate pieces because of flexing. Bonding them together may create some problems.