Cabover leaks - Would This Work

Mocoondo wrote:
The cabover has to flex otherwise it would break right off the motorhome.

Sorry ... but I disagree ... at least with regards to up-down (vertical) flexing.

A too-cheaply constructed Class C's cabover might flex more than it should but a properly designed Class C's cabover will have, and needs, almost the same amount of side-wall and roof-wall internal rectangular and triangular bracing as a 5th wheel's out-stretched front support section does.

Here's some - IMHO - things to consider:

Do truck camper cabover overhang sections break off?

Do truck camper cabover overhang sections need to rest on the cab roof?

Wood internal framing has no business being relied upon to support a Class C's cantilevered cabover (or a truck camper's) section. Metal internal roof/wall framing is the name of the game. Aluminum framing is probably adequate for supporting/bracing a Class C's cantilevered cabover section, but steel should be used for supporting/bracing a 5th wheel's front portion.

Overall cabover support/bracing strength is one reason we did not buy a Class C with a slide -> as internal wall stength needed for adequate cabover cantilever support is compromised when you have slides breaking up a Class C's internal wall integrity. The same thing can ultimately be said of 5th wheels with and without slides.

That earlier RV-vibration video in this thread shows the RV coach as (almost gently) only rolling and bouncing, not receiving sharp vertical jolts like the suspension system is absorbing in the video. Sharp vertical jolts are far more likely to loosen poorly designed and/or constructed wall material seals than rolling and bouncing motions.

I think that cabover leaks are primarily the result of too much flexing from inadequately designed/constructed internal wall framing, inadequately designed and/or poorly maintained outer wall material joints, front clearance lights not kept sealed around their bases, front facing cabover windows and their frames not being sealed using enough over-kill, and the cabover sections not being kept out of the sun and it's killing UV rays even though the rest of the RV may be outdoors. Our Class C is kept outdoors - but we intentionally park it with the front end under a large tree's shade so this part or the coach gets no sun.

Here's a photo of a 1969 Class C folks prior to us, and us, had for many years with nary a cabover leak, ever. It's cantilevered cabover section had air clearance between the undisturbed cab roof so it did not rely on support from the cab's steel roof. As best I can remember we never re-sealed anything on the roof or walls around the cabover part of the RV. Both the DW and myself and all the owners before us slept in the cabover section - so it was subjected to plenty of cantilevered weight every camping night. I believe that the RV was kept stored outdoors it's whole life, at least it was during our ownerhip years. However, we kept it's cabover section kindof parked away from the worst of the summmer sun. Also note that it's cabover section and whole roof were one-piece fiberglass: